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

Thinner Average Choroidal Thickness Is a Risk Factor for the Onset of Diabetic Retinopathy

PURPOSE

To analyze the relationships between choroidal thickness (CT) and diabetes mellitus (DM), diabetic retinopathy (DR), and DR severity in community residents diagnosed with type 2 DM, and to explore whether CT can improve the discriminatory ability of other risk factors to predict the incidence of DR.

METHODS

A total of 1,250 type 2 DM residents and 1,027 healthy controls in Xinjing community of Shanghai participated a cross-sectional survey of eye diseases in 2016. CT was measured using swept-source optical coherence tomography. DR was classified according to the 2002 international clinical classification of DR. A total of 537 subjects with type 2 DM without DR at the 2016 survey were followed up in 2018 to investigate the 2-year incidence of DR. Receiver operating characteristic curve analysis was used to test the accuracy of different indicators in predicting the onset of DR.

RESULTS

The central CT of the control, no DR, mild non-proliferative DR (NPDR), moderate NPDR, severe NPDR, and PDR groups were 223.40, 216.22, 213.57, 211.91, 178.47, and 168.15 μm, respectively (p for trend <0.001), and the average CT (ACT) were 197.83, 186.94, 182.03, 178.00, 156.91, and 136.72 μm respectively (p for trend <0.001). Body mass index (BMI), DM duration, fasting blood glucose, glycosylated hemoglobin (HbA1C), and ACT were risk factors for 2-year DR incidence. For the onset of DR, as predicted by ACT, after tenfold cross validation the average area under the curve was 0.55 (p = 0.048). Addition of ACT did not improve the discriminatory ability of DM duration, BMI, glucose and HbA1C on the incidence of DR (Z = 0.48; p = 0.63).

CONCLUSIONS

As the severity of DR increased, the CT of community type 2 DM patients showed a significant downward trend compared with the healthy controls. Thinner ACT was found to be a risk factor for DR incidence, but it did not improve the discriminatory ability of other risk factors to predict the incidence of DR.

Clinically relevant factors associated with quantitative optical coherence tomography angiography metrics in deep capillary plexus in patients with diabetes

Background

To test clinically relevant factors associated with quantitative artifact-free deep capillary plexus (DCP) metrics in patients with diabetes mellitus (DM).

Methods

563 eligible eyes (221 with no diabetic retinopathy [DR], 135 with mild DR, 130 with moderate DR, and 77 with severe DR) from 334 subjects underwent optical coherence tomography-angiography (OCT-A) with a swept-source OCT (Triton DRI-OCT, Topcon, Inc., Tokyo, Japan). Strict criteria were applied to exclude from analysis those DCP images with artifacts and of poor quality, including projection artifacts, motion artifacts, blurriness, signal loss, B-scan segmentation error, or low-quality score. A customized MATLAB program was then used to quantify DCP morphology from the artifact-free DCP images by calculating three metrics: foveal avascular zone (FAZ), vessel density (VD), and fractal dimension (FD).

Results

166 (29.5%) eyes were excluded after quality control, leaving in the analysis 397 eyes (170 with no DR, 101 with mild DR, 90 with moderate DR, 36 with severe DR) from 250 subjects. In the multiple regression models, larger FAZ area was associated with more severe DR (β = 0.687; p = 0.037), shorter axial length (AL) (β = − 0.171; p = 0.003), thinner subfoveal choroid thickness (β = − 0.122; p = 0.031), and lower body mass index (BMI) (β = − 0.090; p = 0.047). Lower VD was associated with more severe DR (β = − 0.842; p = 0.001), shorter AL (β = 0.107; p = 0.039), and poorer visual acuity (VA) (β = − 0.133; p = 0.021). Lower FD was associated with more severe DR (β = − 0.891; p < 0.001) and with older age (β = − 0.142; p = 0.004).

Conclusions

Quantitative artifact-free DCP metrics are associated with VA, DR severity, AL, subfoveal choroidal thickness, age, and BMI in diabetic patients. The effects of ocular and systemic factors should be considered for meaningful interpretations of DCP changes in DM patients.

Clinical and angiographic characterization of choroidal neovascularization in diabetic retinopathy

BACKGROUND

To report the clinical and angiographic characteristics of choroidal neovascularization in patients with diabetic retinopathy.

