Changes in retinal sensitivity in geographic atrophy progression as measured by microperimetry

Censoring the Floor Effect in Long-Term Stargardt Disease Microperimetry Data Produces a Faster Rate of Decline

Purpose

To evaluate progression rate estimation in long-term Stargardt disease microperimetry data by accounting for floor effect.

Design

Cohort study.

Subjects

Thirty-seven subjects (23 females, 14 males) with biallelic ABCA4 pathogenic or likely pathogenic variants and more than >2 years of longitudinal microperimetry data.

Methods

Cross-sectional and longitudinal microperimetry data (Grid A: 18° diameter, Grid B: 6° diameter; Macular Integrity Assessment microperimeter, dynamic range 0-36 decibels [dB]) was extracted from patients with biallelic mutation in the adenosine triphosphate-binding cassette subfamily A member 4 (ABCA4) gene. For each eye, mean sensitivity (MS) and responding point sensitivity (RPS) rates were extracted. Floor censored sensitivity (FCS) progression rate, which accounts for the floor effect at each locus by terminating calculation when scotoma was observed in 2 consecutive visits, was also calculated. In a subset of eyes with ≥1 scotomatous locus at baseline (Grid A), sensitivity progression of loci around the scotoma (edge of scotoma sensitivity [ESS]) was examined against other progression parameters. Paired t test compared progression rate parameters across the same eyes.

Main Outcome Measures

Microperimetry grid parameters at baseline and progression rates.

Results

A total of 37 subjects with biallelic ABCA4 mutations and >2 years of longitudinal microperimetry data were included in the study. In Grid A, at baseline, the average MS and RPS were 16.5 ± 7.9 and 19.1 ± 5.7 dB, respectively. Similar MS (18.4 ± 7.6 dB) and RPS (20.0 ± 5.5 dB) values were found at baseline for Grid B. In Grid A, overall, MS, RPS, and FCS progression rates were -0.57 ± 1.05, -0.74 ± 1.24, and -1.26 ± 1.65 (all dB/year), respectively. Floor censored sensitivity progression rate was significantly greater than the MS or RPS progression rates. Similar findings were observed in Grid B (MS -1.22 ± 1.42, RPS -1.44 ± 1.44, FCS -2.16 ± 2.24, all dB/year), with paired t test again demonstrated that FCS had a significantly faster rate of decline than MS or RPS. In patients with progression data in both grids, MS, RPS, and FCS progression rates were significantly faster in the smaller Grid B. In 24 eyes with scotoma at baseline, fastest rate of decline was ESS combined with FCS compared with other progression parameters.

Conclusions

Incorporation of FCS can reduce confound of floor effect in perimetry analysis and can in turn detect a faster rate of decline.

Financial Disclosures

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

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.

Visual Sensitivity Loss in Geographic Atrophy: Structure-Function Evaluation Using Defect-Mapping Microperimetry

Purpose

To examine the structure-function relationship in eyes with geographic atrophy (GA) using defect-mapping microperimetry, a testing strategy optimized to quantify the spatial extent of deep visual sensitivity losses.

Methods

Fifty participants with GA underwent defect-mapping microperimetry testing of the central 8°-radius region (208 locations tested once with a 10-decibel stimuli) and fundus autofluorescence imaging in one eye. The GA extent in the corresponding central 8°-radius was derived by manual annotations and image co-registration to examine the global structure-function relationship. The distance of each test location from the GA margin was also derived, and regions defined, to examine the local structure-function relationship.

Results

GA extent in the central 8° explained a substantial proportion of variance in the percentage of locations missed (nonresponse) on microperimetry at the global level (R2 = 0.90). At a local level, the probability of missing stimuli at the outer junctional zone (0-500 µm outside the GA margin) and GA margin (probability = 7% and 34%, respectively) was higher than at the outer nonlesional zone (>500 µm outside the GA margin; probability = 2%; P < 0.001 for both). The probability of missing stimuli at the inner junctional zone (0-250 µm inside the GA margin) was also lower than at the inner lesional zone (>250 µm inside the GA margin; probability = 64% and 88%; P < 0.001).

Conclusions

This study confirms the expected functional relevance of the region with GA on fundus autofluorescence imaging and underscores the potential effectiveness of defect-mapping microperimetry testing for capturing visual function changes when evaluating new GA treatments.

Macular Sensitivity Endpoints in Geographic Atrophy: Exploratory Analysis of Chroma and Spectri Clinical Trials

Purpose

To assess different microperimetry (MP) macular sensitivity outcome measures capturing functional deterioration in eyes with geographic atrophy (GA) secondary to age-related macular degeneration (AMD).

Design

Patients were included from 2 identically designed, phase III, double-masked, randomized controlled clinical trials, Chroma (NCT02247479) and Spectri (NCT02247531).

Participants

Patients enrolled were aged ≥ 50 years with bilateral GA and no evidence of previous or active neovascular AMD.

Methods

Patients were randomized 2:1:2:1 to receive through 96 weeks intravitreal lampalizumab 10 mg every 4 weeks (LQ4W), every 6 weeks (LQ6W), or corresponding sham procedures. For this study, mesopic macular sensitivity of the central 20° was assessed using MP-1 microperimeter at selected sites.

Main Outcome Measures

Two exploratory endpoints were developed, namely perilesional sensitivity (average of points adjacent to absolute scotomatous points) and responding sensitivity (average of all nonscotomatous points; > 0 dB at baseline) by using customized masks for each patient. These were compared with conventional MP endpoints (mean macular sensitivity and number of absolute scotomatous points).

Results

Of 1881 Chroma and Spectri participants, 277 agreed to participate in the present study. Of these, 197 (LQ4W, n = 63; LQ6W, n = 68; pooled sham, n = 66) had reliable MP results. Enlargement of GA lesion area by approximately 2 mm2/year across treatment groups was accompanied by deterioration in all MP parameters. There was no difference in worsening of macular sensitivity or absolute scotomatous points among treatment groups. Perilesional and responding sensitivities showed greater decline over time than mean macular sensitivity. Change in GA lesion area at week 48 showed better correlation with perilesional sensitivity (r = -0.17) and responding sensitivity (r = -0.20) than mean macular sensitivity (r = -0.03), while the correlation was highest with the number of absolute scotomatous points (r = 0.37).

Conclusions

Perilesional or responding macular sensitivity measured by MP should be considered more sensitive endpoints than mean macular sensitivity for monitoring functional decline over time in GA. Although perilesional, responding, and mean macular sensitivity had weak correlation with GA lesion area, the number of absolute scotomatous points may provide additional information on the anatomic/functional correlation.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Fractal Phototherapy in Maximizing Retina and Brain Plasticity

The neuroplasticity potential is reduced with aging and impairs during neurodegenerative diseases and brain and visual system injuries. This limits the brain's capacity to repair the structure and dynamics of its activity after lesions. Maximization of neuroplasticity is necessary to provide the maximal CNS response to therapeutic intervention and adaptive reorganization of neuronal networks in patients with degenerative pathology and traumatic injury to restore the functional activity of the brain and retina.Considering the fractal geometry and dynamics of the healthy brain and the loss of fractality in neurodegenerative pathology, we suggest that the application of self-similar visual signals with a fractal temporal structure in the stimulation therapy can reactivate the adaptive neuroplasticity and enhance the effectiveness of neurorehabilitation. This proposition was tested in the recent studies. Patients with glaucoma had a statistically significant positive effect of fractal photic therapy on light sensitivity and the perimetric MD index, which shows that methods of fractal stimulation can be a novel nonpharmacological approach to neuroprotective therapy and neurorehabilitation. In healthy rabbits, it was demonstrated that a long-term course of photostimulation with fractal signals does not harm the electroretinogram (ERG) and retina structure. Rabbits with modeled retinal atrophy showed better dynamics of the ERG restoration during daily stimulation therapy for a week in comparison with the controls. Positive changes in the retinal function can indirectly suggest the activation of its adaptive plasticity and the high potential of stimulation therapy with fractal visual stimuli in a nonpharmacological neurorehabilitation, which requires further study.

