A Systematic Comparison of Spectral-Domain Optical Coherence Tomography and Fundus Autofluorescence in Patients with Geographic Atrophy

[Complement inhibition treatment for geographic atrophy (GA): functional and morphological efficacy and relevant biomarkers in clinical practice]

The approval of complement inhibitory therapeutic agents for the treatment of geographic atrophy (GA) has highlighted the need for reliable and reproducible measurement of disease progression and therapeutic efficacy. Due to its availability and imaging characteristics optical coherence tomography (OCT) is the method of choice. Using OCT analysis based on artificial intelligence (AI), the therapeutic efficacy of pegcetacoplan was demonstrated at the levels of both the retinal pigment epithelium (RPE) and photoreceptors (PR). Cloud-based solutions that enable monitoring of GA are already available.

Effect of Pro Re Nata Regimen with Anti-VEGF on Type 3 Macular Neovascularization: Long-Term Outcomes

INTRODUCTION

The purpose of this study was to investigate long-term outcomes of intravitreal injections (IVI) of antivascular endothelial growth factor (VEGF) in neovascular age-related macular degeneration (nAMD) with type 3 macular neovascularization (MNV).

METHODS

This retrospective study included 19 eyes of 17 patients with nAMD and type 3 MNV treated with anti-VEGF IVI with a loading dose and a PRN regimen. Best corrected visual acuity (BCVA), central macular thickness (CMT), presence of macular intraretinal fluid (IRF) and subretinal fluid (SRF), flow area (FA), subfoveal choroidal thickness (CT), and macular atrophy (MA) were assessed at baseline (T0) and during follow-up (T1, post-loading phase; T2, 1 year; T3, 2 years; T4 >2 years). The correlations between MA at the last follow-up and standard deviation (SD) values of CMT and CT during follow-up were assessed. The influence of the number of injections on the change in MA over time was also analyzed. MA differences at T4 were assessed for pseudodrusen presence.

RESULTS

BCVA improved significantly during follow-up (p = 0.013) particularly increasing from baseline to post-loading phase and then did not modify significantly thereafter. CMT significantly reduced from T0 to T1 and remained stable during follow-up (p = <0.001). MNV flow area showed a trend toward an increase in the post-loading phase that was not statistically significant (p = 0.082) and CT decreased significantly during follow-up (p < 0.001). MA changed significantly during follow-up (p < 0.001) with a significant increase from T0 to T3 and from T0 to T4 (p < 0.010). A Cochran-Armitage test for trend showed a significant reduction (p = 0.001) of macular IRF and SRF during follow-up. MA at T4 showed a significant positive correlation with SD (standard deviation) values of CMT (p = 0.040) and CT (p = 0.020). Indeed, the number of injections did not influence the change over time of MA (p = 0.709). MA at T4 was not statistically significantly different between patients with pseudodrusen at baseline (p = 0.497).

CONCLUSIONS

Intravitreal anti-VEGF injections with PRN regimen in MNV type 3 showed functional and anatomical benefits. Variations of retinal thickness and choroidal thickness during treatment were related to MA modification over time.

Functional Evaluation of Retinal Pigment Epithelium and Outer Retinal Atrophy by High-Density Targeted Microperimetry Testing

Purpose

Complete retinal pigment epithelium (RPE) and outer retinal atrophy (cRORA) on OCT imaging has recently been proposed to describe end-stage atrophy in age-related macular degeneration (AMD) by international consensus and expected to be associated with a dense scotoma, but such functional evidence is lacking. This study sought to examine the visual sensitivity defects associated with cRORA and to determine OCT features associated with deep defects.

Design

Observational study.

Participants

Sixty eyes from 53 participants, including 342 microperimetry tests over 171 study visits.

Methods

Participants underwent targeted high-density threshold-based microperimetry testing of atrophic lesions (with at least incomplete RPE and outer retinal atrophy [iRORA]) with a 3.5° diameter grid. The maximum extent of signs of atrophy for all lesions was graded on OCT imaging.

Main Outcome Measures

Number of deep visual sensitivity defects (threshold ≤ 10 decibels [dB]).

Results

Presence of choroidal signal hypertransmission ≥ 500 μm, complete RPE loss ≥250 μm, and inner nuclear layer and outer plexiform layer subsidence, and hyporeflective wedge-shaped band (defined as nascent geographic atrophy [nGA]) ≥ 500 μm (P ≤ 0.020), but not RPE attenuation or disruption (P ≥ 0.192), were all independently associated with a significant increase in the number of deep visual sensitivity defects ≤ 10 dB. Only cRORA lesions with hypertransmission ≥ 500 μm or complete RPE loss ≥ 250 μm, or with both of these features (P < 0.001), but not lesions with only hypertransmission 250-499 μm (P = 0.303), had significantly more deep visual sensitivity defects ≤ 10 dB compared with iRORA lesions. Lesions with nGA ≥ 500 μm, irrespective of the presence of hypertransmission ≥ 500 μm and/or complete RPE loss ≥ 250 μm, also showed a higher number of deep visual sensitivity defects ≤ 10 dB compared with lesions without nGA ≥ 500 μm (P ≤ 0.011).

Conclusions

Not all cRORA lesions show a difference in the number of deep visual sensitivity defects compared with iRORA. Instead, hypertransmission ≥ 500 μm, complete RPE loss ≥ 250 μm, and nGA ≥ 500 μm are all OCT features independently associated with deep visual sensitivity detects that could help inform the definition of end-stage atrophy on OCT imaging.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Evolution of macular atrophy in eyes with neovascular age-related macular degeneration compared to fellow non-neovascular eyes

PURPOSE

Τo evaluate the evolution of macular atrophy (MA) in patients with neovascular AMD (nAMD), compared with their fellow eyes exhibiting dry AMD (dAMD).

METHODS

This retrospective study included 124 patients from three centers treated with anti-VEGF in their nAMD eye and having dAMD in the fellow eye. Patients without MA at baseline were analyzed to study the time to first MA development. Synchronous and unsynchronous time course of MA was also studied. MA was evaluated using near-infrared images, while all available optical coherence tomography (OCT) images were used to confirm the criteria proposed by the Classification of Atrophy Meetings group for complete MA.

RESULTS

MA first detection in nAMD eyes increased significantly from year 2 to 6 compared to dAMD eyes. Over the study's follow-up, 45.1% of nAMD-E developed MA, compared to 16.5% of fellow eyes (p < 0.001). When MA in the two eyes was compared in a synchronous paired manner over 4 years, nAMD eyes had an average MA progression rate of 0.275 mm/year versus 0.110 mm/year in their fellow dAMD eyes. Multivariate ANOVA revealed significant time (p < 0.001), eye (p = 0.003), and time-eye interaction (p < 0.001) effects. However, when MA did develop in dAMD eyes and was compared in an asynchronous manner to MA of nAMD eyes, it was found to progress faster in dAMD eyes (dAMD: 0.295 mm/year vs. nAMD: 0.176 mm/year) with a significant time-eye interaction (p = 0.015).

CONCLUSIONS

In this study, a significant difference in MA incidence and progression was documented in eyes with nAMD under treatment, compared to fellow eye exhibiting dAMD. Eyes with nAMD tended to develop more MA compared to fellow dAMD eyes. However, when atrophy did develop in the fellow dAMD eyes, it progressed faster over time compared to MA in nAMD eyes.

Comparison between B-Scan and En Face Images for Incomplete and Complete Retinal Pigment Epithelium and Outer Retinal Atrophy

PURPOSE

To evaluate and compare the detection of incomplete retinal pigment epithelium and outer retinal atrophy (iRORA) and complete retinal pigment epithelium and outer retinal atrophy (cRORA) assessed on OCT B-scans versus persistent choroidal hypertransmission defects (hyperTDs) assessed by en face choroidal OCT images.

DESIGN

Retrospective, cross-sectional study.

PARTICIPANTS

Patients with late atrophic age-related macular degeneration imaged on the same day using both Spectralis OCT and Cirrus OCT.

MAIN OUTCOME MEASURE

Agreement between the B-scan and en face OCT for the detection of hyperTDs, cRORA, and iRORA.

METHODS

Two independent graders examined en face OCT and structural OCT to determine the presence and location of hyperTDs, iRORA, and cRORA.

RESULTS

A total of 239 iRORA and cRORA lesions were detected on the B-scans, and 249 hyperTD lesions were identified on the en face OCT images. There was no significant difference (P = 0.88) in the number of lesions. There was no significant difference in the 134 cRORA lesions identified on B-scans and the 131 hyperTDs detected on en face OCT images (P = 0.13). A total of 105 iRORA lesions were identified by B-scan assessment; however, 50 of these iRORA lesions met the criteria for persistent hyperTDs on en face OCT images (P < 0.001). When considering the topographic correspondence between B-scan and en face OCT detected lesions, the mean percentage of agreement between B-scan detection of cRORA lesions with en face OCT detection was 97.6 % (P = 0.13).

CONCLUSIONS

We observed high overall agreement between cRORA lesions identified on B-scans and persistent hyperTDs identified on en face OCT. However, en face imaging was able to detect iRORA lesions that had a greatest linear dimension ≥ 250 μm in a nonhorizontal en face dimension.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

A systematic evaluation of human expert agreement on optical coherence tomography biomarkers using multiple devices

OBJECTIVES

To assess the agreement in evaluating optical coherence tomography (OCT) variables in the leading macular diseases such as neovascular age-related macular degeneration (nAMD), diabetic macular oedema (DMO) and retinal vein occlusion (RVO) among OCT-certified graders.

METHODS

SD-OCT volume scans of 356 eyes were graded by seven graders. The grading included presence of intra- and subretinal fluid (IRF, SRF), pigment epithelial detachment (PED), epiretinal membrane (ERM), conditions of the vitreomacular interface (VMI), central retinal thickness (CRT) at the foveal centre-point (CP) and central millimetre (CMM), as well as height and location of IRF/SRF/PED. Kappa statistics (κ) and intraclass correlation coefficient (ICC) were used to report categorical grading and measurement agreement.

RESULTS

The overall agreement on the presence of IRF/SRF/PED was κ = 0.82/0.85/0.81; κ of VMI condition was 0.77, that of ERM presence 0.37. ICC for CRT measurements at CP and CMM was excellent with an ICC of 1.00. Height measurements of IRF/SRF/PED showed robust consistency with ICC = 0.85-0.93. There was substantial to almost perfect agreement in locating IRF/SRF/PED with κ = 0.67-0.86. Between diseases, κ of IRF/SRF presence was 0.69/0.80 for nAMD, 0.64/0.83 for DMO and 0.86/0.89 for RVO.

