Diabetic choroidopathy

Stratified choroidal vascular structure in treatment-naïve diabetic retinopathy

OBJECTIVE

To analyze the anatomical choroidal vascular layers in topical treatment-naïve diabetic retinopathy (DR) eyes.

DESIGN

A retrospective, clinical case-control study.

METHODS

A total of 328 eyes from 228 patients with treatment-naive DR and 192 eyes matched for axial length from 174 healthy controls were enrolled in the study. Choroidal structure was quantitatively analyzed using enhanced depth imaging optical coherence tomography (EDI-OCT). Each choroidal vascular layer was divided into the choriocapillaris, Sattler's layer, and Haller's layer, and then the choroidal area (CA), luminal area (LA), stromal area (SA), and central choroidal thickness (CCT) were calculated using binarization techniques. The ratio of LA to CA was defined as the L/C ratio.

RESULTS

In the choriocapillaris, CA was significantly lower in the mild/moderate non-proliferative DR (mNPDR) group than in the control group, and SA was significantly higher in all DR groups (each P < 0.01). The L/C ratio was significantly lower in all DR groups than controls (P < 0.01). In Sattler's layer, CA, LA, and SA were significantly higher in the severe NPDR (sNPDR) and PDR groups than in the control group (P < 0.01). In Haller's layer, the L/C ratio was significantly high among the PDR groups (P < 0.05).

CONCLUSIONS

The choroidal parameters of DR patients by the binarization method were associated with the stage of DR, in which the choriocapillaris lumen decreased in all the DR stages. The expansion of CA seen in more advanced DR eyes mainly resulted from changes in the Sattler's and Haller's layers.

Glucose tolerance and insulin resistance/sensitivity associate with retinal layer characteristics: the LIFE-Adult-Study

AIMS/HYPOTHESIS

As the prevalence of insulin resistance and glucose intolerance is increasing throughout the world, diabetes-induced eye diseases are a global health burden. We aim to identify distinct optical bands which are closely related to insulin and glucose metabolism, using non-invasive, high-resolution spectral domain optical coherence tomography (SD-OCT) in a large, population-based dataset.

METHODS

The LIFE-Adult-Study randomly selected 10,000 participants from the population registry of Leipzig, Germany. Cross-sectional, standardised phenotyping included the assessment of various metabolic risk markers and ocular imaging, such as SD-OCT-derived thicknesses of ten optical bands of the retina. Global and Early Treatment Diabetic Retinopathy Study (ETDRS) subfield-specific optical retinal layer thicknesses were investigated in 7384 healthy eyes of 7384 participants from the LIFE-Adult-Study stratified by normal glucose tolerance, prediabetes (impaired fasting glucose and/or impaired glucose tolerance and/or HbA1c 5.7-6.4% [39-47 mmol/mol]) and diabetes. The association of optical retinal band characteristics with different indices of glucose tolerance (e.g. fasting glucose, area under the glucose curve), insulin resistance (e.g. HOMA2-IR, triglyceride glucose index), or insulin sensitivity (e.g. estimated glucose disposal rate [eGDR], Stumvoll metabolic clearance rate) was determined using multivariable linear regression analyses for the individual markers adjusted for age, sex and refraction. Various sensitivity analyses were performed to validate the observed findings.

RESULTS

In the study cohort, nine out of ten optical bands of the retina showed significant sex- and glucose tolerance-dependent differences in band thicknesses. Multivariable linear regression analyses revealed a significant, independent, and inverse association between markers of glucose intolerance and insulin resistance (e.g. HOMA2-IR) with the thickness of the optical bands representing the anatomical retinal outer nuclear layer (ONL, standardised β=-0.096; p<0.001 for HOMA2-IR) and myoid zone (MZ; β=-0.096; p<0.001 for HOMA2-IR) of the photoreceptors. Conversely, markers of insulin sensitivity (e.g. eGDR) positively and independently associated with ONL (β=0.090; p<0.001 for eGDR) and MZ (β=0.133; p<0.001 for eGDR) band thicknesses. These global associations were confirmed in ETDRS subfield-specific analyses. Sensitivity analyses further validated our findings when physical activity, neuroanatomical cell/tissue types and ETDRS subfield categories were investigated after stratifying the cohort by glucose homeostasis.

CONCLUSIONS/INTERPRETATION

An impaired glucose homeostasis associates with a thinning of the optical bands of retinal ONL and photoreceptor MZ. Changes in ONL and MZ thicknesses might predict early metabolic retinal alterations in diabetes.

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.

Analysis of the Choroidal Structure in the Early Stage of Type 2 Diabetic Retinopathy

BACKGROUND AND OBJECTIVE

Our aim was to evaluate the choroidal structure in the early stage of Type 2 diabetic retinopathy (DR).

MATERIALS AND METHODS

The study included patients with nonproliferative diabetic retinopathy (NPDR) without edema (n = 30, NPDR group), patients with diabetes without retinopathy (n = 30, No DR group), and healthy subjects (n = 33, control group). Choroidal thickness (CT), total choroidal area (TCA), luminal area (LA), stromal area (SA), and choroidal vascularity index (CVI) were evaluated.

RESULTS

The hypertension (HT) rate was highest in patients with NPDR (63.3%), and lowest in the control group (27.3%). Subfoveal, nasal, temporal CT, TCA, and LA were thinner in patients with diabetes compared to the control group for both patients with and without HT, although not significantly. CTs, TCA, LA, and SA were lower in hypertensive patients than patients without HT in all groups. CVI and LA/SA were significantly lower in NPDR group compared to the controls for both patients with and without HT.

CONCLUSION

In patients with diabetes and before clinical retinopathy develops, the thinning of the CT and CVI begins. A decrease in CVI continues as the retinopathy progresses. HT appears to be a factor that can reduce CT, TCA, LA, and SA. [Ophthalmic Surg Lasers Imaging Retina 2024;55:xx-xx.].

Outer Retinal and Choroidal Changes in Adolescents with Long-Lasting Type 1 Diabetes

This study aimed to assess outer retinal layer (ORL), retinal pigment epithelium (RPE), choroid (Ch) and choriocapillaris (CC) modifications in adolescents with long-lasting (>10 years) type 1 diabetes (T1D) without (noDR) or with diabetic retinopathy (DR). ORL and RPE thickness were measured at optical coherence tomography (OCT) macular scans. Vascular parameters of Ch and CC were quantified after elaboration of macular OCT-angiography (OCTA) images. Insulin dose and auxological and metabolic parameters were correlated with OCT and OCTA findings in patients. ORL thickness was higher in DR eyes than in noDR and healthy controls (HC), and RPE thickness was higher in noDR and DR eyes than in HC, with statistical significance for some sectors in noDR versus HC. No OCTA parameters of CC and Ch differed among groups, and no significant correlation was observed with auxological and metabolic parameters. In conclusion, ORL and RPE were both increased in adolescents with long-lasting T1D. Such changes were not associated with insulin dose and glycemia control, nor to any choroid or choriocapillaris flow change clinically detectable at OCTA, and they could be potential imaging biomarkers of disease progression.

