Comparison of color fundus photographs and fundus autofluorescence images in measuring geographic atrophy area

Oral Antioxidant and Lutein/Zeaxanthin Supplements Slow Geographic Atrophy Progression to the Fovea in Age-Related Macular Degeneration

PURPOSE

The only treatments approved to slow geographic atrophy (GA) progression in age-related macular degeneration (AMD) require frequent intraocular injection and suffer from modest efficacy, important risks, and high costs. The purpose of this study was to determine whether oral supplements slow GA progression in AMD.

DESIGN

Post hoc analysis of the Age-Related Eye Diseases Study (AREDS) and AREDS2, multi-center randomized placebo-controlled trials of oral micronutrient supplementation, each with 2x2 factorial design.

PARTICIPANTS

392 eyes (318 participants) with GA in AREDS; 1210 eyes (891 participants) with GA in AREDS2.

METHODS

AREDS participants were randomly assigned to oral antioxidants (500 mg vitamin C; 400 IU vitamin E; 15 mg β-carotene); 80 mg zinc; combination; or placebo. AREDS2 participants were randomly assigned to 10 mg lutein/2 mg zeaxanthin; 350 mg docosahexaenoic acid/650 mg eicosapentaenoic acid; combination; or placebo. Consenting AREDS2 participants were also randomly assigned to alternative AREDS formulations: original; no beta-carotene; 25 mg zinc instead of 80 mg; both.

MAIN OUTCOME MEASURES

(1) Change in GA proximity to central macula over time, and (2) change in square root GA area over time, each measured from color fundus photographs at annual visits and analyzed by mixed-model regression according to randomized assignments.

RESULTS

In AREDS eyes with non-central GA (n=208), proximity-based progression towards the central macula was significantly slower with randomization to antioxidants versus none, at 50.7 μm/year (95% CI 38.0-63.4 μm/year) versus 72.9 μm/year (95% CI 61.3-84.5 μm/year; p=0.012), respectively. In AREDS2 eyes with non-central GA, in participants assigned to AREDS antioxidants without β-carotene (n=325 eyes), proximity-based progression was significantly slower with randomization to lutein/zeaxanthin versus none, at 80.1 μm/year (95% CI 60.9-99.3 μm/year) versus 114.4 μm/year (95% CI 96.2-132.7 μm/year; p=0.011), respectively. In AREDS eyes with any GA (n=392), area-based progression was not significantly different with randomization to antioxidants versus none (p=0.63). In AREDS2 eyes with any GA, in participants assigned to AREDS antioxidants without β-carotene (n=505 eyes), area-based progression was not significantly different with randomization to lutein/zeaxanthin versus none (p=0.64).

CONCLUSIONS

Oral micronutrient supplementation slowed GA progression towards the central macula, likely by augmenting the natural phenomenon of foveal sparing.

Geographic Atrophy Natural History Versus Treatment: Time to Fovea

BACKGROUND AND OBJECTIVE

The Food and Drug Administration recently approved treatments of geographic atrophy (GA). Our study aims to quantify the time for a lesion to reach the central fovea based on reduction of GA growth rates from therapeutics compared to the natural history.

PATIENTS AND METHODS

A previously published study calculates local border expansion rate of GA lesions at varying retinal eccentricities. In this study, we use these rates to model GA expansion toward the fovea and the effects of treatments that reduce growth in GA area by 15% to 45% on lesions of varying sizes with posterior margin 250, 500, 750, 1000, 1250, 1500, and 3000 µm from the fovea.

RESULTS

Lesions with an area 8 mm2 and posterior edge 500 µm from the fovea will reach the fovea in 5.08 years with no treatment, but the same lesions will reach the fovea in 5.85, 6.52, 7.36, and 8.46 years with a treatment that reduces growth in GA area by 15%, 25%, 35%, and 45%, respectively.

CONCLUSIONS

Distance of the posterior edge of the lesion was the primary factor in GA growth toward the fovea, and lesion size only minimally affects growth rates of GA. Based on the efficacy of current and future therapeutics and distance of GA to the fovea, our study provides the marginal time benefit of treatment to guide patients and clinicians, placing both the natural history of GA and the effects of current and future treatments into clinical context. [Ophthalmic Surg Lasers Imaging Retina 2024;55:XX-XX.].

Imaging geographic atrophy: integrating structure and function to better understand the effects of new treatments

Geographic atrophy (GA) is an advanced and irreversible form of age-related macular degeneration (AMD). Chronic low grade inflammation is thought to act as an initiator of this degenerative process, resulting in loss of photoreceptors (PRs), retinal pigment epithelium (RPE) and the underlying choriocapillaris. This review examined the challenges of clinical trials to date which have sought to treat GA, with particular reference to the successful outcome of C3 complement inhibition. Currently, optical coherence tomography (OCT) seems to be the most suitable method to detect GA and monitor the effect of treatment. In addition, the merits of using novel anatomical endpoints in detecting GA expansion are discussed. Although best-corrected visual acuity is commonly used to monitor disease in GA, other tests to determine visual function are explored. Although not widely available, microperimetry enables quantification of retinal sensitivity (RS) and macular fixation behaviour related to fundus characteristics. There is a spatial correlation between OCT/fundus autofluorescence evaluation of PR damage outside the area of RPE loss and RS on microperimetry, showing important associations with visual function. Standardisation of testing by microperimetry is necessary to enable this modality to detect AMD progression. Artificial intelligence (AI) analysis has shown PR layers integrity precedes and exceeds GA loss. Loss of the ellipsoid zone has been recognised as a primary outcome parameter in therapeutic trials for GA. The integrity of the PR layers imaged by OCT at baseline has been shown to be an important prognostic indicator. AI has the potential to be invaluable in personalising care and justifying treatment intervention.

American Society of Retina Specialists Clinical Practice Guidelines on Multimodal Imaging for Retinal Disease

Purpose: Advancements in retinal imaging have augmented our understanding of the pathology and structure-function relationships of retinal disease. No single diagnostic test is sufficient; rather, diagnostic and management strategies increasingly involve the synthesis of multiple imaging modalities. Methods: This literature review and editorial offer practical clinical guidelines for how the retina specialist can use multimodal imaging to manage retinal conditions. Results: Various imaging modalities offer information on different aspects of retinal structure and function. For example, optical coherence tomography (OCT) and B-scan ultrasonography can provide insights into the microstructural anatomy; fluorescein angiography (FA), indocyanine green angiography (ICGA), and OCT angiography (OCTA) can reveal vascular integrity and perfusion status; and near-infrared reflectance and fundus autofluorescence (FAF) can characterize molecular components within tissues. Managing retinal vascular diseases often includes fundus photography, OCT, OCTA, and FA to evaluate for macular edema, retinal ischemia, and the secondary complications of neovascularization (NV). OCT and FAF play a key role in diagnosing and treating maculopathies. FA, OCTA, and ICGA can help identify macular NV, posterior uveitis, and choroidal venous insufficiency, which guides treatment strategies. Finally, OCT and B-scan ultrasonography can help with preoperative planning and prognostication in vitreoretinal surgical conditions. Conclusions: Today, the retina specialist has access to numerous retinal imaging modalities that can augment the clinical examination to help diagnose and manage retinal conditions. Understanding the capabilities and limitations of each modality is critical to maximizing its clinical utility.

Non-Neovascular Age-Related Macular Degeneration Assessment: Focus on Optical Coherence Tomography Biomarkers

The imagistic evaluation of non-neovascular age-related macular degeneration (AMD) is crucial for diagnosis, monitoring progression, and guiding management of the disease. Dry AMD, characterized primarily by the presence of drusen and retinal pigment epithelium atrophy, requires detailed visualization of the retinal structure to assess its severity and progression. Several imaging modalities are pivotal in the evaluation of non-neovascular AMD, including optical coherence tomography, fundus autofluorescence, or color fundus photography. In the context of emerging therapies for geographic atrophy, like pegcetacoplan, it is critical to establish the baseline status of the disease, monitor the development and expansion of geographic atrophy, and to evaluate the retina's response to potential treatments in clinical trials. The present review, while initially providing a comprehensive description of the pathophysiology involved in AMD, aims to offer an overview of the imaging modalities employed in the evaluation of non-neovascular AMD. Special emphasis is placed on the assessment of progression biomarkers as discerned through optical coherence tomography. As the landscape of AMD treatment continues to evolve, advanced imaging techniques will remain at the forefront, enabling clinicians to offer the most effective and tailored treatments to their patients.