CONCLUSION

Even in the optimized setting, featuring certified graders, standardized image acquisition and the use of a professional reading platform, there is a disease dependent variability in biomarker evaluation that is most pronounced for IRF in nAMD as well as DMO. Our findings highlight the variability in the performance of human expert OCT grading and the need for AI-based automated feature analyses.

Geographic Atrophy in AMD: Prognostic Factors Based on Long-Term Follow-Up

INTRODUCTION

The aim of this large-scale long-term retrospective study was to show the enlargement rate (ER) of geographic atrophy (GA) in age-related macular degeneration (AMD), defined as complete retinal pigment epithelium and outer retinal atrophy (cRORA), to find predictors of progression in a clinical routine setting and to compare GA evaluation methods.

METHODS

All patients available in our database with follow-up of at least 24 months and cRORA in at least one eye, regardless of neovascular AMD being present, were included. SD-OCT and fundus autofluorescence (FAF) evaluations were performed according to a standardized protocol. The cRORA area ER, the cRORA square root area ER, the FAF GA area, and the condition of the outer retina (inner-/outer-segment [IS/OS] line and external limiting membrane [ELM] disruption scores) were determined.

RESULTS

204 eyes of 129 patients were included. Mean follow-up time was 4.2 ± 2.2 (range 2-10) years. 109 of 204 (53.4%) eyes were classified as MNV-associated GA in AMD (initially or during follow-up); 95 of 204 (46.6%) eyes were classified as pure GA in AMD. The primary lesion was unifocal in 146 (72%) eyes and multifocal in 58 (28%) eyes. A strong correlation was observed between the area of cRORA (SD-OCT) and the FAF GA area (r = 0.924; p < 0.001). Mean ER was 1.44 ± 1.2 mm2/year, mean square root ER 0.29 ± 0.19 mm/year. There was no significant difference in mean ER between eyes without (pure GA) and with intravitreal anti-VEGF injections (MNV-associated GA) (0.30 ± 0.19 mm/year vs. 0.28 ± 0.20 mm/year; p = 0.466). Eyes with multifocal atrophy pattern at baseline had a significantly higher mean ER compared to eyes with unifocal pattern (0.34 ± 0.19 mm/year vs. 0.27 ± 1.19 mm/year; p = 0.008). There were moderate significant correlations between ELM and IS/OS disruption scores and visual acuity at baseline, 5 and 7 years (all r values ca. -0.5; p < 0.001). In multivariate regression analysis, a multifocal cRORA pattern at baseline (p = 0.022) and a smaller baseline lesion size (p = 0.036) were associated with a higher mean ER.

CONCLUSION

SD-OCT-evaluated cRORA area might serve as a GA parameter comparable to traditional FAF measurement in clinical routine. The dispersion pattern and baseline lesion size might be predictors of ER, whereas anti-VEGF treatment seems not to be associated with ER.

Clinical validation for automated geographic atrophy monitoring on OCT under complement inhibitory treatment

Geographic atrophy (GA) represents a late stage of age-related macular degeneration, which leads to irreversible vision loss. With the first successful therapeutic approach, namely complement inhibition, huge numbers of patients will have to be monitored regularly. Given these perspectives, a strong need for automated GA segmentation has evolved. The main purpose of this study was the clinical validation of an artificial intelligence (AI)-based algorithm to segment a topographic 2D GA area on a 3D optical coherence tomography (OCT) volume, and to evaluate its potential for AI-based monitoring of GA progression under complement-targeted treatment. 100 GA patients from routine clinical care at the Medical University of Vienna for internal validation and 113 patients from the FILLY phase 2 clinical trial for external validation were included. Mean Dice Similarity Coefficient (DSC) was 0.86 ± 0.12 and 0.91 ± 0.05 for total GA area on the internal and external validation, respectively. Mean DSC for the GA growth area at month 12 on the external test set was 0.46 ± 0.16. Importantly, the automated segmentation by the algorithm corresponded to the outcome of the original FILLY trial measured manually on fundus autofluorescence. The proposed AI approach can reliably segment GA area on OCT with high accuracy. The availability of such tools represents an important step towards AI-based monitoring of GA progression under treatment on OCT for clinical management as well as regulatory trials.

The pseudohypopyon stage in adult-onset foveomacular vitelliform dystrophy

PURPOSE

To gain insight into the pathogenesis of adult-onset foveomacular vitelliform dystrophy (AFVD) via assessment of its pseudohypopyon stage (PHS).

METHODS

Retrospectively, data were collected in a tertiary center from established cohorts of a genetically evaluated AFVD and best vitelliform macular dystrophy (BVMD) eyes in the pseudohypopyon stage. Best-corrected visual acuity (BCVA, LogMAR), lesion characterization, including lesion dimensions, liquefaction areas and patterns (altitudinal or lateral), and ellipsoid zone integrity were analyzed from spectral-domain optical coherence tomography images.

RESULTS

Out of 167 eyes of 90 AFVD patients and 56 eyes of 28 BVMD patients, 8 eyes of six AFVD patients and five eyes of four BVMD patients were at the PHS were included. The mean LogMAR BCVA ± SD was 0.21 ± 0.20 and 0.41 ± 0.10 in AFVD and BVMD diseases, respectively (p = 0.13). Seven AFVD eyes (87.5%) demonstrated lateral liquefaction, while all BVMD eyes demonstrated an altitudinal pattern (p = 0.005). Maximal horizontal lesion diameters were 1.41 ± 0.46 mm and 2.64 ± 0.77 mm in AFVD and BVMD, respectively (p = 0.02). AFVD patients were older (69 ± 14) than BVMD patients (22 ± 13; p = 0.009).

CONCLUSION

The pseudohypopyon stage in AFVD is often characterized by a lateral liquefaction pattern, unlike the altitudinal pattern characterizing BVMD. Age, lesion size, or pathogenesis pathways may underline the different pseudohypopyon stage patterns in AFVD and BVMD.

A Deep Learning Model for Automated Segmentation of Geographic Atrophy Imaged Using Swept-Source OCT

PURPOSE

To present a deep learning algorithm for segmentation of geographic atrophy (GA) using en face swept-source OCT (SS-OCT) images that is accurate and reproducible for the assessment of GA growth over time.

DESIGN

Retrospective review of images obtained as part of a prospective natural history study.

SUBJECTS

Patients with GA (n = 90), patients with early or intermediate age-related macular degeneration (n = 32), and healthy controls (n = 16).

METHODS

An automated algorithm using scan volume data to generate 3 image inputs characterizing the main OCT features of GA-hypertransmission in subretinal pigment epithelium (sub-RPE) slab, regions of RPE loss, and loss of retinal thickness-was trained using 126 images (93 with GA and 33 without GA, from the same number of eyes) using a fivefold cross-validation method and data augmentation techniques. It was tested in an independent set of one hundred eighty 6 × 6-mm² macular SS-OCT scans consisting of 3 repeated scans of 30 eyes with GA at baseline and follow-up as well as 45 images obtained from 42 eyes without GA.

MAIN OUTCOME MEASURES

The GA area, enlargement rate of GA area, square root of GA area, and square root of the enlargement rate of GA area measurements were calculated using the automated algorithm and compared with ground truth calculations performed by 2 manual graders. The repeatability of these measurements was determined using intraclass coefficients (ICCs).

RESULTS

There were no significant differences in the GA areas, enlargement rates of GA area, square roots of GA area, and square roots of the enlargement rates of GA area between the graders and the automated algorithm. The algorithm showed high repeatability, with ICCs of 0.99 and 0.94 for the GA area measurements and the enlargement rates of GA area, respectively. The repeatability limit for the GA area measurements made by grader 1, grader 2, and the automated algorithm was 0.28, 0.33, and 0.92 mm², respectively.

CONCLUSIONS

When compared with manual methods, this proposed deep learning-based automated algorithm for GA segmentation using en face SS-OCT images was able to accurately delineate GA and produce reproducible measurements of the enlargement rates of GA.

Comparison of Fundus Autofluorescence Versus Optical Coherence Tomography-based Evaluation of the Therapeutic Response to Pegcetacoplan in Geographic Atrophy

PURPOSE

To perform an optical coherence tomography (OCT)-based analysis of geographic atrophy (GA) progression in patients treated with pegcetacoplan.

DESIGN

Post hoc analysis of a phase 2 multicenter, randomized, sham-controlled trial.

METHODS

Manual annotation of retinal pigment epithelium (RPE), ellipsoid zone (EZ), and external limiting membrane (ELM) loss was performed on OCT volumes from baseline and month 12 from the phase 2 FILLY trial of intravitreal pegcetacoplan for the treatment of GA secondary to age-related macular degeneration.

MAIN OUTCOME MEASURES

Correlation of GA areas measured on fundus autofluorescence and OCT. Difference in square root transformed growth rates of RPE, EZ, and ELM loss between treatment groups (monthly injection [AM], injection every other month [AEOM], and sham [SM]).

RESULTS

OCT volumes from 113 eyes of 113 patients (38 AM, 36 AEOM, and 39 SM) were included, resulting in 11 074 B-scans. The median growth of RPE loss was significantly slower in the AM group (0.158 [0.057-0.296]) than the SM group (0.255 [0.188-0.359], P = .014). Importantly, the growth of EZ loss was also significantly slower in the AM group (0.127 [0.041-0.247]) than the SM group (0.232 [0.130-0.349], P = .017). There was no significant difference in the growth of ELM loss between the treatment groups (P = .114).

CONCLUSIONS

OCT imaging provided consistent results for GA growth compared with fundus autofluorescence. In addition to slower RPE atrophy progression in patients treated with pegcetacoplan, a significant reduction in EZ impairment was also identified by OCT, suggesting the use of OCT as a potentially more sensitive monitoring tool in GA therapy.

Does the Outer Retinal Thickness Around Geographic Atrophy Represent Another Clinical Biomarker for Predicting Growth?

PURPOSE

To determine whether the outer retinal layer (ORL) thickness around geographic atrophy (GA) could serve as a clinical biomarker to predict the annual enlargement rate (ER) of GA.

DESIGN

Retrospective analysis of a prospective, observational case series.

