Diabetic Choroidopathy: Choroidal Vascular Density and Volume in Diabetic Retinopathy With Swept-Source Optical Coherence Tomography

Insights into scleral violaceous hue in anterior scleritis: anterior segment optical coherence tomography evaluation

PURPOSE

To determine the scleral thickness of inactive scleritis characterized by a violaceous hue (violaceous sclera) using anterior segment optical coherence tomography (AS-OCT).

METHODS

Retrospective observational case series of patients with inactive unilateral anterior scleritis featuring a violaceous hue. Mean scleral thickness was measured by AS-OCT in violaceous areas and compared with the same region in the contralateral unaffected eye. Measurements were performed by two masked graders.

RESULTS

Nine patients with median age of 52 ± 12.8 years were assessed. Eight patients were female. Rheumatoid arthritis and history of treated latent tuberculosis (33.3%) were the most common causes of anterior scleritis. Mean scleral thickness was 582.93 ± 124.03 µm and 648.59 ± 103.61 µm for violaceous sclera and the corresponding unaffected areas of the contralateral eye, respectively (mean difference = -65.65 µm, 95% CI: -143.73 to 12.42, p = 0.0885). The mean image contrast percentage of scleral hyperreflectivity as assessed by image conversion in an area of violaceous hue was 65.07 µm ± 6.49 µm compared to 42.70 µm ± 5.46 µm of unaffected areas (mean difference = 22.37 µm, 95% CI: 14.72 µm to 30.03 µm, p = 0.0001).

CONCLUSION

Using AS-OCT, the thicknesses of violaceous sclerae were not significantly thinner than the contralateral unaffected areas, despite a mean difference of approximately 65 microns. The increased scleral hyperreflectivity observed in the violaceous sclera may suggest collagen remodeling in these areas. Such remodeling could play a role in the sclera reflecting violaceous hues while still preventing direct visualization of the underlying choroid.

En face OCT: Breakthroughs in understanding the pathoanatomy of retinal disease and clinical applications

En face optical coherence tomography (OCT) is a practical and informative imaging modality to noninvasively visualize distinct retinal and choroidal layers by providing coronal images using boundary-specific segmentation. Ongoing research with this method is generating breakthroughs in the illustration of new perspectives of retinal disease. The clinical value of en face OCT as an advanced retinal imaging tool is growing steadily and it has unveiled many new insights into the pathoanatomy of retinal disorders. Moreover, this modality can capture various en face OCT biomarkers that correspond to different cell or tissue subtypes, which were previously only identified through histological or electron microscopy methods, underscoring the significance of this technique in providing valuable pathoanatomical information. In this comprehensive review, we will systematically summarize the en face OCT findings across a broad spectrum of retinal diseases, including disorders of the vitreoretinal interface and retinal vascular system (e.g. paracentral acute middle maculopathy or PAMM and diabetic retinopathy), in addition to the en face OCT features of other conditions such as age-related macular degeneration, pachychoroid disease spectrum, myopic degeneration, uveitis and inflammatory disorders, inherited retinal dystrophies, and drug toxicity. We will discuss and highlight the unique clinical and pathoanatomical findings uncovered with en face OCT of each these diseases mentioned above.

Clinical and imaging characteristics associated with foveal neovascularization in proliferative diabetic retinopathy

PURPOSE

To assess the prevalence of foveal neovascularization (FNV) and its associated clinical features in proliferative diabetic retinopathy (PDR) eyes.

METHODS

Cross-sectional observational study. Participants underwent ultra-widefield photography, optical coherence tomography (OCT), and swept-source OCT angiography (SS-OCTA). FNV was defined as a hyperreflective lesion breaching the internal limiting membrane and displaying flow signal on OCTA, within 1-mm of foveal avascular zone. Vascular metrics were obtained from the ARI Network portal. Ischemic index (ISI) and inner choroid flow deficit percentage were calculated using FIJI from 12 × 12 and 6 × 6-mm scans, respectively. Logistic regression models were used to compare eyes with and without FNV.

RESULTS

We included 249 eyes of 164 patients (age: 58 [50-65] years). FNV was identified in 20 eyes (8%). Univariate logistic regression revealed significant associations between FNV and younger age (p = 0.03), higher maximal HbA1c (p = 0.04), worse visual acuity (VA) (p = 0.01), presence of disorganization of retinal inner layers (DRIL) (p = 0.01), no macular posterior vitreous detachment (PVD) (p = 0.03), neovascularization elsewhere (NVE) and at the disc (NVD) (p = 0.01 and p = 0.001), and greater ISI (p = 0.04). In multivariable analysis, a significant association remained between FNV and worse VA (p = 0.04), NVD (p < 0.001), DRIL (p < 0.001), and absence of macular PVD (p = 0.01). No associations were found with SS-OCTA vascular metrics.

CONCLUSIONS

This study provides a comprehensive characterization of FNV in PDR. FNV was identified in 8% of our cohort, being more prevalent in younger patients with severe PDR, as evidenced by NVD and DRIL presence. The absence of macular PVD may explain its association with younger age.

KEY MESSAGES

What is known • Neovascularization at the fovea occurs rarely in proliferative diabetic retinopathy. • OCT and OCT-angiography can be used to evaluate foveal neovascularization, which may be associated with choroidal vascular abnormalities. What is new • Foveal neovascularization was seen in 8% of eyes with proliferative diabetic retinopathy in this cohort. • Risk factors for foveal neovascularization included younger age, absence of macular posterior vitreous detachment, presence of neovascularization of the disc, and presence of disorganization of retinal inner layers. • We did not identify an association between foveal neovascularization and choroidal perfusion abnormalities in this study.

Diabetic uveopathy

Diabetes can involve several ocular structures -- including the cornea, lens, and retina -- and cause vascular and neural changes in these tissues. Although retinopathy is the most common ocular complication of diabetes, uveopathy can also be observed. This includes vascular, neural, muscular, and basement membrane changes. The main clinical manifestations of diabetic uveopathy are anterior uveitis and abnormal pupillary dynamics. Fluorescein angiography, optical coherence tomography, and optical coherence tomography angiography are ideal for the imaging of vascular changes of the iris and choroid, while dynamic pupillometry is a simple screening tool to detect neuropathy. Additionally, ultrasound biomicroscopy can provide clear images of the ciliary body. Iris abnormalities, primarily angiopathy and neuropathy, can appear as alterations in vascular diameter, neovascularization, and abnormal pupillary dynamics. Choroidal abnormalities primarily affect blood vessels, including alterations in vascular diameter, microaneurysm formation, and neovascularization. The abnormal manifestations in the ciliary body include a decrease in vessel count, alterations in their diameter, isolated angiomatous dilatation, and diffuse thickening of the basal membrane of the pigment epithelium.

A high-fat plus high-sucrose diet induces age-related macular degeneration in an experimental rabbit model

Age-related macular degeneration (AMD) is a leading cause of blindness. Metabolic disorders and diets are risk factors. We compared lipid profiles and retinal phenotypes with long-term feeding of four diets in male Chinchilla rabbits. Animals were fed a normal diet (ND), high-fat diet (HFD), high-sucrose diet (HSD) or a high-fat plus high-sucrose diet (HFSD) for 6 months. Eyes were examined using multimodal imaging modalities and electroretinograms. Retinal sections were analyzed using H&E staining, Toluidine Blue staining, immunostaining and transmission electron microscopy. Lipids and complement C3 protein (C3) in serum or aqueous humor were measured. RNA sequencing was performed to evaluate the retinal transcriptomes. HFD and HSD had minor effects on lipid profiles but, when fed concomitantly, synergistically induced severe dyslipidemia. None of the four diets caused obesity. HFSD induced retinal lesions, such as reticular pseudodrusen (RPDs) and other pigmentary abnormalities. RPD-like lesions were mainly lipid droplets around cells of the retinal pigment epithelium. HFSD also induced elevated levels of ocular C3 and reduced the density of retinal vessels. In conclusion, HFD and HSD can - when combined - induce normal-weight dyslipidemia and RPD-like retinal lesions. HFSD-fed male Chinchilla rabbits are a good model of early AMD.

Regional assessment of choroidal vascularity index in patients with pre- and early-stage diabetic retinopathy using ultra-wide-field OCTA

Purpose

To characterize the regional variations of choroidal vascularity index (CVI) in patients with diabetes mellitus (DM) using ultra-wide-field optical coherence tomography angiography (UWF-OCTA) and identify their correlations with the onset of diabetic retinopathy (DR).

Methods

This cross-sectional, monocular-sampling study recruited 141 participants from four age-matched groups: no DM (NDM), no DR with early DM (EDM) and late DM (LDM), and mild-moderate non-proliferative diabetic retinopathy (mNPDR). UWF-OCTA was employed for circular scans centered on the fovea. CVI in the central region (0-1 mm) and four quadrants of the concentric rings with different ranges (1-3, 3-6, 6-9, 9-12, 12-15, 15-18 mm) was obtained for analysis together with their demographic and clinical data. The Area under the receiver operating characteristic curve (AUC) was calculated to assess the diagnostic efficacy for mNPDR and compared using the DeLong test.

Results

The average CVI was lower in patients with mNPDR compared to other groups across all regions. Although there was no significant difference in DM duration between the LDM and mNPDR groups, a notable variance in CVI was observed, particularly (p = 0.0004) in the temporal quadrant of the 15-18 mm range (T18). CVI in T18 region was negatively correlated with creatinine levels, while positively correlated with body mass index and estimated glomerular filtration rate (ps < 0.05). The CVI in the T18 region demonstrated superior diagnostic efficacy (AUC = 0.755), and when combined with those in other regions and clinical data, the AUC rose to 0.907, which was significantly better (p = 0.0280) than using clinical data alone.

Conclusion

Reduced CVI was observed in the most peripheral region, highly predictive for mNPDR and associated with the declining renal function, thus enhancing the potential of UWF-OCTA to integrate into DM management and promote early DR screening.