Effects of donor-specific microvascular anatomy on hemodynamic perfusion in human choriocapillaris

Evidence from histopathology and clinical imaging suggest that choroidal anatomy and hemodynamic perfusion are among the earliest changes in retinal diseases such as age-related macular degeneration (AMD). However, how inner choroidal anatomy affects hemodynamic perfusion is not well understood. Therefore, we sought to understand the influences of choroidal microvascular architecture on the spatial distribution of hemodynamic parameters in choriocapillaris from human donor eyes using image-based computational hemodynamic (ICH) simulations. We subjected image-based inner choroid reconstructions from eight human donor eyes to ICH simulation using a kinetic-based volumetric lattice Boltzmann method to compute hemodynamic distributions of velocity, pressure, and endothelial shear stress. Here, we demonstrate that anatomic parameters, including arteriolar and venular arrangements and intercapillary pillar density and distribution exert profound influences on inner choroidal hemodynamic characteristics. Reductions in capillary, arteriolar, and venular density not only reduce the overall blood velocity within choriocapillaris, but also substantially increase its spatial heterogeneity. These first-ever findings improve understanding of how choroidal anatomy affects hemodynamics and may contribute to pathogenesis of retinal diseases such as AMD.

The Haemodialysis Session Effect on the Choroidal Thickness and Retinal and Choroidal Microcirculation-A Literature Review

Haemodialysis (HD) is currently the most commonly used method of renal replacement therapy. The process of dialysis involves numerous changes that affect many systems, including the eye. The changes occurring in the course of HD may affect the ocular parameters, such as intraocular pressure, central corneal thickness, retinal thickness, retinal nerve fibre layer thickness, and choroidal thickness (CT). The choroid, being one of the most vascularized tissues, is characterized by the highest ratio of blood flow to tissue volume in the entire body, may be particularly susceptible to changes occurring during HD, and at the same time reflect the microcirculatory status and its response to HD. Patients with end-stage renal disease subjected to dialysis are highly susceptible to systemic microvascular dysfunction. Moreover, it is considered that the process of HD itself contributes to vascular dysfunction. Nowadays, thanks to the development of imaging techniques, the widely available optical coherence tomography (OCT) tests allow for the assessment of CT, while OCT-angiography allows for a quick, non-invasive, and repeatable assessment of the condition of retinal and choroidal microcirculation, which significantly expands our knowledge regarding the reaction of ocular microcirculation due to HD. The assessment of both retinal and choroidal circulation is even more attractive because retinal circulation is autoregulated, while choroidal circulation is mainly controlled by extrinsic autonomic innervation. Thus, assessment of the choroidal response to an HD session may provide the possibility to indirectly evaluate the functions of the autonomic system in patients subjected to HD. At a time when the importance of microcirculation in systemic and renal diseases is becoming increasingly evident, the assessment of ocular microcirculation appears to be a potential biomarker for assessing the condition of systemic microcirculation. In this work, we present a review of the literature on the effect of the HD session on CT and the retinal and choroidal microcirculation.

Evaluation of the effect of sodium-glucose cotransporter-2 inhibitor treatment on choroidal vascular parameters in patients with type 2 diabetes mellitus

BACKGROUND

To evaluate the effect of sodium-glucose cotransporter-2 inhibitor treatment on choroidal vascular parameters in patients with type 2 diabetes mellitus (T2DM).

METHODS

Twenty eyes of 20 patients with T2DM without diabetic retinopathy and 20 eyes of 20 age- and sex-matched patients as the control group were included in the study. The patients were evaluated using enhanced depth imaging optic coherence tomography before treatment and at the third month of treatment. The choroidal images were binarized into luminal areas (LAs) and stromal areas (SAs). The choroidal vascularity index (CVI) was defined as the ratio of the LA to the total circumscribed choroid area (TCA).

RESULTS

The mean age of the patients was 56.65±8.41 years. The patients' mean disease duration was 6.65±5.72 years, the mean HbA1c level was 8.89±1.62%, and the mean body mass index was 33.13±4.84 kg/m2. The subfoveal TCA, subfoveal LA, subfoveal SA, total TCA, total LA, and total SA values ​​of the patient group were found to be significantly lower than those of the control group (p = 0.006, p = 0.003, p = 0.028, p = 0.001, p = 0.001, and p = 0.006, respectively). There was a significant increase in the subfoveal TCA, subfoveal LA, subfoveal SA, subfoveal CVI, total TCA, total LA, and total SA values ​​after empagliflozin treatment compared to before empagliflozin treatment (p = 0.005, p = 0.003, p = 0.021, p = 0.032, p < 0.001, p < 0.001, and p = 0.001 respectively).

CONCLUSIONS

Empagliflozin provides an improvement in diabetic choroidal changes through its effect on choroidal vascularity parameters.

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.

LONGITUDINAL MICROVASCULAR AND NEURONAL RETINAL EVALUATION IN PATIENTS WITH DIABETES MELLITUS TYPES 1 AND 2 AND GOOD GLYCEMIC CONTROL

PURPOSE

To evaluate microvascular and neuronal changes over 3 years in patients with Type 1/2 diabetes mellitus (DM1/DM2), good metabolic control, and no signs of diabetic retinopathy.

METHODS

In this prospective, longitudinal study, 20 DM1, 48 DM2, and 24 controls underwent macular optical coherence tomography and optical coherence tomography angiography at baseline and after 3 years. Following parameters were considered: thickness of the central macula, retinal nerve fiber layer, ganglion cell (GCL+/GCL++) complex; perfusion and vessel density and fractal dimension at the superficial and deep capillary plexuses; choriocapillaris flow deficits; and foveal avascular zone metrics. MATLAB and ImageJ were used for optical coherence tomography angiography scans analyses.

RESULTS

The mean HbA1c was 7.4 ± 0.8% in DM1 and 7.2 ± 0.8% in DM2 at baseline, with no change at 3 years. No eye developed diabetic retinopathy. In longitudinal analyses, perfusion density at superficial capillary plexuses ( P = 0.03) and foveal avascular zone area and perimeter ( P < 0.0001) significantly increased in DM2 compared with other groups. No longitudinal changes occurred in optical coherence tomography parameters. In comparisons within groups, DM2 had a significant thinning of GCL++ in the outer ring, decreased perfusion density at deep capillary plexuses and choriocapillaris flow deficits, and increase in foveal avascular zone perimeter and area in deep capillary plexuses; DM1 had an increase in foveal avascular zone perimeter in deep capillary plexuses ( P < 0.001 for all comparisons).

CONCLUSION

Longitudinal data showed significant microvascular retinal changes in DM2. No changes were detected in neuronal parameters and in DM1. Longer and larger studies are needed to confirm these preliminary data.