METHODS

Eyes with GA were imaged with a swept-source OCT 6 × 6 mm scan pattern. GA lesions were measured from customized en face OCT images and the annual ERs were calculated. The ORL was defined and segmented from the inner boundary of outer plexiform layer (OPL) to the inner boundary of retinal pigment epithelium (RPE) layer. The ORL thickness was measured at different subregions around GA.

RESULTS

A total of 38 eyes from 27 participants were included. The same eyes were used for the choriocapillaris (CC) flow deficit (FD) analysis and the RPE to the Bruch membrane (RPE-BM) distance measurements. A negative correlation was observed between the ORL thickness and the GA growth. The ORL thickness in a 300-μm rim around GA showed the strongest correlation with the GA growth (r = -0.457, P = .004). No correlations were found between the ORL thickness and the CC FDs; however, a significant correlation was found between the ORL thickness and the RPE-BM distances around GA (r = -0.398, P = .013).

CONCLUSIONS

ORL thickness showed a significant negative correlation with annual GA growth, but also showed a significant correlation with the RPE-BM distances, suggesting that they were dependently correlated with GA growth. This finding suggests that the loss of photoreceptors was associated with the formation of basal laminar deposits around GA.

The effect of pegcetacoplan treatment on photoreceptor maintenance in geographic atrophy monitored by AI-based OCT analysis

PURPOSE

To investigate the therapeutic effect of intravitreal pegcetacoplan on the inhibition of photoreceptor (PR) loss and thinning in geographic atrophy (GA) on conventional spectral domain-optical coherence tomography (SD-OCT) imaging by deep learning-based automated PR quantification.

DESIGN

Post-hoc analysis of a prospective, multicenter, randomized, sham-controlled, masked phase II trial investigating the safety and efficacy of pegcetacoplan for the treatment of GA due to age-related macular degeneration.

PARTICIPANTS

Study eyes of 246 patients, randomized 1:1:1 to monthly (AM), bimonthly (AEOM) and sham (SM) treatment.

METHODS

We performed fully automated, deep learning-based segmentation of retinal pigment epithelium (RPE) loss and PR thickness on SD-OCT volumes acquired at baseline, month 2, 6 and 12. The difference in the change of PR loss area was compared between treatment arms. Change in PR thickness adjacent to the GA borders and in the whole 20 degrees scanning area was compared between treatment arms.

MAIN OUTCOME MEASURES

Square root transformed PR loss area in μm or mm, PR thickness in μm, PR loss/RPE loss ratio.

RESULTS

A total of 31,556 B-Scans of 644 SD-OCT volumes of 161 study eyes (AM: 52, AEOM: 54, SM: 56) were evaluated from baseline to month 12. Comparison of mean change in PR loss area revealed statistically significantly less growth in the AM group at month 2, 6 and 12 compared to SM (-41μm ± 219 vs. 77μm ± 126, p=0.0004; -5μm ± 221 vs. 156μm ± 139, p<0.0001; 106μm ± 400 vs. 283μm ± 226 p=0.0014). PR thinning was significantly reduced under monthly treatment compared to sham within the GA junctional zone as well as throughout the 20 degrees area. A trend towards greater inhibition of PR loss compared to RPE loss was observed under therapy.

CONCLUSIONS

Distinct and reliable quantification of PR loss using deep learning-based algorithms offers an essential tool to evaluate therapeutic efficacy in slowing disease progression. PR loss and thinning are reduced by intravitreal complement C3 inhibition. Automated quantification of PR loss/maintenance based on OCT images is an ideal approach to reliably monitor disease activity and therapeutic efficacy in GA management in clinical routine and regulatory trials.

Optical Coherence Tomography Measurements of the Retinal Pigment Epithelium to Bruch Membrane Thickness Around Geographic Atrophy Correlate With Growth

PURPOSE

The retinal pigment epithelium (RPE) to Bruch membrane (BM) distance around geographic atrophy (GA) was measured using an optical attenuation coefficient (OAC) algorithm to determine whether this measurement could serve as a clinical biomarker to predict the annual square root enlargement rate (ER) of GA.

DESIGN

A retrospective analysis of a prospective, observational case series.

METHODS

Eyes with GA secondary to age-related macular degeneration (AMD) were imaged with swept-source OCT (SS-OCT) using a 6 × 6-mm scan pattern. GA lesions were identified and measured using customized en face OCT images, and GA annual square root ERs were calculated. At baseline, the OACs were calculated from OCT datasets to generate customized en face OAC images for GA visualization. RPE-BM distances were measured using OAC data from different subregions around the GA.

RESULTS

A total of 38 eyes from 27 patients were included in this study. Measured RPE-BM distances were the highest in the region closest to GA. The RPE-BM distances immediately around the GA were significantly correlated with GA annual square root ERs (r = 0.595, P < .001 for a 0- to 300-µm rim around the GA). No correlations were found between RPE-BM distances and previously published choriocapillaris (CC) flow deficits in any subregions.

CONCLUSIONS

RPE-BM distances from regions around the GA significantly correlate with the annual ERs of GA. These results suggest that an abnormally thickened RPE/BM complex contributes to GA growth and that this effect is independent of CC perfusion deficits.

Progression of cRORA (Complete RPE and Outer Retinal Atrophy) in Dry Age-Related Macular Degeneration Measured Using SD-OCT

Purpose

The purpose of this study was to evaluate the long-term rate of progression and baseline predictors of geographic atrophy (GA) using complete retinal pigment epithelium and outer retinal atrophy (cRORA) annotation criteria.

Methods

This is a retrospective study. Columns of GA were manually annotated by two graders using a self-developed software on optical coherence tomography (OCT) B-scans and projected onto the infrared images. The primary outcomes were: (1) rate of area progression, (2) rate of square root area progression, and (3) rate of radial progression towards the fovea. The effects of 11 additional baseline predictors on the primary outcomes were analyzed: total area, focality (defined as the number of lesions whose area is >0.05 mm2), circularity, total lesion perimeter, minimum diameter, maximum diameter, minimum distance from the center, sex, age, presence/absence of hypertension, and lens status.

Results

GA was annotated in 33 pairs of baseline and follow-up OCT scans from 33 eyes of 18 patients with dry age-related macular degeneration (AMD) followed for at least 6 months. The mean rate of area progression was 1.49 ± 0.86 mm2/year (P < 0.0001 vs. baseline), and the mean rate of square root area progression was 0.33 ± 0.15 mm/year (P < 0.0001 vs. baseline). The mean rate of radial progression toward the fovea was 0.07 ± 0.11 mm/year. A multiple variable linear regression model (adjusted r2 = 0.522) revealed that baseline focality and female sex were significantly correlated with the rate of GA area progression.

Conclusions

GA area progression was quantified using OCT as an alternative to conventional measurements performed on fundus autofluorescence images. Baseline focality correlated with GA area progression rate and lesion's minimal distance from the center correlated with GA radial progression rate toward the center. These may be important markers for the assessment of GA activity.

Translational Relevance

Advanced method linking specific retinal micro-anatomy to GA area progression analysis.

Correlation between Topographic Progression of Geographic Atrophy and Visual Acuity Changes

Purpose

To analyze topographic progression of geographic atrophy with different concentric circles centered on the fovea in correlation with decrease of visual acuity.

Methods

We retrospectively analyzed 36 eyes of 26 patients diagnosed with geographic atrophy and followed at least 1 year. One millimeter circular area at the foveal center were defined as zone 1, and doughnut shape areas from between 1 and 2 mm to between 5 and 6 mm were defined as zone 2 to 6. Then, changes of geographic atrophy area in each zone were measured with semi-automatic software. Correlation analysis and regression analysis were performed to determine the relationship between changes in visual acuity and atrophic area in each zone.

Results

Mean age was 76.9 years and follow-up period were 3.38 years. The mean atrophic area increased from 8.09 to 16.34 mm² and visual acuity decreased from 0.39 to 0.69 on logarithm of the minimal angle of resolution. Mean change of total geographic atrophy area was not significantly correlated with visual acuity decrease. While geographic atrophy progression within zone 1, 2, and 3 showed significant causal relationship with decrease of visual acuity (all, p < 0.05).

Conclusions

In contrast to the total geographic atrophy area, progression of geographic atrophy in parafoveal area was significantly correlated with decrease of visual acuity.

OCT Signs of Early Atrophy in Age-Related Macular Degeneration: Interreader Agreement: Classification of Atrophy Meetings Report 6

PURPOSE

To determine the interreader agreement for incomplete retinal pigment epithelium (RPE) and outer retinal atrophy (iRORA) and complete RPE and outer retinal atrophy (cRORA) and their related features in age-related macular degeneration (AMD).

DESIGN

Interreader agreement study.

PARTICIPANTS

Twelve readers from 6 reading centers.

METHODS

After formal training, readers qualitatively assessed 60 OCT B-scans from 60 eyes with AMD for 9 individual features associated with early atrophy and performed 7 different annotations to quantify the spatial extent of OCT features within regions of interest. The qualitative and quantitative features were used to derive the presence of iRORA and cRORA and also in an exploratory analysis to examine if agreement could be improved using different combinations of features to define OCT atrophy.

MAIN OUTCOME MEASURES

Interreader agreement based on Gwet's first-order agreement coefficient (AC₁) for qualitatively graded OCT features and classification of iRORA and cRORA, and smallest real difference (SRD) for quantitatively graded OCT features.

RESULTS

Substantial or better interreader agreement was observed for all qualitatively graded OCT features associated with atrophy (AC₁ = 0.63-0.87), except for RPE attenuation (AC₁ = 0.46) and disruption (AC₁ = 0.26). The lowest SRD for the quantitatively graded horizontal features was observed for the zone of choroidal hypertransmission (± 190.8 μm). Moderate agreement was found for a 3-category classification of no atrophy, iRORA, and cRORA (AC₁ = 0.53). Exploratory analyses suggested a significantly higher level of agreement for a 3-category classification using (1) no atrophy; (2) presence of inner nuclear layer and outer plexiform layer subsidence, or a hyporeflective wedge-shaped band, as a less severe atrophic grade; and (3) the latter plus an additional requirement of choroidal hypertransmission of 250 μm or more for a more severe atrophic grade (AC₁ = 0.68; P = 0.013).

CONCLUSIONS

Assessment of iRORA and cRORA, and most of their associated features, can be performed relatively consistently and robustly. A refined combination of features to define early atrophy could further improve interreader agreement.

Reliability of Retinal Pathology Quantification in Age-Related Macular Degeneration: Implications for Clinical Trials and Machine Learning Applications

Purpose

To investigate the interreader agreement for grading of retinal alterations in age-related macular degeneration (AMD) using a reading center setting.