Recent Advances in Imaging Macular Atrophy for Late-Stage Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a leading cause of blindness worldwide. In late-stage AMD, geographic atrophy (GA) of dry AMD or choroidal neovascularization (CNV) of neovascular AMD eventually results in macular atrophy (MA), leading to significant visual loss. Despite the development of innovative therapies, there are currently no established effective treatments for MA. As a result, early detection of MA is critical in identifying later central macular involvement throughout time. Accurate and early diagnosis is achieved through a combination of clinical examination and imaging techniques. Our review of the literature depicts advances in retinal imaging to identify biomarkers of progression and risk factors for late AMD. Imaging methods like fundus photography; dye-based angiography; fundus autofluorescence (FAF); near-infrared reflectance (NIR); optical coherence tomography (OCT); and optical coherence tomography angiography (OCTA) can be used to detect and monitor the progression of retinal atrophy. These evolving diverse imaging modalities optimize detection of pathologic anatomy and measurement of visual function; they may also contribute to the understanding of underlying mechanistic pathways, particularly the underlying MA changes in late AMD.

Geographic atrophy: pathophysiology and current therapeutic strategies

Geographic atrophy (GA) is an advanced stage of age-related macular degeneration (AMD) that leads to gradual and permanent vision loss. GA is characterized by the loss of photoreceptor cells and retinal pigment epithelium (RPE), leading to distinct atrophic patches in the macula, which tends to increase with time. Patients with geographic atrophy often experience a gradual and painless loss of central vision, resulting in difficulty reading, recognizing faces, or performing activities that require detailed vision. The primary risk factor for the development of geographic atrophy is advanced age; however, other risk factors, such as family history, smoking, and certain genetic variations, are also associated with AMD. Diagnosis is usually based on a comprehensive eye examination, including imaging tests such as fundus photography, optical coherence tomography (OCT), and fluorescein angiography. Numerous clinical trials are underway, targeting identified molecular pathways associated with GA that are promising. Recent approvals of Syfovre and Izervay by the FDA for the treatment of GA provide hope to affected patients. Administration of these drugs resulted in slowing the rate of progression of the disease. Though these products provide treatment benefits to the patients, they do not offer a cure for geographic atrophy and are limited in efficacy. Considering these safety concerns and limited treatment benefits, there is still a significant need for therapeutics with improved efficacy, safety profiles, and better patient compliance. This comprehensive review discusses pathophysiology, currently approved products, their limitations, and potential future treatment strategies for GA.

Investigating the Spatiotemporal Summation of Perimetric Stimuli in Dry Age-Related Macular Degeneration

Purpose

To measure achromatic spatial, temporal, and spatiotemporal summation in dry age-related macular degeneration (AMD) compared to healthy controls under conditions of photopic gaze-contingent perimetry.

Methods

Twenty participants with dry AMD (mean age, 74.6 years) and 20 healthy controls (mean age, 67.8 years) performed custom, gaze-contingent perimetry tests. An area-modulation test generated localized estimates of Ricco's area (RA) at 2.5° and 5° eccentricities along the 0°, 90°, 180°, and 270° meridians. Contrast thresholds were measured at the same test locations for stimuli of six durations (3.7-190.4 ms) with a Goldmann III stimulus (GIII, 0.43°) and RA-scaled stimuli. The upper limit (critical duration) of complete temporal summation (using the GIII stimulus) and spatiotemporal summation (using the RA stimuli) was estimated using iterative two-phase regression analysis.

Results

Median (interquartile range [IQR]) RA estimates were significantly larger in AMD participants (2.5°: 0.21 [0.09-0.41] deg2; 5°: 0.32 [0.15-0.65 deg2]) compared to healthy controls (2.5°: 0.08 [0.05-0.13] deg2; 5°: 0.15 [0.08-0.22] deg2) at all test locations (all P < 0.05). No significant difference in median critical duration was found in AMD participants with the GIII stimulus (19.6 [9.9-30.4] ms) and RA-scaled stimuli (22.9 [13.9-40.3] ms) compared to healthy controls (GIII: 17.0 [11.3-24.0] ms; RA-scaled: 22.4 [14.3-33.1] ms) at all test locations (all P > 0.05).

Conclusions

Spatial summation is altered in dry AMD, without commensurate changes in temporal summation.

Translational Relevance

The sensitivity of perimetry to AMD may be improved by utilizing stimuli that probe alterations in spatial summation in the disease.

Complement inhibitors for age-related macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is a common eye disease and leading cause of sight loss worldwide. Despite its high prevalence and increasing incidence as populations age, AMD remains incurable and there are no treatments for most patients. Mounting genetic and molecular evidence implicates complement system overactivity as a key driver of AMD development and progression. The last decade has seen the development of several novel therapeutics targeting complement in the eye for the treatment of AMD. This review update encompasses the results of the first randomised controlled trials in this field.

OBJECTIVES

To assess the effects and safety of complement inhibitors in the prevention or treatment of AMD.

SEARCH METHODS

We searched CENTRAL on the Cochrane Library, MEDLINE, Embase, LILACS, Web of Science, ISRCTN registry, ClinicalTrials.gov, and the WHO ICTRP to 29 June 2022 with no language restrictions. We also contacted companies running clinical trials for unpublished data.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) with parallel groups and comparator arms that studied complement inhibition for advanced AMD prevention/treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed search results and resolved discrepancies through discussion. Outcome measures evaluated at one year included change in best-corrected visual acuity (BCVA), untransformed and square root-transformed geographic atrophy (GA) lesion size progression, development of macular neovascularisation (MNV) or exudative AMD, development of endophthalmitis, loss of ≥ 15 letters of BCVA, change in low luminance visual acuity, and change in quality of life. We assessed risk of bias and evidence certainty using Cochrane risk of bias and GRADE tools.