Generation of a 3D Outer Blood-Retinal Barrier with Advanced Choriocapillaris and Its Application in Diabetic Retinopathy in a Microphysiological System

The outer blood-retinal barrier (oBRB) provides an optimal environment for the function of the photoreceptor by regulating the exchange of molecules between subretinal space and the choriocapillaris, and its dysfunction could impair the photoreceptor's function and vision. The existing in vitro models have limitations in reproducing the barrier function or physiological characteristics of oBRB and choriocapillaris. Here, we engineered a microphysiological system-based oBRB-choriocapillaris model that simultaneously incorporates the desired physiological characteristics and is simple to fabricate. First, we generated microvascular networks to mimic choriocapillaris and investigated the role of fibroblasts in vasculogenesis. By adding retinal pigment epithelial cells to one side of blood vessels formed with endothelial cells and fibroblasts and optimizing their culture medium conditions, we established an oBRB-choriocapillaris model. To verify the physiological similarity of our oBRB-choriocapillaris model, we identified the polarization and expression of the tight junction of the retinal pigment epithelium, Bruch's membrane, and the fenestral diaphragm of choriocapillaris. Finally, we tried to recapitulate the diabetes mellitus environment in our model with hyperglycemia and diabetes-related cytokines. This induced a decrease in tight junction integrity, loss of barrier function, and shrinkage of blood vessels, similar to the in vivo pathological changes observed in the oBRB and choriocapillaris. The oBRB-choriocapillaris model developed using a microphysiological system is expected to offer a valuable in vitro platform for retinal and choroidal vascular diseases in preclinical applications.

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.

Analysis of retinal and choroidal characteristics in patients with early diabetic retinopathy using WSS-OCTA

Introduction

Diabetic retinopathy (DR) is one of the most common and destructive microvascular complications of DM, and has become a major cause of irreversible visual impairment. The purpose of this study was to evaluate the changes in fundus microcirculation in non-diabetic retinopathy (NDR) and mild non-proliferative diabetic retinopathy (NPDR) in patients with type 2 diabetic mellitus (T2DM) using widefield swept-source optical coherence tomography angiography (WSSOCTA), and to investigate the correlation with laboratory indices of T2DM.

Methods

Eighty nine, 58 and 28 eyes were included in the NDR, NPDR and Control groups, respectively, were enrolled in this study. The 12mm×12mm fundus images obtained by WSS-OCTA were divided into 9 regions (supratemporal, ST; temporal, T; inferotemporal, IT; superior, S; central macular area, C; inferior, I; supranasal, SN; nasal, N; inferonasal, IN) to evaluate changes in vessel density (VD) of the superficial capillary plexus (SCP), deep capillary plexus (DCP), choriocapillaris, and mid-large choroidal vessel (MLCV), as well as changes in inner retinal thickness (IRT), outer retinal thickness (ORT), and choroidal thickness (CT). Results: Compared with control group, MLCV VD (I, N, IN) was significantly decreased in NDR group, SCP VD (IT, C, I) and DCP VD (T, IT, I) were significantly decreased in NPDR group. In NPDR group, DCP VD (IT) was significantly decreased compared with that in NDR group. Compared with control group, CT (ST, T, IT, S, SN, IN) was significantly declined in NDR group, and IRT (ST, IT) and ORT (ST, N) were significantly increased in NPDR group. In NPDR group, IRT (ST) and ORT (T, S) were significantly increased compared with NDR group. Correlation analysis showed that age, body mass index, fasting blood glucose, fasting insulin, fasting C-peptide, and estimated glomerular filtration rate in T2DM patients were statistically correlated with retinal and choroidal thickness/VD.

Discussion

Structural and blood flow changes in the choroid occur before the onset of DR and precede changes in the retinal microcirculation, and MLCV thickness/VD is a more sensitive imaging biomarker for the clinical detection of DR. WSS-OCTA enables large-scale non-invasive visual screening and follow-up of the retinal and choroidal vasculature in DR patients, providing a new strategy for the prevention and monitoring of DR in patients with T2DM.

Pathological Neurovascular Unit Mapping onto Multimodal Imaging in Diabetic Macular Edema

Diabetic retinopathy is a form of diabetic microangiopathy, and vascular hyperpermeability in the macula leads to retinal thickening and concomitant reduction of visual acuity in diabetic macular edema (DME). In this review, we discuss multimodal fundus imaging, comparing the pathogenesis and interventions. Clinicians diagnose DME using two major criteria, clinically significant macular edema by fundus examination and center-involving diabetic macular edema using optical coherence tomography (OCT), to determine the appropriate treatment. In addition to fundus photography, fluorescein angiography (FA) is a classical modality to evaluate morphological and functional changes in retinal capillaries, e.g., microaneurysms, capillary nonperfusion, and fluorescein leakage. Recently, optical coherence tomography angiography (OCTA) has allowed us to evaluate the three-dimensional structure of the retinal vasculature and newly demonstrated that lamellar capillary nonperfusion in the deep layer is associated with retinal edema. The clinical application of OCT has accelerated our understanding of various neuronal damages in DME. Retinal thickness measured by OCT enables us to quantitatively assess therapeutic effects. Sectional OCT images depict the deformation of neural tissues, e.g., cystoid macular edema, serous retinal detachment, and sponge-like retinal swelling. The disorganization of retinal inner layers (DRIL) and foveal photoreceptor damage, biomarkers of neurodegeneration, are associated with visual impairment. Fundus autofluorescence derives from the retinal pigment epithelium (RPE) and its qualitative and quantitative changes suggest that the RPE damage contributes to the neuronal changes in DME. These clinical findings on multimodal imaging help to elucidate the pathology in the neurovascular units and lead to the next generation of clinical and translational research in DME.

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.

Qualitative and quantitative evaluation of diabetic choroidopathy using ultra-widefield indocyanine green angiography

To investigate angiographic characteristic features of diabetic choroidopathy, as well as choroidal vascular density (CVD) and fractal dimension (CFD) in diabetic eyes and controls using ultra-widefield (UWF) indocyanine green angiography (ICGA). All patients underwent UWF fluorescein angiography and ICGA. Using imageJ software, CVD and CFD was analyzed. SFCT was assessed using spectral-domain optical coherence tomography. The image parameters were compared based on the DR stage and the presence of diabetic macular edema (DME). One-hundred six eyes from 63 patients (59.11 ± 16.31 years; male [%]: 23 [36.5%]) were included in the DM group, and 40 eyes from 22 subjects were included in the control group. The DM group had a mean age of 59.11 ± 16.31 years and a mean HbA1c percentage of 7.72 ± 1.28%. The most common ICGA findings of DC were choroidal hyperpermeability (57.5%), hypofluorescent spots (48.1%). Salt and pepper pattern (19.8%), inverted inflow phenomenon (3.8%), choroidal arterial tortuosity (24.5%), and late choroidal non-perfusion (6.6%) were more common in advanced DR. The CVD, CFD, and SFCT increased as the DR severity progressed. The DME group had a significantly higher CFD and SFCT than the non-DME group (P < 0.001 and P = 0.019, respectively). The qualitative and quantitative UWF ICGA image analysis revealed that choroidal blood vessels became dilated, complex, and hyperpermeable as the DR progressed. These features of diabetic choroidopathy (DC) were more severe in eyes with DME than the non-DME eyes.

Rates of Choroidal and Neurodegenerative Changes Over Time in Diabetic Patients Without Retinopathy: A 3-Year Prospective Study

PURPOSE

To evaluate the longitudinal changes of retinal neurodegeneration and choroidal thickness in diabetic patients with and without diabetic retinopathy (DR).

DESIGN

Prospective observational cohort study.