Critical Dependence on Area in Relationship between ARMS2/HTRA1 Genotype and Faster Geographic Atrophy Enlargement: Age-Related Eye Disease Study 2 Report Number 33

PURPOSE

To analyze ARMS2/HTRA1 as a risk factor for faster geographic atrophy (GA) enlargement according to (1) GA area and (2) contiguous enlargement versus progression to multifocality.

DESIGN

Age-Related Eye Disease Study 2 (AREDS2) cohort analysis.

PARTICIPANTS

Eyes with GA: 546 eyes of 406 participants.

METHODS

Geographic atrophy area was measured from color fundus photographs at annual visits. Mixed-model regression of square root of GA area and proportional hazards regression of progression to multifocality were analyzed by ARMS2 genotype.

MAIN OUTCOME MEASURES

Change in square root GA area and progression to multifocality.

RESULTS

Geographic atrophy enlargement was significantly faster with ARMS2 risk alleles (P < 0.0001) at 0.224 mm/year (95% CI, 0.195-0.252 mm/year), 0.298 mm/year (95% CI, 0.271-0.324 mm/year), and 0.317 mm/year (95% CI, 0.279-0.355 mm/year), for 0 to 2 risk alleles, respectively. However, a significant interaction (P = 0.011) was observed between genotype and baseline area. In eyes with very small area (< 1.9 mm2), enlargement was significantly faster with ARMS2 risk alleles (P < 0.0001) at 0.193 mm/year (95% CI, 0.162-0.225 mm/year) versus 0.304 mm/year (95% CI, 0.280-0.329 mm/year) for 0 versus 1 to 2 risk alleles, respectively. With moderately small (1.9-3.8 mm2) or medium to large (≥ 3.8 mm2) area, enlargement was not significantly faster with ARMS2 risk alleles (P = 0.66 and P = 0.70, respectively). In nonmultifocal GA, enlargement was significantly faster with ARMS2 risk alleles (P = 0.001) at 0.175 mm/year (95% CI, 0.142-0.209 mm/year), 0.226 mm/year (95% CI, 0.193-0.259 mm/year), and 0.287 mm/year (95% CI, 0.237-0.337 mm/year) with 0 to 2 risk alleles, respectively. ARMS2 genotype was not associated significantly with progression to multifocal GA.

CONCLUSIONS

The relationship between ARMS2/HTRA1 genotype and faster GA enlargement depends critically on GA area: risk alleles represent a strong risk factor for faster enlargement only in eyes with very small area. They increase the growth rate more through contiguous enlargement than progression to multifocality. ARMS2/HTRA1 genotype is more important in increasing risk of progression to GA and initial GA enlargement (contiguously) than in subsequent enlargement or progression to multifocality. These findings may explain some discrepancies between previous studies and have implications for both research and clinical practice.

FINANCIAL DISCLOSURE(S)

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

Interreader Agreement and Longitudinal Progression of Incomplete/Complete Retinal Pigment Epithelium and Outer Retinal Atrophy in Age-Related Macular Degeneration

OBJECTIVE

To analyze the ability to evaluate changes over time of individual lesions of incomplete or complete retinal pigment epithelium (RPE) and outer retinal atrophy (iRORA and cRORA, respectively) in patients with intermediate age-related macular degeneration (iAMD).

DESIGN

OCT images from patients enrolled in Proxima B clinical trial (NCT02399072) were utilized.

PARTICIPANTS

Patients enrolled in the Proxima B clinical trial, from the cohort with geographic atrophy (GA) in 1 eye and iAMD in the other eye at baseline, were included.

METHODS

Junior and senior readers analyzed OCT images for the qualitative presence of 9 distinct early atrophic features (presence of zone of choroidal hypertransmission, attenuation and/or disruption of RPE, disruption of ellipsoid zone [EZ] and external limiting membrane [ELM], outer nuclear layer [ONL] thinning, outer plexiform layer [OPL]/inner nuclear layer [INL] subsidence, and hyporeflective wedge-shaped band). If deemed "present," 7 features were quantified with a predefined tolerance level of 50 μm (diameter for the zone of choroidal hypertransmission, zone of attenuation and/or disruption of the RPE, outer retinal thickness left/right vertical diameter, outer retinal thickness thinnest vertical diameter, annotation of EZ, and ELM disruption).

MAIN OUTCOME MEASURES

Interreader agreements for qualitative assessments (κ-type statistics) and quantitative measurements (Bland-Altman statistics) were assessed. Progression of the lesion features over time was described.

RESULTS

Moderate agreement was found for presence of choroidal hypertransmission (κ = 0.54), followed by ELM disruption (κ = 0.58), OPL/INL subsidence (κ = 0.46), and a hyporeflective wedge-shaped band (κ = 0.47). Quantification measurements showed that choroidal hypertransmission had the highest agreement, whereas RPE attenuation/disruption had the lowest agreement. Longitudinal adjudicated changes for quantitative measurements of lesion progression showed that choroidal hypertransmission and ELM disruption showed significant progression, whereas EZ disruption and RPE attenuation/disruption did not.

CONCLUSIONS

The ability to evaluate changes over time for specific features of iRORA and cRORA was explored. The most robust biomarker was found to be choroidal hypertransmission, followed by ELM disruption and the qualitative markers of OPL/INL subsidence, as well as a wedge-shaped band. Disease progression over time could be assessed by some, but not all, spectral-domain OCT features that were explored.

FINANCIAL DISCLOSURE(S)

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

Longitudinal Changes of Retinal Structure in Molecularly Confirmed C1QTNF5 Patients With Late-Onset Retinal Degeneration

Purpose

The purpose of this study was to present our findings on the natural history of late-onset retinal degeneration (LORD) in patients with molecularly confirmed C1QTNF5 heterozygous pathogenic variants and assess suitability of retinal structure parameters for disease monitoring.

Methods

Sixteen patients with C1QTNF5-LORD were retrospectively identified from Moorfields Eye Hospital, UK. Fundus autofluorescence (FAF), optical coherence tomography (OCT) scans, and best-corrected visual acuity (BCVA) were collected. Area of atrophy (AA) was manually drawn in FAF images. Ellipsoid zone (EZ) width and foveal retinal thickness of the whole retina and outer retina were extracted from OCT scans. Age-related changes were tested with linear-mixed models.

Results

Patients had median age of 62.3 years (interquartile range [IQR] = 58.8-65.4 years) at baseline, and median follow-up of 5.1 years (IQR = 2.6-7.6 years). AA, EZ width, and retinal thickness parameters remained unchanged until age 50 years, but showed significant change with age thereafter (all P < 0.0001). AA and EZ width progressed rapidly (dynamic range normalized rates = 4.3-4.5%/year) from age 53.9 and 50.8 years (estimated inflection points), respectively. Retinal thickness parameters showed slower progression rates (range = 1.6-2.5%/year) from age 60 to 62.3. BCVA (median = 0.3 LogMAR, IQR = 0.0-1.0 at baseline) showed a rapid decline (3.3%) from age 70 years. Findings from patients with earlier disease showed FAF atrophy manifests in the temporal retina initially, and then progresses nasally.

Conclusions

Patients with LORD remained asymptomatic until age 50 years, before suffering rapid outer retinal degeneration. EZ width and AA showed rapid progression and high interocular correlation, representing promising outcome metrics. Clinical measures also capturing the temporal retina may be preferable, enabling earlier detection and better disease monitoring.

Translational Relevance

Area of atrophy in FAF images and OCT-measured EZ width represent promising outcome metrics for disease monitoring in patients with C1QTNF5-LORD.

