Choriocapillaris flow impairment predicts the development and enlargement of drusen

Purpose: To evaluate the choriocapillaris flow in regions of enlarged or new incident drusen in patients with early and intermediate age-related macular degeneration (AMD). Methods: We retrospectively reviewed and analyzed structural optical coherence tomography (OCT) and OCT angiography (OCTA) images of consecutive patients with early or intermediate AMD evaluated at the Doheny-UCLA Eye Centers between 2015 and 2018. All patients were imaged using a Cirrus OCT, and only one eye was included in the study. To be eligible for this analysis, patients were required to have a 3 7 3-mm OCTA scan acquired during the first visit (considered as baseline) and a fovea-centered 512 7 128 macular cube (6 7 6 mm) acquired at both the baseline visit and after a minimum of 1 year follow-up. The drusen maps generated from the macular cubes were used to generate a drusen area (DA) measurement and compute the difference between baseline and follow-up (\u394DA). After registering the structural OCTs to the baseline choriocapillaris (CC) OCTA, we analyzed and compared the baseline flow deficits (FD) within drusen-free region (FDDF), regions into which drusen enlarged or expanded at follow-up (FDEN), and regions in which new incident drusen (FDND) appeared at follow-up. Results: Forty-six patients were eligible for the analysis and had a mean follow-up of 1.47 years. Twelve eyes of 12 subjects had a \u394DA < 0.1 mm2. In these eyes, only the FDDF was calculated (40.37 \ub1 2.29%) and it was not significantly different from the FDDF of eyes with \u394DA 65 0.1 mm2 (40.25 \ub1 4.37%, p = 0.849). When comparing the different regions within the eyes with \u394DA 65 0.1 mm2, there was no significant difference between FDED and FDND (43.61 \ub1 4.36% and 44.16 \ub1 2.38%, p = 528), but both were significantly higher than FDDF (p = 0.001 and p < 0.001, respectively). Conclusions: Significant CC flow impairment is present under regions of intact retinal pigment epithelium (RPE) where existing drusen will enlarge into or new drusen will appear within 2 years. These findings suggest that location of drusen may not be stochastic but may be driven by regional deficits in the choriocapillaris

Choriocapillaris impairment around the atrophic lesions in patients with geographic atrophy: A swept-source optical coherence tomography angiography study

Aims To evaluate the choriocapillaris (CC) flow alterations around geographic atrophy (GA) in eyes with dry age-related macular degeneration. Methods Using a swept-source optical coherence tomography angiography (SS-OCTA) device, two volume 6 76 mm scans were acquired in patients with GA presenting between June and December 2017 at the Doheny-UCLA Eye Centers. The area of GA was delineated on the en face structural OCT fundus images. For each eye, the en face OCTA slabs at the level of the CC from the two acquisitions were averaged and compensated for signal loss using the corresponding structural en face images. The resulting images were binarised and analysed for the percentage of flow voids in the para-atrophy zone (a 500 \u3bcm wide ring around the immediate edge of the atrophy) and in the peri-atrophy zone (a 500 \u3bcm wide ring around the para-atrophy zone edge), the latter considered as a reference in the comparative analysis. Results Thirty eyes of 20 patients were enrolled. The percentage of flow voids in the para-atrophy zone was 27.23%\ub16.29% and was significantly higher than in the surrounding peri-atrophy zone (23.4%\ub16.01%; p<0.001). There was no significant correlation between the flow void percentage in these regions and age, visual acuity, extent of the atrophic area or central choroidal thickness. Conclusions A significant impairment of the CC flow is present in the zone immediately surrounding the GA lesions strengthening the hypothesis that CC alterations may be relevant to the progression of GA

Ultra-wide-field imaging in diabetic retinopathy; an overview

Purpose: To present an overview on ultra-wide-field imaging in diabetic retinopathy. Methods: A comprehensive search of the pubmed database was performed using the search terms of "ultra-wide-field imaging", "ultra-wide-field fluorescein angiography" and "diabetic retinopathy". The relevant original articles were reviewed. Results: New advances in ultra-wide-field imaging allow for precise measurements of the peripheral retinal lesions. A consistent finding amongst these articles was that ultra-wide-field imaging improved detection of peripheral lesion. There was discordance among the studies, however, on the correlation between peripheral diabetic lesions and diabetic macular edema. Conclusions: Visualization of the peripheral retina using ultra-wide-field imaging improves diagnosis and classification of diabetic retinopathy. Additional studies are needed to better define the association of peripheral diabetic lesions with diabetic macular edema. © 2016 Iranian Society of Ophthalmology

Optical coherence tomography angiography

Optical coherence tomography (OCT) was one of the biggest advances in ophthalmic imaging. Building on that platform, OCT angiography (OCTA) provides depth resolved images of blood flow in the retina and choroid with levels of detailed far exceeding that obtained with older forms of imaging. This new modality is challenging because of the need for new equipment and processing techniques, current limitations of imaging capability, and rapid advancements in both imaging and in our understanding of the imaging and applicable pathophysiology of the retina and choroid, and the requirement for understanding the origins of image artifacts. These factors lead to a steep learning curve, even for those with a working understanding dye-based ocular angiography. All for a method of imaging that is a little more than 10 years old. This review begins with a historical account of the development of OCTA, and the methods used in OCTA, including signal processing, image generation, and display techniques. This forms the basis to understand what OCTA images show as well as how image artifacts arise. The anatomy and imaging of specific vascular layers of the eye are reviewed. The integration of OCTA in multimodal imaging in the evaluation of retinal vascular occlusive diseases, diabetic retinopathy, uveitis, inherited diseases, age-related macular degeneration, and disorders of the optic nerve is presented. OCTA is an exciting, disruptive technology. Its use is rapidly expanding in clinical practice as well as for research into the pathophysiology of diseases of the posterior pole