Methods

In this cross-sectional case series, spectral-domain optical coherence tomography (OCT; Topcon 3D OCT, Tokyo, Japan) scans of 112 eyes of 112 patients with neovascular AMD (56 treatment naive, 56 after three anti-vascular endothelial growth factor injections) were analyzed by four independent readers. Imaging features specific for AMD were annotated using a novel custom-built annotation platform. Dice score, Bland-Altman plots, coefficients of repeatability, coefficients of variation, and intraclass correlation coefficients were assessed.

Results

Loss of ellipsoid zone, pigment epithelium detachment, subretinal fluid, and drusen were the most abundant features in our cohort. Subretinal fluid, intraretinal fluid, hypertransmission, descent of the outer plexiform layer, and pigment epithelium detachment showed highest interreader agreement, while detection and measures of loss of ellipsoid zone and retinal pigment epithelium were more variable. The agreement on the size and location of the respective annotation was more consistent throughout all features.

Conclusions

The interreader agreement depended on the respective OCT-based feature. A selection of reliable features might provide suitable surrogate markers for disease progression and possible treatment effects focusing on different disease stages.

Translational Relevance

This might give opportunities for a more time- and cost-effective patient assessment and improved decision making as well as have implications for clinical trials and training machine learning algorithms.

Local Anatomic Precursors to New-Onset Geographic Atrophy in Age-Related Macular Degeneration as Defined on OCT

PURPOSE

In macula-wide analyses, spectral-domain (SD) optical coherence tomography (OCT) features including drusen volume, hyperreflective foci, and OCT-reflective drusen substructures independently predict geographic atrophy (GA) onset secondary to age-related macular degeneration (AMD). We sought to identify SD OCT features in the location of new GA before its onset.

DESIGN

Retrospective study.

PARTICIPANTS

Age-Related Eye Disease Study 2 Ancillary SD OCT Study participants.

METHODS

We analyzed longitudinally captured SD OCT images and color photographs from 488 eyes of 488 participants with intermediate AMD at baseline. Sixty-two eyes with sufficient image quality demonstrated new-onset GA on color photographs during study years 2 through 7. The area of new-onset GA and one size-matched control region in the same eye were segmented separately, and corresponding spatial volumes on registered SD OCT images at the GA incident year and at 2, 3, and 4 years previously were defined. Differences in SD OCT features between paired precursor regions were evaluated through matched-pairs analyses.

MAIN OUTCOME MEASURES

Localized SD OCT features 2 years before GA onset.

RESULTS

Compared with paired control regions, GA precursor regions at 2, 3, and 4 years before (n = 54, 33, and 25, respectively) showed greater drusen volume (P = 0.01, P = 0.003, and P = 0.003, respectively). At 2 and 3 years before GA onset, they were associated with the presence of hypertransmission (P < 0.001 and P = 0.03, respectively), hyperreflective foci (P < 0.001 and P = 0.045, respectively), OCT-reflective drusen substructures (P = 0.004 and P = 0.03, respectively), and loss or disruption of the photoreceptor zone, ellipsoid zone, and retinal pigment epithelium (RPE, P < 0.001 and P = 0.005-0.045, respectively). At 4 years before GA onset, precursor regions were associated with photoreceptor zone thinning (P = 0.007) and interdigitation zone loss (P = 0.045).

CONCLUSIONS

Evolution to GA is heralded by early local photoreceptor changes and drusen accumulation, detectable 4 years before GA onset. These precede other anatomic heralds such as RPE changes and drusen substructure emergence detectable 1 to 2 years before GA. This study thus identified earlier end points for GA as potential therapeutic targets in clinical trials.

Automatic Quantification Software for Geographic Atrophy Associated with Age-Related Macular Degeneration: A Validation Study

Aims

To determine the accuracy and repeatability of new software to automatically quantify GA areas associated to age-related macular degeneration (AMD) by swept-source optical coherence tomography (SS-OCT). Settings and Design. Tertiary referral hospital in Spain. Cross-sectional and noninterventional. Methods and Material. Forty-six eyes from 33 AMD patients with GA, without previous choroidal neovascularization, were scanned using a SS-OCT (Topcon Corporation, Japan), including three consecutive 7 × 7 mm OCT scans. Three independent masked observers manually measured the GA area using FAF images. These measures were compared to the three automatic determinations of the GA. Lesions were classified according to their morphology and number as regular/irregular and single/multiple. Statistical Analysis Used. Intraclass correlation coefficients (ICCs) were estimated to study the agreement between the three physicians in manual measurements. ICC through a two-way mixed effects model was used for the software measures, and Lin's concordance correlation coefficient (CCC) was used to analyse the agreement between the physicians and the software.

Results

The mean age was 76.3 ± 11.7 years. Eighteen cases showed regular lesions, and 30 showed single lesions. The CCC between manual and automatic measures was 0.95 for the whole sample. The CCC for the area according to the lesion type was 0.92 and 0.97; it was 0.99 for single lesions and 0.89 for multiple lesions. The ICC between the three physicians was 0.94 for the whole sample and 0.88 in multiple lesions. The ICC between the three automatic measures for the area was 0.98 for the whole sample, regular or irregular lesions, and single or multiple lesions.

Conclusions

The accuracy of this new software is substantial for the area with a high degree of repeatability agreement, being very precise in single lesions.

Role of Deep Learning-Quantified Hyperreflective Foci for the Prediction of Geographic Atrophy Progression

PURPOSE

To quantitatively measure hyperreflective foci (HRF) during the progression of geographic atrophy (GA) secondary to age-related macular degeneration (AMD) using deep learning (DL) and investigate the association with local and global growth of GA.

METHODS

Eyes with GA were prospectively included. Spectral-domain optical coherence tomography (SDOCT) and fundus autofluorescence images were acquired every 6 months. A 500-μm-wide junctional zone adjacent to the GA border was delineated and HRF were quantified using a validated DL algorithm. HRF concentrations in progressing and nonprogressing areas, as well as correlations between HRF quantifications and global and local GA progression, were assessed.

RESULTS

A total of 491 SDOCT volumes from 87 eyes of 54 patients were assessed with a median follow-up of 28 months. Two-thirds of HRF were localized within a millimeter adjacent to the GA border. HRF concentration was positively correlated with GA progression in unifocal and multifocal GA (all P < .001) and de novo GA development (P = .037). Local progression speed correlated positively with local increase of HRF (P value range <.001-.004). Global progression speed, however, did not correlate with HRF concentrations (P > .05). Changes in HRF over time did not have an impact on the growth in GA (P > .05).

CONCLUSION

Advanced artificial intelligence (AI) methods in high-resolution retinal imaging allows to identify, localize, and quantify biomarkers such as HRF. Increased HRF concentrations in the junctional zone and future macular atrophy may represent progressive migration and loss of retinal pigment epithelium. AI-based biomarker monitoring may pave the way into the era of individualized risk assessment and objective decision-making processes. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Visual Function Decline Resulting from Geographic Atrophy: Results from the Chroma and Spectri Phase 3 Trials

PURPOSE

To assess visual function outcomes to 48 weeks in patients with bilateral geographic atrophy (GA) secondary to age-related macular degeneration included in 2 interventional clinical trials: relationship to baseline lesion size, outcomes by baseline lesion characteristic subgroups, and correlation of visual function outcomes with GA area.

DESIGN

The Chroma and Spectri studies (ClinicalTrials.gov identifiers, NCT02247479 and NCT02247531, respectively) were identically designed phase 3, double-masked, multicenter, randomized, sham injection-controlled clinical trials that evaluated intravitreal lampalizumab in GA.

PARTICIPANTS

Eligible patients were 50 years of age or older with well-demarcated bilateral GA (lesion size, 1-7 disc areas) without evidence of or previous treatment for choroidal neovascularization in either eye and best-corrected visual acuity (BCVA) letter score of 49 letters or more (≥1 GA lesion within 250 μm of foveal center if BCVA ≥79 letters).

METHODS

Patients (pooled n = 1881) were randomized 2:1:2:1 to lampalizumab every 4 weeks, sham every 4 weeks, lampalizumab every 6 weeks, or sham every 6 weeks. Sham arms were pooled for analysis.

MAIN OUTCOME MEASURES

Functional end points included change in BCVA from baseline to week 48, low-luminance visual acuity, mesopic microperimetry (number of absolute scotomatous points, mean macular sensitivity), binocular and monocular maximum reading speed, and 2 validated patient-reported outcome measures: Functional Reading Independence Index and 25-item National Eye Institute Visual Function Questionnaire.

RESULTS

Enlargement of GA area, approximately 2 mm²/year on average across all treatment groups in each study, was accompanied by overall deterioration in all functional end points. No statistically significant differences were found between lampalizumab or sham arms for changes from baseline in functional assessment scores. Of visual function tests, only microperimetry outcomes were correlated moderately with GA lesion area when assessed cross-sectionally at baseline and week 48.

CONCLUSIONS

Chroma and Spectri provide a unique data set of functional end points in GA that are relevant for future clinical trials. Patients with bilateral GA experienced a consistent decline in visual function over 48 weeks, but measures of visual function were not correlated strongly with GA lesion area. It is not possible to predict visual function outcomes from GA lesion size.

Outer Retinal Thickness and Fundus Autofluorescence in Geographic Atrophy

PURPOSE

Most studies of fundus autofluorescence (FAF) in geographic atrophy (GA) have been nonquantitative, with inadequate registration of image modalities. Furthermore, as pointed out in the recent Consensus Definition for Atrophy Associated with Age-Related Macular Degeneration on OCT, it is unclear whether decreased FAF would be correlated exclusively with a single category of OCT-defined atrophy. We sought to determine how FAF intensity in eyes with GA correlates with structural changes of the outer retina and choroid as seen on co-registered spectral domain OCT (SD-OCT) images.

DESIGN

Retrospective cross-sectional.

PARTICIPANTS

Twenty eyes of 11 patients with GA secondary to non-neovascular age-related macular degeneration (AMD).

METHODS

Spectral domain OCT and FAF images for each eye were co-registered using MATLAB (MathWorks Inc, Natick, MA). On B-scans, the choroid, retinal pigment epithelium (RPE), photoreceptor (PR) layer, and outer nuclear layer (ONL) were segmented. Regions of interest (ROIs) including all atrophic and border regions were selected manually on the FAF scans. Regions of interest were subdivided into quartiles of FAF level to correlate with retinal thickness measurements taken along the B-scans. Mean choroid, RPE, PR, and ONL thicknesses were compared across quartiles using an analysis of variance factorial design testing for interaction effects, adjusted for repeated measures (on both eyes) with a within-subjects factor.