A deep learning model for generating fundus autofluorescence images from color fundus photography

Background

Fundus Autofluorescence (FAF) is a valuable imaging technique used to assess metabolic alterations in the retinal pigment epithelium (RPE) associated with various age-related and disease-related changes. The practical uses of FAF are ever-growing. This study aimed to evaluate the effectiveness of a generative deep learning (DL) model in translating color fundus (CF) images into synthetic FAF images and explore its potential for enhancing screening of age-related macular degeneration (AMD).

Methods

A generative adversarial network (GAN) model was trained on pairs of CF and FAF images to generate synthetic FAF images. The quality of synthesized FAF images was assessed objectively by common generation metrics. Additionally, the clinical effectiveness of the generated FAF images in AMD classification was evaluated by measuring the area under the curve (AUC), using the LabelMe dataset.

Results

A total of 8410 FAF images from 2586 patients were analyzed. The synthesized FAF images exhibited an impressive objectively assessed quality, achieving a multi-scale structural similarity index (MS-SSIM) of 0.67. When evaluated on the LabelMe dataset, the combination of generated FAF images and CF images resulted in a noteworthy improvement in AMD classification accuracy, with the AUC increasing from 0.931 to 0.968.

Conclusions

This study presents the first attempt to use a generative deep learning model to create authentic and high-quality FAF images from CF images. The incorporation of the translated FAF images on top of CF images improved the accuracy of AMD classification. Overall, this study presents a promising approach to enhance large-scale AMD screening.

Reticular Pseudodrusen Status, ARMS2/HTRA1 Genotype, and Geographic Atrophy Enlargement: Age-Related Eye Disease Study 2 Report 32

PURPOSE

To determine whether reticular pseudodrusen (RPD) status, ARMS2/HTRA1 genotype, or both are associated with altered geographic atrophy (GA) enlargement rate and to analyze potential mediation of genetic effects by RPD status.

DESIGN

Post hoc analysis of an Age-Related Eye Disease Study 2 cohort.

PARTICIPANTS

Eyes with GA: n = 771 from 563 participants.

METHODS

Geographic atrophy area was measured from fundus photographs at annual visits. Reticular pseudodrusen presence was graded from fundus autofluorescence images. Mixed-model regression of square root of GA area was performed by RPD status, ARMS2 genotype, or both.

MAIN OUTCOME MEASURES

Change in square root of GA area.

RESULTS

Geographic atrophy enlargement was significantly faster in eyes with RPD (P < 0.0001): 0.379 mm/year (95% confidence interval [CI], 0.329-0.430 mm/year) versus 0.273 mm/year (95% CI, 0.256-0.289 mm/year). Enlargement was also significantly faster in individuals carrying ARMS2 risk alleles (P < 0.0001): 0.224 mm/year (95% CI, 0.198-0.250 mm/year), 0.287 mm/year (95% CI, 0.263-0.310 mm/year), and 0.307 mm/year (95% CI, 0.273-0.341 mm/year) for 0, 1, and 2, respectively. In mediation analysis, the direct effect of ARMS2 genotype was 0.074 mm/year (95% CI, 0.009-0.139 mm/year), whereas the indirect effect of ARMS2 genotype via RPD status was 0.002 mm/year (95% CI, -0.006 to 0.009 mm/year). In eyes with incident GA, RPD presence was not associated with an altered likelihood of central involvement (P = 0.29) or multifocality (P = 0.16) at incidence. In eyes with incident noncentral GA, RPD presence was associated with faster GA progression to the central macula (P = 0.009): 157 μm/year (95% CI, 126-188 μm/year) versus 111 μm/year (95% CI, 97-125 μm/year). Similar findings were observed in the Age-Related Eye Disease Study.

CONCLUSIONS

Geographic atrophy enlargement is faster in eyes with RPD and in individuals carrying ARMS2/HTRA1 risk alleles. However, RPD status does not mediate the association between ARMS2/HTRA1 genotype and faster enlargement. Reticular pseudodrusen presence and ARMS2/HTRA1 genotype are relatively independent risk factors, operating by distinct mechanisms. Reticular pseudodrusen presence does not predict central involvement or multifocality at GA incidence but is associated with faster progression toward the central macula. Reticular pseudodrusen status should be considered for improved predictions of enlargement rate.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Optometrists' attitudes toward using OCT angiography lag behind other retinal imaging types

PURPOSE

While optometrists' attitudes toward established retinal imaging types are generally positive, they are unknown for optical coherence tomography angiography (OCTA). We performed a cross-sectional survey to estimate attitudes toward OCTA and identify clinician and/or practice characteristics that influence them.

METHODS

A paper-based survey was mailed to 252 randomly selected optometrists in Australia. Five-point Likert-scale items from a previous survey assessing attitudes toward new technology were included to probe respondent characteristics and attitudes toward retinal imaging. Performance expectancy attitudes toward OCTA were elicited by the statement 'I believe OCTA is useful in daily practice'. Mean scores out of five (mean [SD]) were rounded and mapped to appropriate descriptive statements.

RESULTS

The response rate was 47% (118/252). The mean (SD) age of respondents was 44.0 (13.8) years and 50.8% (60/118) were female. Optometrists had 19.9 (14.0) years of clinical experience and 66.9% (79/118) worked at independent practices. In total, 8.5% (10/118) of respondents used OCTA to provide clinical care. Optometrists agreed that optical coherence tomography (OCT), colour fundus imaging, ultra-wide field imaging and fundus autofluorescence (mean scores 3.6-4.7 out of 5) were useful in daily practice but felt neutral about whether OCTA was useful (3.4 [0.8]). Optometrists believed that OCTA was less enjoyable to use (p < 0.0001), less endorsed by peers (p < 0.0001) and felt less confident that they had the knowledge to interpret OCTA (p < 0.0001) compared to other retinal imaging types.

CONCLUSIONS

Optometrists are undecided on whether OCTA is useful in daily practice and had lower expectations that using OCTA would confer job performance benefits compared to other retinal imaging types. Further work is needed to advocate the benefits of using OCTA across the profession.

Retro mode illumination for detecting and quantifying the area of geographic atrophy in non-neovascular age-related macular degeneration

PURPOSE

To evaluate the ability of retro mode illumination imaging for quantifying atrophy compared to confocal color fundus photography (c-CFP), green light fundus autofluorescence (G-FAF), blue light fundus autofluorescence (B-FAF) using the scanning laser ophthalmoscope (SLO) Mirante device by Nidek (Nidek Co., Ltd, Gamogori, Japan).

METHODS

Eyes with clinical evidence of geographic atrophy (GA) associated with non-neovascular age-related macular degeneration, evaluated at the Doheny Eye Centers-UCLA and Hospital Sacco Milan, were included in this prospective, cross-sectional study. All eyes were imaged with multiple retinal imaging modalities using the SLO Nidek Mirante device: c-CFP, G-FAF, B-FAF, retro mode illumination deviated-right (RMDR), and deviated-left (RMDL). Masked graders measured the GA lesion on each modality and inter-modality and inter-grader repeatability were assessed.

RESULTS

The mean (SD) area of GA measured 9.76 (3.82) mm², 9.75 (3.91) mm², 9.76 (3.92) mm², 9.82 (3.87) mm², and 9.81 (3.86) mm² using c-CFP, G-FAF, B-FAF, RMDR, and RMDL, respectively (p = 0.2). Inter-modality correlation was high (Pearson's r > 0.9 and p < 0.0001). Agreement between graders was excellent for all modalities.

CONCLUSIONS

Retro mode imaging demonstrated good agreement for measuring GA compared to other imaging modalities, with a high level of repeatability. Given that retro mode imaging uses infrared light and is comfortable, it may prove to be a useful tool for the assessment of GA in the clinic.

The Use of Fundus Autofluorescence in Dry Age-Related Macular Degeneration

Fundus autofluorescence (FAF) has been a well-known imaging method for quite some time. However, with developing technologies and novel imaging devices, FAF is being used more often to diagnose and monitor retinal diseases. The density of lipofuscin (LF) and other fluorophores in the retina have a determining role in FAF images. In dry age-related macular degeneration (AMD), hyperautofluorescence is seen in cases of increasing LF in the retina pigment epithelium, whereas hypoautofluorescence is detected in decreasing LF resulting from geographic atrophy. In recent years, studies have shown that FAF images provide prognostic information in patients with AMD. This review aims to highlight the importance of FAF imaging in dry AMD.

