Longitudinal changes in pigment epithelial detachment composition indices (PEDCI): new biomarkers in neovascular age-related macular degeneration.

PURPOSE: To evaluate novel, automated biomarkers, pigment epithelial detachment composition indices (PEDCI) in eyes with neovascular age-related macular degeneration (nAMD) undergoing anti-vascular endothelial growth factor (anti-VEGF) therapy through 24 months. METHODS: Retrospective analysis of 37 eyes (34 patients) with PED associated with nAMD receiving as-needed anti-VEGF treatment was performed. Best-corrected visual acuity (BCVA) and optical coherence tomography images were acquired at a treatment-naïve baseline and 3-, 6-, 12-, 18-, and 24-month visits. Previously validated automated imaging biomarkers, PEDCI-S (serous), PEDCI-N (neovascular), and PEDCI-F (fibrous) within PEDs were measured. ANOVA analysis and Spearman correlation were performed. RESULTS: Mean BCVA (in logMAR) was 0.60 ± 0.47, 0.45 ± 0.41, 0.49 ± 0.49, 0.61 ± 0.54, 0.59 ± 0.56, and 0.67 ± 0.57 at baseline, 3, 6, 12, 18, and 24 months respectively. Overall, BCVA showed minimal worsening of 0.07 ± 0.54 logMAR (p = 0.07). 13.38 ± 3.77 anti-VEGF injections were given through 24 months. PEDCI-F showed an increase of 0.116, 0.122, 0.036, and 0.006 at months 3, 6, 12, and 18 respectively and a decrease of 0.004 at month 24 (p = 0.03); PEDCI-S showed a decrease of 0.064, 0.130, 0.091, 0.092, and 0.095 at months 3, 6, 12, 18, and 24 respectively (p = 0.16); PEDCI-N showed a decrease of 0.052 at month 3 and an increase of 0.008, 0.055, 0.086, and 0.099 at months 6, 12, 18, and 24 respectively (p = 0.06). BCVA was negatively correlated with PEDCI-F (r = -0.28, p < 0.01), and positively correlated with PEDCI-N (r = 0.28, p < 0.01) and PEDCI-S (r = 0.15, p = 0.03). CONCLUSION: Longitudinal analysis of PEDCI supports their utility as biomarkers that characterize treatment related effects by quantifying the relative composition of PEDs.

Choroidal Vascularity Index versus Choroidal Thickness as Biomarkers of Acute Central Serous Chorioretinopathy.

INTRODUCTION: The aim of this study was to analyze the choroidal vascularity index (CVI) versus choroidal thickness (CT) as biomarkers in acute central serous chorioretinopathy (CSCR). METHODS: In this multicenter retrospective, cross-sectional, noninterventional study carried out at Puerta de Hierro-Majadahonda University Hospital, Madrid, Spain; Jules-Gonin, Lausanne, Switzerland; and Pittsburg University, USA. 40 eyes from 40 patients with acute CSCR, 40 eyes from 40 patients with keratoconus (KC), and 40 eyes from 40 healthy patients were included. The variables analyzed were age, CT, CVI, and the presence of neurosensory retinal detachment. CT and the CVI were obtained from a 12-mm horizontal single-line B-scan (Triton SS-OCT, Topcon Co., Japan). Blinded measurements of the subfoveal CT were performed manually by two independent investigators. The images of the choroid were automatically binarized using a validated algorithm, and a percentage of vascularity was calculated. RESULTS: There were no significant differences in age between the three groups (ANOVA, p = 0.092). There were statistically significant differences in CT and the CVI (ANOVA, p < 0.001). After Bonferroni correction, pairwise analysis between CSCR group against the KC group showed no significant differences in age and CT (p = 0.10 and p = 0.27, respectively). CVI was statistically greater among CSCR patients (p = 0.03). CONCLUSION: CT does not meet the criteria to be considered a biomarker of acute CSCR, while CVI may prove to be a more specific and reliable biomarker. Further studies with larger sample sizes, standardized procedures, and a wider representation of all CSCR stages are necessary to confirm the validity of CVI as biomarker in this disease. Further studies with larger samples are required in order to validate the use of CVI/CT correlation as a new biomarker.