Translational physiologically-based pharmacokinetic model for ocular disposition of monoclonal antibodies

We have previously published a PBPK model comprising the ocular compartment to characterize the disposition of monoclonal antibodies (mAbs) in rabbits. While rabbits are commonly used preclinical species in ocular research, non-human primates (NHPs) have the most phylogenetic resemblance to humans including the presence of macula in the eyes as well as higher sequence homology. However, their use in ocular research is limited due to the strict ethical guidelines. Similarly, in humans the ocular samples cannot be collected except for the tapping of aqueous humor (AH). Therefore, we have translated this rabbit model to monkeys and human species using literature-reported datasets. Parameters describing the tissue volumes, physiological flows, and FcRn-binding were obtained from the literature, or estimated by fitting the model to the data. In the monkey model, the values for the rate of lysosomal degradation for antibodies (Kdeg), intraocular reflection coefficients (σaq, σret, σcho), bidirectional rate of fluid circulation between the vitreous chamber and the aqueous chamber (QVA), and permeability-surface area product of lens (PSlens) were estimated; and were found to be 31.5 h-1, 0.7629, 0.6982, 0.9999, 1.64 × 10-5 L/h, and 4.62 × 10-7 L/h, respectively. The monkey model could capture the data in plasma, aqueous humor, vitreous humor and retina reasonably well with the predictions being within twofold of the observed values. For the human model, only the value of Kdeg was estimated to fit the model to the plasma pharmacokinetics (PK) of mAbs and was found to be 24.4 h-1 (4.14%). The human model could also capture the ocular PK data reasonably well with the predictions being within two- to threefold of observed values for the plasma, aqueous and vitreous humor. Thus, the proposed framework can be used to characterize and predict the PK of mAbs in the eye of monkey and human species following systemic and intravitreal administration. The model can also facilitate the development of new antibody-based therapeutics for the treatment of ocular diseases as well as predict ocular toxicities of such molecules following systemic administration.

Choriocapillaris Perfusion after 8 Weeks of High-Speed Circuit Training in Older Healthy Adults

PURPOSE

The aim of this study was to examine the impact of an 8-week high-speed circuit resistance training program (HSCT) on choriocapillaris density (CCD) in healthy older adults.

METHODS

Eighteen cognitively normal older adults were enrolled and randomly assigned to either the HSCT or the control group (CON). The HSCT group was comprised of 11 participants who trained three times a week for eight weeks, while the CON group consisted of 7 participants who did not engage in formal training. Optical coherence tomography angiography (OCTA) was employed to image both eyes of each subject at baseline and at the 8-week follow-up. The choriocapillaris density (CCD) of 2.5 mm in diameter centered on the fovea was measured.

RESULTS

The average age of the HSCT group was 70.3 ± 5.7 years, which was not different from the CON group (average age: 71.6 ± 5.2 years, p = 0.62). There were no significant changes in CCD between baseline and the 8-week follow-up in either the HSCT or the CON group-specifically, the baseline CCD in the HSCT group was 63.3% ± 5% (Mean ± SD), which did not differ significantly from the 8-week follow-up after HSCT training (64.7% ± 4%, p = 0.19). Likewise, there was no significant difference in CCD between baseline and the 8-week follow-up in the CON group (63.3% ± 3% and 62.7% ± 5%, respectively, p = 0.66).

CONCLUSION

CCD appeared to remain stable after 8 weeks of HSCT in healthy older individuals, possibly due to autoregulation. Further research with extended training may be necessary to verify these findings.

Optical coherence tomography angiography analysis of choroidal microvasculature in various forms of diabetic macular edema

INTRODUCTION

Optical coherence tomography angiography (OCTA) research in diabetic macular edema (DME) has focused on the retinal microvasculature with little attention to the choroid. The goal of this study was to analyze the association between quantitative choroidal OCTA parameters and various forms of DME observed on optical coherence tomography.

METHODS

We conducted a retrospective study of 61 eyes of 53 patients with DME. DME was classified as early or advanced, and as sponge-like diffuse retinal thickening (DRT), cystoid macular edema (CME) or serous retinal detachment (SRD). Quantitative OCTA parameters (vessel density [VD] in the superficial capillary plexus [SCP], middle capillary plexus [MCP], deep capillary plexus [DCP] and choriocapillaris [CC]) were recorded.

RESULTS

The VD in the CC and SCP was significantly higher in patients with early DME compared to patients with advanced DME (P value<0.01). CC VD was lower in subjects with SRD compared to DRT and CME (P value<0.001). Moreover, it was lower in CME compared to DRT (P value<0.05). No statistical differences were found between VD in the MCP and DCP (P value>0.05). Furthermore, CC VD was lower in patients with increased retinal thickness, disruption of the ellipsoid zone (EZ) or external limiting membrane (ELM), and disorganization of the inner retinal layers (DRIL) (P value<0.05).

CONCLUSION

CC ischemia plays an important role in the pathogenesis of DME. We demonstrated a decrease in CC VD in patients with severe DME, SRD, retinal thickening, EZ and/or ELM disruption and DRIL.

Changes in the choroid detected by ultrawide-field optical coherence tomography angiography in type 2 diabetes mellitus patients without diabetic retinopathy

AIM

The study objective was to investigate the choroidal changes in type 2 diabetes mellitus (T2DM) patients without diabetic retinopathy (DR).

METHODS

This was a cross-sectional study. Controls without diabetes and T2DM patients without DR (NDR) were included. Ultrawide-field (24 × 20 mm2) optical coherence tomography angiography (OCTA) was performed to analyse choroidal thickness and vessel density. All OCTA images were divided into 3 × 3 grids. The grid centre was considered the central area, while the rest was defined as the peripheral area.

RESULTS

No differences between groups were observed in the flow density of the choriocapillaris (CC), choroidal thickness (ChT) and choroidal vascular index (CVI) of the large and medium choroidal vessel (LMCV) in the central area. In the eight peripheral areas, the mean flow density of the CC did not differ between the groups, while the mean CVI and ChT were decreased in the NDR group (P< 0.05). In each peripheral area, the mean CVI and ChT were decreased in the NDR group (P< 0.05, except in the infratemporal area and nasal area for ChT and in the infratemporal area for CVI). In the correlation analysis, both mean peripheral CVI and ChT correlated with age and the duration of diabetes.

CONCLUSION

Early choroidal lesions tended to be peripheral in the LMCV in patients with diabetes without DR and correlated with age and the duration of diabetes.

Diabetes-Related Risk Factors for Exudative Age-Related Macular Degeneration: A Nationwide Cohort Study of a Diabetic Population

Purpose

The purpose of this study was to identify diabetes-related risk factors for exudative age-related macular degeneration (AMD).

Methods

This was a nationwide population-based cohort study using authorized clinical data provided by the Korean National Health Insurance Service. A total of 1,768,018 participants with diabetes over 50 years of age participated in the Korean National Health Screening Program between 2009 and 2012. Data on covariates, including age, sex, income level, systemic comorbidities, behavioral factors, and diabetes-related parameters, including duration of diabetes, use of insulin for diabetes control, number of oral hypoglycemic agents used, and accompanying vision-threatening diabetic retinopathy, were collected from health screening results and claims data. Patients were followed up until December 2018. Incident cases of exudative AMD were identified using registered diagnostic codes from the claims data. The prospective association of diabetes-related parameters with incident exudative AMD was investigated using the multivariable-adjusted Cox proportional hazard model.

Results

During an average follow-up period of 5.93 years, 7331 patients were newly diagnosed with exudative AMD. Compared to those who had diabetes for less than 5 years, individuals with diabetes for 5 years or more had a greater risk of future exudative AMD development, with a hazard ratio (95% confidence interval) of 1.13 (1.07-1.18) in the fully adjusted model. Use of insulin for diabetes control and the presence of vision-threatening diabetic retinopathy were also associated with an increased risk of exudative AMD with a hazard ratio (95% confidence interval) of 1.16 (1.07-1.25) and 1.40 (1.23-1.61), respectively.

Conclusions

A longer duration of diabetes, administration of insulin for diabetes control, and comorbid vision-threatening diabetic retinopathy were associated with an increased risk of developing exudative AMD.

The Role of Diabetic Choroidopathy in the Pathogenesis and Progression of Diabetic Retinopathy

Diabetic choroidopathy was first described on histopathological specimens of diabetic eyes. This alteration was characterized by the accumulation of PAS-positive material within the intracapillary stroma. Inflammation and polymorphonuclear neutrophils (PMNs) activation are crucial elements in choriocapillaris impairment. The evidence of diabetic choroidopathy in vivo was confirmed with multimodal imaging, which provides key quantitative and qualitative features to characterize the choroidal involvement. The choroid can be virtually affected in each vascular layer, from Haller's layer to the choriocapillaris. However, the damage on the outer retina and photoreceptor cells is essentially driven by a choriocapillaris deficiency, which can be assessed through optical coherence tomography angiography (OCTA). The identification of characteristic features of diabetic choroidopathy can be significant for understanding the potential pathogenic and prognostic implications in diabetic retinopathy.

The Association between Decreased Choriocapillary Flow and Electroretinogram Impairments in Patients with Diabetes

PURPOSE

To evaluate the association between choriocapillary flow (CCF) and electroretinogram (ERG) in patients with diabetes.

METHOD

This was a cross-sectional study. Patients with type 2 diabetes and healthy controls who had undergone both flicker ERG and optical coherence tomography angiography (OCTA) were included, while patients with severe diabetic retinopathy (DR) and macular edema were excluded. Correlations among OCTA and ERG parameters were conducted by generalized linear mixed models (GLMM).

RESULT

One hundred ninety-four eyes of 102 patients with diabetes and fifty-six eyes of 28 controls were included. The implicit time of 30-Hz flicker ERG successively increased, while the amplitudes, inner-retina vessel density and CCF were decreased from the control to the nondiabetic retinopathy (NDR) to DR group. In patients with diabetes, all GLMM models of ERG parameters had statistically significance (P<0.05), and CCF was correlated with ERG parameters (coefficient index=-0.601, P< 0.001 with 16 Td-s implicit time; coefficient index=-0.687, P< 0.001 with 32 Td-s implicit time; coefficient index=0.933, P=0.035 with 32 Td-s amplitude) and the thickness of retinal pigment epithelium, while in the GLMM model of CCF, it was correlated with the thickness of retinal pigment epithelium and the level of glycosylated hemoglobin(both P= 0.001).

CONCLUSION

CCF decreased in patients with diabetes, and it was related with ERG. Choroidopathy and its functional impairment in the retina may occur very early in patients with diabetes by influencing the outer retina.

Prognostic value of choroidal vascular index in determining response to intravitreal dexamethasone implant treatment used in refractory diabetic macular edema

To investigate the effect of intravitreal dexamethasone (IVD) implant injection, which was used in the treatment of DME, on CVI and to investigate whether CVI can be used as a prognostic marker in the treatment of anti-VEGF resistant DME. A retrospective observational and comparative study. Twenty-five eyes of 25 patients with refractory diabetic macular edema who underwent intravitreal dexamethasone (IVD) implant and 50 eyes of 50 healthy patients were included in the study. Central macular thickness (CMT), subfoveal choroidal thickness (SFCT), luminal choroidal area (LCA), total choroidal area (TCA), stromal choroidal area (SCA), and choroidal vascularity index (CVI) were measured on optical coherence tomography. There was no significant difference between the groups in terms of age and gender. When the pre-treatment values in the IVD group were compared with the healthy group, LCA and SCA values were higher, and CVI ratios were lower in the IVD group compared to the control group. When baseline, 1st, and 3rd months after injection were compared, it was determined that there was a significant decrease in CMT and LCA. There was no statistically significant difference in SFCT, TCA, and CVI. There was a significant negative correlation between baseline CVI and 3rd month CMT after IVD (rho: - 0.643, p: 0.001). It was observed that the baseline and 1st month LCA values were significantly higher than the 3rd month. The choroidal vascular structure may be affected by IVD treatment. CVI may also have value as a prognostic marker in monitoring the response to treatment.