Geographic atrophy severity and mortality in age-related macular degeneration

PURPOSE

To examine the association between geographic atrophy (GA) disease characteristics and mortality risk.

METHODS

We manually delineated color fundus photographs of 209 Age-Related Eye Disease Study (AREDS) participants with GA secondary to age-related macular degeneration to identify total area of atrophy, GA effective radius growth rate, disease laterality, and the presence of foveal center involvement. Associations between GA characteristics and mortality were assessed with Cox proportional hazards models adjusted for health status indicators.

RESULTS

During a median follow-up of 6.8 years, 48 (23.0%) participants with GA died. In adjusted models, accounting for age, sex, and health status, participants with total GA area in the highest quartile had a significantly increased risk of all-cause mortality compared to those with total GA area in the lowest quartile (hazard ratio [HR], 3.42; 95% confidence interval [CI], 1.32-8.86; P = 0.011). GA effective radius growth rate, bilateral disease, and the presence of foveal center involvement were not significantly associated with mortality. In a multivariable model, including health status indicators and all GA characteristics, total area of atrophy in the highest quartile remained significantly associated with mortality (HR, 4.65; 95% CI, 1.29-16.70; P = 0.019).

CONCLUSIONS

More extensive GA, as indicated by a greater total area of atrophy, was associated with an increased risk of all-cause mortality in our cohort. The extent of GA may reflect the extent of underlying disease processes that contribute to greater mortality risk, further suggesting that GA may be part of a systemic rather than purely ocular disease process.

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.

Geographic Atrophy Growth Is Strongly Related to Lesion Perimeter: Unifying Effects of Lesion Area, Number, and Circularity on Growth

PURPOSE

To investigate the underlying reason for the previously observed impact of baseline lesion size, number, and circularity on geographic atrophy (GA) growth rate.

DESIGN

Retrospective analysis of a multicenter, prospective, randomized controlled trial.

PARTICIPANTS

Age-Related Eye Disease Study participants with GA secondary to nonexudative age-related macular degeneration.

METHODS

We manually delineated atrophic lesions on color fundus photographs of 318 eyes with GA followed up over at least 2 visits (mean follow-up duration, 5.1 ± 3.0 years). We calculated GA area growth rate for each eye based on the first and last visit. GA perimeter-adjusted growth rate was defined as the ratio between GA area growth rate and mean GA perimeter between the first and last visit for each eye.

MAIN OUTCOME MEASURES

GA area growth rate, growth rate of the square root of GA area, and GA perimeter-adjusted growth rate.

RESULTS

GA area growth rate was correlated strongly with mean GA perimeter (r² = 0.66). GA area growth rate was associated with baseline GA area (r² = 0.39; P < 0.001), lesion number (r² = 0.10; P < 0.001), and circularity index (r² = 0.28; P < 0.001). The use of the square root of GA area reduced the influence of baseline GA area (but not lesion number or circularity) on GA growth rate. In comparison, GA perimeter-adjusted growth rate (0.098 ± 0.062 mm/year) was not correlated with baseline GA area (r² = 0.005; P = 0.20), lesion number (r² = 0.00009; P = 0.86), or circularity index (r² = 0.007; P = 0.14). GA perimeter-adjusted growth rate was 50.0% higher in eyes whose fellow eyes showed GA at any visit (0.102 ± 0.062 mm/year) than in eyes whose fellow eyes never demonstrated GA during follow-up (0.068 ± 0.049 mm/year).

CONCLUSIONS

The growth rate of GA area is associated strongly with lesion perimeter. This relationship explains the previously observed influences of baseline GA size, lesion number, and circularity on GA growth rate. GA perimeter-adjusted growth rate is uncorrelated with the 3 morphologic factors and may serve as a surrogate outcome measure to monitor GA progression in future studies.

Early Detection of Incipient Retinal Pigment Epithelium Atrophy Overlying Drusen with Fundus Autofluorescence vs. Spectral Domain Optical Coherence Tomography

Purpose

This study aims to find out which tool, fundus autofluorescence (FAF) or spectral domain optical coherence tomography (SD-OCT), is more sensitive in detecting retinal pigment epithelium (RPE) demise overlying drusen and can, therefore, help predict geographic atrophy (GA) appearance in Age-Related Macular Degeneration (AMD).

Methods

A single-site, retrospective, observational, longitudinal study was conducted. Patients with intermediate AMD (iAMD) (large (>125 μm) or intermediate (63–125 μm) drusen with hyper/hypopigmentation) with a minimum follow-up of 18 months were included. Drusen with overlying incipient RPE atrophy were identified on SD-OCT defined as choroidal hypertransmission or nascent geographic atrophy (nGA). These selected drusen were, then, traced backwards in time to determine if incipient RPE atrophy overlying drusen was observed on FAF (well-demarcated region of absence of autofluorescence) before, simultaneously, or after having detected the first signs of incipient RPE atrophy on SD-OCT. The number of drusen in which signs of incipient RPE atrophy was detected earlier using FAF or SD-OCT was compared. The time elapsed from the identification with the more sensitive method to the other was recorded and analyzed.

Results

One hundred and thirty-three drusen in 22 eyes of 22 patients were included. Of these, 112 (84.2%) drusen showed choroidal hypertransmission and 21(15.8%) nGA. Early signs of atrophy overlying drusen were found simultaneously on SD-OCT and FAF in 52 cases (39.1%, 95% CI 30.8–47.9%), earliest on FAF in 51 (38.3%, 95% CI 30.0–47.2%) and first on SD-OCT in 30 (22.6%, 95% CI 15.8–30.6%; p < 0.05). Statistically significant differences were found between both techniques (p=0.005), with FAF detecting it earlier than SD-OCT. When RPE atrophy was found first on FAF, the median time to diagnosis with SD-OCT was 6.6 months (95% CI 5.5 to 8.6), while if detection occurred earlier on SD-OCT, the median time until identification with FAF was 12.6 months (95% CI 6.0 to 23.4; p=0.0003).

Conclusions

In iAMD cases in which early atrophy overlying drusen is not detected simultaneously in FAF and SD-OCT, FAF was significantly more sensitive. Nevertheless, a multimodal approach is recommended and required to evaluate these patients.

Progression of Unifocal versus Multifocal Geographic Atrophy in Age-Related Macular Degeneration: A Systematic Review and Meta-analysis

TOPIC

Determining the natural history of unifocal versus multifocal geographic atrophy (GA) secondary to nonexudative age-related macular degeneration.

CLINICAL RELEVANCE

The association between GA focality (i.e., unifocal vs. multifocal lesions) and enlargement rate is inconsistent in the literature. Some studies report a comparable growth rate between unifocal and multifocal GA, whereas others suggest the growth rate varies widely between the 2 groups.

METHODS

We searched 5 literature databases up to May 3, 2019, for studies that classified treatment-naïve GA patients based on lesion focality. We performed a random effects meta-analysis to determine the growth rates of GA. To account for different entry times among cohorts, we introduced a horizontal translation factor to the dataset of each cohort. Heterogeneity and study quality were assessed using the I² statistic and Quality in Prognosis Studies tool, respectively. Publication bias was evaluated by funnel plots and the Egger test.

RESULTS

We included 12 studies with 3489 eyes from 3001 patients. After the introduction of translation factors, the effective radius of unifocal and multifocal GA enlarged linearly over approximately 7 years. The effective radius growth rate of multifocal GA (0.199±0.012 mm/year) was 46.3% higher than the growth rate of unifocal GA (0.136±0.008 mm/year; P < 0.001). Interestingly, unifocal and multifocal GA lesions with the same total baseline area grew at vastly different rates, with an estimated ratio of the growth rate as 1.46 (between 2 and 3). This difference disappeared after we accounted for different baseline total perimeters between unifocal and multifocal groups. The measured GA growth rate was consistent across studies using color fundus photography, fundus autofluorescence, or OCT (P = 0.35-0.99).