Do rectus muscle parameters vary between emmetropes and myopes?

PURPOSE: This study investigated the thickness, area, and insertion site of the medial (MR) and lateral (LR) rectus muscles in individuals with emmetropia and different degrees of myopia. METHODS: Swept-source optical coherence tomography images of the MR and LR muscles in 80 participants including emmetropes (spherical equivalent refractive error [SER] ±0.50 D, N = 14) and myopes (≤ -0.75 D, N = 66), were analysed. Custom-designed, semi-automated software was used to measure parameters such as insertion distance from limbus, muscle thickness at every 1 mm interval to 3 mm periphery and muscle area from insertion site to 3 mm. RESULTS: The median (Q1, Q3) SER error and axial length were -6.00 D (-13.25, -2.12) and 25.78 mm (23.78, 28.61), respectively. The MR was significantly thinner (mean ± SE: 137.7 ± 8.9 vs. 159.7 ± 8.9 µm, p < 0.01) and occupied less area than the LR (0.35 ± 0.01 vs. 0.42 ± 0.01 mm2 , respectively, p < 0.01). The thickness of the MR gradually increased from the insertion site to a 3 mm peripheral eccentric location (106.5 3.8 µm at 1 mm, 135.5 ± 4.5 µm at 2 mm and 156.1 ± 5.9 µm at 3 mm, p < 0.01). The overall median thickness of the MR was significantly less in myopes (129 µm [111.5, 152.2]) than emmetropes (158.1 [134.3, 167.7] µm, p = 0.03). However, no such trend was seen in the LR muscle. Muscle area and insertion distance were not different between emmetropes and myopes in both horizontal rectus muscles. CONCLUSION: Unlike the LR, the parameters of the MR (thin and occupying less area) show significant association with myopia. While the key finding of this study indicates the possible association of MR parameters with myopia, the clinical relevance of this finding and its role in myopiogenesis/progression needs to be investigated further.

Prospective evaluation of changes in choroidal vascularity index after half-dose photodynamic therapy versus micropulse laser treatment in chronic central serous chorioretinopathy.

PURPOSE: To assess whether treatment of chronic central serous chorioretinopathy (cCSC) with photodynamic therapy (PDT) and high-density subthreshold micropulse laser (HSML) results in choroidal vascularity index (CVI) changes that may account for the treatment effect. METHODS: Patients with cCSC were prospectively included and analyzed. Patients received either half-dose PDT or HSML treatment. CVI of the affected and unaffected eye was obtained before treatment, 6 to 8 weeks after treatment, and 7 to 8 months after treatment. RESULTS: At baseline, 29 eyes (29 patients) were included both in the PDT and in the HSML group. The mean (± standard deviation) CVI change in the HSML group between before PDT and 6 to 8 weeks after PDT was - 0.009 ± 0.032 (p = 0.127), whereas this was 0.0025 ± 0.037 (p = 0.723) between the visit before PDT and final visit. The patients in the PDT group had a CVI change of - 0.0025 ± 0.037 (p = 0.723) between the visit before PDT and first visit after PDT, and a mean CVI change of - 0.013 ± 0.038 (p = 0.080) between the visit before PDT and final visit. There was no significant correlation between CVI and BCVA at the measured time points, in both the HSML group (p = 0.885), and in the PDT group (p = 0.904). Moreover, no significant changes in CVI occurred in the unaffected eye at any time point. CONCLUSIONS: PDT and HSML do not significantly affect CVI, and therefore a CVI change may not be primarily responsible for the treatment effect. The positive treatment effect of both interventions may rely on other mechanisms, such as an effect on choriocapillaris and/or retinal pigment epithelium function.