RESULTS

Seventeen eyes of 10 patients were selected for analysis. The mean choroidal thicknesses were not significantly different across FAF quartiles, but the overall differences in mean RPE, PR layer, and ONL thicknesses across quartiles were statistically significant (analysis of variance, P < 0.001, P < 0.001, and P = 0.015, respectively). Post hoc analysis demonstrated significant differences in thickness among quartiles 1, 2, and 3 for the RPE and PR layers (Tukey, P < 0.01 in each case). The FAF quartiles within GA did not correlate exclusively with single categories of Consensus Definition for Atrophy Associated with Age-Related Macular Degeneration-defined atrophy.

CONCLUSIONS

Not only RPE but also PR layer thickness on SD-OCT varies significantly with FAF levels in GA. This suggests that although the RPE cells are losing thickness and function, evidenced by decreased FAF from fluorophores, delicate PR cells also succumb early in the disease process. These relationships should be pursued as a possibly better-detailed mechanism in GA.

Semi-automated quantification of geographic atrophy with blue-light autofluorescence and spectral-domain optical coherence tomography: a comparison between the region finder and the advanced retinal pigment epithelium tool in the clinical setting

Purpose

To compare inter‐ and intraobserver reliability and intermodality agreement on quantification of geographic atrophy, using two routinely available quantification tools, based on blue‐light fundus autofluorescence (BAF) and spectral‐domain optical coherence tomography (SD‐OCT).

Methods

Quantifications of atrophic lesions within the central 5 mm of 30 eyes from 30 patients (mean age: 76.1 years) were independently performed by two clinicians on BAF images using the region finder (RF; Heidelberg Engineering) and on SD‐OCT using the advanced retinal pigment epithelium tool (ARPET; Carl Zeiss Meditec) at baseline and follow‐up (mean interval: 336 days). Inter‐ and intraobserver reliability was determined by intraclass correlation coefficients (ICC) and Bland–Altmann plots. Additionally, graders rated the experienced difficulty of each measurement.

Results

Intraclass correlation coefficients (ICC) showed excellent inter‐ and intraobserver reliability with values between 0.994 and 0.998 for RF and slightly higher values for ARPET of 0.997 and 0.999. Bland–Altman plots showed smaller variability for ARPET. Mean interobserver differences (95% CI) for size measurements were −0.11 (−0.27; 0.05) (baseline) and −0.05 mm² (−0.18; 0.08) (follow‐up) for RF and −0.04 (−0.14; 0.06) and −0.06 mm² (−0.14; 0.02) for ARPET. Measurements of lesions were on average 0.57 mm² (0.35; 0.79) or 7.6% larger in ARPET. Lesion size between graders did not differ significantly. There was no statistically significant difference in relative enlargement rates between methods. There was poor to moderate agreement between graders when rating the experienced difficulty of each measurement.

Conclusion

Semi‐automated analysis of geographic atrophy with RF and ARPET is equally reliable and reproducible in clinical settings, despite both algorithms require frequent adjustment by users. The ARPET restricts size measurements to the central 5 mm, which limits its ability to fully track GA progression. Results of both tools are not interchangeable as measurements with ARPET result in larger lesion sizes.

HISTOLOGY OF GEOGRAPHIC ATROPHY SECONDARY TO AGE-RELATED MACULAR DEGENERATION: A Multilayer Approach

Supplemental Digital Content is Available in the Text.

High-resolution histology at the border of geographic atrophy (or complete retinal pigment epithelium and outer retinal atrophy) secondary to age-related macular degeneration reveals marked gliosis and near-total photoreceptor depletion, abundant extracellular deposits, and long-standing abnormalities of Bruch membrane and choriocapillaris, indicating severe and potentially irreversible tissue damage at this stage of the disease.

Purpose:

To systematically characterize histologic features of multiple chorioretinal layers in eyes with geographic atrophy, or complete retinal pigment epithelium (RPE) and outer retinal atrophy, secondary to age-related macular degeneration, including Henle fiber layer and outer nuclear layer; and to compare these changes to those in the underlying RPE-Bruch membrane—choriocapillaris complex and associated extracellular deposits.

Methods:

Geographic atrophy was delimited by the external limiting membrane (ELM) descent towards Bruch membrane. In 13 eyes, histologic phenotypes and/or thicknesses of Henle fiber layer, outer nuclear layer, underlying supporting tissues, and extracellular deposits at four defined locations on the non-atrophic and atrophic sides of the ELM descent were assessed and compared across other tissue layers, with generalized estimating equations and logit models.

Results:

On the non-atrophic side of the ELM descent, distinct Henle fiber layer and outer nuclear layer became dyslaminated, cone photoreceptor inner segment myoids shortened, photoreceptor nuclei and mitochondria translocated inward, and RPE was dysmorphic. On the atrophic side of the ELM descent, all measures of photoreceptor health declined to zero. Henle fiber layer/outer nuclear layer thickness halved, and only Müller cells remained, in the absence of photoreceptors. Sub-RPE deposits remained, Bruch membrane thinned, and choriocapillaris density decreased.

Conclusion:

The ELM descent sharply delimits an area of marked gliosis and near-total photoreceptor depletion clinically defined as Geographic atrophy (or outer retinal atrophy), indicating severe and potentially irreversible tissue damage. Degeneration of supporting tissues across this boundary is gradual, consistent with steady age-related change and suggesting that RPE and Müller cells subsequently respond to a threshold of stress. Novel clinical trial endpoints should be sought at age-related macular degeneration stages before intense gliosis and thick deposits impede therapeutic intervention.

Characterization of Patients With Geographic Atrophy in Routine Clinical Practice

BACKGROUND AND OBJECTIVE

Geographic atrophy (GA) affects millions of patients with age-related macular degeneration (AMD) worldwide, leading to significant, irreversible visual impairment. This study aims to characterize the visual impairment of patients with GA in a routine clinical practice.

PATIENTS AND METHODS

This single-center, cross-sectional study used a novel natural language processing to select 1,045 GA cases utilizing the macula examination records from 19,359 patients with AMD.

RESULTS

Patients were classified based on the diagnosis of the fellow-eye as follow: 502 in group 1 (GA:GA), 403 in group 2 (GA : choroidal neovascularization), and 234 in group 3 (GA : early / intermediate AMD). Best-corrected visual acuity (BCVA) in the affected eye was 50.3 (± 22.1) letters in group 1, 52.5 (± 21.3) letters in group 2, and 48.5 (± 23.6) letters in group 3 (P < .05). Visual impairment (ineligibility for an unrestricted driver license) was present in 70.5% of group 1, 59.7% of group 2, and 39.6% of group 3. Legal blindness (BCVA < 20 letters in the best-seeing eye) was seen in 2.2% of group 1, 3% of group 2, and 0.8% of group 3.

CONCLUSION

Differences in visual impairment between subgroups of patients with GA can be seen in routine clinical practice. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:93-98.].

The role of placental growth factor (PlGF) and its receptor system in retinal vascular diseases

Placental growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family. Upon binding to VEGF- and neuropilin-receptor sub-types, PlGF modulates a range of neural, glial and vascular cell responses that are distinct from VEGF-A. As PlGF expression is selectively associated with pathological angiogenesis and inflammation, its blockade does not affect the healthy vasculature. PlGF actions have been extensively described in tumor biology but more recently there has been accumulating preclinical evidence that indicates that this growth factor could have an important role in retinal diseases. High levels of PlGF have been found in aqueous humor, vitreous and/or retina of patients exhibiting retinopathies, especially those with diabetic retinopathy (DR) and neovascular age-related macular degeneration (nvAMD). Expression of this growth factor seems to correlate closely with many of the key pathogenic features of early and late retinopathy in preclinical models. For example, studies using genetic modification and/or pharmacological treatment to block PlGF in the laser-induced choroidal neovascularization (CNV) model, oxygen-induced retinopathy model, as well as various murine diabetic models, have shown that PlGF deletion or inhibition can reduce neovascularization, retinal leakage, inflammation and gliosis, without affecting vascular development or inducing neuronal degeneration. Moreover, an inhibitory effect of PlGF blockade on retinal scarring in the mouse CNV model has also been recently demonstrated and was found to be unique for PlGF inhibition, as compared to various VEGF inhibition strategies. Together, these preclinical results suggest that anti-PlGF therapy might have advantages over anti-VEGF treatment, and that it may have clinical applications as a standalone treatment or in combination with anti-VEGF. Additional clinical studies are clearly needed to further elucidate the role of PlGF and its potential as a therapeutic target in ocular diseases.

The Border of Macular Atrophy in Age-Related Macular Degeneration: A Clinicopathologic Correlation

PURPOSE

To correlate in vivo imaging to histology in an eye with macular atrophy owing to age-related macular degeneration (AMD; complete retinal pigment epithelium [RPE] and outer retinal atrophy [cRORA]) to evaluate the utility of new optical coherence tomography (OCT) suggested by previous histology.

DESIGN

Case study with clinicopathologic correlation.

METHODS

In vivo eye-tracked cross-sectional OCT scans at 13 and 8 months before death were compared to postmortem histopathology. On OCT, the atrophy border was identified as either the descent of the external limiting membrane (ELM) toward the Bruch membrane (BrM) (representing gliosis) or the presence of choroidal hypertransmission (representing lack of shadowing by RPE). Thicknesses of RPE, basal laminar deposit (BLamD), and BrM were measured at 500 and 100 μm on the nonatrophic and atrophic sides of these borders, on in vivo eye-tracked OCT and histology matched to the same location.

RESULTS

In all OCT scans, the ELM descent was visible. The RPE-BLamD band significantly thickened toward it (P < .005), over time (P = .015 and P = .043, at 500 and 100 μm, respectively). On OCT, the ELM descent delineated a smaller atrophic area than did hypertransmission. RPE-BLamD thicknesses manually measured on OCT overestimated histologic thicknesses. BrM visibility varied with RPE status.

CONCLUSION

Visible on OCT, the ELM descent is a histopathologic atrophy border supporting new terminology of cRORA, whereas hypertransmission reveals RPE degeneration. RPE-BLamD thickening across the macula, toward the atrophy and over time is confirmed. The presence of gliosis and thick RPE-BLamD suggests that macular atrophy is a late stage in disease progression, encouraging anatomic endpoints at earlier AMD stages than atrophy enlargement.