CONCLUSIONS

The effective radius of GA enlarges linearly and steadily over time in both unifocal and multifocal GA. The lesion focality is a significant prognostic factor for the GA effective radius growth rate. We propose that the growth rate of GA area is directly proportional to the total lesion perimeter (a measure of the number of retinal pigment epithelium cells exposed at the lesion border). Additional studies are needed to understand the cellular mechanisms underlying this relationship.

Progression of Geographic Atrophy in Age-related Macular Degeneration: AREDS2 Report Number 16

PURPOSE

To analyze the prevalence, incidence, and clinical characteristics of eyes with geographic atrophy (GA) in age-related macular degeneration (AMD), including clinical and genetic factors affecting enlargement.

DESIGN

Prospective cohort study within a controlled clinical trial.

PARTICIPANTS

Age-Related Eye Disease Study 2 (AREDS2) participants, aged 50-85 years.

METHODS

Baseline and annual stereoscopic color fundus photographs were evaluated for GA presence and area. Analyses included GA prevalence and incidence rates, Kaplan-Meier rates, mixed-model regression, and multivariable analysis of the square root of GA, area adjusted for covariates, including clinical/imaging characteristics and genotype.

MAIN OUTCOME MEASURES

(1) Presence or development of GA; (2) change in the square root of GA area over time.

RESULTS

At baseline, 517 eyes (6.2%) of 411 participants (9.8%) had pre-existing GA (without neovascular AMD), with the following characteristics: 33% central, 67% noncentral; and the following configurations: 36% small, 26% solid/unifocal, 24% multifocal, 9% horseshoe/ring, and 6% indeterminate. Of the remaining 6530 eyes at risk, 1099 eyes (17.3%) of 883 participants developed incident GA without prior neovascular disease during mean follow-up of 4.4 years. The Kaplan-Meier rate of incident GA was 19% of eyes at 5 years. In eyes with incident GA, 4-year risk of subsequent neovascular AMD was 29%. In eyes with incident noncentral GA, 4-year risk of central involvement was 57%. GA enlargement rate (following square root transformation) was similar in eyes with pre-existing GA (0.29 mm/year; 95% confidence interval 0.27-0.30) and incident GA (0.28 mm/year; 0.27-0.30). In the combined group, GA enlargement was significantly faster with noncentrality, multifocality, intermediate baseline size, and bilateral GA (P < 0.0001 for interaction in each case) but not with AREDS2 treatment assignment (P = 0.33) or smoking status (P = 0.05). Enlargement was significantly faster with ARMS2 risk (P < 0.0001), C3 non-risk (P = 0.0002), and APOE non-risk (P = 0.001) genotypes.

CONCLUSIONS

Analyses of AREDS2 data on natural history of GA provide representative data on GA evolution and enlargement. GA enlargement, which was influenced by lesion features, was relentless, resulting in rapid central vision loss. The genetic variants associated with faster enlargement were partially distinct from those associated with risk of incident GA. These findings are relevant to further investigations of GA pathogenesis and clinical trial planning.

The Progression of Geographic Atrophy Secondary to Age-Related Macular Degeneration

Geographic atrophy (GA) is an advanced form of age-related macular degeneration (AMD) that leads to progressive and irreversible loss of visual function. Geographic atrophy is defined by the presence of sharply demarcated atrophic lesions of the outer retina, resulting from loss of photoreceptors, retinal pigment epithelium (RPE), and underlying choriocapillaris. These lesions typically appear first in the perifoveal macula, initially sparing the foveal center, and over time often expand and coalesce to include the fovea. Although the kinetics of GA progression are highly variable among individual patients, a growing body of evidence suggests that specific characteristics may be important in predicting disease progression and outcomes. This review synthesizes current understanding of GA progression in AMD and the factors known or postulated to be relevant to GA lesion enlargement, including both affected and fellow eye characteristics. In addition, the roles of genetic, environmental, and demographic factors in GA lesion enlargement are discussed. Overall, GA progression rates reported in the literature for total study populations range from 0.53 to 2.6 mm²/year (median, ∼1.78 mm²/year), assessed primarily by color fundus photography or fundus autofluorescence (FAF) imaging. Several factors that could inform an individual's disease prognosis have been replicated in multiple cohorts: baseline lesion size, lesion location, multifocality, FAF patterns, and fellow eye status. Because best-corrected visual acuity does not correspond directly to GA lesion enlargement due to possible foveal sparing, alternative assessments are being explored to capture the relationship between anatomic progression and visual function decline, including microperimetry, low-luminance visual acuity, reading speed assessments, and patient-reported outcomes. Understanding GA progression and its individual variability is critical in the design of clinical studies, in the interpretation and application of clinical trial results, and for counseling patients on how disease progression may affect their individual prognosis.

Advanced imaging for the diagnosis of age-related macular degeneration: a case vignettes study

Background

The aim of this study is to evaluate the diagnosis, staging, imaging and management preferences, and the effect of advanced imaging among practising optometrists in age‐related macular degeneration (AMD).

Methods

Up to 20 case vignettes (computer‐based case simulations) were completed online in a computer laboratory in random order by 81 practising optometrists of Australia. Each case presented findings from a randomly selected patient seen previously at the Centre for Eye Health for a macular assessment in the following order: case history, preliminary tests and colour fundus photography. Participants were prompted to provide their diagnosis, management and imaging preference. One additional imaging result (either modified fundus photographs and infrared images, fundus autofluorescence, or optical coherence tomography [OCT]) was then provided and the questions repeated. Finally, all imaging results were provided and the questions repeated a third time.

Results

A total of 1,436 responses were analysed. The presence of macular pathology in AMD was accurately detected in 94 per cent of instances. The overall diagnostic accuracy of AMD was 61 per cent using colour fundus photography. This improved by one per cent using one additional imaging modality and a further four per cent using all imaging. Across all responses, a greater improvement in the diagnostic accuracy of AMD occurred following the presentation of OCT findings (versus other modalities). OCT was the most preferred imaging modality for AMD, while multimodal imaging was of greatest benefit in cases more often misdiagnosed using colour fundus photography alone. Overall, the cohort also displayed a tendency to underestimate disease severity.

Conclusion

Despite reports that imaging technologies improve the stratification of AMD, our findings suggest that this effect may be small when applied among practising optometrists without additional or specific training.

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).

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.

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.

Evolution of Geographic Atrophy in Participants Treated with Ranibizumab for Neovascular Age-related Macular Degeneration

PURPOSE

To evaluate the risk factors, incidence, and rate of progression of geographic atrophy (GA) in eyes with neovascular age-related macular degeneration (nAMD) treated with ranibizumab.

DESIGN

Post-hoc analysis of a prospective clinical study.

PARTICIPANTS

69 participants with nAMD in at least one eye.

METHODS

Participants were prospectively treated in the study eye with 0.5 mg intravitreal ranibizumab. Study eyes received 4 monthly injections followed by pro re nata injections until a fluid-free macula was achieved on optical coherence tomography. Risk factors assessed included baseline demographics, treatment, and ocular characteristics on imaging. Eyes were evaluated on fundus autofluorescence (FAF) for GA. The rate of GA area growth in study and fellow eyes was analyzed by linear regression of square-root transformed areas.

MAIN OUTCOME MEASURES

Development of new-onset GA and rate of GA area growth measured on ocular imaging, including FAF images of the study eyes.

RESULTS

Sixty-nine participants (mean age 78.8±7.8 years) with an average of 40.0±13.6 months of follow-up were analyzed. Twenty-two of 69 study eyes (32%) were treatment naïve. During their first year of the study, participants received an average of 9.2±3.3 injections in the study eye. Of 63 study eyes with quality baseline images, 22 (35%) had pre-existing GA. Of the remaining 41 eyes, 7 (17%) developed new-onset GA during study follow-up. Those who developed new GA were older (all ≥79 years old) and had received fewer study injections on average (6.9 vs. 10.4 injections at 1 year) compared to those who did not develop new GA. Of the 12 treatment naïve study eyes without GA at baseline, 1 (8.3%) developed new GA during the study. In 21 study eyes with quantifiable GA area, eyes with GA present at baseline (16/21) enlarged by 0.34±0.26 mm/year, compared to 0.19±0.12 mm/year in eyes developing new-onset GA (5/21).