Association of reduced inner retinal thicknesses with chronic kidney disease.

BACKGROUND: Tissue derived biomarkers may offer utility as indicators of accumulated damage. Reduced thickness of retinal neuronal tissue and the vascular choroid have previously been associated with vascular damage and diabetes. We evaluated associations between retinal thickness, retinal microvascular and choroidal measures, and renal function in a population with a high burden of comorbidity. METHODS: Participants were recruited from nuclear cardiology or renal medicine clinics. Retinal and choroidal thickness were measured from spectral-domain optical coherence tomograms. Retinal microvascular parameters were assessed from digital fundus photographs using a semi-automated software package. MAIN OUTCOME MEASURE: Chronic kidney disease (CKD) categorised as: CKD stages 1-2, eGFR ≥60 ml/min/1.73m2; CKD stage 3, eGFR 30-59 ml/min/1.73m2, and CKD stages 4-5, eGFR ≤29 ml/min/1.73m2. RESULTS: Participants (n = 241) had a mean age of 65 years and a mean eGFR of 66.9 ml/min/1.73m2. Thirty-nine % of the cohort had diabetes and 27% were using diuretics. Thinning of the inner retina and changes to its microvascular blood supply were associated with lower eGFR and CKD stages 4 and 5, while no associations were found between the outer retinal layers or their choroidal blood supply and CKD of any stage. These associations remained following adjustment for age, mean arterial blood pressure, diabetes status, low-density lipoprotein, body mass index, and sex. CONCLUSIONS: Inner retinal thinning and retinal microvascular variation is associated with advanced CKD (stages 4 & 5) independent of important confounding factors, but not with earlier stage CKD (stage 3) and, therefore, its utility as a biomarker for early CKD is not supported in this study.

AGE-RELATED CHANGES IN CHOROIDAL VASCULAR DENSITY OF HEALTHY SUBJECTS BASED ON IMAGE BINARIZATION OF SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY.

PURPOSE: To analyze the vascular density of the choroid in a healthy population using swept-source optical coherence tomography. METHODS: A cross-sectional, noninterventional study. INCLUSION CRITERIA: best-corrected visual acuity between 20/20 and 20/25, spherical equivalent between ±3 diopters, no systemic or ocular diseases, and ages ranging between 3 and 85 years. One hundred and thirty-six eyes from 136 subjects were analyzed, 86 eyes (63.2%) were from male and 50 eyes (36.8%) from female subjects. The eyes were divided into different age groups to analyze the possible age-related changes. Twelve-millimeter horizontal, fovea-centered B-scans were used. Choroidal stroma and vessel area analysis involved automated segmentation and binarization using validated algorithms. RESULTS: Mean age was 33.1 ± 24.5 years. Mean choroidal area was 0.5554 ± 0.1377 mm. Mean stromal area was 0.2524 ± 0.0762 mm, and mean vascular region area was 0.3029 ± 0.0893 mm. The percentage of choroidal vascularity (vascular area/total area) was 54.40 ± 8.35%. Choroid area, vascular region, and percentage of choroidal vascular density were statistically higher in the <18-year-old group versus the >18-year-old group (P < 0.001). The stromal region was not different (P = 0.46). In the same way, choroid area, vascular region, and percentage of choroidal vascular density between the 5 age groups were statistically different (P < 0.001), showing larger figures in the 0 to 10-year-old group, but not stromal region (P = 0.71). There were no gender-related differences. CONCLUSION: The luminal area and the percentage of vascular/total area decrease with increasing age, while the stromal area remains stable.

Comparative Evaluation of Foveal Avascular Zone on Two Optical Coherence Tomography Angiography Devices.