CLASSIFICATION AND QUANTITATIVE ANALYSIS OF GEOGRAPHIC ATROPHY JUNCTIONAL ZONE USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY

PURPOSE

The junctional zone at the border of areas of geographic atrophy (GA) in eyes with nonneovascular age-related macular degeneration is an important target region for future therapeutic strategies. The goal of this study was to perform a detailed classification and quantitative characterization of the junctional zone using spectral domain optical coherence tomography.

METHODS

Spectral domain optical coherence tomography volume cube scans (Spectralis OCT, 1024 × 37, Automatic Real Time > 9) were obtained from 15 eyes of 11 patients with GA because of nonneovascular age-related macular degeneration. Volume optical coherence tomography data were imported into previously described validated grading software (3D-OCTOR), and manual segmentation of the retinal pigment epithelium (RPE) and photoreceptor layers was performed on all B-scans (total of 555). Retinal pigment epithelium and photoreceptor defect maps were produced for each case. The borders of the photoreceptor defect area and RPE defect area were delineated individually on separate annotation layers. The two outlines were then superimposed to compare the areas of overlap and nonoverlap. The perimeter of the RPE defect area was calculated by the software in pixels. The superimposed outline of the photoreceptor defect area and the RPE defect area was scrutinized to classify the overlap configuration of the junctional zone into one of three categories: Type 0, exact correspondence between the edge of the RPE defect and photoreceptor defect; Type 1, loss of photoreceptors outside and beyond the edge of the RPE defect; Type 2, preservation of photoreceptors beyond the edge of the RPE defect. The relative proportion of the various border configurations was expressed as a percentage of the perimeter of the RPE defect. Each configuration was then classified into four subgroups according to irregularity of the RPE band and the presence of debris.

RESULTS

Fifteen eyes of 11 patients (mean age: 79.3 ± 4.3 years; range: 79-94 years) were included in this study. Seventeen GA lesions were analyzed. Two hundred and thirty-two B-scans were found to pass through the GA lesions, yielding 612 individual GA borders which were separately analyzed and classified. The mean area of the RPE defect was 4.0 ± 4.4 mm, which was significantly smaller than that of the photoreceptor defect which measured 4.4 ± 4.1 mm (paired t test, P = 0.037). On average, 18.0 ± 9.6% (range, 2.3-36.6%) of the junctional zone was of the Type 0 configuration, 57.3 ± 19.0% (range, 21.3-96.8%) was Type 1, and 24.7 ± 18.0% (range, 0.9-64.4%) was Type 2. Type 1 was more prevalent than Type 0 and 2 (analysis of variance, P = 0.000). Debris was present at the margin of the defect in 24.3% (149 of 612) of all assessed junctional zones; 20.0% (14 of 70) of Type 0 junctions, 28.7% (120 of 418) of Type 1, and 12.1% (15 of 124) of Type 2. Debris was more common in Type 1 than Type 2 junctions (P < 0.001). Retinal pigment epithelial irregularity was present at the margin of the defect in 34.8% (213 of 612) of all assessed junctional zones; 52.9% (37 of 70) of Type 0 junctions, 38.0% (159 of 418) of Type 1, and 13.7% (17 of 124) of Type 2. Retinal pigment epithelial irregularity was present more often at Type 0 and Type 1 than at Type 2 junctions (P < 0.001 for both).

CONCLUSION

The size of the optical coherence tomography-visible RPE and photoreceptor defect in GA lesions differ significantly. There were significant areas where the photoreceptor outer segments were preserved despite the absence of visible RPE cells, and also areas of photoreceptor outer segment loss despite apparent RPE preservation. These findings have implications for development of therapeutic strategies, particularly cell-replacement approaches.

OPTICAL COHERENCE TOMOGRAPHY AND HISTOLOGY OF AGE-RELATED MACULAR DEGENERATION SUPPORT MITOCHONDRIA AS REFLECTIVITY SOURCES

PURPOSE

Widespread adoption of optical coherence tomography has revolutionized the diagnosis and management of retinal disease. If the cellular and subcellular sources of reflectivity in optical coherence tomography can be identified, the value of this technology will be advanced even further toward precision medicine, mechanistic thinking, and molecular discovery. Four hyperreflective outer retinal bands are created by the exquisite arrangement of photoreceptors, Müller cells, retinal pigment epithelium, and Bruch membrane. Because of massed effects of these axially compartmentalized and transversely aligned cells, reflectivity can be localized to the subcellular level. This review focuses on the second of the four bands, called ellipsoid zone in a consensus clinical lexicon, with the central thesis that mitochondria in photoreceptor inner segments are a major independent reflectivity source in this band, because of Mie scattering and waveguiding.

METHODS

We review the evolution of Band 2 nomenclature in published literature and discuss the origins of imaging signals from photoreceptor mitochondria that could make these organelles visible in vivo.

RESULTS

Our recent data pertain to outer retinal tubulation, a unique neurodegenerative and gliotic structure with a highly reflective border, prominent in late age-related macular degeneration. High-resolution histology and multimodal imaging of outer retinal tubulation together provide evidence that inner segment mitochondria undergoing fission and translocation toward the nucleus provide the reflectivity signal.

CONCLUSION

Our data support adoption of the ellipsoid zone nomenclature. Identifying subcellular signal sources will newly inform clinical.

THE PATHOPHYSIOLOGY OF GEOGRAPHIC ATROPHY SECONDARY TO AGE-RELATED MACULAR DEGENERATION AND THE COMPLEMENT PATHWAY AS A THERAPEUTIC TARGET

Geographic atrophy is an advanced form of age-related macular degeneration that can significantly impact visual function, but has no approved treatment. This review focuses on the pathophysiology of geographic atrophy, particularly the role of complement cascade dysregulation and emerging therapies targeting the complement cascade.

Purpose:

Geographic atrophy (GA) is an advanced, vision-threatening form of age-related macular degeneration (AMD) affecting approximately five million individuals worldwide. To date, there are no approved therapeutics for GA treatment; however, several are in clinical trials. This review focuses on the pathophysiology of GA, particularly the role of complement cascade dysregulation and emerging therapies targeting the complement cascade.

Methods:

Primary literature search on PubMed for GA, complement cascade in age-related macular degeneration. ClinicalTrials.gov was searched for natural history studies in GA and clinical trials of drugs targeting the complement cascade for GA.

Results:

Cumulative damage to the retina by aging, environmental stress, and other factors triggers inflammation via multiple pathways, including the complement cascade. When regulatory components in these pathways are compromised, as with several GA-linked genetic risk factors in the complement cascade, chronic inflammation can ultimately lead to the retinal cell death characteristic of GA. Complement inhibition has been identified as a key candidate for therapeutic intervention, and drugs targeting the complement pathway are currently in clinical trials.

Conclusion:

The complement cascade is a strategic target for GA therapy. Further research, including on natural history and genetics, is crucial to expand the understanding of GA pathophysiology and identify effective therapeutic targets.

Fundus Autofluorescence in Age-related Macular Degeneration

: Fundus autofluorescence (FAF) provides detailed insight into the health of the retinal pigment epithelium (RPE). This is highly valuable in age-related macular degeneration (AMD) as RPE damage is a hallmark of the disease. The purpose of this paper is to critically appraise current clinical descriptions regarding the appearance of AMD using FAF and to integrate these findings into a chair-side reference. A wide variety of FAF patterns have been described in AMD, which is consistent with the clinical heterogeneity of the disease. In particular, FAF imaging in early to intermediate AMD has the capacity to reveal RPE alterations in areas that appear normal on funduscopy, which aids in the stratification of cases and may have visually significant prognostic implications. It can assist in differential diagnoses and also represents a reliable, sensitive method for distinguishing reticular pseudodrusen. FAF is especially valuable in the detection, evaluation, and monitoring of geographic atrophy and has been used as an endpoint in clinical trials. In neovascular AMD, FAF reveals distinct patterns of classic choroidal neovascularization noninvasively and may be especially useful for determining which eyes are likely to benefit from therapeutic intervention. FAF represents a rapid, effective, noninvasive imaging method that has been underutilized, and incorporation into the routine assessment of AMD cases should be considered. However, the practicing clinician should also be aware of the limitations of the modality, such as in the detection of foveal involvement and in the distinction of phenotypes (hypo-autofluorescent drusen from small areas of geographic atrophy).

Activated Retinal Pigment Epithelium, an Optical Coherence Tomography Biomarker for Progression in Age-Related Macular Degeneration

Purpose

To summarize and contextualize recent histology and clinical imaging publications on retinal pigment epithelium (RPE) fate in advanced age-related macular degeneration (AMD); to support RPE activation and migration as important precursors to atrophy, manifest as intraretinal hyperreflective foci in spectral-domain optical coherence tomography (SDOCT).

Methods

The Project MACULA online resource for AMD histopathology was surveyed systematically to form a catalog of 15 phenotypes of RPE and RPE-derived cells and layer thicknesses in advanced disease. Phenotypes were also sought in correlations with clinical longitudinal eye-tracked SDOCT and with ex vivo imaging–histopathology correlations in geographic atrophy (GA) and pigment epithelium detachments (PED).

Results

The morphology catalog suggested two main pathways of RPE fate: basolateral shedding of intracellular organelles (apparent apoptosis in situ) and activation with anterior migration. Acquired vitelliform lesions may represent a third pathway. Migrated cells are packed with RPE organelles and confirmed as hyperreflective on SDOCT. RPE layer thickening due to cellular dysmorphia and thick basal laminar deposit is observed near the border of GA. Drusenoid PED show a life cycle of slow growth and rapid collapse preceded by RPE layer disruption and anterior migration.

Conclusions

RPE activation and migration comprise an important precursor to atrophy that can be observed at the cellular level in vivo via validated SDOCT. Collapse of large drusen and drusenoid PED appears to occur when RPE death and migration prevent continued production of druse components. Data implicate excessive diffusion distance from choriocapillaris in RPE death as well as support a potential benefit in targeting drusen in GA.

Geographic atrophy phenotype identification by cluster analysis

Background/aims

To identify ocular phenotypes in patients with geographic atrophy secondary to age-related macular degeneration (GA) using a data-driven cluster analysis.