METHODS

This prospective observational cohort study recruited type 2 diabetic patients from a community registry in Guangzhou. All participants underwent annual ocular examinations via swept-source optical coherence tomography that obtained choroid thickness (CT), retinal thickness (RT), and ganglion cell-inner plexiform layer (GC-IPL) thickness. The changes in GC-IPL, CT, and RT between patients who developed incident DR (IDR) or remained non-DR (NDR) were compared during a 3-year follow-up.

RESULTS

Among 924 patients, 159 (17.2%) patients developed IDR within the 3-year follow-up. A reduction in GC-IPL, RT, and CT was observed in NDR and IDR; however, CT thinning in patients with IDR was significantly accelerated, with an average CT reduction of -6.98 (95% CI: -8.26, -5.71) μm/y in patients with IDR and -3.98 (95% CI: -4.60, -3.36) μm/y in NDR patients (P < .001). Reductions in average GC-IPL thickness over 3 years were -0.97 (95% CI: -1.24, -0.70) μm/y in patients with IDR and -0.76 (95% CI: -0.82, -0.70) μm/y in NDR patients (P = .025). After adjusting for confounding factors, the average CT and GC-IPL thinning were significantly faster in patients with IDR compared with those who remained NDR by 2.09 μm/y (95% CI: 1.01, 3.16; P = .004) and -0.29 μm/y (95% CI: -0.49, -0.09; P = .004), respectively. The RT in the IDR group increased, whereas the RT in the NDR group decreased over time, with the adjusted difference of 2.09 μm/y (95% CI: 1.01, 3.16; P < .001) for central field RT.

CONCLUSIONS

The rate of retinal neurodegeneration and CT thinning were significantly different between the eyes that developed IDR and remained NDR during the 3-year follow-up, but both groups observed thickness reduction. This indicates that GC-IPL and CTs may decrease before the clinical manifestations of DR.

Hertel Exophthalmometry Values in a Greek Adult Outpatient Clinic-Based Population: Association With Demographic Factors and Systemic Disease

PURPOSE

To investigate correlations of exophthalmometry values (EVs) with age, gender, and the presence of diabetes mellitus, arterial hypertension, and dyslipidemia.

METHODS

In a cross-sectional, clinic-based study, consecutive adult Greek patients presenting for evaluation at the outpatient general clinic on a scheduled appointment basis at a tertiary care referral center were submitted to Hertel exophthalmometry in both eyes by the same observer. Subjects with signs of history or orbital pathology, including thyroid-associated ophthalmopathy, were excluded. Demographics, as well as a detailed systemic history report, were recorded. Mixed effect linear regression analysis was performed to account for the correlation between the eyes of the same participant.

RESULTS

A total of 800 eyes (400 subjects) were included, 194 males and 206 females, with a mean age of 67.82 ± 12 years (range: 18-92 years). The mean exophthalmometry value was 15.7 ± 2.6 mm (range: 11-21 mm). Every one year of increase in age is associated with a decrease in EVs by 0.03 mm (95% CI -0.04, -0.02/p-value<0.001). Female gender was associated with lower EVs by 0.33mm (95% CI-0.56, -0.1/p-value=0.005). Patients with diabetes mellitus had higher EVs by 0.47 mm (95% CI 0.25, 0.70/p-value<0.001) compared to patients without diabetes, and patients with arterial hypertension had lower EVs by 0.26 mm (95% CI -0.5, -0.02/p-value=0.034) compared to patients without hypertension. No association was found between dyslipidemia and systemic history of thyroid dysfunction.  Conclusions: A negative correlation of EVs was noted with increasing age, female gender, as well as history of arterial hypertension and a positive correlation with diabetes mellitus.

Comparison of Chorioretinal Parameters in Diabetic Retinopathy with or without Pan-Retinal Photocoagulation Using Ultrawide-Field Swept-Source Optical Coherence Tomography Angiography

INTRODUCTION

To compare structural and vascular parameters in the central and peripheral retina and choroid of eyes diagnosed with severe nonproliferative diabetic retinopathy (NPDR) or proliferative diabetic retinopathy (PDR) with or without pan-retinal photocoagulation (PRP) using ultrawide-field swept-source optical coherence tomography angiography (SS-OCTA).

METHODS

All participants underwent SS-OCTA imaging centered on the fovea. Retinal and choroidal thickness, vessel density of the superficial capillary plexus (SCP), deep capillary plexus (DCP), choroidal capillary plexus (CCP), and choroidal Sattler's and Haller's layer (CSHL) were analyzed in nine grids using built-in angiography analysis software.

RESULTS

A total of 82 eyes from 82 participants were enrolled in this study, including 40 eyes diagnosed with severe NPDR or PDR without PRP and 42 eyes with PRP. Retinal thickness in part grids was higher in eyes with PRP than in eyes without PRP. Vessel density of the SCP in nasal-superior (p = 0.003) grid was lower in eyes with PRP than in eyes without PRP. No significant difference was found in the vessel density of the DCP between the two groups (all p > 0.05). The choroidal thickness and vessel density of the CSHL of all grids were significantly lower in eyes with PRP than in eyes without PRP (all p < 0.05). A statistically significant decrease in vessel density in CCP was found in the superior (p = 0.043), nasal-superior grid (p = 0.003), macular grid (p < 0.001), and optic disc grid (p = 0.001) of eyes with PRP, compared to eyes without PRP. A significant decrease in the vessel density of CSHL was observed in all grids of PDR eyes with PRP compared to PDR eyes without PRP (all p < 0.05). Significant decrease in choroidal thickness was observed in most grids of PDR eyes with PRP, except for macular grid (p = 0.090) and optic disc grid (p = 0.057).

CONCLUSION

Structural and vascular parameters in the central and peripheral retinal and choroidal layers in eyes diagnosed with severe NPDR or PDR with or without PRP could be quantified using a ultrawide-field SS-OCTA. Eyes with PRP showed a significant decrease in choroidal thickness and vessel density of CCP and CSHL, compared with eyes without PRP. This trend was more obvious in eyes with PDR.

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.

Mechanisms of macular edema

Macular edema is the pathological accumulation of fluid in the central retina. It is a complication of many retinal diseases, including diabetic retinopathy, retinal vascular occlusions and uveitis, among others. Macular edema causes decreased visual acuity and, when chronic or refractory, can cause severe and permanent visual impairment and blindness. In most instances, it develops due to dysregulation of the blood-retinal barrier which permits infiltration of the retinal tissue by proteins and other solutes that are normally retained in the blood. The increase in osmotic pressure in the tissue drives fluid accumulation. Current treatments include vascular endothelial growth factor blockers, corticosteroids, and non-steroidal anti-inflammatory drugs. These treatments target vasoactive and inflammatory mediators that cause disruption to the blood-retinal barrier. In this review, a clinical overview of macular edema is provided, mechanisms of disease are discussed, highlighting processes targeted by current treatments, and areas of opportunity for future research are identified.

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.