Clinical endpoints for the study of geographic atrophy secondary to age-related macular degeneration

Purpose: To summarize the recent literature describing the application of modern technologies in the study of patients with geographic atrophy (GA) secondary to age-related macular degeneration. Methods: Review of the literature describing the terms and definitions used to describe GA, imaging modalities used to capture and measure GA, and the tests of visual function and functional deficits that occur in patients with GA. Results: In this paper, we describe the evolution of the definitions used to describe GA. We compare imaging modalities used in the characterization of GA, report on the sensitivity and specificity of the techniques where data exist, and describe the correlations between these various modes of capturing the presence of GA. We review the functional tests that have been used in patients with GA, and critically examine their ability to detect and quantify visual deficits. Conclusion: Ophthalmologists and retina specialists now have a wide range of assessments available for the functional and anatomic characterization of GA in patients with age-related macular degeneration. To date, studies have been limited by their unimodal approach, and we recommend that future studies of GA use multimodal imaging. We also suggest strategies for the optimal functional testing of patients with GA

Efficacy and Safety of Lampalizumab for Geographic Atrophy Due to Age-Related Macular Degeneration Chroma and Spectri Phase 3 Randomized Clinical Trials

Ophthalmic researc

Advanced Imaging Technologies

[No abstract available

Impact of Slab Selection on Quantification of Choriocapillaris Flow Deficits by Optical Coherence Tomography Angiography

Purpose: To assess the impact of slab selection on quantitative measurements of choriocapillaris (CC) flow deficits (FDs) using optical coherence tomography angiography (OCTA). Design: Cross-sectional study. Methods: Using a swept-source OCTA device, en face slabs to isolate the CC were first generated using the manufacturer's default setting: a 20-\u3bcm-thick slab starting 29 \u3bcm posterior to the centerline of the automatically segmented retinal pigment epithelium (RPE) band. The inner and/or outer borders were then adjusted by 2-\u3bcm increments to generate CC slabs with a range of offsets relative to the center of the RPE band. FDs of the modified slabs were compared to that of the default slab. Results: Twenty-seven eyes of healthy subjects (mean age, 42.0 years) were prospectively enrolled. FD% increased when the slab was shifted outward by 654 \u3bcm and inward by 20 \u3bcm (P <.05). Fifteen eyes (55.6%) showed large hypointense regions precluding quantification when the slab was shifted inward by 20 \u3bcm. Those without hypointensity demonstrated a decrease in FD% when the slab was shifted inward by 10-18 \u3bcm (P <.05). When modulating slab thickness, CC FD% increased and decreased when the slab thickness became thinner or thicker by 658 \u3bcm, respectively (P <.05). Conclusions: Quantitative CC parameters may be significantly influenced by small differences in the slab selection. Slab close to the RPE can be susceptible to segmentation errors. These findings highlight the importance of accurate, precise, and consistent slab definition to reliably generate quantitative CC metrics from OCTA

Relationship between choriocapillaris flow and scotopic microperimetry in early and intermediate age related macular degeneration

Purpose: To evaluate the correlation between choriocapillaris (CC) flow alterations and scotopic macular sensitivity (sMS) in patients with early and intermediate age-related macular degeneration (AMD). Design: prospective cross-sectional study METHODS: We acquired two 3x3mm and two 6x6mm swept-source optical coherence tomography angiography (OCTA) images of one eye of consecutive early or intermediate AMD patients at the Doheny UCLA Eye Centers. After 30 minutes of dark adaptation, the same eye underwent scotopic microperimetry with an 18\ub0-wide grid (52 stimuli) centered on the fovea. The two en-face CC angiograms obtained from each scan pattern were compensated for signal loss and averaged. Main outcome measures: correlation between percentages of flow deficits (FD3mm and FD6mm) and sMS in the central 10\ub0 (MS10) and the overall pattern (MS18). Results: Thirty eyes of 30 patients were enrolled, with 14 (46.7%) having subretinal drusenoid deposits (SDD). In the averaged OCTA scans, the FD3mm was 12.56\ub12.41 % while the FD6mm was 9.33\ub11.84 %. The mean MS10 and MS18 were 13.84\ub15.89 dB and 14.64\ub15.21 dB, respectively. For the MS10, the multivariate regression analysis showed a significant association only with FD3mm (\u3b2:-0.628, p<0.001) while the MS18 was significantly correlated with both SDD (\u3b2:-0.32, p=0.047) and FD6mm (\u3b2:-0.473, p=0.005). Conclusions: Our study reports a significant correlation between the CC flow impairment and the sMS in eyes with early or intermediate AMD. If replicated in future longitudinal studies, the choriocapillaris FD may prove to be a useful parameter for evaluating the functional status and prognosis of these eyes