CONCLUSIONS

While 17% of study eyes without GA present at baseline receiving ranibizumab developed new GA, the role of ranibizumab in the development of GA is unclear. Further prospective longitudinal studies are required to determine the eyes most at risk of developing GA in the setting of anti-VEGF treatment.

Fundus autofluorescence applications in retinal imaging

Fundus autofluorescence (FAF) is a relatively new imaging technique that can be used to study retinal diseases. It provides information on retinal metabolism and health. Several different pathologies can be detected. Peculiar AF alterations can help the clinician to monitor disease progression and to better understand its pathogenesis. In the present article, we review FAF principles and clinical applications.

Semiautomatic Segmentation of Rim Area Focal Hyperautofluorescence Predicts Progression of Geographic Atrophy Due to Dry Age-Related Macular Degeneration

Purpose

To develop image analysis software usable by nonexpert graders to segment geographic atrophy (GA) from dry AMD and to quantify rim area focal hyperautofluorescence (RAFH) surrounding GA on fundus autofluorescence (FAF) images. To compare the GA progression predictions based on RAFH with those of a validated qualitative classification system.

Methods

Retrospective analysis of serial FAF images from 49 eyes of 30 subjects with GA was performed using MATLAB-based software (MathWorks, Natick, MA, USA). Correlation between RAFH and progression of GA was analyzed using Spearman correlation. Comparisons of lesion growth rate between RAFH tertiles used generalized estimating equations and Kruskal-Wallis testing. Interobserver variability in lesion size, growth rate and RAFH were compared between two expert and one nonexpert grader using Bland-Altman statistics.

Results

Rim area focal hyperautofluorescence was positively correlated with GA progression rate (ρ = 0.49, P < 0.001). Subjects in the middle or highest RAFH tertile were at greater risk of progression (P = 0.005 and P = 0.001, respectively). Mean difference in RAFH was 0.012 between expert and −0.005 to 0.017 between expert and nonexperts. Mean difference in lesion size (mm²) was 0.11 between expert and −0.29 to 0.41 between expert and nonexperts. Mean difference in lesion growth rate (mm²/mo) was 0.0098 between expert and −0.027 to 0.037 between expert and nonexperts. Risk stratification based on RAFH tertile was 96% identical across all graders.

Conclusions

Our semiautomated image analysis software facilitates stratification of progression risk based on RAFH and enabled a nonexpert grader with minimal training to obtain results comparable to expert graders. Predictions based on RAFH were similar to those of a validated qualitative classification system.

Evaluation of Geographic Atrophy from Color Photographs and Fundus Autofluorescence Images: Age-Related Eye Disease Study 2 Report Number 11

PURPOSE

To compare measurements of area of geographic atrophy (GA) and change in GA area from color photographs and fundus autofluorescence (FAF) images.

DESIGN

The Age-Related Eye Disease Study 2 (AREDS2) was a prospective multicenter randomized clinical trial evaluating progression of dry age-related macular degeneration (AMD) using color photographs at annual visits over a 5-year study period. The FAF images were acquired in a subset of participants who joined the FAF ancillary study at any of the annual visits over the study period.

PARTICIPANTS

The AREDS2 FAF ancillary study included 8070 corresponding color and FAF visits of 2202 participants with variable follow-up.

METHODS

Corresponding color and FAF images were independently evaluated at a central reading center for GA area measurement, lesion growth, and involvement of the macula center.

MAIN OUTCOME MEASURES

Presence, area, growth rate of GA, and involvement of center of macula from color and FAF images.

RESULTS

Hypoautofluorescence was visible in 2048 visits (25.4%). Agreement for the presence of GA between the 2 modalities had a kappa of 0.79, with 23% of visits with hypoautofluorescence not presenting with GA on color photographs. Percentage agreement for GA presence ranged from 43% at baseline to 81% at year 5 with improving agreement over time. The mean difference in GA area between the 2 modalities was 0.5 mm², with larger areas on FAF. Growth rate of GA was 1.45 mm² from color photographs and 1.43 mm² from FAF images. The center of the macula was involved in 51% of color photographs and 56% with FAF images.

CONCLUSIONS

Geographic atrophy may be detected earlier by the use of FAF images, but over the course of the study, the 2 modalities become comparable. Progression of GA area is comparable between color photographs and FAF images, but evaluating involvement of the center of the macula may differ, probably because of macular pigmentation blocking autofluorescence.

Natural History of Geographic Atrophy Progression Secondary to Age-Related Macular Degeneration (Geographic Atrophy Progression Study)

PURPOSE

The Geographic Atrophy Progression (GAP) study was designed to assess the rate of geographic atrophy (GA) progression and to identify prognostic factors by measuring the enlargement of the atrophic lesions using fundus autofluorescence (FAF) and color fundus photography (CFP).

DESIGN

Prospective, multicenter, noninterventional natural history study.

PARTICIPANTS

A total of 603 participants were enrolled in the study; 413 of those had gradable lesion data from FAF or CFP, and 321 had gradable lesion data from both FAF and CFP.

METHODS

Atrophic lesion areas were measured by FAF and CFP to assess lesion progression over time. Lesion size assessments and best-corrected visual acuity (BCVA) were conducted at screening/baseline (day 0) and at 3 follow-up visits: month 6, month 12, and month 18 (or early exit).

MAIN OUTCOME MEASURES

The GA lesion progression rate in disease subgroups and mean change from baseline visual acuity.

RESULTS

Mean (standard error) lesion size changes from baseline, determined by FAF and CFP, respectively, were 0.88 (0.1) and 0.78 (0.1) mm(2) at 6 months, 1.85 (0.1) and 1.57 (0.1) mm(2) at 12 months, and 3.14 (0.4) and 3.17 (0.5) mm(2) at 18 months. The mean change in lesion size from baseline to month 12 was significantly greater in participants who had eyes with multifocal atrophic spots compared with those with unifocal spots (P < 0.001) and those with extrafoveal lesions compared with those with foveal lesions (P = 0.001). The mean (standard deviation) decrease in visual acuity was 6.2 ± 15.6 letters for patients with image data available. Atrophic lesions with a diffuse (mean 0.95 mm(2)) or banded (mean 1.01 mm(2)) FAF pattern grew more rapidly by month 6 compared with those with the "none" (mean, 0.13 mm(2)) and focal (mean, 0.36 mm(2)) FAF patterns.

CONCLUSIONS

Although differences were observed in mean lesion size measurements using FAF imaging compared with CFP, the measurements were highly correlated with one another. Significant differences were found in lesion progression rates in participants stratified by hyperfluorescence pattern subtype. This large GA natural history study provides a strong foundation for future clinical trials.

Prognostic implications of imaging in atrophic macular degeneration and its use in clinical practice and clinical trial design

Clinical prognostic markers in atrophic age-related macular degeneration include the extent of existing atrophy, fundus autofluorescence (FAF) patterns and optical coherence tomography changes in the outer retina/retinal pigment epithelium interface. The prognostic implications of these findings may be used to determine not just the rate of disease progression but also influence the likelihood, magnitude and clinical relevance of therapy responses. FAF phenotypes have been extensively investigated; however, the pathophysiological mechanisms behind their appearance have not been fully elucidated. Optical coherence tomography imaging is additive to FAF imaging in atrophic age-related macular degeneration, allowing the visualization of detail not available through FAF imaging whilst also displaying subtle changes correlating with the FAF phenotypes themselves, thereby giving clues to their histological determinates. The developing understanding of these imaging modalities and consequent development of prognostically useful classification systems have widespread implication in clinical care and clinical trial design.

MultiColor imaging in the evaluation of geographic atrophy due to age-related macular degeneration

PURPOSE

To compare different imaging modalities and to investigate the ability of MultiColor to evaluate geographic atrophy (GA) due to age-related macular degeneration (AMD).

METHODS

Twenty-two consecutive patients with GA underwent MultiColor, colour fundus photography, blue fundus autofluorescence (FAF) (excitation=488 nm; emission >500 nm), near-infrared FAF (NIR-FAF) (excitation=787 nm; emission >800 nm) and spectral-domain optical coherence tomography (SD-OCT) (Spectralis HRA+OCT; Heidelberg Engineering) imaging. Two readers independently measured the size (area) and the width of GA (on horizontal SD-OCT scan cutting the fovea), and evaluated the foveal sparing in each examination.