Methods

This was a retrospective analysis of data from a prospective, natural history study of patients with GA who were followed for ≥6 months. Cluster analysis was used to identify subgroups within the population based on the presence of several phenotypic features: soft drusen, reticular pseudodrusen (RPD), primary foveal atrophy, increased fundus autofluorescence (FAF), greyish FAF appearance and subfoveal choroidal thickness (SFCT). A comparison of features between the subgroups was conducted, and a qualitative description of the new phenotypes was proposed. The atrophy growth rate between phenotypes was then compared.

Results

Data were analysed from 77 eyes of 77 patients with GA. Cluster analysis identified three groups: phenotype 1 was characterised by high soft drusen load, foveal atrophy and slow growth; phenotype 3 showed high RPD load, extrafoveal and greyish FAF appearance and thin SFCT; the characteristics of phenotype 2 were midway between phenotypes 1 and 3. Phenotypes differed in all measured features (p≤0.013), with decreases in the presence of soft drusen, foveal atrophy and SFCT seen from phenotypes 1 to 3 and corresponding increases in high RPD load, high FAF and greyish FAF appearance. Atrophy growth rate differed between phenotypes 1, 2 and 3 (0.63, 1.91 and 1.73 mm²/year, respectively, p=0.0005).

Conclusion

Cluster analysis identified three distinct phenotypes in GA. One of them showed a particularly slow growth pattern.

Associations Between β-Peripapillary Atrophy and Reticular Pseudodrusen in Early Age-Related Macular Degeneration

Purpose

Choroidal thinning has been associated with reticular pseudodrusen (RPD) and β-peripapillary atrophy (β-PPA), which have been linked to normal-tension glaucoma (NTG). This analysis sought to determine whether RPD are independently associated with β-PPA in early AMD patients. Secondary outcomes included the association of RPD and preexisting diagnosis of glaucoma, cup-to-disc ratio (CDR), subfoveal choroidal thickness (SFCT), and IOP.

Methods

This prospective cross-sectional study examined 78 age- and sex-matched early AMD patients: 43 RPD patients (63 eyes) and 35 non-RPD patients (64 eyes). Exclusion criteria included advanced AMD, high myopia, and vitreoretinal conditions/surgery. RPD and non-RPD groups were identified by confocal scanning laser ophthalmoscopy. β-PPA as well as CDR were graded on digital, nonstereoscopic fundus photos. SFCT was measured on spectral-domain optical coherence tomography for 69 patients (35 RPD and 34 non-RPD). IOP and glaucoma diagnosis were extracted from charts.

Results

β-PPA had a greater prevalence in RPD than non-RPD (44% vs. 19%, P = 0.002); however, this relationship was not significant when SFCT was added to the model (P = 0.150). A preexisting diagnosis of glaucoma (P = 0.156), CDR (P = 0.176), and IOP (P = 0.98) was not different between groups.

Conclusions

RPD in early AMD are associated with presence of β-PPA, but choroidal thickness is a confounder in this relationship. Because β-PPA is a common finding in NTG, focusing on a potential shared pathway between RPD and NTG could improve the understanding of pathophysiology and expand therapies for each condition.

Geographic Atrophy and Foveal-Sparing Changes Related to Visual Acuity in Patients With Dry Age-Related Macular Degeneration Over Time

PURPOSE

To correlate the area of geographic atrophy (GA) and residual foveal sparing (FS), and to identify the minimum FS and maximum GA area allowing sufficient visual acuity (VA) for daily tasks.

DESIGN

Prospective cohort study.

METHODS

Thirty-six eyes of 25 patients with GA and FS were followed for 18 months using spectral-domain optical coherence tomography and VA tests. Volume scans were imported into software enabling grading of areas in B-scans and computing of planimetric measurements in complete volume scans. Correlation of areas 1 (complete atrophy), 2 (FS in the central millimeter), and 3 (FS in the central 3 mm) with each other and with best-corrected VA (BCVA) were evaluated.

RESULTS

Baseline means of areas 1, 2, and 3 were 6.15 mm², 0.49 mm², and 3.08 mm², respectively. At 1 year, area 1 increased by a mean of 1.33 mm², while areas 2 and 3 were decreased by 0.12 mm² and 0.65 mm², respectively. From baseline to 18 months and from visit to visit, all areas and BCVA changed progressively (P < .001). Significant thresholds in GA size and FS for achieving a BCVA ≥ 70 ETDRS letters were detected (area 1: ≤6 mm²; area 2: ≥0.48 mm²; and area 3: ≥3.28 mm²).

CONCLUSION

GA and FS changed inversely over time. In general, FS highly correlated with BCVA, while GA progression correlated with the central 3-mm FS regression, but not with BCVA. A threshold in GA and FS area could be determined for BCVA necessary for daily activity.

En Face Spectral-Domain Optical Coherence Tomography for the Monitoring of Lesion Area Progression in Stargardt Disease

Purpose

We investigated the progression of Stargardt disease (STGD1) over a multiyear follow-up by evaluating the macular lesion area as computed by an automatic algorithm from spectral-domain optical coherence tomography (SD-OCT).

Methods

We reviewed medical records of STGD1 patients, with a clinical and molecular diagnosis of STGD1 at a single institution, who underwent best-corrected visual acuity (BCVA), fundus photography, SD-OCT, full-field electroretinography, and, when available, fundus autofluorescence (FAF). Regression models were fitted on the selected clinical parameters; in particular, on the macular lesion area computed by SD-OCT, to evaluate the disease progression over a multiyear follow-up.

Results

The comparison between SD-OCT and FAF, available for 22 patients, showed that macular lesion area, assessed by SD-OCT, significantly correlated with the area of absent FAF (P < 0.001). Moreover, the longitudinal analysis, performed in 98 patients, showed a significant enlargement of macular lesion area at an estimated exponential rate of 4.6% per year (P = 0.046), together with a significant worsening of BCVA (0.06 logMAR per year; P < 0.001) and a significant decrease of macular thickness (1.6% per year; P = 0.005) over the follow-up.

Conclusions

The current study describes, for the first time in literature, a longitudinal analysis of the macular lesion area assessed by SD-OCT in STGD1 disease, showing a significant progression over the follow-up. Our findings suggest that the evaluation of macular lesion area by en face SD-OCT, together with FAF, could drive the choice of the most amenable candidates and the most suitable area to be treated in gene therapy clinical trials.

Photobiomodulation reduces drusen volume and improves visual acuity and contrast sensitivity in dry age-related macular degeneration

Purpose

To evaluate the efficacy of photobiomodulation (PBM) treatment for patients with dry age‐related macular degeneration (AMD).

Methods

Assessments on 42 eyes with dry AMD (age related eye disease study (AREDS) 2–4) were conducted. Multiwavelength light emitting diode (LED) light comprising of yellow (590 nm), red (670 nm) and near‐infrared (790 nm) bandwidths was applied to subjects’ eyes for a treatment course of 3 weeks. Outcome measures were changes in best‐corrected visual acuity (BCVA), contrast sensitivity (CS), drusen volume and central drusen thickness.

Results

Significant improvement in mean BCVA of 5.90 letters (p < 0.001) was seen on completion of the 3‐week treatment and 5.14 letters (p < 0.001) after 3 months. Contrast sensitivity improved significantly (log unit improvement of 0.11 (p = 0.02) at 3 weeks and 3 months (log unit improvement of 0.16 (p = 0.02) at three cycles per degree. Drusen volume decreased by 0.024 mm³ (p < 0.001) and central drusen thickness was significantly reduced by a mean of 3.78 μm (p < 0.001), while overall central retinal thickness and retinal volume remained stable.

Conclusion

This is the first study demonstrating improvements in functional and anatomical outcomes in dry AMD subjects with PBM therapy. These findings corroborate an earlier pilot study that looked at functional outcome measures. The addition of anatomical evidence contributes to the basis for further development of a non‐invasive PBM treatment for dry AMD.

Associations Between Retinal Pigment Epithelium and Drusen Volume Changes During the Lifecycle of Large Drusenoid Pigment Epithelial Detachments

Purpose

Drusenoid pigment epithelial detachments (PEDs) are a defined path to atrophy in age-related macular degeneration (AMD). We analyzed the relationships between retinal pigment epithelium (RPE) and drusen volume changes during the PED lifecycle, using spectral-domain optical coherence tomography (SD-OCT).

Methods

Twenty-one cases of drusenoid PED tracked using SD-OCT through periods of growth and collapse were evaluated. Volumetric calculations and piece-wise linear regression analysis were used to determine the breakpoint between growth and collapse. Spectral-domain OCT scans were independently evaluated for the appearance of intraretinal hyperreflective foci, acquired vitelliform lesions (AVLs), and disruptions to the RPE+basal lamina band. Timing of these events with respect to the breakpoint was statistically evaluated. Morphometric characteristics of drusenoid PEDs were correlated with rate of PED collapse and final visual acuity.

Results

Mean age of subjects was 75.3 years and mean period of follow up was 4.1 years (median 4.5 years; range, 0.6–6.6 years). The lifecycle of drusenoid PEDs was asymmetric, in that the rate of collapse (0.199 mm³/month) is significantly faster (P < 0.001) than the rate of growth (0.022 mm³/month). Appearance of intraretinal hyperreflective foci and AVLs preceded the breakpoint (both P < 0.001). The timing of disruptions to the RPE+basal lamina band did not differ from the breakpoint (P = 0.510). Maximal height, volume, and diameter of drusenoid PEDs were inversely correlated with final visual acuity (all P < 0.001) and positively correlated with the rate of PED collapse (all P < 0.001).

Conclusions

Spectral-domain OCT signatures, plausibly attributable to anteriorly migrated RPE and disintegration of the RPE layer, precede or occur simultaneously with changes in volume of drusenoid PED during the lifecycle of this lesion.

Atypical retinal pigment epithelial defects with retained photoreceptor layers: a so far disregarded finding in age related macular degeneration

BACKGROUND

To report patients with age-related macular degeneration and atypical central retinal pigment epithelium (RPE) defects not attributable to geographic atrophy (GA) or RPE-tears with overlying preserved photoreceptor layers.

METHODS

Multimodal imaging case-series evaluating the course of atypical RPE- defects in patients with AMD using Color fundus images, Optical coherence tomography (OCT), OCT-Angiography, fundus autofluorescence (FAF) and fluorescein-angiography (FA).