Choroidal Vascular Density Quantification in High Myopia with or without Choroidal Neovascularization Using Optical Coherence Tomography Angiography

Purpose

The aim of this study was to analyze choroidal vascular density alteration in high myopia with or without choroidal neovascularization by using optical coherence tomography angiography (OCTA).

Methods

This was a cross-sectional, observational study that included 60 high-myopia eyes. All the participants had comprehensive ophthalmic assessments with visual acuity, intraocular pressure, slit lamp-assisted biomicroscopy, color fundus photography, axial length, optometry, and OCTA. Age, sex, and comorbidities were collected from their medical charts. Univariate and multiple analyses were made to compare the age, spherical equivalent, choroidal vascular density, gender, and choroidal thickness between normal and patients with choroidal neovascularization.

Results

60 eyes with high myopia were included in our study, including 30 eyes with choroidal neovascularization and 30 eyes without choroidal neovascularization or other fundus pathology. The mean age of high myopic patients was older in the choroidal neovascularization group than in the normal group (48.43 ± 19.06 years vs. 28.83 ± 9.92 years, p < 0.01). The mean choroidal thickness of high myopic patients was thinner in the neovascularization group than in the normal group (68.81 ± 48.81 μm vs. 137.80 ± 66.33 μm, p < 0.01). The mean choroidal vascular density in the normal group was greater than in the choroidal neovascularization group (82.43 ± 8.73 vs. 67.54 ± 12.56, p < 0.01). There was no significant difference in spherical equivalent between the choroidal neovascularization group and the normal group (-10.56 ± 2.97D vs. -11.93 ± 3.38D, p = 0.11). Multivariate analysis showed that after adjusting for covariates, less choroidal vascular density and older age were independent factors associated with choroidal neovascularization in the high myopic eye.

Conclusion

Decreased choroidal vascular density and older age played an important role in the development of choroidal neovascularization in high myopic eyes. OCTA may help us to identify the highly myopic patients that need to intervene.

CHOROIDAL VASCULAR DENSITY IN DIABETIC RETINOPATHY ASSESSED WITH SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY

PURPOSE

We aimed to assess choroidal vascularity by diabetic retinopathy (DR) stage using the choroidal vascular density (CVD) obtained from swept-source optical coherence tomography en-face images.

METHODS

This prospective, cross-sectional, multicenter study included patients from Niigata City General Hospital and Saiseikai Niigata Hospital between October 2016 and October 2017. Choroidal vascular density was obtained by binarizing swept-source optical coherence tomography en-face images of patients with diabetes and those with DR, patients without DR, and healthy age-matched volunteers.

RESULTS

Patients were allocated to the healthy control (n = 28), no DR (n = 23), nonproliferative DR (NPDR) without diabetic macular edema (DME) (n = 50), NPDR + DME (n = 38), and proliferative DR (PDR) or any previous treatment with panretinal photocoagulation (n = 26) groups. Investigation of the choriocapillaris slab level indicated that the no DR group had significantly high CVD values ( P < 0.05), and the PDR groups had significantly low CVD values ( P < 0.01). Investigation of the large choroidal vessel level indicated that the NPDR + DME and PDR groups had significantly lower CVD values than the control group ( P < 0.05 and P < 0.01, respectively).

CONCLUSION

We found that at the choriocapillaris slab level, the no DR group had a higher CVD and the NPDR with DME and PDR groups had a lower CVD than the control group. At the level of the large choroidal vessels, the NPDR with DME and PDR groups had a lower CVD than the control group. There were significant differences in choroidal vasculature found using CVD obtained from swept-source optical coherence tomography en-face images of patients with diabetes and DR.

Imaging-based Assessment of Choriocapillaris: A Comprehensive Review

PURPOSE

Over the past two decades, advancements in imaging modalities have significantly evolved the diagnosis and management of retinal diseases. Through these novel platforms, we have developed a deeper understanding of the anatomy of the choroidal vasculature and the choriocapillaris. The recently developed tools such as optical coherence tomography (OCT) and OCT angiography (OCTA) have helped elucidate the pathological mechanisms of several posterior segment diseases. In this review, we have explained the anatomy of the choriocapillaris and its close relationship to the outer retina and retinal pigment epithelium.

METHODS

A comprehensive search of medical literature was performed through the Medline/PubMed database using search terms: choriocapillaris, choroid, quantification, biomarkers, diabetic retinopathy, age-related macular degeneration, choroidal blood flow, mean blur rate, flow deficit, optical coherence tomography, optical coherence tomography angiography, fluorescein angiography, indocyanine green angiography, OCTA, Doppler imaging, uveitis, choroiditis, white dot syndrome, tubercular serpiginous-like choroiditis, choroidal granuloma, pachychoroid, toxoplasmosis, central serous chorioretinopathy, multifocal choroiditis, choroidal neovascularization, choroidal thickness, choroidal vascularity index, choroidal vascular density, and choroidal blood supply. The search terms were used either independently or combined with choriocapillaris/choroid.

RESULTS

The imaging techniques which are used to qualitatively and quantitatively analyze choriocapillaris are described. The pathological alterations in the choriocapillaris in an array of conditions such as diabetes mellitus, age-related macular degeneration, pachychoroid spectrum of diseases, and inflammatory disorders have been comprehensively reviewed. The future directions in the study of choriocapillaris have also been discussed.

CONCLUSION

The development of imaging tools such as OCT and OCTA has dramatically improved the assessment of choriocapillaris in health and disease. The choriocapillaris can be delineated from the stromal choroid using the OCT and quantified by manual or automated methods. However, these techniques have inherent limitations due to the lack of an anatomical distinction between the choriocapillaris and the stromal choroid, which can be overcome with the use of predefined segmentation slabs on OCT and OCTA. These segmentation slabs help in standardizing the choriocapillaris imaging and obtain repeatable measurements in various conditions such as diabetic retinopathy, age-related macular degeneration, pachychoroid spectrum, and ocular inflammations. Additionally, Doppler imaging has also been effectively used to evaluate the choroidal blood flow and quantifying the choriocapillaris and establishing its role in the pathogenesis of various retinochoroidal diseases. As tremendous technological advancements such as wide-field and ultra-wide field imaging take place, there will be a significant improvement in the ease and accuracy of quantifying the choriocapillaris.

Choroidal Assessment in Patients with Type 2 Diabetes Mellitus and Non-Proliferative Diabetic Retinopathy by Swept-Source Ocular Coherence Tomography and Image Binarization

Background and Objectives: The aim of this study was to evaluate choroidal structure and vascularity indices in patients with non-proliferative diabetic retinopathy (NPDR). Materials and Methods: Sixty-three eyes from sixty-three patients were evaluated: 21 from healthy subjects, 20 with diabetes mellitus (DM) and no diabetic retinopathy (DR), and 22 with DM and non-proliferative diabetic retinopathy without diabetic macular edema (DME). Each patient underwent ocular examination, macular swept-source ocular coherence tomography (SS-OCT) imaging, glycemic control, and systemic high blood pressure (HBP) evaluation. Subfoveal choroidal thickness (SF-CT) was manually assessed on a line scan. Line scan OCT images were exported to ImageJ program. The areas under a 1.5, 3 and 6 mm horizontal line centered on the fovea were assessed by converting the OCT images to binary images, and total choroidal area (TCA), luminal area (LA), stromal area (SA), LA:SA ratio, and choroidal vascularity index (CVI) were evaluated. SF-CT and choroidal parameters were compared between groups, and correlations with ocular and systemic factors were analyzed. Results: SF-CT, TCA, LA, and SA were similar between groups. CVIs were significantly different between groups for all three studied areas (CVI-1.5: 66.21% vs. 66.06% vs. 63.74%, p = 0.003; CVI-3: 65.88% vs. 66.46% vs. 63.79%, p = 0.008; CVI-6: 64.79% vs. 65.40% vs. 63.61%, p = 0.032). NPDR patients had significantly lower CVIs compared to DM patients (p < 0.05). No association of choroidal parameters with glycemic control, DM duration and HBP was found significant (p < 0.05). Conclusions: Choroidal assessment by SS-OCT and image binarization in healthy subjects, subjects with DM without DR, and subjects with DM and NPDR indicated that CVI changes were identifiable and significant in early DR. The lack of association with ocular and systemic factors suggest that CVIs are reliable assessment parameters of choroidal vascular structure.

Sex-Specific Changes in Choroid Vasculature Among Patients with Schizophrenia and Bipolar Disorder

Purpose

While structural changes within the retina of psychosis patients have been established, no detailed studies of choroidal microvasculature in these patients have been performed. Given evidence of microvascular disruption in psychosis patients, this study sought to determine whether there exists evidence of microvascular disruption in the choroids in these patients.

Methods

Fifty-six subjects (20 controls and 36 psychosis patients) were recruited from April 2018 to February 2020. Five were excluded due to imaging artifact or missing demographic information. Swept-source optical coherence tomography angiography (SS-OCTA) images were obtained. Choroid vascular enface images (12 mm × 9mm) were exported every 2.6 μm from Bruch’s membrane to the choroid–scleral interface from Topcon to ImageJ. The images were binarized using Otsu’s method, signal from the optic disk and retinal vasculature was removed, and average choroid vascular density (CVD) was calculated as the average of percent area occupied by choroidal vasculature across images in the stack. Choroid vascular volume (CVV) was calculated as the CVD multiplied by maximum CT and image area. During image analysis, study staff were blinded to the phenotype of the study subjects.

Results

Compared with same-sex controls, male psychiatric patients had significantly lower CVD. Compared with same-sex controls, female psychiatric patients had significantly lower maximum CT with correspondingly decreased CVV, after adjusting for age. When all psychiatric patients were compared with all healthy controls, no significant differences in CT, CVD, or CVV were noted.

Conclusion

These results suggest that the pathogenesis of psychotic illness affects choroidal microvasculature in a sex-specific manner.

Alterations in the Choroidal Sublayers in Relationship to Severity and Progression of Diabetic Retinopathy: A Swept-Source OCT Study

Purpose

To examine the association of baseline choroidal sublayers metrics with the risk of diabetic retinopathy (DR) progression over 2 years, with adjustment for confounding factors that affect choroidal measurements.

Design

Prospective, observational cohort study.

Participants

One hundred three eyes from 62 patients with diabetes mellitus (DM).