MAIN RESULTS

Ten RCTs with 4052 participants and eyes with GA were included. Nine evaluated intravitreal (IVT) administrations against sham, and one investigated an intravenous agent against placebo. Seven studies excluded patients with prior MNV in the non-study eye, whereas the three pegcetacoplan studies did not. The risk of bias in the included studies was low overall. We also synthesised results of two intravitreal agents (lampalizumab, pegcetacoplan) at monthly and every-other-month (EOM) dosing intervals. Efficacy and safety of IVT lampalizumab versus sham for GA For 1932 participants in three studies, lampalizumab did not meaningfully change BCVA given monthly (+1.03 letters, 95% confidence interval (CI) -0.19 to 2.25) or EOM (+0.22 letters, 95% CI -1.00 to 1.44) (high-certainty evidence). For 1920 participants, lampalizumab did not meaningfully change GA lesion growth given monthly (+0.07 mm², 95% CI -0.09 to 0.23; moderate-certainty due to imprecision) or EOM (+0.07 mm², 95% CI -0.05 to 0.19; high-certainty). For 2000 participants, lampalizumab may have also increased MNV risk given monthly (RR 1.77, 95% CI 0.73 to 4.30) and EOM (RR 1.70, 95% CI 0.67 to 4.28), based on low-certainty evidence. The incidence of endophthalmitis in patients treated with monthly and EOM lampalizumab was 4 per 1000 (0 to 87) and 3 per 1000 (0 to 62), respectively, based on moderate-certainty evidence. Efficacy and safety of IVT pegcetacoplan versus sham for GA For 242 participants in one study, pegcetacoplan probably did not meaningfully change BCVA given monthly (+1.05 letters, 95% CI -2.71 to 4.81) or EOM (-1.42 letters, 95% CI -5.25 to 2.41), as supported by moderate-certainty evidence. In contrast, for 1208 participants across three studies, pegcetacoplan meaningfully reduced GA lesion growth when given monthly (-0.38 mm², 95% CI -0.57 to -0.19) and EOM (-0.29 mm², 95% CI -0.44 to -0.13), with high certainty. These reductions correspond to 19.2% and 14.8% versus sham, respectively. A post hoc analysis showed possibly greater benefits in 446 participants with extrafoveal GA given monthly (-0.67 mm², 95% CI -0.98 to -0.36) and EOM (-0.60 mm², 95% CI -0.91 to -0.30), representing 26.1% and 23.3% reductions, respectively. However, we did not have data on subfoveal GA growth to undertake a formal subgroup analysis. In 1502 participants, there is low-certainty evidence that pegcetacoplan may have increased MNV risk when given monthly (RR 4.47, 95% CI 0.41 to 48.98) or EOM (RR 2.29, 95% CI 0.46 to 11.35). The incidence of endophthalmitis in patients treated with monthly and EOM pegcetacoplan was 6 per 1000 (1 to 53) and 8 per 1000 (1 to 70) respectively, based on moderate-certainty evidence. Efficacy and safety of IVT avacincaptad pegol versus sham for GA In a study of 260 participants with extrafoveal or juxtafoveal GA, monthly avacincaptad pegol probably did not result in a clinically meaningful change in BCVA at 2 mg (+1.39 letters, 95% CI -5.89 to 8.67) or 4 mg (-0.28 letters, 95% CI -8.74 to 8.18), based on moderate-certainty evidence. Despite this, the drug was still found to have probably reduced GA lesion growth, with estimates of 30.5% reduction at 2 mg (-0.70 mm², 95% CI -1.99 to 0.59) and 25.6% reduction at 4 mg (-0.71 mm², 95% CI -1.92 to 0.51), based on moderate-certainty evidence. Avacincaptad pegol may have also increased the risk of developing MNV (RR 3.13, 95% CI 0.93 to 10.55), although this evidence is of low certainty. There were no cases of endophthalmitis reported in this study.

AUTHORS' CONCLUSIONS

Despite confirmation of the negative findings of intravitreal lampalizumab across all endpoints, local complement inhibition with intravitreal pegcetacoplan meaningfully reduces GA lesion growth relative to sham at one year. Inhibition of complement C5 with intravitreal avacincaptad pegol is also an emerging therapy with probable benefits on anatomical endpoints in the extrafoveal or juxtafoveal GA population. However, there is currently no evidence that complement inhibition with any agent improves functional endpoints in advanced AMD; further results from the phase 3 studies of pegcetacoplan and avacincaptad pegol are eagerly awaited. Progression to MNV or exudative AMD is a possible emergent adverse event of complement inhibition, requiring careful consideration should these agents be used clinically. Intravitreal administration of complement inhibitors is probably associated with a small risk of endophthalmitis, which may be higher than that of other intravitreal therapies. Further research is likely to have an important impact on our confidence in the estimates of adverse effects and may change these. The optimal dosing regimens, treatment duration, and cost-effectiveness of such therapies are yet to be established.

Methodological Appraisal of Phase 3 Clinical Trials in Geographic Atrophy

Geographic atrophy (GA) secondary to age-related macular degeneration is a common cause of blindness worldwide. Given the recent approval of the first therapy for GA, pegcetacoplan, we critically appraise methodological aspects of the phase 3 clinical trials published so far in this disease in relation to their design, analysis and interpretation. We reviewed some of the key attributes of all phase 3 clinical trials in GA available in the main public registry of clinical trials as of 20 May 2023. The topics discussed included types of endpoints, eligibility criteria, p-value and effect size, study power and sample size, the intention to treat principle, missing data, consistency of results, efficacy-safety balance and application of results. Five phase 3 clinical trials have reported results, either partially or completely: GATHER1, DERBY/OAKS, CHROMA/SPECTRI, SEATTLE and GATE. Although there are many similarities between these trials in terms of endpoints or broad eligibility criteria, they differ in several aspects (metric of the primary endpoint, sample size, type of adverse events, etc.) that can influence the results, which are discussed. Readers should understand key methodological aspects of clinical trials to improve their interpretation. On the other hand, authors should adhere to clinical trial reporting guidelines to communicate what was done and how it was done.

Spectral-domain optical coherence tomography combined with electroretinography in the assessment of conbercept for neovascular age-related macular degeneration: a preliminary study

Objective

To observe the effect of three consecutive intravitreal injections of conbercept in the treatment of neovascular age-related macular degeneration (nAMD), to investigate the correlation between retinal anatomy and retinal function by spectral-domain optical coherence tomography (SD-OCT) and electroretinography (ERG), to evaluate the short-term clinical efficacy of conbercept in the treatment of nAMD, and to explore the value of ERG as a predictor of treatment efficacy.

Method

A retrospective investigation was conducted on 36 patients (36 eyes) treated with intravitreal injections of conbercept at 0.5 mg a month for three consecutive courses. Data collected included the best corrected visual acuity (BCVA), central retinal thickness (CRT), retinal pigment epithelium (RPE) elevation volume in 1 mm-diameter (1RV), 3 mm-diameter (3RV), and 6 mm-diameter circles around the fovea (6RV), amplitude density and latency of the P1 wave in the multifocal electroretinography (mf-ERG) R1 ring and amplitude and latency in full-field electroretinography (ff-ERG) at baseline and monthly. The paired t test was used to compare the difference between pre- and posttreatment. Pearson correlation analysis was used to analyze the correlation between macular retinal structure and function. The difference was significant when p < 0.05.

Results

At 12 weeks, the BCVA, CRT, 1RV, 3RV, 6RV, the P1 wave amplitude density of the mf-ERG R1 ring and the ff-ERG amplitude parameters were all significantly improved (p < 0.001). The BCVA in logMAR was positively correlated with CRT; 1RV, 3RV, and 6RV were negatively correlated with the amplitude density and latency of the mf-ERG R1 ring P1 wave. There were no severe ocular or systemic complications during the follow-up period.

Conclusion

Conbercept is useful for the short-term treatment of nAMD. It can safely improve the visual acuity of affected eyes and restore the structure and function of the retina. ERG could serve as an objective indicator of function for evaluating the efficacy of and determining the need for retreatment during nAMD treatment.

Microperimetry to predict disease progression in eyes at high risk of age-related macular degeneration disease: The PREVISION study

PURPOSE

The aim of the present study was to determine whether microperimetric parameters could predict the progression of an eye at high risk of age-related macular degeneration (AMD) at 24 months.

METHODS

We conducted a multicentric prospective non-comparative open-label study including patients with one eye in stage 4 of the Age-Related Eye Disease Study Group (AREDS) classification, and the other eye in AREDS stage 3 (study eye). A microperimetry examination (MAIA™, CenterVue, Padova, Italy) was performed at baseline and every 6 months during the 2-year follow-up. At the end of the follow-up, each study eye was classified as 'progressive' (i.e. AREDS stage 4) or 'non-progressive' (i.e. AREDS stage 3).

RESULTS

A total of 147 patients were analysed, of which 30.6% progressed from AREDS stage 3 to stage 4. The microperimetry criterion 'mean retinal sensitivity' was significantly different at baseline between non-progressive and progressive eyes (p = 0.022), with lower values for the latter. With a threshold for mean retinal sensitivity set at 24.7 dB, diagnostic sensitivity was 80% [95%CI (65.4-90.4)], specificity was 30.4% [95%CI (21.7-40.3)], positive predictive value was 33.6% [95%CI (24.8-43.4)], and negative predictive value was 77.5% [95%CI (61.5-89.2)]. In the multivariate analysis including microperimetric parameters and other routine ophthalmologic examinations, mean retinal sensitivity was the only predictive parameter statistically associated with progression (p = 0.0004).