SIGNIFICANCE: This study compares foveal avascular zone (FAZ) geometry in healthy eyes as imaged by two commercially available optical coherence tomography angiography (OCTA) devices. Foveal avascular zone measurements are repeatable and reproducible with each OCTA device, but interdevice agreement was poor. We provide conversion factors between devices. PURPOSE: The purpose of this study was to perform comparative evaluation of FAZ geometry in healthy eyes as imaged by two commercially available OCTA devices. METHODS: Ninety-six eyes of 48 healthy subjects were imaged prospectively on each of two OCTA devices (DRI-OCT [Topcon Corporation, Tokyo, Japan]; Cirrus 5000 [Carl Zeiss Meditec Inc., Dublin, CA]). The FAZ was evaluated in the superficial capillary plexus layer of 6 × 6-mm foveal scans by two masked observers. Intraobserver and interobserver agreement was determined using intraclass correlation by using linear mixed models and Bland-Altman plots. K-means clustering was used to provide conversion values between two devices. Foveal avascular zone acircularity was calculated using scans from each device and compared. RESULTS: The intraobserver repeatability for DRI-OCT was 0.95 (95% confidence interval [CI], 0.90 to 0.98) for observer A and 0.92 (95% CI, 0.83 to 0.96) for observer B. Intraobserver repeatability for Cirrus 5000 was 0.988 (95% CI, 0.972 to 0.995) for observer A and 0.993 (95% CI, 0.983 to 0.997) for observer B. The interobserver variability between observers A and B for DRI-OCT was 0.87 (0.73 to 0.94) and for Cirrus 5000 was 0.984 (95% CI, 0.964 to 0.993). Poor interdevice agreement (0.205 [95% CI, -0.202 to 0.554]) was noted, and conversion formulas were devised to convert FAZ area measurements from one device to another. No significant correlation was found when comparing FAZ acircularity indices between devices (P = .39). CONCLUSIONS: Repeatable and reproducible FAZ area measurements were obtained with each respective OCTA device, but interdevice agreement was poor, yet quantifiable and systematic with calculable conversion factors between devices.

Semi-automated quantification of hard exudates in colour fundus photographs diagnosed with diabetic retinopathy.

BACKGROUND: Hard exudates (HEs) are the classical sign of diabetic retinopathy (DR) which is one of the leading causes of blindness, especially in developing countries. Accordingly, disease screening involves examining HEs qualitatively using fundus camera. However, for monitoring the treatment response, quantification of HEs becomes crucial and hence clinicians now seek to measure the area of HEs in the digital colour fundus (CF) photographs. Against this backdrop, we proposed an algorithm to quantify HEs using CF images and compare with previously reported technique using ImageJ. METHODS: CF photographs of 30 eyes (20 patients) with diabetic macular edema were obtained. A robust semi-automated algorithm was developed to quantify area covered by HEs. In particular, the proposed algorithm, a two pronged methodology, involved performing top-hat filtering, second order statistical filtering, and thresholding of the colour fundus images. Subsequently, two masked observers performed HEs measurements using previously reported ImageJ-based protocol and compared with those obtained through proposed method. Intra and inter-observer grading was performed for determining percentage area of HEs identified by the individual algorithm. RESULTS: Of the 30 subjects, 21 were males and 9 were females with a mean age of the 50.25 ± 7.80 years (range 33-66 years). The correlation between the two measurements of semi-automated and ImageJ were 0.99 and 0.99 respectively. Previously reported method detected only 0-30% of the HEs area in 9 images, 30-60% in 12 images and 60-90% in remaining images, and more than 90% in none. In contrast, proposed method, detected 60-90% of the HEs area in 13 images and 90-100% in remaining 17 images. CONCLUSION: Proposed method semi-automated algorithm achieved acceptable accuracy, qualitatively and quantitatively, on a heterogeneous dataset. Further, quantitative analysis performed based on intra- and inter-observer grading showed that proposed methodology detects HEs more accurately than previously reported ImageJ-based technique. In particular, we proposed algorithm detect faint HEs also as opposed to the earlier method.