Methods

Patients were followed up at 6-month intervals for at least 2 years. Choroidal metrics including choroidal area, choroidal thickness (CT), and choroidal vascularity index were measured for both (1) the choriocapillaris plus Sattler's layer and (2) the Haller's layer within the subfoveal and parafoveal region. Cox proportional models were constructed to estimate the relationship between baseline choroidal metrics and DR progression, adjusted for intereye correlation, established risk factors (i.e., duration of DM, glycated hemoglobin [HbA1c] level, body mass index [BMI], use of insulin, and mean arterial blood pressure [MABP]) and confounding factors of choroidal measurements (i.e., age and axial length). Additional predictive value of choroidal metrics was assessed using the C-statistic.

Main Outcome Measures

Hazard ratios (HRs) calculated by Cox proportional hazards model to demonstrate the associations between baseline choroidal metrics and DR progression.

Results

After adjusting for age, axial length, and intereye correlation, choroidal metrics in Haller's layer at baseline that were associated with a higher risk of DR progression included increases in subfoveal choroidal area (HR, 2.033; 95% confidence interval [CI], 1.179-3.505; P = 0.011), subfoveal plus parafoveal choroidal area (HR, 1.909; 95% CI, 1.096-3.326; P = 0.022), subfoveal CT (HR, 2.032; 95% CI, 1.181-3.498; P = 0.010), and subfoveal plus parafoveal CT (HR, 1.908; 95% CI, 1.097-3.319; P = 0.022). These associations remained statistically significant after additionally adjusting for duration of DM, HbA1c level, BMI, use of insulin, and MABP. Addition of these choroidal metrics significantly improved the discrimination for DR progression when compared with established risk factors alone (e.g., duration of DM and HbA1c; increase in C-statistic ranged from 8.08% to 9.67% [P < 0.05]).

Conclusions

Eyes with a larger choroidal area and CT in Haller's layer at baseline were associated with a higher risk of DR progression over 2 years.

Retinal and Choroidal Vascular Perfusion and Thickness Measurement in Diabetic Retinopathy Patients by the Swept-Source Optical Coherence Tomography Angiography

Purpose

To observe the changes in retinal and choroidal microstructures in patients with different stages of diabetic retinopathy (DR) and to evaluate the vascular perfusion of retina and choroid retinal thickness, retinal and choroidal vessel density by the swept-source optical coherence tomography angiography (SS-OCTA).

Methods

Subjects were divided into three groups: healthy control group (30 cases, 51 eyes), non-proliferative diabetic retinopathy (NPDR, 42 cases, 71 eyes) and proliferative diabetic retinopathy (PDR, 31 cases, 53 eyes). The area of the foveal avascular zone (FAZ), retinal and choroidal vascular perfusion, and the deep vascular complexes, including the intermediate capillary plexus (ICP) and deep capillary plexus (DCP) within the radius of 3, 6, 9, and 12 mm around the fovea were measured by SS-OCTA.

Results

Compared with the healthy control group, DR patients presented significantly increased fovea avascular area, while vessel density (VD) in the ICP and DCP, vascular perfusion rate, and the retinal thickness were considerably decreased. There were significant differences in the retinal thickness, ICP, and DCP vessel densities between the control and NPDR groups, or control and PDR groups, or PDR and NPDR groups. The deep vascular perfusion rate also significantly differed between the control and PDR groups, but there was no significant difference between the PDR and NPDR groups. The choroidal perfusion exhibited significant differences across different areas and amongst the three groups. Furthermore, the choroidal thickness showed a significant difference between the PDR and NPDR groups.

Conclusion

Our results showed significant differences in the area of the avascular fovea and the VD of deep vascular complexes between DR patients and healthy control subjects. Moreover, there were significant differences in retinal VD, especially in the deep-retinalregions, choroidal perfusion, and the volume of large vessel choroid in DR patients with different degrees of disease severity. Notably, SS-OCTA provided in-depth information for detecting the potential VD damage in DR patients caused by a multitudeof factors.

Assessment of Diabetic Choroidopathy Using Ultra-Widefield Optical Coherence Tomography

Purpose

The purpose of this study was to investigate a confocal scanning laser ophthalmoscopy (cSLO) ultra-widefield (UWF) swept-source optical coherence tomography (S-SOCT) in assessment of diabetic choroidopathy and to evaluate the agreement of measurements with a spectral-domain OCT (SD-OCT) instrument.

Methods

We conducted a cross-sectional study of patients with diabetes evaluating the choroidal vascularity index (CVI) in the nasal, temporal, and central macula segments of a UWF SS-OCT scan centered to the fovea. UWF pseudocolored fundus images were used for diabetic retinopathy (DR) severity staging. The CVI values were compared between different degrees of severity of DR and different posterior-pole sectors with linear mixed models. Central macula CVI measurements were repeated on SD-OCT scans; the interobserver intraclass coefficient (ICC) was calculated between SS-OCT and SD-OCT.

Results

A total of 151 eyes of 85 patients were included. The CVI values decreased from nonproliferative DR to proliferative DR, with high-risk proliferative DR having significantly lower CVI values than moderate to severe nonproliferative DR (P = 0.03). The central macula region was the most evidently affected; the nasal sector was the least affected. The agreement between SS-OCT and SD-OCT was moderate (ICC = 0.50).

Conclusions

Diabetic choroidopathy progresses with worsening of DR toward proliferative disease; choroidal depletion is more prominent in the macula. Caution is recommended in comparing CVI values between different devices.

Translational Relevance

Choroidal vascularity informs about the severity of DR and its complications, such as macular edema. The agreement between readers and between instruments may be suboptimal in certain cases.

INFLUENCE OF HIGH MYOPIA ON CHORIOCAPILLARIS PERFUSION AND CHOROIDAL THICKNESS IN DIABETIC PATIENTS WITHOUT DIABETIC RETINOPATHY

PURPOSE

To investigate the impact of high myopia on choriocapillaris (CC) perfusion and choroidal thickness (CT) in diabetic patients without diabetic retinopathy.

METHODS

Healthy subjects and patients with diabetes mellitus were recruited from communities in Guangzhou. They were divided into four groups according to the presence of diabetes and high myopia: healthy control (n = 77), diabetes (n = 77), high myopia (n = 77), and diabetes with high myopia (n = 77). Swept-source optical coherence tomography angiography (SS-OCTA) measured CC perfusion and CT. CC perfusion was quantified using the choriocapillaris perfusion index (CPI).

RESULTS

A total of 308 subjects (308 eyes) were included in the study. The average CPI was 91.11 ± 0.84, 90.16 ± 1.46, 89.80 ± 1.42, and 89.36 ± 1.19% in the control, diabetes, high myopia, and diabetes with high myopia groups, respectively (p < 0.001); the average CT was 227.55 ± 43.13, 205.70 ± 59.66, 158.38 ± 45.24, and 144.22 ± 45.12μm, respectively (p < 0.001). After adjusting for age and sex, the average CPI decreased 0.95 ± 0.20% (p < 0.001) in the diabetes group, 1.33 ± 0.20% (p < 0.001) in the high myopia group, and 1.76 ± 0.20% (p < 0.001) in the diabetes with high myopia group relative to the control group; the average CT decreased 23.53 ± 8.12 (p = 0.004), 70.73 ± 9.41 (p < 0.001), and 85.90 ± 8.12 μm (p < 0.001), respectively. Further adjustment for other risk factors yielded a similar result.

CONCLUSION

Diabetes and high myopia significantly impact CPI and CT, and the presence of both conditions is more damaging to CPI and CT than diabetes or high myopia alone.

Comparison of choroidal thickness in eyes of diabetic patients with eyes of healthy individuals using optical coherence tomography in a tertiary care hospital

Objectives:

To compare the choroidal thickness in eyes of diabetic patients with eyes of age matched controls using optical coherence tomography in a tertiary care hospital.

Methods:

This Cross sectional study was conducted at the Department of Ophthalmology, Jinnah Postgraduate Medical Centre Karachi, for six months from13^thJanuary 2020 to13^thJuly 2020. The study group comprised of 44 patients with 88 eyes. Patients who fulfill the inclusion criteria that is age ranging from 35 to 80years, either gender, known case of diabetes mellitus and having any type of diabetic retinopathy (HbA1c >7), non-diabetic healthy individuals (HbA1c < 7) and those giving informed consent were included in the study. However, patients having active ocular infections, history of myocardial infarction, stroke, uveitis, any ocular surgery, lasers, intravitreal injections, poor fundus view and not giving consent were excluded. A pre-designed proforma was filled. A baseline ocular examination was performed and choroidal thickness was assessed from retinal pigment epithelium to choroid sclera junction in diabetic and healthy participants of the study group using high resolution Swept source OCT (DRI-OCT-2 Triton; Topcon).

Results:

The average age of the patients was 39.41±15.95 years. According to our study mean central subfoveal choroidal thickness in diabetic eyes was 268.5 ± 66.22 (95% CI 240 – 297) and in non-diabetic healthy participants it was 339.3 ± 71.49 (95% CI 308 – 369) with a p-value of 0.001. However, average choroidal thickness was 261.8 ± 61.93 (95% CI 235 – 288) and 336.0 ± 74.35 (95% CI 304 – 367) in diabetic and non-diabetic healthy population with a p-value of 0.001. Choroidal thickness comparison between gender in diabetic and non-diabetic population also showed similar trend.

Conclusion:

In this study, mean central choroidal thickness as well as average choroidal thickness was significantly reduced in eyes having diabetic retinopathy as compared to participants with non-diabetic healthy eyes. These findings indicate that changes in choroid may be a probable route in the pathogenesis of diabetic retinopathy.

Choroidal changes and associations with visual acuity in diabetic patients

Background

The variable visual function observed in diabetic retinopathy (DR) patients is not fully explained by the classic staging system. Our purpose was to evaluate choroidal changes, in standardized sectors, in DR patients and to find associations between choroidal measurements and visual function.

Methods

Cross-sectional study that included the right eye of diabetic patients (n = 265) without active edema, ischemia or neovascularization and age-matched controls (n = 73). Optical coherence tomography (OCT) imaging was performed with enhanced depth imaging protocol. Choroidal vascularity index (CVI) was calculated in a 5 mm scan centered in the fovea.

Results

CVI decreased with age (p < 0.001) but was not influenced by axial length. A multivariate analysis adjusting for age confirmed a significant difference in CVI between DR eyes that had previous treatments (intravitreal injections and/or photocoagulation) compared to control eyes (p = 0.013) and to DR eyes that never required treatment (p = 0.002). There was no significant difference between non-DR diabetic patients and normal controls. Considering the group of DR patients that had previous treatments, in eyes without optic media opacification, BCVA correlated with CVI (r = − 0.362, p < 0.001), whereas full retina thickness and individual retinal layer thickness did not (p > 0.066).

Conclusions

A reduction in CVI was observed in patients with a more advanced stage of DR. In treated DR patients with stable disease, choroidal biomarkers correlated with best-corrected visual acuity whereas retinal biomarkers did not.

Trial registration: N/A

Supplementary Information

The online version contains supplementary material available at 10.1186/s40942-021-00355-z.