RESULTS

A total of 32 eyes (22 patients, mean age 79.2±8 years) with GA were included. Intragrader and intergrader agreement considering the evaluation of the size and width of GA was high for all the examinations. MultiColor and FAF showed the greatest intergrader agreement for GA area measurement (intraclass correlation (ICC)=0.990, 95% CI 0.980 to 0.995; ICC=0.998, 95% CI 0.996 to 0.999, respectively). SD-OCT showed the highest intergrader agreement of foveal involvement (k=1), followed by MultiColor and NIR-FAF (k=0.68).

CONCLUSIONS

We demonstrated that several different imaging modalities currently available in clinical practice are reliable for evaluating GA due to AMD. MultiColor is an excellent tool for the measurement of GA area and width, and for the detection of foveal sparing.

Automated segmentation of geographic atrophy in fundus autofluorescence images using supervised pixel classification

Geographic atrophy (GA) is a manifestation of the advanced or late stage of age-related macular degeneration (AMD). AMD is the leading cause of blindness in people over the age of 65 in the western world. The purpose of this study is to develop a fully automated supervised pixel classification approach for segmenting GA, including uni- and multifocal patches in fundus autofluorescene (FAF) images. The image features include region-wise intensity measures, gray-level co-occurrence matrix measures, and Gaussian filter banks. A [Formula: see text]-nearest-neighbor pixel classifier is applied to obtain a GA probability map, representing the likelihood that the image pixel belongs to GA. Sixteen randomly chosen FAF images were obtained from 16 subjects with GA. The algorithm-defined GA regions are compared with manual delineation performed by a certified image reading center grader. Eight-fold cross-validation is applied to evaluate the algorithm performance. The mean overlap ratio (OR), area correlation (Pearson's [Formula: see text]), accuracy (ACC), true positive rate (TPR), specificity (SPC), positive predictive value (PPV), and false discovery rate (FDR) between the algorithm- and manually defined GA regions are [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], respectively.

Quantification of retinal pigment epithelium tear area in age-related macular degeneration

PURPOSE

To compare different quantification tools based on confocal scanning laser ophthalmoscopy for assessment of retinal pigment epithelium (RPE) tear area size.

METHODS

Confocal scanning laser ophthalmoscopy fundus autofluorescence (FAF) and near-infrared reflectance (IR) images were retrospectively evaluated in 23 patients with RPE tear after intravitreal injection for pigment epithelium detachment due to exudative age-related macular degeneration at baseline and additionally in 11 patients after 5.1 ± 1.8 months of follow-up. Retinal pigment epithelium tear area was measured by three independent readers using three methods: manually on confocal scanning laser ophthalmoscopy FAF images, manually on confocal scanning laser ophthalmoscopy IR images, and using an FAF-based semiautomated software.

RESULTS

Confidence intervals were 0.08 and 0.12 for FAF, 0.11 and 0.09 for FAF-based semiautomated software, and 0.25 and 0.27 for IR for intraobserver (Reader 1) and interobserver agreements (Readers 1 and 2), respectively. The average values of the square errors of the quantification methods were 0.040 ± 0.033 mm (FAF), 0.035 ± 0.060 mm (software), and 0.187 ± 0.219 mm (IR). Mean area of RPE tears at baseline given as the average measurement of all 3 readers using FAF-based semiautomated software was 5.77 ± 4.62 mm (range, 0.13-14.74 mm). Follow-up measurements of unilobular RPE tears (8 patients) showed no change in lesion area size (0.14 ± 0.33 mm); in contrast, multilobular RPE tears (3 patients) showed a progression in lesion area size of 1.80 ± 0.74 mm.

CONCLUSION

Manual FAF-based and semiautomated FAF-based quantifications of RPE tear area are accurate and reproducible and superior to manual IR-based measurement. Retinal pigment epithelium tear area quantification is clinically relevant regarding further intravitreal treatment, particularly in multilobular RPE tears.

Reticular macular disease is associated with multilobular geographic atrophy in age-related macular degeneration

PURPOSE

To investigate the incidence of reticular macular disease (RMD), a subphenotype of age-related macular degeneration, in multilobular geographic atrophy (GA) and its relation to GA progression.

METHODS

One hundred and fifty-seven eyes of 99 subjects with age-related macular degeneration, primary GA, and good quality autofluorescence, and/or infrared images were classified into unilobular GA (1 lesion) or multilobular GA (≥ 2 distinct and/or coalescent lesions). Thirty-four subjects (50 eyes) had serial imaging. The authors determined the spatiotemporal relationships of RMD to GA and GA progression rates in five macular fields.

RESULTS

91.7% eyes (144 of 157) had multilobular GA, 95.8% of which exhibited RMD. In subjects with serial imaging, the mean GA growth rate significantly differed between the unilobular and multilobular groups (0.40 vs. 1.30 mm2/year, P < 0.001). Of the macular fields in these eyes, 77.1% of fields with RMD at baseline showed subsequent GA progression, while 53.4% of fields without RMD showed progression (P < 0.001). Percentage of fields with RMD significantly correlated with GA progression rate (P = 0.01).

CONCLUSION

Autofluorescence and infrared imaging demonstrates that RMD is nearly always present with multilobular GA in age-related macular degeneration. Furthermore, GA lobules frequently develop in areas of RMD, suggesting progression of a single underlying disease process.

Association between geographic atrophy progression and reticular pseudodrusen in eyes with dry age-related macular degeneration

PURPOSE

To evaluate geographic atrophy (GA) progression in eyes with dry AMD and to determine factors related to GA expansion, notably reticular pseudodrusen (RPD), also known as subretinal drusenoid deposits (SDD) or reticular macular disease (RMD).

METHODS

This was a retrospective cohort study of patients with dry AMD who were diagnosed with GA in at least one eye and were imaged with sequential fundus autofluorescence (FAF) and/or near infrared reflectance (NIR-R) imaging. Images were analyzed for the presence of GA within the macular region. Geographic atrophy progression was measured in the fields of a modified Wisconsin grid and spatially correlated with RPD. Factors also evaluated for association with GA progression included initial GA size and pattern.

RESULTS

The study sample included 126 eyes of 92 patients, with an average follow up of 20.4 months (SD = 11.7). At baseline, 93.6% of eyes had RPD, and the average GA area was 2.8 mm(2) (SD = 2.9). The average GA progression rate was 0.8 mm(2)/y (SD = 0.6), with a statistically significant difference between the unilobular and multilobular phenotype groups (0.3 mm(2)/y vs. 0.9 mm(2)/y, P = 0.02). Patients in the lower 50th percentile of initial GA area had a lower progression rate than patients in the upper 50th percentile (0.6 mm(2)/y vs. 1.1 mm(2)/y, P < 0.001). Geographic atrophy progression was more frequent in fields with RPD than in those without RPD (74.2% vs. 41.7%, P < 0.001).

CONCLUSIONS

The high correlation between the presence of RPD (also known as SDD or RMD) and the presence of GA, and the expansion of GA into areas with these lesions suggest that they are an early manifestation of the process leading to GA.

Geographic chorioretinal atrophy in pseudoxanthoma elasticum

PURPOSE

To describe a series of patients with geographic atrophy independent of choroidal neovascularization (CNV) in pseudoxanthoma elasticum and to report progression over time.

DESIGN

Retrospective observational case series.

METHODS

Records of all Vanderbilt Eye Institute patients with pseudoxanthoma elasticum and at least 1 set of color fundus photographs were reviewed (41 eyes of 21 patients). Fluorescein angiography, fundus autofluorescence, and optical coherence tomography images were reviewed, when available. In patients with geographic atrophy and at least 1 year of follow-up, atrophy was measured using fundus photographs. Main outcome measures included incidence of geographic atrophy, progression over time, and macular features associated with development or progression of geographic atrophy.