METHODS

Patients of type 2 diabetes mellitus with presence of choroidal neovascularization in at least one eye were retrospectively analyzed. The study eyes were divided into three groups based on presence (active or scarred) or absence of choroidal neovascularization (fellow eyes). Imaging characteristics of active choroidal neovascularization were recorded using optical coherence tomography, fluorescein, and indocyanine angiography. Central macular thickness, subfoveal choroidal thickness, and large choroidal vessel layer thickness were compared at baseline and final visit.

RESULTS

Our study reports the prevalence rate of choroidal neovascularization in eyes with diabetic retinopathy (0.27%; 36 out of 13,382 eyes). A total of 64 eyes of 32 patients (age, mean ± standard deviation: 68.5 ± 9.3 years) with baseline visual acuity of 0.69 ± 0.69 logarithm of minimum angle of resolution (Snellen equivalent 20/100) were included. Nonproliferative diabetic retinopathy (57 eyes) comprised the majority followed by proliferative diabetic retinopathy (7 eyes). Eyes with choroidal neovascularization (36, 56.25%) included both active (25) and scarred (11) choroidal neovascularization, with bilateral choroidal neovascularization in 4 patients. Type 1 choroidal neovascularization was the most common subtype of choroidal neovascularization on optical coherence tomography. Common etiologies for active choroidal neovascularization included age-related macular degeneration (3; 12%), myopia (1; 4%), and inflammatory choroidal neovascularization secondary to chorioretinitis (1; 4%). In the remaining 20 eyes, choroidal neovascularization formation was primarily due to diabetic choroidopathy.

CONCLUSION

The prevalence of choroidal neovascularization in eyes with diabetic retinopathy is very low, with a lower prevalence of age-related macular degeneration. Diabetic choroidopathy plays a significant role in formation of choroidal neovascularization in eyes with diabetic retinopathy.

Changes in retinal and choriocapillaris density in diabetic patients receiving anti-vascular endothelial growth factor treatment using optical coherence tomography angiography

Background

Optical coherence tomography angiography (OCTA) enables detailed, non-invasive assessment of ocular vasculature. This study uses OCTA imaging to evaluate choriocapillaris and retinal capillary perfusion density (CPD) changes in diabetic retinopathy following anti-vascular endothelial growth factor (VEGF) treatment.

Methods

Records of 38 eyes at a single institution were reviewed, grouped as non-diabetic controls (19 eyes), diabetes mellitus patients with diabetic retinopathy (DR, 19 eyes) and macular edema (DME). DR eyes were imaged at baseline, 6-months and 12-months after anti-VEGF treatment. Quantitative analyses assessed CPD of the choriocapillaris and retinal plexus.

Results

DR eyes showed decreased choriocapillaris whole-image CPD (62.6 ± 6.1 vs. 68.4 ± 5.1, p < 0.003), foveal CPD (61.2 ± 7.4 vs. 66.3 ± 9.8, p < 0.014), and parafoveal CPD (61.9 ± 6.6 vs. 68.2 ± 4.8, p < 0.002) at baseline. DR eyes also showed decreased retinal density, including whole-image CPD (46.9 ± 5.1 vs. 50.7 ± 5.6, p < 0.04), foveal CPD (27.6 ± 5.9 vs. 34.1 ± 6.1, p < 0.002), and parafoveal CPD (49.0 ± 5.6 vs. 53.1 ± 6.0, p < 0.011). Following 12 months of anti-VEGF treatment, no changes to retinal or choriocapillaris or CPD were observed. Retinal central subfield thickness decreased (397.1 ± 93.2 µm vs. 294.2 ± 71.5 µm, p < 0.005). Lastly, FAZ area (0.307 ± 0.133 mm² vs. 0.184 ± 0.058 mm², p = 0.008) and perimeter (2.415 ± 0.692 mm² vs. 1.753 ± 0.408 mm², p = 0.002) were increased in DR eyes at baseline. No changes to FAZ area or perimeter were seen with anti-VEGF treatment in DR eyes.

Conclusions

Compared to control, choriocapillaris and retinal CPD are reduced in DR, while FAZ area and perimeter are increased. No retinal capillary or choriocapillaris CPD changes were observed in DR eyes following anti-VEGF treatment.