CONCLUSIONS

Our findings are encouraging as regards the use of microperimetry, and mean retinal sensitivity value in particular, to predict the 2-year risk of progression to AREDS stage 4 eye.

Microperimetry in Retinal Diseases

Retinal microperimetry (MP) is a procedure that assesses the retinal sensitivity while the fundus is directly observed, and an eye tracker system is active to compensate for involuntary eye movements during testing. With this system, the sensitivity of a small locus can be accurately determined, and it has become an established ophthalmic test for retinal specialists. Macular diseases are characterized by chorioretinal changes; therefore, the condition of the retina and choroid requires careful and detailed evaluations to perform effective therapy. Age-related macular degeneration is a representative retinal disease in which the macular function has been evaluated by the visual acuity throughout the course of the disease process. However, the visual acuity represents the physiological function of only the central fovea, and the function of the surrounding macular area has not been sufficiently evaluated throughout the different stages of the macula disease process. The new technique of MP can compensate for such limitations by being able to test the same sites of the macular area repeatedly. This is especially useful in the recent management of age-related macular degeneration or diabetic macular edema during anti-vascular endothelial growth factor treatments because MP can assess the effectiveness of the treatment. MP examinations are also valuable in diagnosing Stargardt disease as they can detect visual impairments before any abnormalities are found in the retinal images. The visual function needs to be carefully assessed along with morphologic observations by optical coherence tomography. In addition, the assessment of retinal sensitivity is useful in the presurgical or postsurgical evaluations.

Gene Therapy for Inherited Retinal Disease: Long-Term Durability of Effect

The recent approval of voretigene neparvovec (Luxturna®) for patients with biallelic RPE65 mutation-associated inherited retinal dystrophy with viable retinal cells represents an important step in the development of ocular gene therapies. Herein, we review studies investigating the episomal persistence of different recombinant adeno-associated virus (rAAV) vector genomes and the preclinical and clinical evidence of long-term effects of different RPE65 gene replacement therapies. A targeted review of articles published between 1974 and January 2021 in Medline®, Embase®, and other databases was conducted, followed by a descriptive longitudinal analysis of the clinical trial outcomes of voretigene neparvovec. Following an initial screening, 14 publications examining the episomal persistence of different rAAV genomes and 71 publications evaluating gene therapies in animal models were included. Viral genomes were found to persist for at least 22 months (longest study follow-up) as transcriptionally active episomes. Treatment effects lasting almost a decade were reported in canine disease models, with more pronounced effects the earlier the intervention. The clinical trial outcomes of voretigene neparvovec are consistent with preclinical findings and reveal sustained results for up to 7.5 years for the full-field light sensitivity threshold test and 5 years for the multi-luminance mobility test in the Phase I and Phase III trials, respectively. In conclusion, the therapeutic effect of voretigene neparvovec lasts for at least a decade in animal models and 7.5 years in human subjects. Since retinal cells can retain functionality over their lifetime after transduction, these effects may be expected to last even longer in patients with a sufficient number of outer retinal cells at the time of intervention.

Fixation Pattern Analysis With Microperimetry In Strabismic Subjects: A Pilot Study

OBJECTIVE

Strabismic amblyopia is a motor and sensory deficit produced by unilateral constant strabismus and binocular imbalance. The aim of this study was to analyse the retinal fixation pattern using microperimetry in subjects with strabismus with and without amblyopia associated, and to compare the results with those obtained in normal subjects.

METHODS

Prospective comparative study conducted at the Optometric Clinic of the University of Valencia and Oftalvist Alicante (Spain) including 46 eyes with ages from 3 to 16 years. Three groups were differentiated: patients with persistent strabismic amblyopia after occlusion and active therapy (group 1, 7 patients, 30.4%), strabismic patients without amblyopia (group 2, 8 patients, 34.8%) and a control group (8 patients, 34.8%). Microperimetric analysis was performed with the Macular Integrity Assessment (MAIA) system (Centervue, Padova, Italy) and using the following parameters: P1% and P2% fixation indexes, and the ellipse areas (BCEA) for 95% and 63% of points for the first 10 seconds, 30 seconds, 60 seconds, and the total examination time.

RESULTS

Significant differences were found between groups for dominant eyes in P2 calculated at 30 (p = .04) and 60 seconds (p = .03). However, these differences between groups in non-dominant eyes were close to statistical significance (p = .07 and p = .08). Specifically, P2 was significantly lower in group 1 compared to control group (p = .01). Best corrected visual acuity was found to be significantly correlated (p ≤ .04) with total P1 (dominant eye, r = -0.51; non-dominant eye, r = -0.50), total P2 (dominant eye, r = -0.50; non-dominant eye, r = -0.50), and BCEA63 (dominant eye, r = 0.50; non-dominant eye, r = 0.40) and BCEA95 (dominant eye, r = 0.50; non-dominant eye, r = 0.40) measured at 10 seconds.

CONCLUSIONS

The preliminary results of this study seem to indicate that subjects with strabismus have fixation instability regardless of the presence or absence of amblyopia.

Efficacy of MP-3 microperimeter biofeedback fixation training for low vision rehabilitation in patients with maculopathy

BACKGROUND

To evaluate the efficacy of MP-3 microperimeter biofeedback fixation training (MBFT) in vision rehabilitation of low-vision patients affected by macular disease with central vision loss.

METHODS

Seventeen eyes (7 age-related macular degeneration, 10 myopic maculopathy) of 17 patients were included in this prospective, interventional study. The preferred retinal locus was determined by comprehensive ophthalmoscopic fundus evaluation including fundus photography, autofluorescence, optical coherence tomography, and microperimetry. The rehabilitation consisted of three 10-min sessions per eye to be performed twice per week for 20 consecutive weeks using the MP-3 microperimeter. Best corrected visual acuity (BCVA), reading speed, mean central sensitivity, the percentages of fixation points within specified regions, bivariate contour ellipse area (BCEA) and the 25-item National Eye Institute visual function questionnaire (NEI-VFQ-25) were recorded pre- and post-training.

RESULTS

The final BCVA, reading speed and mean central sensitivity all showed significant improvements after rehabilitation (P <  0.0001, P = 0.0013, and P = 0.0002, respectively). The percentages of fixation points located within 2° and 4° diameter circles both significantly increased after training (P = 0.0008 and P = 0.0007, respectively). The BCEA encompassing 68.2, 95.4, 99.6% of fixation points were all significantly decreased after training (P = 0.0038, P = 0.0022, and P = 0.0021, respectively). The NEI-VFQ-25 scores were significantly increased at the end of the rehabilitation training (P <  0.0001).

CONCLUSION

Rehabilitation with MP-3 MBFT is a user-friendly therapeutic option for improving visual function, fixation stability, and quality of life in advanced macular disease.

TRIAL REGISTRATION

The prospective study was registered with the Chinese Clinical Trial Registry ( http://www.chictr.org.cn/ ).

TRIAL REGISTRATION NUMBER

ChiCTR2000029586 . Date of registration: 05/02/2020.

Fundus-controlled perimetry (microperimetry): Application as outcome measure in clinical trials

Fundus-controlled perimetry (FCP, also called 'microperimetry') allows for spatially-resolved mapping of visual sensitivity and measurement of fixation stability, both in clinical practice as well as research. The accurate spatial characterization of visual function enabled by FCP can provide insightful information about disease severity and progression not reflected by best-corrected visual acuity in a large range of disorders. This is especially important for monitoring of retinal diseases that initially spare the central retina in earlier disease stages. Improved intra- and inter-session retest-variability through fundus-tracking and precise point-wise follow-up examinations even in patients with unstable fixation represent key advantages of these technique. The design of disease-specific test patterns and protocols reduces the burden of extensive and time-consuming FCP testing, permitting a more meaningful and focused application. Recent developments also allow for photoreceptor-specific testing through implementation of dark-adapted chromatic and photopic testing. A detailed understanding of the variety of available devices and test settings is a key prerequisite for the design and optimization of FCP protocols in future natural history studies and clinical trials. Accordingly, this review describes the theoretical and technical background of FCP, its prior application in clinical and research settings, data that qualify the application of FCP as an outcome measure in clinical trials as well as ongoing and future developments.