RESULTS

Ten patients were identified. Three patients had a prior RPE-rip and were excluded. Seven patients with a mean follow-up period of 47 ± 38 months after the occurrence of the RPE-defect were included (age range 71-87 years). Mean distance Best corrected visual acuity (BCVA) at initial presentation was 0.36 ± 0.29logMAR and at last follow-up visit 0.51 ± 0.43logMAR. Patients presented with clinically apparent GA on funduscopy and FAF, but preserved photoreceptor layers on optical coherence tomography (OCT). On FA there was early hyperfluorescence and late pooling visible. Over time, migration of RPE/drusenoid material right above the Bruch's membrane with concomitant decrease of hypoautofluorescence was detectable in 4 cases. An enlargement of the RPE-defect was apparent in the remaining 3 cases. The majority (n = 4) showed a drusenoid pigment epithelium detachment (PED) preceding the lesion.

CONCLUSIONS

Beside GA and characteristic RPE-tears, another atypical form of RPE-defect with overlying preserved photoreceptor layers are found in AMD. This so far disregarded subgroup of patients present with reasonable visual function and long-term survival of photoreceptors layers. Repair mechanisms such as ingrowth of RPE/drusenoid material and persistent subretinal fluid (SRF), but also a RPE-independent visual cycle for cone photopigment within the neurosensory retina may contribute to their favorable course.

The Evolution of Outer Retinal Tubulation, a Neurodegeneration and Gliosis Prominent in Macular Diseases

PURPOSE

To document outer retinal tubulation (ORT) formation in advanced retinal disorders.

DESIGN

Retrospective, observational study.

PARTICIPANTS

Consecutive cases with retinal diseases showing outer retinal disruption and atrophy of the retinal pigment epithelium (RPE) associated with ORT on spectral-domain (SD) optical coherence tomography (OCT) at the final available visit.

METHODS

Cross-sectional SD OCT scans showing ORT at the last available visit were compared with eye-tracked baseline scans. Only patients showing the formation of ORT over time with absence of ORT at baseline were analyzed.

MAIN OUTCOME MEASURES

Steps in ORT formation based on shapes of the external limiting membrane (ELM) descent (flat, curved, reflected, and scrolled) at the border of outer retinal and RPE atrophy, ORT characteristics (open, closed), and time between steps through a long-term follow-up.

RESULTS

From 170 eyes of 86 patients with ORT, 38 eyes of 30 patients (11 men, 19 women) with a mean age of 78.87 years (range, 56-96 years) met inclusion criteria. Of these 38 eyes, 23 (60%) had geographic atrophy secondary to age-related macular degeneration (AMD) and 2 eyes (5%) had geographic atrophy secondary to pattern dystrophy. Twelve eyes (32%) had neovascular AMD and 1 eye (3%) had neovascularization secondary to pseudoxanthoma elasticum, all showing similar ORT formative steps. Seventy-three different retinal areas (1434 cross-sectional images) were analyzed over a mean follow-up of 69.5 months (range, 21-93 months). At 73 borders, grading of eye-tracked follow-up SD OCT line scans showed a flat ELM descent at least once at 34 borders (47%), a curved ELM at 47 borders (64%), a reflected ELM at 37 borders (51%), and a scrolled ELM at 24 borders (33%). Of 81 ORTs, 73 (90%) were closed and 8 (10%) were open. The mean time for ORT formation was 14.9 months (range, 1.4-71.3 months).

CONCLUSIONS

We propose progressive steps in the development of ORT and analyze the time of progression between these steps. Analyzing the borders of atrophy to determine the origin of ORT provides new insights into the pathophysiology of advanced retinal disease highlighting a role for Müller cells and may inform future therapeutic strategies.

VISUALIZING RETINAL PIGMENT EPITHELIUM PHENOTYPES IN THE TRANSITION TO GEOGRAPHIC ATROPHY IN AGE-RELATED MACULAR DEGENERATION

PURPOSE

To inform the interpretation of clinical optical coherence tomography and fundus autofluorescence imaging in geographic atrophy (GA) of age-related macular degeneration by determining the distribution of retinal pigment epithelium (RPE) phenotypes in the transition from health to atrophy in donor eyes.

METHODS

In RPE-Bruch membrane flat mounts of two GA eyes, the terminations of organized RPE cytoskeleton and autofluorescent material were compared. In high-resolution histological sections of 13 GA eyes, RPE phenotypes were assessed at ±500 and ±100 μm from the descent of the external limiting membrane (ELM) toward Bruch membrane. The ELM descent was defined as curved, reflected, or oblique in shape. Thicknesses of RPE, basal laminar deposit (BLamD), and RPE plus BLamD were measured.

RESULTS

A border of atrophy that can be precisely delimited is the ELM descent, as opposed to the termination of the RPE layer itself, because of dissociated RPE in the atrophic area. Approaching the ELM descent, the percentage of abnormal RPE morphologies increases, the percentage of age-normal cells decreases, overall RPE thickens, and BLamD does not thin. The combination of RPE plus BLamD is 19.7% thicker at -100 μm from the ELM descent than that at -500 μm (23.1 ± 10.7 μm vs. 19.3 ± 8.2 μm; P = 0.05).

CONCLUSION

The distribution of RPE phenotypes at the GA transition supports the idea that these morphologies represent defined stages of a degeneration sequence. The idea that RPE dysmorphia including rounding and stacking helps explain variable autofluorescence patterns in GA is supported. The ELM descent and RPE plus BLamD thickness profile may have utility as spectral domain optical coherence tomography metrics in clinical trials.

Retinal Pigment Epithelium Degeneration Associated With Subretinal Drusenoid Deposits in Age-Related Macular Degeneration

PURPOSE

To test whether increased light transmission (hypertransmission) through subretinal drusenoid deposits (SDD) into the choroid in age-related macular degeneration (AMD) represented retinal pigment epithelium (RPE) degeneration.

DESIGN

Cross-sectional study.

METHODS

Nineteen eyes of 12 patients with early- to intermediate-stage AMD and 18 eyes of 12 normal subjects were evaluated with color fundus photography, optical coherence tomography (OCT), and high-resolution adaptive optics scanning laser ophthalmoscopy (AOSLO) at baseline and 24 months later. SDD were classified using an OCT-based 3-stage grading system. Hypertransmission beneath SDD into the choroid was examined in OCT. SDD microstructure was assessed with AOSLO. To characterize the hypertransmission-associated chorioretinal degeneration, choroidal thickness and photoreceptor length were measured in OCT at 1 mm and 2 mm superior, inferior, temporal, and nasal to the foveal center.

RESULTS

OCT disclosed hypertransmission beneath stage 3 SDD in 8 eyes. These lesions showed a distinctive regressing structure in AOSLO, compared with stage 3 lesions without hypertransmission. The phenomenon persisted at follow-up, and new hypertransmission developed as SDD advanced. In eyes with hypertransmission, choroids were thinner than those of normal eyes at all sites (by 44%-56%, P ≤ .0028) and those of eyes with SDD but without hypertransmission at superior and temporal sites (by 31%-46%, P ≤ .039). Photoreceptors were significantly shorter than those in normal eyes (by 6%-26%, P ≤ .0379).

CONCLUSIONS

Hypertransmission into the choroid, accompanied with SDD regression and thinning of choroid and photoreceptor layers, indicates RPE degeneration associated with advanced stages in the SDD life cycle.

En Face Optical Coherence Tomography Imaging for the Detection of Nascent Geographic Atrophy

PURPOSE

To determine if en face optical coherence tomography (OCT) imaging can identify nascent geographic atrophy (nGA) in eyes with intermediate age-related macular degeneration (iAMD).

DESIGN

Retrospective observational case series.

METHODS

Patients with iAMD from the COMPLETE study at the Bascom Palmer Eye Institute were evaluated to determine if nGA was present at baseline and at follow-up using high-density Spectralis OCT B-scans and en face OCT images from the Cirrus OCT instrument. If available, additional en face OCT images and B-scans were analyzed at follow-up times beyond the 52-week period.

RESULTS

A total of 37 eyes (27 patients) were evaluated for at least 1 year using both B-scans and en face images. Two drusen suspicious for nGA at baseline were identified, but neither druse developed GA after 24 and 62 months of follow-up, respectively. Another druse displayed hypertransmission into the choroid at week 52 on B-scan imaging and was classified as nGA. En face OCT imaging identified this druse as a focal bright area. Drusen breakdown occurred during a follow-up of 39 months.

CONCLUSIONS

En face OCT imaging appeared to be as useful as routine B-scan imaging for identifying areas suspicious for nGA in this population from the COMPLETE Study. Additional longitudinal follow-up of eyes with drusen is needed to determine if en face OCT imaging can replace the evaluation of individual B-scans for the detection of nGA.

Macular atrophy in patients with long-term anti-VEGF treatment for neovascular age-related macular degeneration

PURPOSE

To identify the prevalence and progression of macular atrophy (MA) in neovascular age-related macular degeneration (AMD) patients under long-term anti-vascular endothelial growth factor (VEGF) therapy and to determine risk factors.

METHOD

This retrospective study included patients with neovascular AMD and ≥30 anti-VEGF injections. Macular atrophy (MA) was measured using near infrared and spectral-domain optical coherence tomography (SD-OCT). Yearly growth rate was estimated using square-root transformation to adjust for baseline area and allow for linearization of growth rate. Multiple regression with Akaike information criterion (AIC) as model selection criterion was used to estimate the influence of various parameters on MA area.

RESULTS

Forty-nine eyes (47 patients, mean age 77 ± 14) were included with a mean of 48 ± 13 intravitreal anti-VEGF injections (ranibizumab:37 ± 11, aflibercept:11 ± 6, mean number of injections/year 8 ± 2.1) over a mean treatment period of 6.2 ± 1.3 years (range 4-8.5). Mean best-corrected visual acuity improved from 57 ± 17 letters at baseline (= treatment start) to 60 ± 16 letters at last follow-up. The MA prevalence within and outside the choroidal neovascularization (CNV) border at initial measurement was 45% and increased to 74%. Mean MA area increased from 1.8 ± 2.7 mm² within and 0.5 ± 0.98 mm² outside the CNV boundary to 2.7 ± 3.4 mm² and 1.7 ± 1.8 mm² , respectively. Multivariate regression determined posterior vitreous detachment (PVD) and presence/development of intraretinal cysts (IRCs) as significant factors for total MA size (R² = 0.16, p = 0.02). Macular atrophy (MA) area outside the CNV border was best explained by the presence of reticular pseudodrusen (RPD) and IRC (R² = 0.24, p = 0.02).

CONCLUSION

A majority of patients show MA after long-term anti-VEGF treatment. Reticular pseudodrusen (RPD), IRC and PVD but not number of injections or treatment duration seem to be associated with the MA size.