Assessment of choroidal structural changes in patients with pre- and early-stage clinical diabetic retinopathy using wide-field SS-OCTA

PURPOSE

To investigate the micro-vascular changes in choroidal structures in patients with pre- and early-stage clinical diabetic retinopathy (DR) using wide-field Swept-Source Optical Coherence Tomography Angiography (SS-OCTA).

METHOD

This observational cross-sectional study included 131 eyes of 68 subjects that were divided into healthy controls (group 1, n = 46), pre-DR (group 2, n = 43), early-stage DR (group 3, n = 42) cohorts. All participants that underwent SS-OCTA examination were inpatients in the department of Ophthalmology and the department of Endocrinology, Qilu Hospital, Shandong University, and Department of Ophthalmology, Aier Eye Hospital, Jinan, from July 11, 2021 to March 17, 2022. The choroidal vascularity index (CVI), choroidal thickness (ChT) and central macular thickness (CMT) in the whole area (diameter of 12 mm) and concentric rings with different ranges (0-3, 3-6, 6-9, and 9-12 mm) were recorded and analyzed from the OCTA image.

RESULT

Compared with healthy eyes, decreases in CVI and ChT were found in the eyes of patients with pre-or early-stage DR. The changes were more significant in the peripheral choroid, with the most prominent abnormalities in the 9-12mm area (P < 0.001). However, there was no obvious difference in the average CMT value. Furthermore, CVI and ChT were significantly correlated with the duration of diabetes in the range of 6-9 and 9-12 mm (Ps < 0.05; Correlation coefficient = -0.549, -0.395, respectively), with the strongest correlation (Ps < 0.01; Correlation coefficient = -0.597, -0.413, respectively) observed at 9-12 mm.

CONCLUSION

The CVI and ChT values of diabetic patients are significantly lower than in healthy controls, especially in patients with early-stage DR. In addition, the peripheral choroidal capillaries are more susceptible to early DM-induced injury than in the central area.

Response to 1-Year Fixed-Regimen Bevacizumab Therapy in Treatment-Naïve DME Patients: Assessment by OCT Angiography

PURPOSE

To evaluate the effectiveness of intravitreal bevacizumab treatment in patients with diabetic macular edema (DME) by assessing retinal changes using optical coherence tomography angiography (OCT-A).

METHODS

This prospective study was performed in patients with treatment-naïve DME. The eyes of patients were imaged using a swept-source OCT system with a scan area of 6 × 6 mm. The DME patients with a central macular thickness (CMT) of ≥300 μm received nine bevacizumab injections within 12 months. The demographic, systemic, and ocular parameters, including the best-corrected visual acuity (BCVA), CMT, microaneurysm (MA) count, and foveal avascular zone (FAZ) area in both superficial capillary plexus (SCP) and deep capillary plexus (DCP), as well as vessel density in SCP, were assessed in the patients. In addition, the response (good or poor) of the DME eyes to bevacizumab treatment and the final visual acuity (BCVA of 75 letters) were analyzed.

RESULTS

Seventy-seven eyes of DME patients were subjected to the final analysis. Bevacizumab treatment reduced CMT from 425.06 μm (±77.15) to 350.25 μm (±82.04) and improved BCVA by about 8.61 letters (from 64.73 to 73.34) in the patients. The mean number of MAs in SCP decreased from 3.51 ± 2.07 to 2.31 ± 1.15 (p < 0.001) and in DCP from 17.12 ± 11.56 to 12.21 ± 6.99 (p < 0.001), whereas the area of FAZ increased in SCP from 328.22 ± 131.38 to 399.70 ± 156.98 (p < 0.001) and in DCP from 571.13 ± 396.01 to 665.89 ± 412.77 (p = 0.001). The final BCVA letter score and CMT were statistically significant in both poor and good responders, as well as in BCVA < 75 and BCVA ≥ 75 groups.

CONCLUSION

The fixed-regimen intravitreal bevacizumab therapy was effective in treating DME. Apart from noninvasive visualization of microvascular damage, OCT-A showed limited usefulness in predicting treatment response. Although the study showed that the number of MAs was significantly reduced during treatment, which is an OCT-A predictor of a good response to bevacizumab treatment at a 12-month visit, commonly observed artifacts may reduce the usefulness of OCT-A.

BRAIN AND EYE AS POTENTIAL TARGETS FOR IONIZING RADIATION IMPACT. PART III / FEATURES MORPHOMETRIC RETINAL PARAMETERS, AMPLITUDE AND LATENCY COMPONENTS OF VISUAL EVOKED POTENTIAL IN RADIATION EXPOSED IN UTERO

One of the current problems of modern radiobiology is determine the characteristics of the manifestation of radiation-induced effects not only at different dose loads, but also at different stages of development of the organism. In previous reports, we have summarized available evidence that at certain ages there is a comparative acceleration of radiation-induced pathological changes in the eye and brain, and the study and assessment of the risk of possible ophthalmic and neurological pathology in remote periods after contamination of radioactive areas. Data of irradiated in utero individuals are possible on the basis of observation of the state of the visual analyzer in persons who underwent intrauterine irradiation in 1986. Therefore, a parallel study of retinal morphometric parameters, amplitude and latency of components of evoked visual potentials in irradiated in utero individuals was performed.

OBJECTIVE

to evaluate the retinal morphometric parameters, amplitude and latency components of the evoked visual potentials in intrauterine irradiated persons.

MATERIALS AND METHODS

The results of surveys of 16 people irradiated in utero in the aftermath of the Chornobyl disaster were used; the comparison group were residents of Kyiv of the corresponding age (25 people). Optical coherence tomography was performed on a Cirrus HD-OCT, Macular Cube 512x128 study technique was used. At the same time, the study of visual evoked potentials on the inverted pattern was performed, and occipital leads wereanalyzed. Visual evoked potentials were recorded on a reversible chess pattern (VEP) - an electrophysiological test, which is a visual response to a sharp change in image contrast when presenting a reversible image of a chessboard.

RESULTS

In those irradiated in utero at the age of 22-25 years, there was a probable increase in retinal thickness in the fovea, there was a tendency to increase the thickness of the retina in the areas around the fovea. When recording visual evoked potentials on a reversible chess pattern in this group, there was a tendency to decrease the amplitudes of components (N75, P100, N145, P200) in the right and left parieto-occipital areas and asymmetric changes in latency of these components.

CONCLUSIONS

Early changes of fovea recorded in OCT and decreasing amplitudes of components of visual evoked potentials on the reversible chess pattern at the age of 22 25 years may indicate a risk of development in patients irradiated in utero, early age-related macular degeneration, as well as increased risk and increased risk structures of the visual analyzer.

Exploring the choroidal vascular labyrinth and its molecular and structural roles in health and disease

The choroid is a key player in maintaining ocular homeostasis and plays a role in a variety of chorioretinal diseases, many of which are poorly understood. Recent advances in the field of single-cell RNA sequencing have yielded valuable insights into the properties of choroidal endothelial cells (CECs). Here, we review the role of the choroid in various physiological and pathophysiological mechanisms, focusing on the role of CECs. We also discuss new insights regarding the phenotypic properties of CECs, CEC subpopulations, and the value of measuring transcriptomics in primary CEC cultures derived from post-mortem eyes. In addition, we discuss key phenotypic, structural, and functional differences that distinguish CECs from other endothelial cells such as retinal vascular endothelial cells. Understanding the specific clinical and molecular properties of the choroid will shed new light on the pathogenesis of the broad clinical range of chorioretinal diseases such as age-related macular degeneration, central serous chorioretinopathy and other diseases within the pachychoroid spectrum, uveitis, and diabetic choroidopathy. Although our knowledge is still relatively limited with respect to the clinical features and molecular pathways that underlie these chorioretinal diseases, we summarise new approaches and discuss future directions for gaining new insights into these sight-threatening diseases and highlight new therapeutic strategies such as pluripotent stem cell‒based technologies and gene therapy.

Diabetic retinopathy and diabetic macular oedema pathways and management: UK Consensus Working Group

The management of diabetic retinopathy (DR) has evolved considerably over the past decade, with the availability of new technologies (diagnostic and therapeutic). As such, the existing Royal College of Ophthalmologists DR Guidelines (2013) are outdated, and to the best of our knowledge are not under revision at present. Furthermore, there are no other UK guidelines covering all available treatments, and there seems to be significant variation around the UK in the management of diabetic macular oedema (DMO). This manuscript provides a summary of reviews the pathogenesis of DR and DMO, including role of vascular endothelial growth factor (VEGF) and non-VEGF cytokines, clinical grading/classification of DMO vis a vis current terminology (of centre-involving [CI-DMO], or non-centre involving [nCI-DMO], systemic risks and their management). The excellent UK DR Screening (DRS) service has continued to evolve and remains world-leading. However, challenges remain, as there are significant variations in equipment used, and reproducible standards of DMO screening nationally. The interphase between DRS and the hospital eye service can only be strengthened with further improvements. The role of modern technology including optical coherence tomography (OCT) and wide-field imaging, and working practices including virtual clinics and their potential in increasing clinic capacity and improving patient experiences and outcomes are discussed. Similarly, potential roles of home monitoring in diabetic eyes in the future are explored. The role of pharmacological (intravitreal injections [IVT] of anti-VEGFs and steroids) and laser therapies are summarised. Generally, IVT anti-VEGF are offered as first line pharmacologic therapy. As requirements of diabetic patients in particular patient groups may vary, including pregnant women, children, and persons with learning difficulties, it is important that DR management is personalised in such particular patient groups. First choice therapy needs to be individualised in these cases and may be intravitreal steroids rather than the standard choice of anti-VEGF agents. Some of these, but not all, are discussed in this document.

Malfunction of outer retinal barrier and choroid in the occurrence and progression of diabetic macular edema

Diabetic macular edema (DME) is the most common cause of vision loss in diabetic retinopathy, affecting 1 in 15 patients with diabetes mellitus (DM). The disruption of the inner blood-retina barrier (BRB) has been largely investigated and attributed the primary role in the pathogenesis and progression in DME, but there is increasing evidence regarding the role of outer BRB, separating the RPE from the underlying choriocapillaris, in the occurrence and evolution of DME. The development of novel imaging technologies has led to major improvement in the field of in vivo structural analysis of the macula allowing us to delve deeper into the pathogenesis of DME and expanding our vision regarding this condition. In this review we gathered the results of studies that investigated specific outer BRB optical coherence tomography parameters in patients with DM with the aim to outline the current status of its role in the pathogenesis and progression of DME and identify new research pathways contributing to the advancement of knowledge in the understanding of this condition.