Artificial intelligence in chorioretinal pathology through fundoscopy: a comprehensive review.

BACKGROUND: Applications for artificial intelligence (AI) in ophthalmology are continually evolving. Fundoscopy is one of the oldest ocular imaging techniques but remains a mainstay in posterior segment imaging due to its prevalence, ease of use, and ongoing technological advancement. AI has been leveraged for fundoscopy to accomplish core tasks including segmentation, classification, and prediction. MAIN BODY: In this article we provide a review of AI in fundoscopy applied to representative chorioretinal pathologies, including diabetic retinopathy and age-related macular degeneration, among others. We conclude with a discussion of future directions and current limitations. SHORT CONCLUSION: As AI evolves, it will become increasingly essential for the modern ophthalmologist to understand its applications and limitations to improve patient outcomes and continue to innovate.

Effects of hydroxychloroquine therapy on choroidal volume and choroidal vascularity index.

PURPOSE: To determine changes in choroidal volume (CV) and choroidal vascularity index (CVI) in patients on hydroxychloroquine (HCQ) therapy. METHODS: Retrospective analysis of patients on HCQ therapy. CV and CVI were assessed below the central foveal region on spectral-domain optical coherence tomography using an automatic denoising and localization algorithm. CV and CVI were compared with age-matched controls. Regression analyses were performed to generate associations between CV and CVI with demographics and HCQ treatment parameters. Associations were assessed using a generalized estimating equation model adjusted for intra-subject inter-eye correlations. RESULTS: A total of 137 adult patients (23 males and 114 females) were included. Mean age was 45.6 ± 13.7 years and most patients identified as Caucasian (79%). Total duration of HCQ therapy ranged from 3 months to 20 years. Daily HCQ intake varied from 150-600 mg (mean = 304 mg), while cumulative doses ranged from 18-2,800 g. At presentation, the median CV was 0.51 (IQR:0.356-0.747) mm, and median CVI was 0.559 (IQR:0.528-0.578). Increased cumulative HCQ dose was associated with decreased CV (p = 0.006). Compared to age-matched controls, CV, CVI, and luminal area were significantly lower in the study group (p = 0.0003, 0.0001, and 0.0002). CONCLUSION: In this study, we present a novel analysis of key biomarkers which predate the occurrence of HCQ retinopathy. Choroidal volume and vascularity index are significantly reduced in patients on HCQ therapy, especially at higher cumulative doses. These findings suggest new tools to guide medical decision-making for patients receiving HCQ therapy for rheumatologic diseases.

Racial Differences in Choroidal Vascularity Index in Healthy Patients: Novel Insights.

BACKGROUND AND OBJECTIVE: Choroidal vascularity index (CVI) measures the ratio of blood vessels in the choroid to the total choroidal area. We aimed to compare CVI between young Black and White patients without a history of ocular or systemic disease. PATIENTS AND METHODS: We used a previously validated algorithm for shadow compensation and choroidal vessel binarization to measure CVI across the Early Treatment of Diabetic Retinopathy Study grid. RESULTS: Black patients had a lower CVI (ß = -0.05, P < 0.001) compared to White patients. Choroidal volume or luminal volume did not significantly differ with respect to race, whereas there was a trend for Black patients to have a greater stromal volume (ß = 3.08, P = 0.01). CONCLUSIONS: Black patients have a lower CVI than do White patients, likely due to a greater proportion of stromal volume. Further study of this parameter is warranted to validate the findings of this exploratory study. [Ophthalmic Surg Lasers Imaging Retina 2024;55:30-38.].

Three-dimensional choroidal contour mapping in healthy population.