[Choroidal changes in patients with diabetes mellitus]

Diabetic retinopathy (DR) is a microvascular complication of diabetes mellitus (DM) and considered one of the leading causes of vision loss worldwide. The choroid supplies blood to the retina, photoreceptors and the retinal pigment epithelium, it is essential for metabolic exchange in the retina. Many experimental studies have reported that choroidal pathology in diabetic patients may play a role in the development of DR. Choroidal thickness (CT) can be used to assess the vascularization of the choroid. Choroidal vascularity index (CVI) is also used as a marker in assessment of choroidal vascularization. Many studies have been conducted to evaluate choroidal changes in various eye diseases. However, the data on CT in DM patients, especially in those with DR, are conflicting. Thus, the choroidal status in diabetic patients with or without DR remains controversial. In this systematic review we analyze a number of articles dedicated to the relationship between structural changes in the choroid in patients with diabetes mellitus and diabetic retinopathy of different stages, paying particular attention to choroidal thickness and certain other parameters that allow assessment of choroidal changes.

Choroidal vascularity profile in diabetic eyes using wide field optical coherence tomography

PURPOSE

To report the wide-field choroidal vascularity up to the mid-equator area in diabetic retinopathy (DR) subjects using wide-field optical coherence tomography (WF-OCT).

DESIGN

Prospective, Cross-sectional study.

PARTICIPANTS

Forty-seven eyes of 25 DR subjects.

METHODS

WF-OCT images (55 degrees) were obtained using Spectralis HRA + OCT (Heidelberg Engineering, Germany) in extremes of gazes in all quadrants and manual montages were created to obtain wide field images up to mid equator. A previously reported semi-automated algorithm was used to calculate choroidal vascularity profile (CVI). Regression analysis was performed to identify the factors influencing CVI.

RESULTS

Forty-seven eyes from 25 patients were enrolled in the study. The mean age was 68.4 ± 10.6 years. The refractive error (spherical equivalent) ranged from -2.25 to +3.75 diopters. Most common DR grade among study subjects was moderate NPDR (29.41%) and 74.5% eyes had diabetic macular edema (DME). The mean CVI in the macular area (58.29 ± 3.63) was significantly lower than in any of the other fundus areas (all p ˂ 0.01). The maximum CVI was seen in the nasal region (66.60 ± 5.61), followed by temporal (65.69 ± 3.81), superior (65.01 ± 4.87), and inferior (63.80 ± 5.42). The vertical macular area had the least coefficient of variation (CV) of CVI (0.06) while the inferior quadrant had the highest CV (0.08).

CONCLUSION

The current study describes the CVI profile on WF-OCT in DR eyes up to mid-equator. The significant increase of the CVI compared to healthy subjects and its significant regional variations introduce this novel quantitative parameter as a reliable biomarker of the diabetes-induced choroidal microangiopathy.

Optical coherence tomography evaluation of choroidal structure changes in diabetic retinopathy patients: A systematic review and meta-analysis

Introduction

Diabetic retinopathy (DR) is one of the major causes of blindness among working-aged adults worldwide. This study aimed to evaluate the differences in the subfoveal choroidal thickness (SFCT) and choroidal vascularity index (CVI) using optical coherence tomography (OCT) of patients with diabetic eyes with no retinopathy (NDR) and with diabetic retinopathy (DR).

Methods

We performed a comprehensive literature search of the PubMed, Embase, and Cochrane Library databases up to October 2021. The weighted mean difference (WMD) with the 95% confidence interval (CI) was pooled for continuous outcomes.

Results

Twenty-three cross-sectional studies comprising 2,534 eyes including 1,070 NDR eyes, 1,464 DR eyes were included in the systematic review and meta-analysis. The pooled results showed SFCT was significantly thicker in DR than in NDR patients after adjusting for axial length (WMD = 27.90 μm; 95% CI: 11.51 to 44.28; P = 0.001), and the CVI was significantly lower in DR patients (WMD = −1.59; 95% CI: −2.67 to −0.52; P = 0.004).

Conclusion

We described changes in the SFCT and CVI in DR. Resultantly, the CVI and SFCT may be valuable parameters for monitoring the onset of DR and helpful for a better understanding of the role of the choroid in the pathological process of DR.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#myprospero, CRD42021228738.

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.

Light color efficiency-balanced trans-palpebral illumination for widefield fundus photography of the retina and choroid

A wide-field fundus camera, which can selectively evaluate the retina and choroid, is desirable for better detection and treatment evaluation of eye diseases. Trans-palpebral illumination has been demonstrated for wide-field fundus photography, but its application for true-color retinal imaging is challenging due to the light efficiency delivered through the eyelid and sclera is highly wavelength dependent. This study is to test the feasibility of true-color retinal imaging using efficiency-balanced visible light illumination, and to validate multiple spectral imaging (MSI) of the retina and choroid. 530 nm, 625 nm, 780 nm and 970 nm light emission diodes (LED)s are used to quantitatively evaluate the spectral efficiency of the trans-palpebral illumination. In comparison with 530 nm illumination, the 625 nm, 780 nm and 970 nm light efficiencies are 30.25, 523.05, and 1238.35 times higher. The light efficiency-balanced 530 nm and 625 nm illumination control can be used to produce true-color retinal image with contrast enhancement. The 780 nm light image enhances the visibility of choroidal vasculature, and the 970 nm image is predominated by large veins in the choroid. Without the need of pharmacological pupillary dilation, a 140° eye-angle field of view (FOV) is demonstrated in a snapshot fundus image. In coordination with a fixation target, the FOV can be readily expanded over the equator of the eye to visualize vortex ampullas.

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.

Correlation between Choroidal Vascularity Index and Outer Retina in Patients with Diabetic Retinopathy

The choroid supplies blood to the outer retina. We quantified outer retinal and choroidal parameters to understand better the pathogenesis of diabetic retinopathy (DR) and diabetic macular edema (DME). The retrospective cross-sectional single-center study included 210 eyes from 139 diabetic patients and 76 eyes from 52 healthy controls. Spectral-domain optical coherence tomography (OCT) was carried out with a Spectralis HRA + OCT imaging device. The outer retinal layer (ORL), outer nuclear layer (ONL), and choroidal thicknesses were assessed along with the choroidal vascularity index (CVI). The presence of DR, whether with DME or without, was associated with choroidal thinning (p < 0.001). Compared with the controls, patients with DR without DME presented with lower ORL and ONL thickness (p < 0.001), whereas those with DR and DME had higher values of both parameters (p < 0.001). Significant correlations between outer retinal and choroidal parameters were found only in patients with DR without DME (ORL with choroidal thickness: p = 0.003, rho = 0.34; ORL with CVI: p < 0.001, rho = 0.49, ONL with CVI: p < 0.027, rho = 0.25). No correlations between choroidal and outer retinal parameters were observed in the controls and patients with DR and concomitant DME. Aside from diabetic choroidopathy, other pathogenic mechanisms seem to predominate in the latter group.

Alterations in the Choroidal Sublayers in Relationship to Severity and Progression of Diabetic Retinopathy

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 [HbA_1c] 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, HbA_1c 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 HbA_1c; 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.

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.

LONGITUDINAL ANALYSIS OF DIABETIC CHOROIDOPATHY IN PROLIFERATIVE DIABETIC RETINOPATHY TREATED WITH PANRETINAL PHOTOCOAGULATION USING WIDEFIELD SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY

PURPOSE

Widefield swept-source optical coherence tomography (OCT) imaging was used to characterize choroidal thickness and vascularity at baseline in proliferative diabetic retinopathy (PDR) and longitudinally after panretinal photocoagulation (PRP).