Atrophy of the central neuroretina in patients treated for diabetic macular edema

Purpose

To examine the prevalence of central retinal atrophy in patients treated for diabetic macular edema (DME) in a clinical setting.

Methods

Retrospective data analysis of patients with DME, focusing on those who developed central retinal thinning after DME treatment at the Department of Ophthalmology, Medical University Vienna. Patient characteristics and clinical data including best‐corrected visual acuity (BCVA), spectral domain optical coherence tomography and fluorescence angiography images were reviewed and DME treatment strategies analysed using descriptive statistics. The correlation between visual acuity and ocular, systemic or DME treatment factors was calculated using linear regression models and ancovas.

Results

A total of 6684 outpatient visits by 1437 patients with diabetes were analysed. Out of 149 patients, who had had a central subfield thickness (CST) below 200 μm, 32 (36 eyes) had previously been diagnosed with a centre involving DME with an average CST of 473 ± 103 μm and average visual acuity of 0.62 ± 0.44 logMAR at first presentation. At the time of central atrophy, 29 (81%) out of 36 eyes had a history of laser treatment, 11 (31%) a vitrectomy, 32 (88%) repeated intravitreal injections of anti‐vascular endothelial growth factor (VEGF; mean 5.3 ± 3.8) and 22 (61%) intravitreal corticosteroid injections (mean 2.5 ± 2.7). Visual function (0.67 ± 0.43 logMAR) at the time of atrophy was not significantly correlated to central retinal thickness (191 ± 7 μm) or any other ocular, systemic or treatment factors.

Conclusions

Only 4% of patients treated for DME developed central retinal thinning in our observation period. On average, our atrophy patients had higher CST and lower BCVA when they first presented with DME compared to the overall DME cohort, and they received a combination of intravitreal injections and laser for DME treatment. Central retinal atrophy might not be attributed to excessive use of intravitreally applied anti‐VEGF or any other DME therapy alone.

Retinal and Choroidal Perfusion Status in the Area of Laser Scars Assessed With Swept-Source Optical Coherence Tomography Angiography

Purpose

To evaluate the perfusion status of the retina and choriocapillaris in the area of laser scars on swept-source optical coherence tomography angiography (OCTA) images of eyes previously treated with panretinal photocoagulation (PRP).

Methods

Cross-sectional exploratory analysis of swept-source OCTA images, which were retrospectively reviewed for laser scars. The appearance of the capillary networks in the area of previous laser were evaluated following a three-step grading system (normal/sparse/missing capillary network). The superficial and deep capillary plexus of the retina and the choriocapillaris were graded separately.

Results

A total of 3140 laser scars in 54 eyes of 31 patients (13 female, mean age 57 ± 12 years) were included in this analysis. In the retina, 6.8% of the superficial and deep capillary network in the area evaluated appeared normal, 58% and 56% sparse, and 35% and 37% missing. Capillary dropout in the retina was not restricted to the area of prior laser treatment. The choriocapillaris decorrelation signal was either sparse (61%) or completely missing (38%) within the laser scar area. The perfusion of the choriocapillaris appeared normal in the area adjacent to laser scars.

Conclusions

Capillary non-perfusion in the choriocapillaris was found within the laser scar area. Laser treatment seems to cause sustained non-perfusion of choriocapillaris in the area treated.

Age-Related Changes in Choroidal Thickness and the Volume of Vessels and Stroma Using Swept-Source OCT and Fully Automated Algorithms

PURPOSE

To determine age-related changes in choroidal thickness and the volume of choroidal vessels and stroma using automated algorithms based on structural swept-source OCT (SS-OCT) scans.

DESIGN

Prospective and observational study.

PARTICIPANTS

The study included 144 normal participants with ages ranging from 20 to 88 years.