Purpose was to study 3-dimensional choroidal contour at choroidal inner boundary (CIB) and choroidal outer boundary (COB) in healthy eyes. Healthy eyes imaged on wide field swept-source optical coherence tomography were included. Delineation of CIB and COB was done based on our previously reported methods. Quantitative analysis of the surfaces of CIB and COB was based on analyzing best fit spherical radius (R) (overall and sectoral). One hundred and seven eyes of 74 subjects with a mean age of 46.4 ± 19.3 years were evaluated. Overall, R COB (mean ± SD: 22.5 ± 4.8 mm) < R CIB (32.4 ± 9.4 mm). Central sector had the least R at COB (7.2 ± 5.9 mm) as well as CIB (25.1 ± 14.3 mm) across all age groups. Regression analysis between R (CIB) and age (r = -0.31, r2 = 0.09) showed negative correlation (P < 0.001) and that between R (COB) and age was positive (r = 0.26, r2 = 0.07) (P = 0.01). To conclude, central sector is the steepest sector in comparison to all the other sectors. This is indicative of a prolate shape of choroidal contour at CIB and COB. Outer boundary of choroid is steeper than inner boundary across all age groups. However, with ageing, outer boundary becomes flatter and inner boundary becomes steeper.

Influence of protocol scan on choroidal vascularity measurements: a spectralis optical coherence tomography study.

OBJECTIVES: To compare choroidal vascularity index (CVI) measurements using the automated image binarization algorithm in healthy subjects with two Spectralis spectral-domain optical coherence tomography (SD-OCT) protocol scans. METHODS: Sixty-nine eyes of 69 healthy volunteers were included in this cross-sectional prospective study. Two subsequent horizontal 20°line scans passing through the fovea were acquired with enhanced-depth imaging mode with high speed (HS) and high resolution (HR) protocol scans. CVI and its subcomponents were measured with the previously validated automated algorithm. Differences between choroidal measurements obtained with HS and HR protocol scans were evaluated with t-test and Bland & Altman plots. RESULTS: A total of 33 male (47.8%) and 36 female (52.2%) subjects with a mean age of 35.1 ± 13.4 years were included. Overall, HS protocol scan was associated with significant lower values of total choroidal area (-0.047 mm2) and stromal choroidal area (-0.036 mm2), and a significant greater value of CVI (+0.010%) if compared to HR protocol. Luminal choroidal area was lower when calculated with the HS protocol, although it did not reach significance. To compare the two different protocols, the number of pixels should be multiplied for 3.87 ×5.73 when the CVI is measured on a HR OCT b scan and 3.87 ×11.46 for the HS OCT b scan. CONCLUSIONS: HS and HR acquisition modes significantly influence CVI and its subcomponents values measured with the automated software. However, adopting the scale factors can minimize the differences between the two protocol scans.

Choroidal vascularity index in leptochoroid: A comparative analysis between reticular pseudodrusen and high myopia.

PURPOSE: To investigate the choroidal vascularity index (CVI) in patients affected by leptochoroid. METHODS: Three distinct age-matched cohorts were collected: patients with reticular pseudodrusen (RPD) secondary to age-related macular degeneration, patients with high-myopia, and healthy controls. CVI was calculated in the subfoveal 6000 µm diameter area. RESULTS: 54 eyes (54 patients) were included (18 eyes in each cohort). No statistical differences were disclosed in terms of age between controls, RPD patients (p = 0.062), and myopic patients (p = 0.070). Total choroidal area showed a different distribution among the 3 cohorts (p < 0.001), due to the reduction of luminal and stromal choroidal area in both RPD and myopic groups in comparison to controls (p < 0.001). Interestingly, CVI showed a different distribution between the 3 cohorts (p < 0.001). In detail, RPD group showed no changes in CVI in comparison to controls (p = 1.000), whereas the myopic group showed a higher CVI in comparison to both RPD group and controls (p < 0.001 in both analyses). CONCLUSIONS: Different changes of the choroidal vascular and stromal components characterize the leptochoroid secondary to RPD eyes and high-myopic eyes. The relative greater impairment of the vascular area in RPD eyes in comparison to myopic eyes could be at the basis of the lower development of RPD in patients with high myopia.