Retinal applications of swept source optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA)

The advent of optical coherence tomography (OCT) revolutionized both clinical assessment and research of vitreoretinal conditions. Since then, extraordinary advances have been made in this imaging technology, including the relatively recent development of swept-source OCT (SS-OCT). SS-OCT enables a fast scan rate and utilizes a tunable swept laser, thus enabling the incorporation of longer wavelengths than conventional spectral-domain devices. These features enable imaging of larger areas with reduced motion artifact, and a better visualization of the choroidal vasculature, respectively. Building on the principles of OCT, swept-source OCT has also been applied to OCT angiography (SS-OCTA), thus enabling a non-invasive in depth-resolved imaging of the retinal and choroidal microvasculature. Despite their advantages, the widespread use of SS-OCT and SS-OCTA remains relatively limited. In this review, we summarize the technical details, advantages and limitations of SS-OCT and SS-OCTA, with a particular emphasis on their relevance for the study of retinal conditions. Additionally, we comprehensively review relevant studies performed to date to the study of retinal health and disease, and highlight current gaps in knowledge and opportunities to take advantage of swept source technology to improve our current understanding of many medical and surgical chorioretinal conditions. We anticipate that SS-OCT and SS-OCTA will continue to evolve rapidly, contributing to a paradigm shift to more widespread adoption of new imaging technology to clinical practice.

Effects of Femtosecond Laser-Assisted Cataract Surgery on Macular and Choroidal Thickness in Diabetic Patients

Introduction

This study aimed to compare the short-term changes in retinal and choroid thickness in diabetic patients after femtosecond laser-assisted cataract surgery (FLACS) and phacoemulsification (PE) surgery.

Methods

A total of 47 eyes in the PE group and 44 eyes in the FLACS group were included. All patients underwent measurement of central macular thickness (CMT) and subfoveal choroidal thickness (SFCT) before and after surgery using optical coherence tomography (OCT).

Results

The effective phaco time (EPT) in the FLACS group was significantly reduced. The BCVA differed significantly between the two groups at 1 week and 1 month after surgery. The CMT in both groups increased at 1 week after the operation. It did not return to the preoperative level until month 12 in the PE group. In the FLACS group, the CMT began to decrease at month 3 and recovered to the preoperative level at month 12. The SFCT of the two groups increased at week 1; it began to decrease at month 6 in the PE group but did not recover to the preoperative level until month 12. The SFCT in the FLACS group recovered to preoperative levels at month 6. In the PE group, baseline CMT values predicted CMT change at week 1 and months 1, 3 and 12 after surgery. In the FLACS group, baseline CMT predicted CMT changes at week 1, month 1 and month 3. In the FLACS group, EPT predicted SFCT change at month 3.

Conclusion

FLACS is safe and effective in patients with no fundus change or mild diabetic retinopathy. It has advantages in effectively reducing EPT, achieving good vision earlier and promoting faster recovery of the retinal and choroidal thickness. Preoperative CMT is a significant predictor of CMT changes in the early period after FLACS.

Analysis of the Choroid and Its Relationship with the Outer Retina in Patients with Diabetes Mellitus Using Binarization Techniques Based on Spectral-Domain Optical Coherence Tomography

(1) Background: We aimed to reveal the relationship between the choroid and the outer retina with optical coherence tomography (OCT) in patients with diabetes mellitus (DM) with mild or no diabetic retinopathy (DR) in order to find early biomarkers for progressing retinopathy. (2) Methods: We performed a prospective study including 61 eyes of patients with type 1 or type 2 DM and 36 eyes of healthy controls. All subjects were imaged with Spectralis OCT. The choroid was assesseed using enhanced depth imaging OCT (EDI-OCT). Binarization of subfoveal choroidal images was done with public domain software, ImageJ (version 1.53a; National Institutes of Health, Bethesda, Maryland, USA). (3) Results: Luminal area, stromal area and total choroidal area were significantly decreased in diabetic patients compared to control: 0.23 ± 0.07 vs. 0.28 ± 0.08, p = 0.012; 0.08 ± 0.03 vs. 0.10 ± 0.04, p = 0.026; 0.31 ± 0.09 vs. 0.38 ± 0.11, p = 0.008. The thickness of retinal pigment epithelium (RPE) correlated positively with the choroidal vascularity index (CVI). The correlations between outer nuclear layer (ONL), photoreceptors (PR) and foveal choroidal thickness (FChT) were moderately negative. (4) Conclusion: Thicker RPE and a thinner PR layer may be assigned the role of early biomarkers signaling the conversion time to progressing retinopathy.

Automatic Segmentation and Visualization of Choroid in OCT with Knowledge Infused Deep Learning

The choroid provides oxygen and nourishment to the outer retina thus is related to the pathology of various ocular diseases. Optical coherence tomography (OCT) is advantageous in visualizing and quantifying the choroid in vivo. However, its application in the study of the choroid is still limited for two reasons. (1) The lower boundary of the choroid (choroid-sclera interface) in OCT is fuzzy, which makes the automatic segmentation difficult and inaccurate. (2) The visualization of the choroid is hindered by the vessel shadows from the superficial layers of the inner retina. In this paper, we propose to incorporate medical and imaging prior knowledge with deep learning to address these two problems. We propose a biomarker-infused global-to-local network (Bio-Net) for the choroid segmentation, which not only regularizes the segmentation via predicted choroid thickness, but also leverages a global-to-local segmentation strategy to provide global structure information and suppress overfitting. For eliminating the retinal vessel shadows, we propose a deep-learning pipeline, which firstly locate the shadows using their projection on the retinal pigment epithelium layer, then the contents of the choroidal vasculature at the shadow locations are predicted with an edge-to-texture generative adversarial inpainting network. The results show our method outperforms the existing methods on both tasks. We further apply the proposed method in a clinical prospective study for understanding the pathology of glaucoma, which demonstrates its capacity in detecting the structure and vascular changes of the choroid related to the elevation of intra-ocular pressure.

Optical Coherence Tomography Angiography Assessment of Macular Choriocapillaris and Choroid Following Panretinal Photocoagulation in a Diverse Population With Advanced Diabetic Retinopathy

PURPOSE

The aim of this study was to evaluate choroidal and retinal microvasculature with optical coherence tomography angiography (OCTA) after panretinal photocoagulation (PRP) for diabetic retinopathy in a primarily Hispanic and Asian population.

DESIGN

Retrospective study.

METHODS

Eyes were examined by OCTA in the macula (3 × 3 mm) just before PRP treatment and 1 to 3 months afterwards. Choroidal thickness (CT) and central retinal thickness (CRT) were measured. Choroidal flow signal voids (CFSV) and choriocapillaris flow signal voids (CCFSV) were acquired. Retinal microvasculature parameters, including superficial and deep vessel density, superficial and deeper perfusion density, foveal avascular zone area, perimeter and circularity, were calculated. Ocular examinations and demographic information were analyzed.

RESULTS

CT at a location 1000 μm temporal to the fovea increased significantly after PRP (from 278.64 μm to 313.44 μm, P = 0.026). CCFSV increased slightly from (46.72 ± 8.52)% to (47.07 ± 10.77)%, but the difference was not statistically significant (P = 0.782). A similar finding was observed in CFSV (increase from 35.81% to 36.64%, P = 0.165). The change in all retinal microvasculature parameters was also not significant. Best-corrected visual acuity (BCVA) decreased from 0.218 ± 0.153 to 0.262 ± 0.147 (P = 0.034). Increased CRT (from 245.41 ± 33.18 μm to 251.14 ± 38.97 μm, P = 0.007) was observed. The change in CRT positively correlated with pre-PRP CRT (r = 0.434, P = 0.019) and BCVA reduction (r = 0.418, P = 0.024). Neither BCVA reduction nor CRT increase correlated with OCTA metrics.

CONCLUSIONS

OCTA demonstrates redistribution of choroidal circulation from the periphery to the macula after PRP, with increased macular CT and stable choroidal blood flow density. Eyes with greater macular thickness are more likely to experience an increase in CRT.

Intravitreal dexamethasone implant in naïve and previously treated patients with diabetic macular edema: a retrospective study

AIM

To assess the effect of the intravitreal dexamethasone implant (DEX) Ozurdex on the best corrected visual acuity (BCVA) and central retinal thickness (CRT) in patients with diabetic macular edema (DME).

METHODS

Totally 43 eyes (24 naïve and 19 previously treated) were included in the study. Retrospective and single-center study involved patients with a clinical diagnosed of DME, who received treatment with DEX implant and had a follow-up of at least 12mo. Primary endpoints included changes in BCVA and CRT.

RESULTS

At month 12, mean improvement in BCVA from baseline was 20.4±20.8 letters and 6.8±6.9 letters in naïve and previously treated patients, respectively (P=0.0132). The naïve patients achieved the BCVA improvement significantly faster (2.4±1.5mo) than the previously treated ones (3.5±2.4mo, P=0.0298; Mann-Whitney test). The proportion of eyes gaining ≥15 letters was 54.2% and 21.1% in the non-previously treated and previously treated groups, respectively (P=0.0293). CRT was significantly reduced from 484.0±119.8 and 487.5±159.9 µm to 272.0±39.2 and 233.5±65.7 µm in the naïve and previously treated patients, respectively; P<0.0001 each, respectively. The presence of subretinal fluid was significantly associated with the proportion of patients achieving a BCVA improvement ≥5 letters [HR (95%CI), 1.23 (1.04 to 1.45), P=0.0145]; ≥10 letters [HR (95%CI), 1.75 (1.10 to 2.77), P=0.0182]; and ≥15 letters [HR (95% CI), 2.04 (1.03 to 4.02), P=0.0407]. Naïve patients received less DEX implants throughout the study than the previously treated ones (1.8±0.6 vs 2.3±0.6, P=0.0172, respectively). Totally 9 patients (20.9%) have developed ocular hypertension, which was successfully controlled with topical hypotensive drugs. Of the 23 phakic eyes at baseline, 5 eyes (21.7%) either had new onset lens opacity or progression of an existing opacity during the study follow-up. Four of them (2 in the naïve group and 2 in the previously treated one) required cataract surgery at months 4, 6, 6, and 6, respectively.

CONCLUSION

The results obtained in this study may support the early use of DEX Ozurdex as first line therapy in naïve patients.

Factors associated with serous retinal detachment in highly myopic eyes with inferior posterior staphyloma

PURPOSE

To investigate the factors associated with persistent serous retinal detachment in highly myopic eyes with inferior posterior staphyloma.

METHODS

A total of 27 highly myopic patients (44 eyes) with an inferior posterior staphyloma were recruited. Serous retinal detachment was investigated; 13 eyes had persistent sub-macular fluid (study group), and 31 eyes lacked sub-macular fluid (control group). All patients underwent complete ophthalmologic examinations, including axial length measurement and fluorescein angiography (FA). Triton Deep Range Imaging (DRI) optical coherence tomography (OCT) (Topcon Corp., Tokyo, Japan) scans through the fovea measured choroidal thicknesses, macular bend height, and vitreoretinal interface factors.