METHODS

Patients with treatment-naive PDR were imaged at baseline and at 1 week, 1 month, and 3 months after PRP. Previously validated algorithms were used to calculate the mean choroidal thickness (MCT) and choroidal vascularity index (CVI) in 5 regions of 12 mm × 12 mm scans.

RESULTS

Fourteen PDR eyes were included. Baseline MCT in PDR eyes did not differ significantly from normal eyes, but CVI measurements in PDR eyes were lower in all regions (P < 0.001-0.008). After PRP, MCT measurements in PDR eyes were significantly lower at 1 month and 3 months in all regions (P < 0.001-0.005) except the fovea (P = 0.074). However, CVI measurements did not change over time in any region after PRP.

CONCLUSION

The choroid in PDR eyes has a smaller CVI than that in normal eyes. After PRP, the choroidal thickness decreases outside the fovea, but the CVI remains constant, which suggests that a relative decrease in choroidal vascularity persists. These widefield swept-source OCT results are consistent with choroidal alterations found in histopathological reports of diabetic choroidopathy.

Choriocapillaris perfusion assessed using swept source optical coherence tomographic angiography and the severity of diabetic retinopathy

AIMS

To investigate the relationship between choriocapillaris (CC) blood perfusion and the severity of diabetic retinopathy (DR) using swept-source optical coherence tomography angiography (SS-OCTA).

METHODS

Type 2 diabetes mellitus in the Guangzhou was recruited. DR was graded according to the standardised seven-field colour retinal images adhering to the ETDRS scale. CC perfusion was quantified by evaluating the flow deficit (FD) density, FD number and FD size using SS-OCTA. Multivariable linear regressions were used to evaluate the correlation between CC FD metrics and DR severity.

RESULTS

A total of 1692 patients (eyes) were included in the final analysis. Participants with DR had a significantly higher FD density than the NDR group, with the differences of 1.61% (95% CI 1.04 to 2.18; p<0.001) among mild non-proliferative DR (NPDR) patients, 2.23% (95% CI 1.76 to 2.70; p<0.001) among moderate NPDR patients and 3.31% (95% CI 2.27 to 4.36; p<0.001) among severe DR than NDR patients after adjusting for confounding factors. Similarly, the higher FD number and size were also correlated with severer degree of DR (all p<0.05). Furthermore, the addition of FD density to conventional risk factors significantly improved the performance for discriminating DR from NDR patients (AUC 0. 829, 95% CI 0. 804 to 0. 855; p<0.001).

CONCLUSION

Quantitative FD density, number and size assessed by using SS-OCTA were independently correlated with the severity of DR. The assessment of the CC perfusion metrics in the macula may be a sensitive biomarker of DR changes.

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.

The role of inflammation and neurodegeneration in diabetic macular edema

The pathogenesis of diabetic macular edema (DME) is complex. Persistently high blood glucose activates multiple cellular pathways and induces inflammation, oxidation stress, and vascular dysfunction. Retinal ganglion cells, macroglial and microglial cells, endothelial cells, pericytes, and retinal pigment epithelium cells are involved. Neurodegeneration, characterized by dysfunction or apoptotic loss of retinal neurons, occurs early and independently from the vascular alterations. Despite the increasing knowledge on the pathways involved in DME, only limited therapeutic strategies are available. Besides antiangiogenic drugs and intravitreal corticosteroids, alternative therapeutic options tackling inflammation, oxidative stress, and neurodegeneration have been considered, but none of them has been currently approved.

Correlation of Renal Profiles with Choroidal Vascularity Index in Eyes with Diabetic Retinopathy

The vascular system is affected by systemic conditions, including diabetes, hypertension, and cardiovascular disease. The choroid is an important vascular tissue surrounding the sensory retina. However, the relationship between the choroid and systemic factors in patients with diabetes has rarely been investigated. Here, we assessed the correlation of renal profiles with choroidal vasculature in eyes with diabetic retinopathy (DR) using a retrospective study design. The study included 131 patients with diabetes who underwent swept-source optical coherence tomography and routine medical work-up within a 4-week period between 1 February 2016 and 30 October 2018. Consecutive patients with treatment-naïve DR who did not receive any subsequent treatment were included. The distribution of patients according to the DR stage was as follows: no DR, 32 patients; mild-to-moderate non-proliferative DR (NPDR), 33 patients; severe NPDR, 34 patients; and treatment-naïve proliferative DR, 32 patients. Multivariate regression analyses showed that the choroidal vascularity index (CVI) of naïve eyes with DR was negatively correlated with age (p = 0.013) and the serum levels of phosphorus (p = 0.002) and positively correlated with subfoveal choroidal thickness (p < 0.001). Taken together, our findings suggest that a lower CVI is associated with phosphorus retention in patients with chronic kidney disease.

Alterations in choroidal vascular parameters following panretinal photocoagulation using enhanced-depth imaging optical coherence tomography in diabetic retinopathy

PURPOSE

To investigate the alteration of choroid in patients with very severe non-proliferative diabetic retinopathy (NPDR) or early proliferative diabetic retinopathy (PDR) following panretinal photocoagulation (PRP).

METHODS

Thirty-nine eyes of 21 patients with very severe non-proliferative diabetic retinopathy (NPDR) (19 eyes) and early proliferative diabetic retinopathy (PDR) (20 eyes) were recruited. Enhanced-depth imaging optical coherence tomography at baseline, 1, and 6 months after PRP was employed to measure choroidal parameters including total choroidal area (TCA) and choroidal vascular index (CVI).

RESULTS

In eyes with very severe NPDR, subfoveal TCA decreased non-significantly at month 1, which increased significantly at month 6 (539 ± 131µm², 502 ± 134µm², and 598 ± 168µm² at baseline and months 1 and 6, respectively; P = 0.003). Subfoveal CVI increased at month 1 and then decreased at month 6 (68.25 ± 3.05, 69.74 ± 3.62, and 67.84 ± 1.77 at baseline and months 1 and 6, respectively; P < 0.001). A reverse pattern occurred in eyes with early PDR, a non-significant increase in TCA at month 1 followed by a decrease at month 6 (497 ± 95µm², 514 ± 133µm², and 425 ± 95µm² at baseline and months 1 and 6, respectively; P = 0.011). CVI decreased at month 1 and remained relatively stable at month 6 (69.34 ± 3.11, 68.33 ± 3.41, and 68.50 ± 5.04 at baseline, and months 1 and 6, respectively; P = 0.023). Alteration of choroidal thickness was not statistically significant in both groups.

CONCLUSION

Eyes with very severe NPDR and early PDR exhibit a reverse pattern regarding choroidal indices after PRP.

Quantitative Assessment of Choroidal Parameters in Patients with Various Types of Diabetic Macular Oedema: A Single-Centre Cross-Sectional Analysis

Simple Summary

Choroidopathy is one of the components in the pathogenesis of diabetic macular oedema (DME). This study investigated the optical coherence tomography-based choroidal parameters: thickness, volume, choroidal vascularity index (CVI), luminal area (LA), stromal area (SA), and total choroidal area (TCA) in relation to the presence and type of DME (cystoid, diffuse, and with subretinal fluid). Diabetic choroidopathy seems to play a role in the development of DME but is less likely involved in the pathogenesis of specific types thereof.