Anatomical-functional concordance of microperimetry and the simplified age-related macular degeneration study classification: A pilot study

PURPOSE

The principal aim of this pilot study was to investigate the concordance between the different stages of Age-Related Macular Degeneration (AMD), as determined by the simplified classification of the Age Related Eye Disease Study Group (AREDS), and new evaluation criteria using a microperimetry system.

METHODS

A complete eye examination and a microperimetry MAIATM (Macular Integrity Assessment, CenterVue, Padova, Italy) examination was performed on 59 eyes with early, intermediate or advanced AMD. We analysed 19 evaluation criteria for every clinical group category.

RESULTS

There were 20 female and 12 male participants included with a median age of 74 years (min: 54, max: 87). Thirteen eyes (22%) were classified as category 1, 11 eyes (18.6%) as category 2, 17 eyes (28.8%) as category 3 and 18 eyes (30.6%) as category 4 AMD.All evaluated microperimetry criteria related to retinal sensitivity were found to have a statistically significant difference among the stages (p < 0.05). Fixation stability was unstable in 55.6% of the eyes classified as stage 4 (p = 0.001). The analysis of the distance between the two PRLs - PRL_initial and PRL_final was larger for the stage 4 (p = 0.0258). The mean sensitivity in stages 2 and 3 correlated with the presence or not of reticular pseudodrusen (p = 0.0137).

CONCLUSIONS

The mean sensitivity and the categorized sensitivity (set to 25, 15 and 5 dB), the five higher and lower stimuli sensitivity appeared to be the most sensitive criteria to differentiate the four AMD categories. Microperimetry provides a new reproducible method of anatomical-functional macular analysis.

Clinical Perspectives and Trends: Microperimetry as a trial endpoint in retinal disease

Endpoint development trials are underway across the spectrum of retinal disease. New validated endpoints are urgently required for the assessment of emerging gene therapies and in preparation for the arrival of novel therapeutics targeting early stages of common sight-threatening conditions such as age-related macular degeneration. Visual function measures are likely to be key candidates in this search. Over the last two decades, microperimetry has been used extensively to characterize functional vision in a wide range of retinal conditions, detecting subtle defects in retinal sensitivity that precede visual acuity loss and tracking disease progression over relatively short periods. Given these appealing features, microperimetry has already been adopted as an endpoint in interventional studies, including multicenter trials, on a modest scale. A review of its use to date shows a concurrent lack of consensus in test strategy and a wealth of innovative disease and treatment-specific metrics which may show promise as clinical trial endpoints. There are practical issues to consider, but these have not held back its popularity and it remains a widely used psychophysical test in research. Endpoint development trials will undoubtedly be key in understanding the validity of microperimetry as a clinical trial endpoint, but existing signs are promising.

Strongest Correlation Between Contrast Sensitivity and Morphological Characteristics in Bilateral nAMD

In patients with neovascular age-related macular degeneration (nAMD) there is often an inconsistency between their subjective visual impairment and a still relatively preserved standard Early Treatment of Diabetic Retinopathy Study (ETDRS) best corrected visual acuity. Therefore, in order to better capture the specific functional defects in nAMD, other tests need to be evaluated. In a previous study, we reported contrast sensitivity of the better eye to best correlate with near distance and distance vision related quality of life in patients with bilateral nAMD. Here, we evaluated Pelli-Robson contrast sensitivity, ETDRS visual acuity, low luminance visual acuity and Radner maximum reading speed and correlated them with several morphologic parameters as measured on fundus autofluorescence imaging, optical coherence tomography and optical tomography angiography in 54 patients. A multiple regression analysis was performed which correlated each visual function parameter with the anatomic features. The results showed the strongest correlations between the total area of macular geographic atrophy as well as the percentage of geographic atrophy in the central 1 mm and contrast sensitivity. Further, the regression model selected the total area of macular geographic atrophy, the photoreceptor inner and outer segments interface disruption score, the presence of subretinal fibrosis in the central 1 mm and the central retinal thickness as the variables that explained 71% of the variation in contrast sensitivity when including all eyes. Hence, our results suggest that among the evaluated measures of vision, contrast sensitivity is best correlated with the morphologic impairment in bilateral nAMD. Thus, contrast sensitivity may complement ETDRS visual acuity in clinical trials and serve as a standard diagnostic tool in clinical practice.

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.

Scotopic microperimetric sensitivity and inner choroid flow deficits as predictors of progression to nascent geographic atrophy

BACKGROUND/AIMS

To assess the role of microperimetric retinal sensitivity (MPRS) and inner choroid flow deficits (IC FD) in predicting the development of incomplete retinal pigment epithelial and outer retinal atrophy (iRORA) in intermediate AMD (i-AMD).

METHODS

Thirty eyes with i-AMD evaluated at the Doheny-UCLA Eye Centres were enrolled in this prospective IRB-approved study. Subjects underwent several diagnostic tests: (a) 6×6 mm swept-source optical coherence tomography angiography (SS-OCTA) with the IC slab used to quantify the FDs, (b) 20°×20° spectral-domain optical coherence tomography (SD-OCT) to monitor progression to iRORA and (c) scotopic MPRS within an area of 18° centred on the fovea. All subjects were followed-up for 24 months. The baseline IC FD and MPRS were correlated with the development of iRORA. At 24-month follow-up, the stage of AMD was re-assessed and the eyes were divided into two sub-groups based on the development of iRORA.

RESULTS

Twenty-eight eyes completed the 2-year follow-up. At baseline, the mean MPRS was 13.40±4.66 dB and the mean IC FD was 27.55±8.67%. The morpho-functional regression showed a significant correlation between baseline MPRS and IC FD and the development of iRORA within 24 months (R²=0.744, p<0.05). A Kaplan-Meier survival curve was fit to determine the cumulative incidence of iRORA over the 24 months.

CONCLUSIONS

A lower MPRS and greater IC FD at baseline were predictors of progression to iRORA in eyes with i-AMD. These parameters may be useful biomarkers for risk stratification and prognostication.

Edge of Scotoma Sensitivity as a Microperimetry Clinical Trial End Point in USH2A Retinopathy

Purpose

Microperimetry is commonly used to assess retinal function. We perform cross-sectional and longitudinal analysis on microperimetry parameters in USH2A retinopathy and explore end points suitable for future clinical trials.

Methods

Microperimetry was performed using two grids, Grid 1 (18° diameter) and Grid 2 (6° diameter). In Grid 1, four parameters (number of nonscotomatous loci, mean sensitivity [MS], responding point sensitivity [RPS], and edge of scotoma sensitivity [ESS]) were analyzed. In Grid 2, number of nonscotomatous loci and MS were examined. Interocular symmetry was also examined. Longitudinal analysis was conducted in a subset of eyes.

Results

Microperimetry could be performed in 16 of 21 patients. In Grid 1 (n = 15; average age, 35.6 years), average number of nonscotomatous loci, MS, RPS, and ESS were 46.6 loci, 10.0 dB, 14.7 and 9.6 dB, respectively. In Grid 2 (n = 13; average age, 37.4 years), 12 eyes had measurable sensitivity across the entire grid. Average MS was 23.8 dB. Interocular analysis revealed large 95% confidence intervals for all parameters. Longitudinally, Grid 1 (n = 12, average follow-up 2.6 years) ESS showed the fastest rate of decline (–1.84 dB/y) compared with MS (–0.34 dB/y) and RPS (–0.90 dB/y).