RESULTS

Of the 44 eyes, 13 had neurosensory retinal detachment and 31 did not. No significant differences were found in any of the studied variables (age, gender, spherical equivalence, axial length, vitreomacular traction, epiretinal membrane, internal limiting membrane detachment), except a higher macular bend height (p = 0.01), and a reduced macular choroidal thickness (p = 0.02), which were associated with the risk of serous retinal detachment. No statistically significant differences in best-corrected visual acuity (BCVA) were observed between the study and control groups. Serous retinal detachment always occurred at the bisected retinal pigment epithelium of the macula corresponding to the upper edge of the staphyloma, and was characterised by multiple hyperfluorescent granular patches on fluorescein angiography.

CONCLUSIONS

A higher macular bend height and a reduced macular choroidal thickness may be important factors in the development of serous retinal detachment in patients with inferior posterior staphyloma.

Repeatability of binarization thresholding methods for optical coherence tomography angiography image quantification

Binarization is a critical step in analysis of retinal optical coherence tomography angiography (OCTA) images, but the repeatability of metrics produced from various binarization methods has not been fully assessed. This study set out to examine the repeatability of OCTA quantification metrics produced using different binarization thresholding methods, all of which have been applied in previous studies, across multiple devices and plexuses. Successive 3 × 3 mm foveal OCTA images of 13 healthy eyes were obtained on three different devices. For each image, contrast adjustments, 3 image processing techniques (linear registration, histogram normalization, and contrast-limited adaptive histogram equalization), and 11 binarization thresholding methods were independently applied. Vessel area density (VAD) and vessel length were calculated for retinal vascular images. Choriocapillaris (CC) images were quantified for VAD and flow deficit metrics. Repeatability, measured using the intra-class correlation coefficient, was inconsistent and generally not high (ICC < 0.8) across binarization thresholds, devices, and plexuses. In retinal vascular images, local thresholds tended to incorrectly binarize the foveal avascular zone as white (i.e., wrongly indicating flow). No image processing technique analyzed consistently resulted in highly repeatable metrics. Across contrast changes, retinal vascular images showed the lowest repeatability and CC images showed the highest.

Development of a physiologically-based pharmacokinetic model for ocular disposition of monoclonal antibodies in rabbits

Development of protein therapeutics for ocular disorders, particularly age-related macular degeneration (AMD), is a highly competitive and expanding therapeutic area. However, the application of a predictive and translatable ocular PK model to better understand ocular disposition of protein therapeutics, such as a physiologically-based pharmacokinetic (PBPK) model, is missing from the literature. Here, we present an expansion of an antibody platform PBPK model towards rabbit and incorporate a novel anatomical and physiologically relevant ocular component. Parameters describing all tissues, flows, and binding events were obtained from existing literature and fixed a priori. First, translation of the platform PBPK model to rabbit was confirmed by evaluating the model's ability to predict plasma PK of a systemically administered exogenous antibody. Then, the PBPK model with the new ocular component was validated by estimation of serum and ocular (i.e. aqueous humor, retina, and vitreous humor) PK of two intravitreally administered monoclonal antibodies. We show that the proposed PBPK model is capable of accurately (i.e. within twofold) predicting ocular exposure of antibody-based drugs. The proposed PBPK model can be used for preclinical-to-clinical translation of antibodies developed for ocular disorders, and assessment of ocular toxicity for systemically administered antibody-based therapeutics.

Decrease in Choroidal Vascularity Index of Haller's layer in diabetic eyes precedes retinopathy

INTRODUCTION

The study aimed to evaluate Choroidal Vascularity Index (CVI) of Haller's and Sattler's layers and their relationships with choroidal and retinal thickness, volumes measured on enhanced depth imaging-optical coherence tomography (OCT) scans in the eyes of patients without diabetes, patients with diabetes with no diabetic retinopathy (DR) and patients with diabetes and DR.

RESEARCH DESIGN AND METHODS

Retrospective analysis of 165 eyes from 84 Singapore Indian Eye Study-2 study participants (group 1: no diabetes, group 2: diabetes with no DR and group 3: with DR). Groups 1 and 2 were matched by age and gender from group 3.

RESULTS

In the eyes of patients with diabetes without DR, the macular CVI of Haller's but not Sattler's layer was significantly reduced compared with eyes of patients without diabetes. Eyes with >5 years of diabetes have significantly decreased CVI of Sattler's layers (mean difference=0.06 ± 0.10, p=0.04) and also decreased subfoveal choroidal volume (mean difference=0.89 ± 0.16 mm³, p=0.02), compared with those with ≤5 years of diabetes.

CONCLUSION

Diabetic eyes without DR had significantly lower CVI of macular Haller's layer than those of healthy controls. With a longer duration of diabetes, CVI of subfoveal Sattler's layer and choroidal volume continue to decrease, irrespective of diabetic control, suggesting that early diabetic choroidopathy mainly affects larger choroidal veins initially before medium-sized arterioles. The CVI of macular Haller's layer could potentially be used as a marker on spectral domain OCT imaging in newly diagnosed patients with diabetes for the onset of DR and as a possible prognostication tool in diabetic eyes. Future prospective longitudinal studies in diabetic eyes would be useful in establishing the relationship between CVIs of Haller's and Sattler's layer with visual acuity as a marker of photoreceptor health and visual prognosis.

Choroidal Thickness in Diabetes and Diabetic Retinopathy: A Swept Source OCT Study

Purpose

Previous studies on the association between choroidal thickness (CT) and severity of diabetic retinopathy (DR) gave conflicting results. The aim of this study was to evaluate the CT changes in diabetic patients and associated factors in a large sample of Chinese patients with diabetes.

Methods

Type 2 diabetes mellitus patients without history of ocular treatment were recruited from the community health system in Guangzhou, China. The swept source OCT instrument was used to obtain high-definition retina and choroid images. The diabetic retinopathy (DR) status was graded based on the guidelines of the United Kingdom National Diabetic Eye Screening Programme. Univariate and multivariate linear regression analyses was used to explore the association of CT with DR severity, diabetic macular edema (DME), hemoglobin A1c, and vision function.

Results

A total of 1347 patients were included in the final analysis. After adjusting for other factors, the patients with stage R3 DR had significantly thinner CT (β = –29.1 µm, 95% CI –53.8 to –4.4, P = 0.021) in comparison in those with R0. After adjusting for other factors, the CTs were thicker than those in R0 patients with difference of 15.6 µm (95% CI 4.3-26.9, P = 0.007) for outer nasal sector, 15.7 µm (95% CI 3.8-25.5, P = 0.008) for outer inferior, and 12.2 µm (95% CI 0.4-24.0, P = 0.042) for inner inferior sector. The presence of DME and hemoglobin A1c levels did not significantly affect average CT. Higher average CT was significantly associated with better best corrected visual acuity, with a –0.02 LogMAR unit per 100 µm increase in average CT (95% CI –0.03 to –0.01, P < 0.001).

Conclusions

CT increased in the early stage of DR, and further decreased with DR progression. DME was not significantly associated with CT. These findings provide more clues to suggest that choroid alterations play a role in the pathogenesis of DR.

Visualization of deep choroidal vasculatures and measurement of choroidal vascular density: a swept-source optical coherence tomography angiography approach

BACKGROUND

To investigate swept-source optical coherence tomography angiography (SS-OCTA) for deep choroid visualization and choroidal vascular density (CVD) measurement.

METHODS

Healthy subjects and central serous chorioretinopathy (CSC) patients were recruited for macular SS-OCTA scans. We evaluated OCTA images at various depths to determine an optimal depth for visualizing choroidal vasculatures. We measured CVD with binarized OCTA images at the optimal depth. In healthy subjects, CVD was studied for its correlation with age, axial length (AL), and subfoveal choroidal thickness (SCT). In CSC eyes, CVD was compared with matched controls.

RESULTS

Ninety-one healthy eyes and 22 CSC eyes were included. SS-OCTA could display deep choroidal vasculatures as dark signals, with 100 μm beneath BM as the optimal depth. In healthy subjects, the CVD at 100 μm beneath BM (56.5 ± 10.9%) was significantly correlated with SCT (P = 0.004) but not with age (P = 0.49) or AL (P = 0.72). In CSC eyes, the CVD at 100 μm beneath BM (62.3 ± 6.6%) was larger than that in 22 matched controls (54.1 ± 8.0%) (P = 0.001). The difference remained statistically significant after adjusting for SCT (P = 0.02).

CONCLUSIONS

SS-OCTA can be used for visualizing deep choroidal vasculatures. CVD measured by OCTA at 100 μm beneath BM is a useful parameter for quantifying choroidal vascular status.

The eye, the kidney, and cardiovascular disease: old concepts, better tools, and new horizons

Chronic kidney disease (CKD) is common, with hypertension and diabetes mellitus acting as major risk factors for its development. Cardiovascular disease is the leading cause of death worldwide and the most frequent end point of CKD. There is an urgent need for more precise methods to identify patients at risk of CKD and cardiovascular disease. Alterations in microvascular structure and function contribute to the development of hypertension, diabetes, CKD, and their associated cardiovascular disease. Homology between the eye and the kidney suggests that noninvasive imaging of the retinal vessels can detect these microvascular alterations to improve targeting of at-risk patients. Retinal vessel-derived metrics predict incident hypertension, diabetes, CKD, and cardiovascular disease and add to the current renal and cardiovascular risk stratification tools. The advent of optical coherence tomography (OCT) has transformed retinal imaging by capturing the chorioretinal microcirculation and its dependent tissue with near-histological resolution. In hypertension, diabetes, and CKD, OCT has revealed vessel remodeling and chorioretinal thinning. Clinical and preclinical OCT has linked retinal microvascular pathology to circulating and histological markers of injury in the kidney. The advent of OCT angiography allows contrast-free visualization of intraretinal capillary networks to potentially detect early incipient microvascular disease. Combining OCT's deep imaging with the analytical power of deep learning represents the next frontier in defining what the eye can reveal about the kidney and broader cardiovascular health.

Therapeutic Effect of Abelmoschus manihot on Type 2 Diabetic Nonproliferative Retinopathy and the Involvement of VEGF

Objective

To evaluate the efficacy of Abelmoschus manihot in treating type 2 diabetic nonproliferative retinopathy.

Methods

It was a randomized controlled clinical trial. The recruited eighty subjects with type 2 diabetic nonproliferative retinopathy were randomly divided into treatment group and control group. The two groups received basic treatments including control of blood glucose, blood pressure and blood lipid, management of diet, exercise and health education, and monitoring of relevant indicators. Additionally, the treatment group was given oral administration of Abelmoschus manihot. All subjects were followed up on monthly basis for consecutive six months. The related parameters including diabetic retinopathy (DR) incidence rates, “Early Treatment Diabetic Retinopathy Study” (ETDRS) vision scores, retinal thicknesses in macular region, serum vascular endothelial growth factor (VEGF) levels, and biochemical indicators of both groups before and after treatment were accurately collected and statistically analyzed.