METHODS

A previously reported strategy was used to automatically segment the choroid using SS-OCT structural images. Attenuation correction was applied on B-scans to enhance the choroidal contrast and facilitate more accurate automatic segmentation of the 3-dimensional choroidal vessel and stroma. The parameters that we investigated included mean choroidal thickness (MCT), choroidal vessel volume (CVV), choroidal stroma volume (CSV), choroid vascularity index (CVI), and the choroidal stroma-to-vessel volume ratio (CSVR). Correlations between MCT and choroidal vessel metrics of CVV, CSV, CVI, and CSVR were studied. Regional distributions of MCT and CVI were analyzed using a grid centered on the fovea. Age-related changes in MCT, CVV, CSV, and CVI were studied in the entire scanning region, as well as in the subregions of the grids.

MAIN OUTCOME MEASURES

Age-related changes in MCT, CVV, CSV, and CVI using 6×6-mm and 12×12-mm SS-OCT scans.

RESULTS

The automated choroid segmentations were validated against manual segmentations, and MCT measurements were shown to be in good agreement (P < 0.0001). Choroidal vessel volume and CSV showed significant correlations with MCT (all P < 0.0001). Interestingly, CVI and CSVR were constant, with little variation among all participants regardless of age and MCT (61.1±1.8% and 0.64±0.05, respectively). Measurements on 12×12-mm and 6×6-mm scans showed excellent agreement in all scan regions (all P < 0.0001). While choroidal thickness and choroidal volume, which includes both choroidal vessels and stroma, decrease with age (all P < 0.0001), the CVI and CSVR vary little among all ages in all regions.

CONCLUSIONS

Whereas MCT, CVV, and CSV decrease with age, the CVI and CSVR remain constant in all regions with age. Ongoing studies are using these automated algorithms on SS-OCT structural datasets to investigate the diagnostic usefulness of these choroidal parameters in a myriad of ocular and systemic diseases.

MORPHOMETRIC PARAMETERS OF RETINAL MACULAR ZONE IN RECONVALESCENTS OF ACUTE RADIATION SICKNESS (IN REMOTE PERIOD)

OBJECTIVE

evaluate the retinal morphometric parameters of the reconvalescents in remote period after acute radi-ation sickness.

MATERIALS AND METHODS

A complete ophthalmologic examination was carried out on 7 reconvalescents of acuteradiation sickness. The examined are divided into two subgroups: 1) patients with macular degeneration of the reti-na (8 eyes); 2) patients without clinical signs of macular pathology (6 eyes). Parameters of the retina in the cen-tral retina zone studied using the method of optical coherence tomography. To evaluate the results of surveys usedstatistical methods: average values of quantitative indicators calculation, estimation of probability difference byStudent's method.

RESULTS

Optical coherence tomography revealed a statistically significant increase of the thickness of the retina inthe fovea in all reconvalescents of acute radiation sickness.

CONCLUSIONS

It was shown that the thickness of the retina in the fovea and paramacular zone in persons who suf-fered acute radiation sickness is significantly higher than in the control. These changes observed in all reconvalis-cents ARS - both in person with sings of macular degeneration, and in those whose clinical manifestations were notdetected. The presence of a correlation between the volume of the retina in the macular zone and the documentedradiation dose of the study group emphasizes the perspectives of next OCT examination of the retina of reconvales-cents of ARS to study the mechanism of retina's damage in this category of victims of the Chornobyl accident.

Choroidal binarization analysis: clinical application

INTRODUCTION

Image processing of optical coherence tomography scans through binarization techniques represent a non-invasive way to separately asses and measure choroidal components, in vivo. In this review, we systematically search the scientific literature regarding binarization studies published so far.

METHODS

A systematic research was conducted at PubMed database, including English literature articles for all of the following terms in various combinations: binarization, choroid/al, enhanced depth spectral domain/swept source optic coherence tomography, and latest publications up to November 2018 were reviewed.

RESULTS

Thirty-seven articles were included and analyzed regarding studied disease, binarization method, studied variables, and outcomes. Most of the studies have focused on the more common retinal pathologies, such as age-related macular degeneration, central serous chorioretinopathy and diabetic retinopathy but binarization techniques have also been applied to the study of choroidal characteristics in ocular inflammatory diseases, corneal dystrophies and in postsurgical follow-up. Advantages and disadvantages of binarization techniques are also discussed.

CONCLUSION

Binarization of choroidal images seems to represent a promising approach to study choroid subcomponents in an increasingly detailed manner.