Conclusions

Our data suggest that ESS may be more useful than MS and RPS in test grids that cover a large extent of the macula. We caution the use of contralateral eye as an internal control.

Translational Relevance

ESS may decrease the duration or sample size of treatment trials in USH2A retinopathy.

Faster Sensitivity Loss around Dense Scotomas than for Overall Macular Sensitivity in Stargardt Disease: ProgStar Report No. 14

PURPOSE

Mean sensitivity (MS) derived from a standard test grid using microperimetry is a sensitive outcome measure in clinical trials investigating new treatments for degenerative retinal diseases. This study hypothesizes that the functional decline is faster at the edge of the dense scotoma (eMS) than by using the overall MS.

DESIGN

Multicenter, international, prospective cohort study: ProgStar Study.

METHODS

Stargardt disease type 1 patients (carrying at least 1 mutation in the ABCA4 gene) were followed over 12 months using microperimetry with a Humphrey 10-2 test grid. Customized software was developed to automatically define and selectively follow the test points directly adjacent to the dense scotoma points and to calculate their mean sensitivity (eMS).

RESULTS

Among 361 eyes (185 patients), the mean age was 32.9 ± 15.1 years old. At baseline, MS was 10.4 ± 5.2 dB (n = 361), and the eMS was 9.3 ± 3.3 dB (n = 335). The yearly progression rate of MS (1.5 ± 2.1 dB/year) was significantly lower (β = -1.33; P < .001) than that for eMS (2.9 ± 2.9 dB/year). There were no differences between progression rates using automated grading and those using manual grading (β = .09; P = .461).

CONCLUSIONS

In Stargardt disease type 1, macular sensitivity declines significantly faster at the edge of the dense scotoma than in the overall test grid. An automated, time-efficient approach for extracting and grading eMS is possible and appears valid. Thus, eMS offers a valuable tool and sensitive outcome parameter with which to follow Stargardt patients in clinical trials, allowing clinical trial designs with shorter duration and/or smaller cohorts.

Multimodal Evaluation of Visual Function in Geographic Atrophy versus Normal Eyes

Purpose

To comprehensively evaluate visual function in eyes with geographic atrophy (GA) as compared to normal eyes.

Patients and Methods

Sixty-three eyes from 63 patients ≥50 years old were recruited for this observational study; 31 were identified as normal macular health eyes and 32 with GA. Visual function was tested with best corrected visual acuity (BCVA), low luminance visual acuity (LLVA), low luminance deficit (LLD), reading speed, macular integrity microperimetry, fixation stability, and contrast sensitivity function (CSF). Anatomic function was evaluated with spectral-domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF). Quality of life and vision were assessed with the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25).

Results

Visual function and quality of life are reduced in patients with GA. Moderate and strong correlations in the GA group were found between maximum reading speed (r = 0.787) (p˂0.01), CS spatial frequency 3 cpd (r = 0.441) (p˂0.05), CS spatial frequency 6 cpd (r = 0.524) (p˂0.01), fixation P1 (r = 0.379) (p˂0.05), macular sensitivity (r = 0.484) (p˂0.05) and atrophic area (r = -0.689) (p˂0.01), and the VFQ-25 composite score.

Conclusion

The decreased visual function is reflected in a poor quality of life in patients with GA. Reading speed, contrast sensitivity, fixation, and macular sensitivity are strongly associated with vision-related quality of life. The results suggest the importance of the reading letter size in patients with GA. Microperimetry and reading speed are useful tools to better assess visual impairment in patients with GA.

Test-retest variability of microperimetry in geographic atrophy

Purpose

Microperimetry (MP) allows for measurement of retinal sensitivity at precise locations and is now commonly employed as a clinical trial endpoint. Test-retest reliability is important when evaluating treatment effects in patients with geographic atrophy (GA). This study aimed to determine the test-retest variability of MP in patients with moderate to severe GA using the MAIA MP device.

Methods

In this prospective study, patients with a confirmed diagnosis of foveal-involving GA were enrolled. Participants performed three MP assessments of a selected eye over two visits with the Macular Integrity Assessment (MAIA) 2 instrument (Centervue, Padova, Italy) utilizing a wide 30° grid, consisting of 93 stimuli (Goldmann III) using a 4-2 representation strategy, encompassing the entire area of GA and beyond. Mean retinal sensitivity (MS) was expressed as an average threshold value (dB) for the entire field tested. Coefficients of Repeatability at a 95% level (CoR₉₅) were calculated for Point Wise Sensitivity (PWS). Fixation stability (FS) was assessed by evaluating the area of an elliptical representation encompassing 95% of the cloud of fixation points (CFP) dataset generated by the MAIA MP, known as the bivariate contour ellipse area (BCEA).

Results

A total of 8 subjects were enrolled (21 tests), with six subjects completing 3 MP assessments. BCVA in these patients ranged from 20/100 to 20/800. The mean area of GA was 18.7 ± 12.3 mm². The average time to complete one MP assessment was 13 min 9 s and mean BCEA@95% was 38.5 ± 19.3°2. The MS was 14.3 ± 4.5 dB. No significant increase in MS was noted between testing pairs 1&2 and 2&3. The preferred retinal locus was maintained in the same quadrant on successive tests. The mean CoR95 for PWS were similar for testing pairs 1&2 (± 3.50 dB) and 2&3 (± 3.40).

Conclusion

Microperimetry using a wide grid can be reliably performed in a reasonable amount of time in patients with moderate and severe vision loss secondary to GA. There was no learning effect seen between sequential assessments when analyzing MS or PWS. A change of approximately 4 dB in PWS provides a threshold for considering a true change in this patient cohort.

Patchy Scotoma Observed in Chorioretinal Patchy Atrophy of Myopic Macular Degeneration

Purpose

To investigate the retinal sensitivity of highly myopic eyes with chorioretinal patchy atrophy (PA) using microperimetry.

Methods

Fifty-two eyes of 32 patients with high myopia were prospectively included. Twenty-two eyes of 16 patients had PA lesions; eyes without PA were analyzed as controls. Testing points on microperimetry in eyes with PA were designated as 3 zones: zone 1 as the PA lesion including its borders; zone 2 including testing points adjoining PA; zone 3 including all other testing points.

Results

In the PA group, the mean retinal sensitivity in zone 1 was 2.1 ± 2.8 dB, zone 2 = 8.3 ± 4.3 dB, and zone 3 = 9.4 ± 4.1 dB. Sensitivity in zone 1 was significantly reduced than zones 2 and 3 (P < 0.001). The mean retinal sensitivity in the PA group was lower than controls (6.5 ± 4.3 vs 13.9 ± 4.1 dB, P < 0.001), and combined zone 2 and 3 in the PA group also presented lower retinal sensitivity (8.8 ± 4.0 dB).

Conclusions

Eyes with PA generate patchy scotoma in PA lesions and reduced retinal sensitivity in regions beyond atrophic lesion on microperimetry. The presence of PA may be an indicator to reflect both significantly anatomical and functional alterations on myopic macular degeneration.

Prognostic value of intermediate age-related macular degeneration phenotypes for geographic atrophy progression

BACKGROUND

To characterise early stages of geographic atrophy (GA) development in age-related macular degeneration (AMD) and to determine the prognostic value of structural precursor lesions in eyes with intermediate (i) AMD on the subsequent GA progression.

METHODS

Structural precursor lesions for atrophic areas (lesion size at least 0.5 mm² in fundus autofluorescence images) were retrospectively identified based on multimodal imaging and evaluated for association with the subsequent GA enlargement rates (square-root transformed, sqrt). A linear mixed-effects model was used to account for the hierarchical nature of the data with a Tukey post hoc test to assess the impact of the local precursor on the subsequent GA progression rate.