Radiomics-Based Prediction of Anti-VEGF Treatment Response in Neovascular Age-Related Macular Degeneration With Pigment Epithelial Detachment.

Purpose: Machine learning models based on radiomic feature extraction from clinical imaging data provide effective and interpretable means for clinical decision making. This pilot study evaluated whether radiomics features in baseline optical coherence tomography (OCT) images of eyes with pigment epithelial detachment (PED) associated with neovascular age-related macular degeneration (nAMD) can predict treatment response to as-needed anti-vascular endothelial growth factor (VEGF) therapy. Methods: Thirty-nine eyes of patients with PED undergoing anti-VEGF therapy were included. All eyes underwent a loading dose followed by as-needed therapy. OCT images at baseline, month 3, and month 6 were analyzed. Images were manually separated into non-responding, recurring, and responding eyes based on the presence or absence of subretinal fluid at month 6. PED radiomics features were then extracted from each image and images were classified as responding or recurring using a machine learning classifier applied to the radiomics features. Results: Linear discriminant analysis classification of baseline features as responsive versus recurring resulted in classification performance of 64.0% (95% confidence interval [CI] = 0.63-0.65), area under the curve (AUC = 0.78, 95% CI = 0.72-0.82), sensitivity 0.79 (95% CI = 0.63-0.87), and specificity 0.58 (95% CI = 0.50-0.67). Further analysis of features in recurring eyes identified a significant shift toward non-responding mean feature values over 6 months. Conclusions: Our results demonstrate the use of radiomics features as predictors for treatment response to as-needed anti-VEGF therapy. Our study demonstrates the potential for radiomics feature in clinical decision support for personalizing anti-VEGF therapy. Translational Relevance: The ability to use PED texture features to predict treatment response facilitates personalized clinical decision making.

Pigment epithelial detachment composition indices (PEDCI) in neovascular age-related macular degeneration.

We provide an automated analysis of the pigment epithelial detachments (PEDs) in neovascular age-related macular degeneration (nAMD) and estimate areas of serous, neovascular, and fibrous tissues within PEDs. A retrospective analysis of high-definition spectral-domain OCT B-scans from 43 eyes of 37 patients with nAMD with presence of fibrovascular PED was done. PEDs were manually segmented and then filtered using 2D kernels to classify pixels within the PED as serous, neovascular, or fibrous. A set of PED composition indices were calculated on a per-image basis using relative PED area of serous (PEDCI-S), neovascular (PEDCI-N), and fibrous (PEDCI-F) tissue. Accuracy of segmentation and classification within the PED were graded in masked fashion. Mean overall intra-observer repeatability and inter-observer reproducibility were 0.86 ± 0.07 and 0.86 ± 0.03 respectively using intraclass correlations. The mean graded scores were 96.99 ± 8.18, 92.12 ± 7.97, 91.48 ± 8.93, and 92.29 ± 8.97 for segmentation, serous, neovascular, and fibrous respectively. Mean (range) PEDCI-S, PEDCI-N, and PEDCI-F were 0.253 (0-0.952), 0.554 (0-1), and 0.193 (0-0.693). A kernel-based image processing approach demonstrates potential for approximating PED composition. Evaluating follow up changes during nAMD treatment with respect to PEDCI would be useful for further clinical applications.

Long-term retinal changes in progressive geographic atrophy.