The Relationship between Carotid Intima-Media Thickness and Ocular Circulation in Type-2 Diabetes

Purpose

To compare clinical findings, including ocular blood flow and intima-media thickness (IMT) of the carotid artery, in mild nonproliferative diabetic retinopathy (NPDR) and no diabetic retinopathy (NDR) patients, and to determine risk factors contributing to mild NPDR.

Methods

In 129 subjects (129 eyes) with type-2 diabetes patients and mild NPDR or NDR, standard statistical techniques were used to determine associations between clinical findings, including diabetes duration, blood levels of creatinine and hemoglobin A1c (HbA1c), central macular thickness (CMT; measured with optical coherence tomography), mean blur rate (MBR; measured with laser speckle flowgraphy), and ultrasound-measured carotid IMT.

Results

Diabetes duration, IMT, and CMT were significantly higher in the mild NPDR patients than the NDR patients (P=0.004, P=0.004, and P=0.003, respectively), while conversely, MBR in the overall optic nerve head (MBR-A) was lower in the mild NPDR patients. Furthermore, a logistic regression analysis showed that diabetes duration (OR, 1.11; P=0.006), diastolic blood pressure (OR, 0.93; P=0.025), heart rate (OR, 1.07; P=0.004), IMT (OR, 8.65; P=0.005), and CMT (OR, 1.03; P=0.007) were independent contributing factors to mild NPDR. Spearman's rank correlation test also showed that IMT was negatively correlated with MBR-A (P=0.011).

Conclusions

Increased IMT showed a close association with ocular ischemia in patients with type-2 diabetes and contributed to the presence of mild NPDR. These findings suggest that IMT may be an early biomarker of mild NPDR.

Choroidal thickness and vascular density in macular telangiectasia type 2 using enface swept-source optical coherence tomography

Purpose

To investigate the choroidal thickness (CT) and choroidal vascular densities (CVD) of patients with macular telangiectasia type 2 (MacTel2) and their association with other multimodal imaging features, using swept-source optical coherence tomography (SS-OCT).

Methods

Prospective, cross-sectional study. Consecutive patients with MacTel2 along with controls without any macular disease were included. Fundus photography, confocal blue reflectance, near-infrared reflectance, autofluorescence, fluorescein angiography, spectral domain OCT and SS-OCT were performed. Images were independently analysed by two graders, and CVD was calculated from binarised en face SS-OCT images. CT was obtained from the SS-OCT platform via built-in automated segmentation. Multilevel mixed-effects models were used for statistical analysis.

Results

Thirty-nine eyes of 20 patients with MacTel2 and 29 eyes of 15 control patients were included. Average CT and perifoveal temporal CT did not differ significantly between eyes with MacTel2 and control eyes (p≥0.350), when accounting for confounding factors. Overall and temporal CVD also did not significantly differ between the two groups (p≥0.490).

Conclusion

CT and CVD did not significantly differ between MacTel2 and control eyes in this study using SS-OCT. Even though MacTel2 may include abnormalities involving the choroid, these are likely minor in comparison to the predominant retinal changes.

Visualization of Choriocapillaris and Choroidal Vasculature in Healthy Eyes With En Face Swept-Source Optical Coherence Tomography Versus Angiography

Purpose

To compare the visualization of the choriocapillaris and deeper choroidal vessels in healthy eyes in en face swept-source optical coherence tomography (SS-OCT) versus SS-OCT angiography (SS-OCTA).

Methods

This is a cross-sectional study of consecutive eyes without chorioretinal disease. En face SS-OCT and SS-OCTA images of the choriocapillaris and choroid were assessed for visualization of the vasculature. Choroidal vessel densities (CVD) of the choriocapillaris, inner choroid, midchoroid, and outer choroid were calculated from binarized en face SS-OCT and SS-OCTA images. Paired t-tests and linear regression were used for statistical analysis.

Results

Twenty-seven eyes of 27 patients were included. There was no statistically significant difference between the CVDs of the midchoroid assessed with en face SS-OCT versus SS-OCTA (P = 0.21). However, there were statistically significant differences between the CVDs for the choriocapillaris (P < 0.001), inner choroid (P < 0.001), and outer choroid (P = 0.006). Qualitative analysis revealed incomplete visualization of vessels in the inner choroid and exaggeration of vessel lumens in the outer choroid with SS-OCTA.