Abstract

Diabetic macular oedema (DME) is an outcome of multiple, complex and not fully understood mechanisms. The aim of this study was to define the role of choroidopathy in the pathogenesis of various DME types. The retrospective cross-sectional single-centre study included 140 eyes from 105 patients with DME and 76 eyes from 52 non-diabetic controls. The eyes were stratified according to the type of DME: cystoid, diffuse, and with subretinal fluid. Optical coherence tomography-based choroidal parameters: thickness, volume, choroidal vascularity index (CVI), luminal area (LA), stromal area (SA), and total choroidal area (TCA) were compared. Eyes with DME, regardless of the type thereof, had lower choroidal thickness, volume, and CVI values than the controls. Further, the eyes with some specific DME types differed significantly from the controls in terms of LA and SA. While the eyes with various DME types did not differ significantly in terms of their choroidal thickness, volume and CVI, some between-group differences were found in LA, SA and TCA. Diabetic choroidopathy seems to play a role in the development of DME but is less likely involved in the pathogenesis of specific types thereof.

Choriocapillaris: Fundamentals and advancements

The choriocapillaris is the innermost structure of the choroid that directly nourishes the retinal pigment epithelium and photoreceptors. This article provides an overview of its hemovasculogenesis development to achieve its final architecture as a lobular vasculature, and also summarizes the current histological and molecular knowledge about choriocapillaris and its dysfunction. After describing the existing state-of-the-art tools to image the choriocapillaris, we report the findings in the choriocapillaris encountered in the most frequent retinochoroidal diseases including vascular diseases, inflammatory diseases, myopia, pachychoroid disease spectrum disorders, and glaucoma. The final section focuses on the development of imaging technology to optimize visualization of the choriocapillaris as well as current treatments of retinochoroidal disorders that specifically target the choriocapillaris. We conclude the article with pertinent unanswered questions and future directions in research for the choriocapillaris.

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.

Photoreceptor cells and RPE contribute to the development of diabetic retinopathy

Diabetic retinopathy (DR) is a leading cause of blindness. It has long been regarded as vascular disease, but work in the past years has shown abnormalities also in the neural retina. Unfortunately, research on the vascular and neural abnormalities have remained largely separate, instead of being integrated into a comprehensive view of DR that includes both the neural and vascular components. Recent evidence suggests that the most predominant neural cell in the retina (photoreceptors) and the adjacent retinal pigment epithelium (RPE) play an important role in the development of vascular lesions characteristic of DR. This review summarizes evidence that the outer retina is altered in diabetes, and that photoreceptors and RPE contribute to retinal vascular alterations in the early stages of the retinopathy. The possible molecular mechanisms by which cells of the outer retina might contribute to retinal vascular damage in diabetes also are discussed. Diabetes-induced alterations in the outer retina represent a novel therapeutic target to inhibit DR.

En-face analysis of short posterior ciliary arteries crossing the sclera to choroid using wide-field swept-source optical coherence tomography

To study the topographic distribution of the short posterior ciliary arteries (SPCA) entry sites into the choroid in normal eyes using structural en-face swept source optical coherence tomography (SS-OCT). Retrospective analysis of SS-OCT scans (wide-field structural SS-OCT 12 × 12 mm) of 13 healthy subjects was performed. Cross-sectional swept-source OCT scans derived from a volume scan were represented as en-face image display following the Choroid-Scleral Interface to obtain en-face OCT. SPCAs in their last scleral location before choroidal entrance were identified manually, counted and localized by two masked observers. Correlations between two masked observers were analyzed using inter- and intra-class correlation. Accuracy for the choroidal inner and outer border segmentation was 95-99%. Eighteen eyes from 13 normal subjects were included for SPCA analysis. The mean number of arteries was 13.8 ± 3.5 per eye. Thirty-six percent were in the center of the posterior pole image; however, 21% were in the temporal part of the posterior pole. Median accuracy of the detection is 0.94. The correlation between the two observers was fair (0.54). Our algorithm allows visualization of the SPCA at the posterior pole of the eye using wide-field en-face SS-OCT. It can also help the clinicians to study the SPCAs in numerous ocular diseases, particularly its relationship with focal choroidal diseases.

Higher choroidal thickness and lower choriocapillaris blood flow signal density based on optical coherence tomography angiography in diabetics

Diabetes mellitus (DM) is one of the fastest growing chronic diseases in the world and one of the main causes of vision loss. Whether or not diabetic choroidopathy (DC) is involved in the initiation and progression of diabetic ocular complications needs to be explored. We included 54 diabetic eyes from 36 diabetic patients, and 54 healthy eyes from 32 control subjects after propensity scores matching. All of the subjects were given pupil light and dark adaptation examination and optical coherence tomography angiography (OCTA). Scotopic pupil diameter (SPD), pupil contraction amplitude, and velocity of pupil contraction of the diabetic group were significantly lower than that of the healthy control group (P < 0.05).Choroidal thickness at temporal quadrant (at 750 μm) and superior quadrant (at 1500 μm and 2250 μm) increased in diabetic group compared to control group(P < 0.05).In the diabetic group, choriocapillaris blood flow signal density (CCBFSD) in the macular area (diameter = 2000 μm) were significantly decreased compared with the healthy control group (P < 0.05). Apparent changes in pupil and choroidal blood flow were observed in the diabetic patients.

Foveal Avascular Zone Does Not Correspond to Choroidal Characteristics in Patients with Diabetic Retinopathy: A Single-Center Cross-Sectional Analysis

PURPOSE

The aim of the study was to compare two non-overlapping blood supply systems of the retina to obtain a better insight into the relation between diabetic macular retinopathy and choroidopathy. Specifically, the study focused on the relationships between (1) retinal vascular changes around the fovea in fluorescein angiography (FA) and (2) choroidal thickness, volume and other parameters assessed by optical coherence tomography (OCT).

PATIENTS AND METHODS

The retrospective cross-sectional single-center study included 210 eyes from 152 patients with diabetic retinopathy (mean age 60.7±12.4 years, 49.3% of women; foveal avascular zone [FAZ] outline: 44.3% grade ≤2, 55.7% grade ≥3). The outline of FAZ, a measure of capillary loss due to ischemic processes, was analyzed on FA according to the Early Treatment Diabetic Retinopathy Study Research Group (ETDRS) standards. The eyes were stratified according to the FAZ outline and size and the presence of clinically significant diabetic macular edema (CSME). Then, resultant groups were compared in terms of the spectral domain OCT parameters: choroidal thickness and volume (within ETDRS subfields), luminal, stromal and total choroidal areas and choroidal vascularity index (based on the foveal scan). Statistical analysis was based on univariate models with the choroidal parameters as independent variables, and age, sex, panretinal photocoagulation, the severity of diabetic retinopathy and CSME as covariates.

RESULTS

No significant relationships were found between the FAZ outline and area and choroidal characteristics of patients with diabetic retinopathy. In patients without CSME, no correlation was observed between the FAZ area and choroidal characteristics. In patients with CSME, no correlation was found between the FAZ area and choroidal characteristics other than the choroidal vascularity index.