RESULTS

Eight eyes (20%) of 5 patients had geographic atrophy independent of CNV. Progression was documented in 6 eyes of 4 patients followed for at least 1 year (mean 3.5 years). Mean initial and final area was 2.9 and 9.5 mm(2), respectively, and growth rate was 1.7 mm(2) per year. Of the 6 eyes, 3 had a final visual acuity of 20/20 and the other 3 ranged from 20/150 to 20/400. All 8 eyes had pattern dystrophy, and 5 had linear pigment deposits that appeared to predict development or growth of atrophy.

CONCLUSIONS

Isolated geographic atrophy independent of CNV can develop in pseudoxanthoma elasticum, causing significant vision loss. Linear pigmented pattern dystrophy appears to predate geographic atrophy. Progression is similar to age-related macular degeneration. Recognition of this feature is important, especially if therapies to slow or reverse geographic atrophy become available.

Risk of geographic atrophy in the comparison of age-related macular degeneration treatments trials

PURPOSE

To describe risk factors for geographic atrophy (GA) in the Comparison of Age-related Macular Degeneration Treatments Trials (CATT).

DESIGN

Cohort within a randomized clinical trial.

PARTICIPANTS

We analyzed 1024 CATT patients with no GA visible on color fundus photographs (CFPs) and/or fluorescein angiograms (FAs) at enrollment.

METHODS

Eyes were assigned to ranibizumab (0.5 mg) or bevacizumab (1.25 mg) treatment and to a 2-year monthly or pro re nata (PRN) injection regimen, or monthly injections for 1 year and PRN for 1 year. Demographic, genetic, and baseline ocular characteristics and lesion features of CFP/FA and optical coherence tomography (OCT) were evaluated as risk factors for GA through 2 years of follow-up. Time-dependent Cox proportional hazard models were used to estimate adjusted hazard ratios (aHRs).

MAIN OUTCOME MEASURES

Development of GA.

RESULTS

By 2 years, GA developed in 187 of 1024 patients (18.3%). Baseline risk factors for GA development included baseline visual acuity (VA) ≤20/200 (aHR, 2.65; 95% confidence interval [CI], 1.43-4.93), retinal angiomatous proliferation (RAP; aHR, 1.69; 95% CI, 1.16-2.47), GA in the fellow eye (aHR, 2.07; 95% CI, 1.40-3.08), and intraretinal fluid at the foveal center (aHR, 2.10; 95% CI, 1.34-3.31). Baseline factors associated with lower risk for GA development included blocked fluorescence (aHR, 0.49; 95% CI, 0.29-0.82), OCT measurements of subretinal fluid thickness of >25 μ (aHR, 0.52; 95% CI, 0.35-0.78), subretinal tissue complex thickness of >275 compared with ≤75 μ (aHR, 0.31; 95% CI, 0.19-0.50), and vitreomacular attachment (aHR, 0.55; 95% CI, 0.31-0.97). Ranibizumab compared with bevacizumab had a higher risk (aHR, 1.43; 95% CI, 1.06-1.93), and monthly dosing had a higher risk (aHR, 1.59; 95% CI, 1.17-2.16) than PRN dosing. There were no strong associations between development of GA and the presence of risk alleles for CFH, ARMS 2, HTRA1, C3, or TLR3.

CONCLUSIONS

Approximately one fifth of CATT patients developed GA within 2 years of treatment. Independent baseline risk factors included poor VA, RAP, foveal intraretinal fluid, monthly dosing, and treatment with ranibizumab. Anti-vascular endothelial growth factor therapy may have a role in the development of GA.

Fundus autofluorescence imaging in age-related macular degeneration

Fundus autofluorescence (FAF) is a noninvasive imaging technology that provides information on the distribution of lipofuscin within the retinal pigment epithelial cells. Progressive accumulation of lipofuscin within retinal pigment epithelial cells is involved in the pathogenesis of age-related macular degeneration (AMD). Fundus autofluorescence imaging using a confocal scanning laser ophthalmoscope is a useful technique to identify high-risk characteristics in patients with nonexudative AMD. It gives also some valuable knowledge and clues in differantial diagnosis of exudative age-related macular degeneration. This review comprises an introduction to fundus autofluorescence, a review of FAF imaging in AMD, and the recent classification of geographic atrophy (GA) and early AMD phenotypes by the Fundus Autofluorescence in Age-related Macular Degeneration Study. The association of phenotype and atrophy progression and choroidal neovascularization development are also summarized.

Multimodal assessment of microscopic morphology and retinal function in patients with geographic atrophy

PURPOSE

To correlate retinal function and visual sensitivity with retinal morphology revealed by ultrahigh-resolution imaging with adaptive optics-optical coherence tomography (AO-OCT), on patients with geographic atrophy.

METHODS

Five eyes from five subjects were tested (four with geographic atrophy [66.3 ± 6.4 years, mean ± 1 SD] and one normal [61 years]). Photopic and scotopic multifocal electroretinograms (mfERGs) were recorded. Visual fields were assessed with microperimetry (mP) combined with a scanning laser ophthalmoscope for high-resolution confocal retinal fundus imaging. The eye tracker of the microperimeter identified the preferred retinal locus that was then used as a reference for precise targeting of areas for advanced retinal imaging. Images were obtained with purpose-built, in-house, ultrahigh resolution AO-OCT. Fundus autofluorescence (FAF) and color fundus (CF) photographs were also acquired.

RESULTS

The AO-OCT imaging provided detailed cross-sectional structural representation of the retina. Up to 12 retinal layers were identified in the normal subject while many severe retinal abnormalities (i.e., calcified drusen, drusenoid pigment epithelium detachment, outer retinal tubulation) were identified in the retinae of the GA patients. The functional tests showed preservation of sensitivities, although somewhat compromised, at the border of the GA.

CONCLUSIONS

The images provided here advance our knowledge of the morphology of retinal layers in GA patients. While there was a strong correlation between altered retinal structure and reduction in visual function, there were a number of examples in which the photoreceptor inner/outer segment (IS/OS) junctions lost reflectivity at the margins of GA, while visual function was still demonstrated. This was shown to be due to changes in photoreceptor orientation near the GA border.

Characteristics of incident geographic atrophy in the complications of age-related macular degeneration prevention trial

OBJECTIVE

To characterize the size, location, conformation, and features of incident geographic atrophy (GA) as detected by annual stereoscopic color photographs and fluorescein angiograms (FAs).

DESIGN

Retrospective cohort study within a larger clinical trial.

PARTICIPANTS

Patients with bilateral large drusen in whom GA developed during the course of the Complications of Age-related Macular Degeneration Prevention Trial (CAPT).

METHODS

Annual stereoscopic color photographs and FAs were reviewed from 114 CAPT patients in whom GA developed in the untreated eye during 5 to 6 years of follow-up. Geographic atrophy was defined according to the Revised GA Criteria for identifying early GA.(23) Color-optimized fundus photographs were viewed concurrently with the FAs during grading.

MAIN OUTCOME MEASURES

Size and distance from the fovea of individual GA lesions, number of areas of atrophy, and change in visual acuity (VA) when GA first developed in an eye.

RESULTS

At presentation, the median total GA area was 0.26 mm(2) (0.1 disc area). Geographic atrophy presented as a single lesion in 89 (78%) eyes. The median distance from the fovea was 395 μm. Twenty percent of incident GA lesions were subfoveal and an additional 18% were within 250 μm of the foveal center. Development of GA was associated with a mean decrease of 7 letters from the baseline VA level compared with 1 letter among matched early age-related macular degeneration eyes without GA. Geographic atrophy that formed in areas previously occupied by drusenoid pigment epithelial detachments on average were larger (0.53 vs. 0.20 mm(2); P = 0.0001), were more central (50 vs. 500 μm from the center of the fovea; P<0.0001), and were associated with significantly worse visual outcome (20/50 vs. 20/25; P = 0.0003) than GA with other drusen types as precursors.

CONCLUSIONS

Incident GA most often appears on color fundus photographs and FAs as a small, singular, parafoveal lesion, although a large minority of lesions are subfoveal or multifocal at initial detection. The characteristics of incident GA vary with precursor drusen types. These data can facilitate design of future clinical trials of therapies for GA.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.