Conclusions

Visualization of the choriocapillaris is superior with SS-OCTA, but it has numerous limitations that make visualization of deeper choroidal vessels less reliable when compared with en face SS-OCT. It is important to understand such limitations when using these technologies to study the choroidal vasculature in chorioretinal disease.

Translational Relevance

The presented study of optimal imaging techniques for the choroidal vessels of healthy eyes provides an important foundation for future investigations into the role of the choroidal vasculature in chorioretinal diseases.

Attenuation correction assisted automatic segmentation for assessing choroidal thickness and vasculature with swept-source OCT

Swept source optical coherence tomography (SS-OCT) is being used more widely in clinical studies to investigate the choroid due to its deeper penetration under the retinal pigment epithelium and improved image quality compared with spectral domain OCT. However, automatic methods to reliably assess choroidal thickness and vasculature are still limited. This paper reports an approach that applies attenuation correction on SS-OCT structural scans to facilitate accurate automatic segmentation of the choroid and provides visualization of the choroidal vasculature without the necessity of OCT angiography. After attenuation correction, enhanced interlayer contrast at the choroidal-scleral interface was observed (from 0.13 ± 0.05 to 0.29 ± 0.10; P < 0.001). An algorithm that segmented the choroid from attenuation compensated B-scans achieved significantly higher accuracy when compared with an automated segmentation performed on regular OCT scans (91.8 ± 3.7% vs.74.5 ± 8.0%; P < 0.01). After attenuation correction, en face images of choroidal vessels were achieved with fewer artifacts from retinal vessels. Measurements of mean choroidal thickness and vessel density showed high repeatability. The attenuation correction assisted segmentation of the choroid and visualization of the choroidal vasculature will be helpful in studying the quantitative changes that occur in a myriad of diseases involving the choroid such as age-related macular degeneration, polypoidal choroidal vasculopathy, pathologic myopia, central serous chorioretinopathy, and inflammatory eye conditions.

Diabetic macular edema: Evidence-based management

Diabetic macular edema (DME) is the most common cause of vision loss in patients with diabetic retinopathy with an increasing prevalence tied to the global epidemic in type 2 diabetes mellitus. Its pathophysiology starts with decreased retinal oxygen tension that manifests as retinal capillary hyperpermeability and increased intravascular pressure mediated by vascular endothelial growth factor (VEGF) upregulation and retinal vascular autoregulation, respectively. Spectral domain optical coherence tomography (SD-OCT) is the cornerstone of clinical assessment of DME. The foundation of treatment is metabolic control of hyperglycemia and blood pressure. Specific ophthalmic treatments include intravitreal anti-VEGF drug injections, intravitreal corticosteroid injections, focal laser photocoagulation, and vitrectomy, but a substantial fraction of eyes respond incompletely to all of these modalities resulting in visual loss and disordered retinal structure and vasculature visible on SD-OCT and OCT angiography. Efforts to close the gap between the results of interventions within randomized clinical trials and in real-world contexts, and to reduce the cost of care increasingly occupy innovation in the social organization of ophthalmic care of DME. Pharmacologic research is exploring other biochemical pathways involved in retinal vascular homeostasis that may provide new points of intervention effective in those cases unresponsive to current treatments.

Longitudinal Wide-Field Swept-Source OCT Angiography of Neovascularization in Proliferative Diabetic Retinopathy after Panretinal Photocoagulation

PURPOSE

Wide-field swept-source (SS) OCT angiography (OCTA) was compared with ultrawide-field (UWF) fluorescein angiography (FA) for evaluating neovascularization (NV) before and after panretinal photocoagulation (PRP) in eyes with treatment-naive proliferative diabetic retinopathy (PDR).

DESIGN

Prospective, observational, consecutive case series.

PARTICIPANTS

Patients with treatment-naive PDR.

METHODS

Patients were imaged using the SS OCTA 12 × 12-mm field of view (PLEX Elite 9000; Carl Zeiss Meditec, Inc, Dublin, CA) at baseline and at 1 week, 1 month, and 3 months after PRP. Select eyes were imaged with 5 SS OCTA 12 × 12-mm scans to create posterior pole montages. Ultrawide-field fundus photography and UWF FA were obtained at baseline and 3 months after PRP.