RESULTS

A total of 39 eyes with GA of 34 patients with a mean age of 74.4±6.7 (±SD) years were included in this study. Five precursor lesions (phenotypes 1-5) preceding GA development were identified: large, sub-retinal pigment epithelial drusen (n=19), reticular pseudodrusen (RPD, n=10), refractile deposits (n=4), pigment epithelial detachment (n=4) and vitelliform lesions (n=2). Precursor lesions exhibited a significant association with the subsequent (sqrt) GA progression rates (p=0.0018) with RPD (phenotype 2) being associated with the fastest GA enlargement (2.29±0.52 (±SE) mm/year.

CONCLUSIONS

The results indicate the prognostic relevance of iAMD phenotyping for subsequent GA progression highlighting the role of structural AMD features across different AMD stages.

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.

Evaluation of retinal function improvement in neovascular age-related macular degeneration after intravitreal aflibercept injections with the use of the assessment of retinal sensitivity: The use of the assessment of retinal sensitivity in anti-VEGF treatment - a STROBE-compliant observational study

This study compares 2 methods of macular function evaluation: the microperimetric examination (mean central retinal sensitivity and fixation stability) and the distance best-corrected visual acuity (BCVA) examination, which is the most frequently used method of assessing macular function in patients with newly diagnosed wet age-related macular degeneration (AMD) who have been treated with anti-vascular endothelial growth factor (VEGF) drug (aflibercept).Prospective analysis was conducted on 44 eyes of 44 patients treated with intravitreal injection of anti-VEGF (aflibercept) because of newly diagnosed neovascular AMD. According to the research protocol, all patients had a 6-month follow-up. The response to treatment was monitored functionallybyMP-1 microperimetry, fixation, and distance BCVA assessment after injection. Improvement of retinal sensitivity and BCVA was found under aflibercept treatment. There was statistically significant improvement in retinal sensitivity in the MP-1 study 3 and 6 months from the beginning of anti-VEGF therapy. Moreover, a significant improvement in retinal sensitivity between 3 and 6 months of observation was demonstrated. At the same time, up to 3 months from the beginning of treatment, BCVA improved significantly compared to the baseline value. In the 6th month of the study BCVA remained stable without further significant improvement.Microperimetric examination with medium sensitivity and fixation stability assessment is a very valuable test determining the retinal function. It is clear that examining the macular morphology itself in modern diagnostics is not enough to assess retinal function. Microperimetry technique is a valuable tool for functional long-term evaluation of retinal function (also for a period of more than 3 months).

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.

Is Retinal Metabolic Dysfunction at the Center of the Pathogenesis of Age-related Macular Degeneration?

The retinal pigment epithelium (RPE) forms the outer blood⁻retina barrier and facilitates the transepithelial transport of glucose into the outer retina via GLUT1. Glucose is metabolized in photoreceptors via the tricarboxylic acid cycle (TCA) and oxidative phosphorylation (OXPHOS) but also by aerobic glycolysis to generate glycerol for the synthesis of phospholipids for the renewal of their outer segments. Aerobic glycolysis in the photoreceptors also leads to a high rate of production of lactate which is transported out of the subretinal space to the choroidal circulation by the RPE. Lactate taken up by the RPE is converted to pyruvate and metabolized via OXPHOS. Excess lactate in the RPE is transported across the basolateral membrane to the choroid. The uptake of glucose by cone photoreceptor cells is enhanced by rod-derived cone viability factor (RdCVF) secreted by rods and by insulin signaling. Together, the three cells act as symbiotes: the RPE supplies the glucose from the choroidal circulation to the photoreceptors, the rods help the cones, and both produce lactate to feed the RPE. In age-related macular degeneration this delicate ménage à trois is disturbed by the chronic infiltration of inflammatory macrophages. These immune cells also rely on aerobic glycolysis and compete for glucose and produce lactate. We here review the glucose metabolism in the homeostasis of the outer retina and in macrophages and hypothesize what happens when the metabolism of photoreceptors and the RPE is disturbed by chronic inflammation.

Microperimetry for geographic atrophy secondary to age-related macular degeneration

Geographic atrophy (GA) is a progressive, advanced form of age-related macular degeneration leading to visual function impairment and irreversible vision loss. Standard clinical tests to evaluate visual function in patients with GA provide poor anatomic-functional correlation, whereas fundus imaging does not assess the visual function deficit. Microperimetry is a psychophysical visual function test that spatially maps retinal sensitivity and allows for identification of correlation of anatomic features with visual function. In this review, we present an overview of mesopic microperimetry for GA, including commercially available microperimetry devices, strategies to capture a mesopic microperimetry test, and strategies to assess and interpret microperimetry data in patients with GA. We demonstrate the importance of microperimetry data for assessing GA progression and for evaluating visual function loss through anatomic-functional correlations. Although valuable, current microperimetry tests require an extensive time commitment from the patient and examiner, and the development of faster, more reproducible and accessible methods is important to enable broader use of microperimetry in both clinical and research settings.

The Rate of Progression of Geographic Atrophy Decreases With Increasing Baseline Lesion Size Even After the Square Root Transformation

Purpose

To determine the relationship between the progression of geographic atrophy (GA) and its baseline area (BA) using the square root transformation (sqrt) for different atrophy sizes.

Methods

Single eyes of patients with GA visiting the Institut de la Màcula (Barcelona, Spain) between December 2009 and January 2018 with a follow-up of ≥6 months were included. The main outcome was the correlation between BA and growth after the sqrt using Pearson's r and Spearman's rho. The graphical relationship was explored using linear and LOWESS regression. In a secondary, prespecified analysis, progression was compared by BA categories (Age-Related Eye Disease Study [AREDS] classification and BA tertiles). In post hoc analyses, the results were evaluated in subgroups defined by location of atrophy, number of lesions, fundus autofluorescence pattern, and fellow-eye status.

Results

We included 128 eyes (mean follow-up, 3.1 years). The correlation between BA and progression was negative (r = -0.30, P = 0.0005; rho = -0.25, P = 0.0042). There was a decrease in the rate of progression in mm/year with increasing BA, but this was significant for tertiles (P = 0.0078) and not AREDS (P = 0.20). The descending trend was driven by high-risk features.

Conclusions

The correlation between GA progression and BA using the sqrt is negative. This has implications for the expected prediction of progression of a given lesion and to avoid overestimating the beneficial effects of interventional therapies.

Translational Relevance

The GA progression/BA relationship using the sqrt currently is regarded as independent. Our results suggest the sqrt slope actually is negative, which should be kept in mind to avoid misinterpretation of results in advanced therapies.

Comparisons of Two Microperimeters: The Clinical Value of an Extended Stimulus Range

SIGNIFICANCE

Fundus-guided perimetry is a common clinical tool used to measure visual field sensitivities. Comparisons between perimeters are often made despite relative differences in hardware parameters. We directly compared two perimeters using Weber contrast, which allowed us to assess the clinical gain associated with the extended stimulus range of the macular integrity assessment (MAIA).

PURPOSE

The purpose of this study was to directly compare sensitivity thresholds for two microperimeters, the MAIA and Optos optical coherence tomography/scanning laser ophthalmoscope, using Weber contrast values. We also examined the clinical utility of the extended stimulus range of the MAIA.

METHODS

Six normally sighted adults with no visual field loss and 16 adults with low vision were recruited. Thresholds were measured on the MAIA and Optos using the same threshold algorithm and test points. To compare equivalent units, decibel thresholds were converted to light increments in apostilbs and then to delta increment intensities relative to each instrument's background luminance. Repeatability was assessed for normally sighted adults by testing both instruments on 3 separate days.

RESULTS

For normally sighted observers, mean thresholds were similar on both instruments, and repeatability within microperimeters was high. The MAIA has a 0.3-log lower contrast range and 1.37 higher contrast range. The lower contrast values did not result in lower thresholds for the normally sighted observers on the MAIA. There was a 25% increase in the number of measurable thresholds owing to the higher contrast values in low-vision observers.