BACKGROUND: Age-related macular degeneration (AMD) is one of the leading causes of blindness with loss of retinal layers over long term. We aim to evaluate these changes in eyes with progressive non-exudative AMD with geographic atrophy (GA). METHODS: This retrospective study included patients with GA with a minimum of 4 years follow up. Retinal layers on spectral domain optical coherence tomography (SD-OCT) were segmented based on their reflectivity patterns using validated semi-automated segmentation algorithm. The thickness of the segmented retinal layers was measured. Horizontal length of GA at baseline and last follow-up were also measured. Regression analysis was performed to correlate changes in RPE layer thickness with other retinal layers and the length of GA on OCT. RESULTS: A total of 351-line scans including 17 foveal scans showing presence of GA at final visit that is, a total of 2457 retinal layer bands were analyzed. Outer nuclear layer (ONL) (p = 0.02), outer segment layers (OSL) (p = 0.01), and retinal pigment epithelium (RPE) (p = 0.01) showed a statistically significant variation between baseline and final visit. Regression analysis showed the change in ONL (r = 0.72; p = 0.01) and OSL (r = 0.93, p < 0.01) correlated significantly with change in RPE thickness whereas rest of the layers failed to show significant correlation. CONCLUSION: Outer retinal layers (ONL and OSL) show more significant and widespread changes in retinal thickness and correlated most significantly with RPE thickness changes in eyes with GA due to AMD. Assessment of various retinal layer bands can be used as surrogate quantitative parameters to study eyes with GA.

Wide-field optical coherence tomography imaging in diabetic retinopathy.

PURPOSE: To report the individual retinal layer thicknesses up to mid-equator in patients with diabetic retinopathy (DR) using Spectralis (Heidelberg Engineering, Heidelberg, Germany) wide-field optical coherence tomography (OCT). METHODS: Retinal layers were segmented using a custom designed semi-automated algorithm, where reference points were marked by the examiner to enable software to automatically compute the thickness values of each retinal sublayer at an interval of 1 mm from reference points. The values of individual retinal thicknesses in eyes with varying severity of DR were compared with the values of healthy subjects. Generalized estimating equation was performed to compensate for inclusion of both eyes of patients. RESULTS: A total of 64 patients (119 eyes) with a mean age of 68.97 ± 10.27 years were included. Overall, ganglion cell layer (GCL)/ inner plexiform layer (IPL) complex (-31.67 microns, p < 0.001), outer plexiform layer (-6.78 microns, p = 0.002) and photoreceptor layer (-22.90 microns, p < 0.001) showed significant thinning, while outer nuclear layer thickening ( + 68.19 microns, <0.001) was noted in eyes with DM compared to healthy subjects. Thickness changes were significantly more in the macular segment compared to nasal and temporal segments. GCL/ IPL complex and photoreceptor layers were found to be significantly thin in all grades of DR. CONCLUSION: Retinal thicknesses vary significantly in patients with diabetic retinopathy and understanding patterns of these changes across different segments of the wide field OCT may help better elucidate the natural progression of the disease in terms of retinal anatomy.

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.

En Face Choroidal Vascularity in Both Eyes of Patients with Unilateral Central Serous Chorioretinopathy.

The aim of this study was to evaluate the choroidal vascularity analyzing en face optical coherence tomography (OCT) images in patients with unilateral central serous chorioretinopathy (CSC). We retrospectively evaluated 40 eyes of 20 CSC patients and 20 eyes of 10 gender- and age-matched healthy individuals. The sample consisted of: (1) CSC affected eyes; (2) unaffected fellow eyes; (3) healthy eyes. Multiple cross-sectional enhanced depth imaging OCT scans were obtained to create a volume scan. En face scans of the whole choroid were obtained at 5µm intervals and were binarized to calculate the choroidal vascularity index (CVI). The latter, defined as the proportion of the luminal area to the total choroidal area, was calculated at the level of choriocapillaris, superficial, medium and deep layers. No significant differences between choriocapillaris, superficial, medium and deep CVI were found in both eyes of CSC patients, whereas a significant different trend of changes was found in healthy eyes. Nevertheless, the en face CVI shows no difference between affected fellow and healthy eyes. In conclusion, CSC-affected eyes and fellow eyes showed a similar vascular architecture, with no statistical difference between all choroidal layers.