MAIN OUTCOME MEASURES

Neovascularization visualized using wide-field SS OCTA and UWF FA.

RESULTS

From January through May 2018, wide-field SS OCTA was performed on 20 eyes with treatment-naive PDR from 15 patients. The en face SS OCTA 12 × 12-mm vitreoretinal interface (VRI) slab images showed NV at baseline in 18 of 20 eyes (90%). Of the remaining 2 eyes, the posterior pole montage captured peripheral NV in one eye, and in the other eye, no evidence of NV was detected with either UWF FA or SS OCTA. After PRP, both SS OCTA and FA demonstrated similar progression or regression of NV, but SS OCTA provided more detailed visualization of the vascular changes.

CONCLUSIONS

Neovascularization in PDR can be identified at baseline and imaged serially after PRP using wide-field SS OCTA. In patients with a high clinical suspicion for PDR, wide-field SS OCTA likely will be the only imaging method needed for diagnosis and longitudinal evaluation of NV.

Changes in choroidal thickness and volume are related to urinary albumin excretion in type 2 diabetic patients without retinopathy

Purpose

To evaluate choroidal thickness and volume in patients with type 2 diabetes and microalbuminuria using spectral-domain optical coherence tomography.

Methods

We recruited 37 diabetic patients without diabetic retinopathy (18 normoalbuminuric and 19 microalbuminuric) and 21 healthy controls. Choroidal thickness and volume were mapped using the automated Early Treatment Diabetic Retinopathy Study grid and a topographic map of thickness was generated manually. Choroid was also measured at 10 locations under the fovea, temporally and nasally.

Results

Mean choroidal thickness and volume among patients with diabetes and microalbuminuria was reduced in all locations compared to controls (P<0.05). A sectoral decrease of choroidal thickness and volume was shown between microalbuminuric and normoalbuminuric groups.

Conclusion

Choroidal changes were present in type 2 diabetic patients before clinical development of retinopathy. Microalbuminuria was associated with a decrease in choroidal thickness and volume in diabetic patients without diabetic retinopathy.

Choriocapillaris and retinal vascular plexus density of diabetic eyes using split-spectrum amplitude decorrelation spectral-domain optical coherence tomography angiography

BACKGROUND/AIMS

Split-spectrum amplitude decorrelation angiography for spectral-domain optical coherence tomography has enabled detailed, non-invasive assessment of vascular flow. This study evaluates choriocapillaris and retinal capillary perfusion density (CPD) in diabetic eyes using optical coherence tomography angiography (OCTA).

METHODS

Records of 136 eyes that underwent OCTA imaging at a single institution were reviewed. Eyes were grouped as non-diabetic controls (37 eyes), patients with diabetes mellitus (DM) without diabetic retinopathy (DM without DR, 31 eyes), non-proliferative diabetic retinopathy (NPDR, 41 eyes) and proliferative diabetic retinopathy (PDR, 27 eyes). Quantitative CPD analyses were performed on OCTA images for assessing perfusion density of the choriocapillaris and retinal plexus for all patients and compared between groups.

RESULTS

Eyes with NPDR and PDR showed significantly decreased choriocapillaris CPD compared with controls, while DM eyes without DR did not show significant change. Choriocapillaris whole-image CPD was decreased by 8.3% in eyes with NPDR (p<0.01) and decreased by 7.1% in eyes with PDR (p<0.01). Choriocapillaris parafoveal CPD was decreased by 8.9% in eyes with NPDR (p<0.01) and decreased by 8.2% in eyes with PDR (p<0.01). Compared with controls, only eyes with PDR showed significantly decreased retinal CPD, as well as significantly increased foveal avascular zone (FAZ) area. In those patients, retinal whole-image CPD was decreased by 9.7% (p<0.01), retinal foveal CPD was decreased by 20.5% (p<0.01) and retinal parafoveal CPD was decreased by 11.4% (p<0.01). FAZ area was increased by 50.9% (p<0.01).

CONCLUSIONS

Choriocapillaris and retinal CPD are reduced in diabetic retinopathy, while FAZ area is increased in eyes with PDR. Vascular changes captured by new imaging modalities can further characterise diabetic choroidopathy.