Results

There were no significant differences of DR severity levels, ETDRS vision scores, macular retinal thicknesses such as cube average thickness (CAT), central subfield thickness (CST), and cube volume (CV), and serum VEGF levels between two groups before treatment. Meanwhile, there were no significant differences of demographic characteristics, case terminations, blood glucose, blood lipid, blood pressure, biochemical indicators of hepatorenal function, hypoglycemic drugs, hypotensive drugs, and other basic treatments between two groups during six months treatment. The present study suggested that the remission rate of DR and the ETDRS vision score in the treatment group were significantly higher than those of the control group (remission rate: 25.4% vs 9.3%, P=0.01; ETDRS score: 78 (72, 82) vs 72 (67, 80), P=0.0002) while the progression rate of DR in the treatment group was significantly lower than that of the control group (progression rate: 4.2% vs 18.7%, P=0.007) after six months treatment. In addition, the CAT, CST, CV, and serum VEGF levels of the treatment group were significantly improved after the treatment (CAT: 286 (278, 302) vs 282 (270, 295) μm, P < 0.0001; CST: 251 (239, 274) vs 248 (235, 265) μm, P < 0.0001; CV: 10.3 (10.0, 10.9) vs 10.1 (9.7, 10.6) mm³, P < 0.0001; VEGF: 0.21 (0.14, 0.58) vs 0.16 (0.10, 0.23) ng/ml, P=0.0026), while there were no significant differences of the control group before and after treatment (CAT: 287 (279, 294) vs 287 (279, 295) μm, P=0.27; CST: 250 (240, 266) vs 252 (238, 266) μm, P=0.72; CV: 10.4 (10.1, 10.6) vs 10.4 (10.1, 10.7) mm³, P=0.53; VEGF: 0.21 (0.13, 0.66) vs 0.23 (0.12, 0.64) ng/ml, P=0.85).

Conclusion

The study offered the novel evidence for the therapeutic effect of Abelmoschus manihot on type 2 diabetic nonproliferative retinopathy, which was associated with improved VEGF. This trial is registered with ChiCTR1800019292.

Changes in Choroidal Thickness Varied by Age and Refraction in Children and Adolescents: A 1-Year Longitudinal Study

PURPOSE

To clarify the changing characteristics of choroidal thickness over time within different age ranges and among different refractive statuses of children aged 6 to 18 years.

DESIGN

Prospective cohort study.

METHODS

Data of axial length, cycloplegic refraction, and choroidal thickness (using swept-source optical coherence tomography) were collected at baseline and at a 1-year follow-up for 756 participants. One-year change in choroidal thickness and its association with age and refraction were analyzed.

RESULTS

Significantly greater attenuation of choroidal thickness was observed in younger children aged 6-9 years for all participants (-9 ± 25 μm) and for those with a myopic shift (-12 ± 25 μm), whereas there was a larger increase in adolescents aged 10-13 years for those without a myopic shift (9 ± 23 μm). There was a marked decrease in the choroidal thickness for newly developed myopic patients compared with persistent-nonmyopic patients and persistent-myopic patients (P < .01). The association between changes in axial length and choroidal thickness was less strong in persistent-myopic patients (β = -15.4, P = .022) than that in persistent-nonmyopic patients (β = -30.4, P < .001) and newly developed myopic patients (β = -33.7, P = .001), whereas among the persistent-myopic patients, the association was less strong in the baseline mild-myopic patients (β = -10.4, P = .193) than that in the baseline moderate-to high-myopic patients (β = -31.4, P = .026).

CONCLUSIONS

Changes in choroidal thickness varied by age. There was an increased rapid thinning of the choroid among newly developed myopic patients, and a nonsignificant association between changes in choroidal thickness and axial length in the early stages of myopia.

Can the dexamethasone intravitreal implant Ozurdex be safely administered in an out-of-operating room setting?

Purpose

To describe a standardized protocol of the dexamethasone intravitreal (DEX) implant Ozurdex (Allergan, Dublin, Ireland) performed in a controlled environment surgical cabin (CESC).

Methods

Retrospective and observational study conducted on patients who underwent a DEX implant between May 2011 and June 2019, in a third level University Hospital. The controlled environment surgical cabin (ArcSterile, Imex, Valencia, Spain) used in this study was the MB 20 (2 m width, 1.60 m depth, and 2 m height) with an uninterrupted power system (ARSSAI1) to keep the cabin working for 20 min. The cabin was used in the open mode. A standardized protocol of intravitreal injections in controlled environment surgical cabin was designed.

Results

From May 2011 to February 2015, a total of 454 DEX implants were performed in the operating room, whereas from March 2015 to June 2019, 1054 DEX devices were implanted using the CESC. The mean number of DEX implants/per week was significantly lower in the operating room than in the CESC [2.3 (2.1 to 2.5) versus 3.8 (3.6 to 4.1), mean difference 1.5 (1.2 to 1.8), p < 0.0001]. The incidence of endophthalmitis was similar in the two populations, 0/454 (0.0%; 95% CI 0.0 to 0.81%) and 0/1054 (0.0%; 95% CI 0.0 to 0.35%) in the operating room and in the CESC, respectively.

Conclusions

The CESC may be a good alternative to the conventional operating room for the administration of the intravitreal DEX implant.

Topographic analysis of macular choriocapillaris flow deficits in diabetic retinopathy using swept-source optical coherence tomography angiography

Background

The purpose of this study was to investigate the association between diabetic retinopathy (DR) severity and macular choriocapillaris (CC) flow deficit percentage (FD %) in different macular regions using swept-source optical coherence tomography angiography (SS-OCTA).

Methods

Diabetic patients with SS-OCTA images were graded by severity and retrospectively assessed. CC FD % was calculated in four different regions of the OCTA image: inner, middle, outer, and full-field region. The generalized estimating equations (GEE) approach for clustered eye data was used to determine effect size and significance of age and disease severity on FD % for each region.

Results

160 eyes from 90 total diabetic patients met inclusion criteria. Out of 90 patients, 33 had no DR, 17 had mild nonproliferative DR (NPDR), 8 had moderate NPDR, 10 had severe NPDR and 22 had proliferative DR. Age and DR severity had a significant positive association with FD % for each region studied with a greater effect in the two centermost regions. The increase in flow deficit percentage per year of age by region was: inner 0.12 (p < 0.001), middle 0.09 (p < 0.001), outer 0.05 (p < 0.001, full-field 0.06 (p < 0.001). The increase in flow deficit percentage per increase in diabetic retinopathy severity stage by region was: inner 0.65 (p < 0.0087), middle 0.56 (p < 0.0012), outer 0.33 (p < 0.045), full-field 0.36 (p < 0.018).

Conclusions

Topographic analysis of the CC FD % in diabetic eyes suggests that CC flow impairment corresponds to DR severity, with all studied regions of the CC significantly affected. There was greater regional impairment due to age and disease severity in the inner and middle regions.

Evaluation of choroidal thickness, macular thickness, and aqueous flare after cataract surgery in patients with and without diabetes: a prospective randomized study

BACKGROUND

In diabetic eyes, various choroidal abnormalities are noted in addition to changes in the retinal circulation, and the risk of increased aqueous flare and retinal thickening after cataract surgery is higher in diabetic eyes. Inflammation caused by surgery induces breakdown of the blood-retinal barrier and affects the retina, although the influence on the choroid is unknown. Several researchers have evaluated the choroidal thickness (CT) after cataract surgery in patients with diabetes; however, the results are inconsistent. The purpose of this study was to evaluate the influence of uneventful small-incision phacoemulsification cataract surgery on the subfoveal choroidal thickness (SCT), the central macular thickness (CMT), and aqueous flare in patients with diabetes.

METHODS

This study included 59 randomly selected eyes (33 eyes of patients with diabetes and 26 eyes of control patients without diabetes) undergoing small-incision cataract surgery. Among the diabetic eyes, 26 were without diabetic retinopathy, and the remaining eyes had non-proliferative diabetic retinopathy. Aqueous flare, CMT, and SCT measurements were performed before and at 1 week, 1 month, and 3 months after surgery.

RESULTS

The postoperative CMT continued to increase significantly until 3 months in both groups. Although the CMT was more in patients with diabetes than in patients without diabetes during the follow-up period, there was no significant difference between the two groups. The aqueous flare value increased until 3 months after surgery in both groups. Although the increase was significant at 3 months after surgery in patients with diabetes, the increase in controls was not significant. The aqueous flare values differed significantly between the two groups before and at 3 months after surgery. There was no significant within-group or between-group difference in pre- and postoperative SCT values.

CONCLUSION

In diabetic eyes with early stage of retinopathy, even small-incision cataract surgery can induce increased aqueous flare and macular thickening until 3 months, although there is no significant change in the choroidal thickness. Further studies are essential to evaluate choroidal changes after the cataract surgery in diabetic eyes.

Change in peripapillary and macular choroidal thickness change in children with type 1 diabetes mellitus without visual impairment or diabetic retinopathy

PURPOSE

To study the characteristics of choroid thickness (CT) of the optic disc and macula in children with type 1 diabetes mellitus (T1DM) without visual impairment and diabetic retinopathy (DR) and analyse associated factors.

METHODS

A square area of 6 × 6 mm around the centre of the optic disc and macula was scanned. The indices analysed mainly included CT at the macular centre (1 mm), and temporal, superior, nasal or inferior aspect of the inner ring (1-3 mm) and outer ring of (3-6 mm) optic disc and macula. Independent risk factors were analysed using multifactor linear regression.

RESULTS

A total of 44 children with T1DM and 48 healthy subjects were enrolled. The diabetic group showed significant increase in the inferior inner ring of parapapillary CT (100.99 ± 30.42 μm versus 89.41 ± 34.00 μm, p = 0.04) and nasal outer ring of parapapillary CT (157.02 ± 47.35 μm versus 131.15 ± 35.17 μm, p = 0.01) as compared to those values in the healthy controls. Spherical equivalent refraction and family history of hypertension are independent factors of both peripappillary choroid thickness (PPCT) and macular choroid thickness (PMCT). Spherical equivalent refraction (p = 0.01) and serum cholesterol (p = 0.03) were independent factors of the inferior inner ring of parapapillary CT, whereas family history of hypertension was an independent factor of the nasal outer ring of parapapillary CT (p = 0.001).

CONCLUSION

In children with diabetes without DR or visual impairment, the CT increase in nasal outer ring of parapapillary (PPNO) and the inferior inner ring of parapapillary (PPII) may be the characteristic pre-DR alteration at the early stage of DM. For children with higher serum cholesterol and family history of hypertension, the change of the nasal outer ring of parapapillary CT and the inferior inner ring of parapapillary CT may be more advanced.