CONCLUSION

In patients with diabetic retinopathy, damage to the macular retinal vasculature (FAZ) does not seem to be associated with changes in the choroidal vasculature, and these two processes appear to occur independently.

Choroidal Vascularity Index in Patients with Type-1 Diabetes Mellitus without Diabetic Retinopathy

Purpose: This study aims to assess choroidal vascularity index (CVI) and choroidal thickness (CT) in patients diagnosed with type 1 diabetes mellitus (DM) and compare them with healthy control subjects.Methods: This retrospective and cross-sectional study includes 43 patients diagnosed with type 1 DM and 43 healthy age/gender-matched subjects as the control group. Enhanced depth imaging optical coherence tomography (EDI-OCT; Spectralis, Heidelberg Engineering GmbH, Heidelberg, Germany) images of all participants were analyzed. CT measurements of five different points (subfoveal, 500 µm temporal, 1500 µm temporal, 500 µm nasal, and 1500 µm nasal to the fovea) were obtained. Choroid images were divided into luminal (LA) and stromal areas (SA) determined by image binarization method. Choroidal vascularity index (CVI) was defined as the ratio of LA to total choroid area (TCA). The effects of age, HbA1c, fasting plasma glucose, duration of DM, mean blood pressure, intraocular pressure, and axial length measurements on CVI were investigated.Results: There was no significant difference between any of the CT measurements of the groups (all p > .05). There was no significant difference between the groups according to TCA (0.82 ± 0.24 vs. 0.80 ± 0.19; p = .065), LA (0.54 ± 0.17 vs. 0.55 ± 0.16; p = .123) and SA (0.28 ± 0.06 vs. 0.25 ± 0.07; p = .068). However, patients had significantly lower CVI compared to control subjects (66.07 ± 3.19 vs. 68.89 ± 2.85, p < .001). Univariate linear regression model revealed that there was a negative correlation between disease duration and CVI (standardized beta coefficient: -0.416, p = .006).Conclusion: According to our findings, reduced CVI may indicate subclinical dysfunction in choroid of patients with type 1 DM.

The Relationship between Choroidal Thickness and Intracellular Oxidised-reduced Glutathione and Extracellular Thiol-disulfide Homeostasis at Different Stages of Diabetic Retinopathy

Purpose: To evaluate the relationship between diabetic retinopathy and oxidative damage by measuring intracellular and extracellular thiol levels, and to compare intracellular and extracellular thiol levels. Method: In this prospective, cross-sectional, and comparative study, 25 healthy control participants (group 1), a total of 25 diabetic macular edema (DME) patients with non-proliferative diabetic retinopathy (DRP) and without DME (group 2), and 25 DME patients with non-proliferative DRP and with DME (group 3) were included. Choroidal thickness (ChT) and central macular thickness (CMT) were measured by spectral domain optic coherence tomography. For the evaluation of antioxidant/oxidant balance, intracellular GSH (reduced glutathione) and GSSG (oxidized glutathione), extracellular SH (thiol) and SS (disulfide) levels were measured and recorded. Results: Comparing intracellular and extracellular thiol levels between groups, intracellular GSSG level and GSSG/GSH percent ratio, and extracellular disulfide and SS/SH percent ratio values were higher in diabetic patients than healthy participants. Choroidal thicknesses were significantly thinner in DRP groups compared to the healthy population. When the relationship between choroidal thicknesses and thiol levels was investigated, there were significant relationships between choroidal thicknesses and thiol levels in group 3. Conclusion: Oxidative stress and impaired intracellular GSH/GSSG and serum SH/SS balances were observed to have an effect on DRP and DME pathogenesis. In addition, in groups with and without DME, thinning in choroidal thicknesses and the relationship between these thicknesses and intra/extracellular oxidative stress indicators can also be explained.

The Role of Inflammation in Diabetic Retinopathy

Inflammation is central to pathogenic processes in diabetes mellitus and the metabolic syndrome and particularly implicates innate immunity in the development of complications. Inflammation is a primary event in Type 1 diabetes where infectious (viral) and/or autoimmune processes initiate disease; in contrast, chronic inflammation is typical in Type 2 diabetes and is considered a sequel to increasing insulin resistance and disturbed glucose metabolism. Diabetic retinopathy (DR) is perceived as a vascular and neurodegenerative disease which occurs after some years of poorly controlled diabetes. However, many of the clinical features of DR are late events and reflect the nature of the retinal architecture and its cellular composition. Retinal microvascular disease is, in fact, an early event pathogenetically, induced by low grade, persistent leukocyte activation which causes repeated episodes of capillary occlusion and, progressive, attritional retinal ischemia. The later, overt clinical signs of DR are a consequence of the retinal ischemia. Metabolic dysregulation involving both lipid and glucose metabolism may lead to leukocyte activation. On a molecular level, we have shown that macrophage-restricted protein tyrosine phosphatase 1B (PTP1B) is a key regulator of inflammation in the metabolic syndrome involving insulin resistance and it is possible that PTP1B dysregulation may underlie retinal microvascular disease. We have also shown that adherent CCR5⁺CD11b⁺ monocyte macrophages appear to be selectively involved in retinal microvascular occlusion. In this review, we discuss the relationship between early leukocyte activation and the later features of DR, common pathogenetic processes between diabetic microvascular disease and other vascular retinopathies, the mechanisms whereby leukocyte activation is induced in hyperglycemia and dyslipidemia, the signaling mechanisms involved in diabetic microvascular disease, and possible interventions which may prevent these retinopathies. We also address a possible role for adaptive immunity in DR. Although significant improvements in treatment of DR have been made with intravitreal anti-VEGF therapy, a sizeable proportion of patients, particularly with sight-threatening macular edema, fail to respond. Alternative therapies targeting inflammatory processes may offer an advantage.

Choroidal Structural Changes Assessed with Swept-Source Optical Coherence Tomography after Cataract Surgery in Eyes with Diabetic Retinopathy

Objective

To determine the influence of phacoemulsification on choroidal vasculature in patients with diabetic retinopathy (DR) undergoing cataract surgery using swept-source optical coherence tomography (SS-OCT).

Methods

The study was conducted in 23 eyes of 23 cataract patients with mild/moderate nonproliferative diabetic retinopathy (NPDR) without diabetic macular edema (DME) and 23 age-matched controls. Choroidal thickness (CT) and choroidal vascularity index (CVI) were measured at baseline and 1 week, 1 month, and 3 months after surgery.

Results

The baseline CVI in the DR group was significantly lower than that in the control group (P=0.001). CVI in DR patients after surgery significantly increased compared with preoperative values (all P < 0.001 for 1 week, 1 month, and 3 months after surgery). Postoperative increase of CVI and CT in the DR group was more than in the control group, and the difference was significant 1 month and 3 months after surgery (all P < 0.05).

Conclusion

Patients with mild/moderate NPDR have reduced CVI compared with nondiabetic patients at baseline; diabetic cataract surgery tended to induce more increase in CVI and CT as compared with nondiabetic patients. This trial is registered with NCT04499768.