CONCLUSIONS

The higher contrast range in the MAIA yielded only a small increase in detectable thresholds for participants with visual field loss.

Retinal AAV8-RS1 Gene Therapy for X-Linked Retinoschisis: Initial Findings from a Phase I/IIa Trial by Intravitreal Delivery

This study evaluated the safety and tolerability of ocular RS1 adeno-associated virus (AAV8-RS1) gene augmentation therapy to the retina of participants with X-linked retinoschisis (XLRS). XLRS is a monogenic trait affecting only males, caused by mutations in the RS1 gene. Retinoschisin protein is secreted principally in the outer retina, and its absence results in retinal cavities, synaptic dysfunction, reduced visual acuity, and susceptibility to retinal detachment. This phase I/IIa single-center, prospective, open-label, three-dose-escalation clinical trial administered vector to nine participants with pathogenic RS1 mutations. The eye of each participant with worse acuity (≤63 letters; Snellen 20/63) received the AAV8-RS1 gene vector by intravitreal injection. Three participants were assigned to each of three dosage groups: 1e9 vector genomes (vg)/eye, 1e10 vg/eye, and 1e11 vg/eye. The investigational product was generally well tolerated in all but one individual. Ocular events included dose-related inflammation that resolved with topical and oral corticosteroids. Systemic antibodies against AAV8 increased in a dose-related fashion, but no antibodies against RS1 were observed. Retinal cavities closed transiently in one participant. Additional doses and immunosuppressive regimens are being explored to pursue evidence of safety and efficacy (ClinicalTrials.gov: NCT02317887).

Measuring Central Retinal Sensitivity Using Microperimetry

Microperimetry is an increasingly often used method of assessing the sensitivity of the central macula, analyzing fixation capabilities and loci, and accurately combining structural and functional information, even in the absence of stable fixation. Ongoing gene therapy trials have targeted the central retina, and utilized microperimetry as a main outcome measure for changes in retinal function. In retinal treatment planning, microperimetry has been used to assess the potential therapeutic window of opportunity. In the following pages, we briefly review the necessary steps to perform the Macular Integrity Assessment (MAIA) microperimetry.

Fixation behavior in macular dystrophy assessed by microperimetry

Purpose

To investigate the fixation behavior in macular dystrophy using microperimetry.

Methods

This retrospective study included patients with macular dystrophy and unilateral macular pucker. Macular dystrophic eyes were compared based on fixation within or outside of the atrophic region. The normal fellow eyes in patients with unilateral macular pucker formed the control group. Clinical and demographic characteristics of age, sex, best-corrected visual acuity, spherical equivalent, and fixation behavior (which included foveal mean sensitivity (MS), fixation MS, MS improvement, stability, centrality, and eccentric distance of fixation) were analyzed. A total of 58 patients were recruited, comprising 29 eyes of 29 patients in the macular dystrophy group and 29 eyes of 29 patients in the control group.

Results

Compared to the control group, patients with macular dystrophy had significantly poorer visual acuity, foveal MS, fixation MS, stability, and centrality, and more eccentric preferred retinal locations (PRLs). In macular dystrophy, the PRLs were most common on the superior side (48.3%). Compared to fixation in the atrophic region, PRLs out of the atrophic lesion gained more MS (7.41 vs. 0.89 dB, p = 0.001), although with less stable fixation (10.0 vs. 47.4%, p = 0.044). By multivariate linear regression, eccentric distance was found to be significantly associated with MS improvement (p = 0.023).

Conclusions

The commonest location of PRLs in macular dystrophy is anatomically superior to the lesion. The dystrophic eye can gain better sensitivity by using PRLs outside the atrophic area.

Peripheral Visual Fields in ABCA4 Stargardt Disease and Correlation With Disease Extent on Ultra-widefield Fundus Autofluorescence

PURPOSE

To evaluate the disease extent on ultra-widefield fundus autofluorescence (UWF-FAF) in patients with ABCA4 Stargardt disease (STGD) and correlate these data with functional outcome measures.

DESIGN

Retrospective cross-sectional study.

METHODS

Setting: Kellogg Eye Center, University of Michigan.

STUDY POPULATION

Sixty-five patients with clinical diagnosis and proven pathogenic variants in the ABCA4 gene. Observational Procedures: The UWF-FAF images were obtained using Optos (200 degrees) and classified into 3 types. Functional testing included kinetic widefield perimetry, full-field electroretinogram (ffERG), and visual acuity (VA). All results were evaluated with respect to UWF-FAF classification.

MAIN OUTCOME MEASURES

Classification of UWF-FAF; area comprising the I4e, III4e, and IV4e isopters; ffERG patterns; and VA.

RESULTS

For UWF-FAF, 27 subjects (41.5%) were classified as type I, 17 (26.2%) as type II, and 21 (32.4%) as type III. The area of each isopter correlated inversely with the extent of the disease and all isopters were able to detect differences among UWF-FAF types (IV4e, P = .0013; III4e, P = .0003; I4e, P < .0001 = 3.93e^-8). ffERG patterns and VA were also different among the 3 UWF-FAF types (P < .001 = 6.61e-⁶ and P < .001 = 7.3e^-5, respectively).

CONCLUSION

Patients with widespread disease presented with more constriction of peripheral visual fields and had more dysfunction on ffERG and worse VA compared to patients with disease confined to the macula. UWF-FAF images may provide information for estimating peripheral and central visual function in STGD.

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.

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.

Visual rehabilitation via microperimetry in patients with geographic atrophy: a pilot study

Background

Age-related macular degeneration (AMD) is the leading cause of blindness in the western world. As a consequence of AMD, patients develop structural damage that comprises the fovea and subsequently present loss of central vision, low visual acuity and unstable fixation. Contrary to what happens with anti-angiogenic treatment in neovascular AMD, there is currently no definitive treatment to reverse geographic atrophy progression. The aim of this study was to determine the effectiveness of the visual rehabilitation treatment via microperimetry in patients with geographic atrophy.

Methods

Longitudinal and prospective study, 18 patients with areas of geographic atrophy in their eye of better visual acuity were included. Macular integrity assessment (Maia) microperimeter (CentreVue, Padova, Italy) was used to diagnose retinal fixation and sensitivity in these patients. Based on these data and using the training module available in the equipment, the patients underwent visual rehabilitation sessions intended to allow the patient to establish the best possible fixation in the best area of retinal sensitivity. To determine the training effectiveness, the following variables were compared before and after: visual acuity in LogMAR scale with ETDRS charts, reading speed with Minnesota Low-Vision Reading Test (MN Read), average sensitivity threshold in microperimetry; P1 and 95% Bivariate Contour Ellipse Area (BCEA) values were used for fixation stability measurement.

Results

Mean age was 77 years old (65–92). Visual acuity of the trained eye was on average 0.7 versus 0.6 LogMAR (p = 0.006) before and one week after training. Reading speed, using both eyes, was 47 words per minute (wpm) before training and 69 wpm after training (p = 0.04). Average retinal sensitivity was 14.1 versus 14.6 db (p = 0.4). Fixation stability improved with P1 values of 45% versus 51% (p = 0.05) and 95% BCEA values of 43 versus 25 (p = 0.02) before and after training, respectively.

Conclusions

Visual training via microperimetry in patients with age-related macular degeneration is effective in improving fixation stability, reading speed, and visual acuity, measured one week after training is completed.

Correlation between retinal function and microstructural foveal changes in intermediate age related macular degeneration

PURPOSE

To assess foveal microstructural changes influencing retinal sensitivity (RS) and fixation stability using microperimeter MP-1 in intermediate age-related macular degeneration (AMD).

METHODS

In this cross-sectional study, 22 eyes of 22 patients (mean age: 75 ± 9.02 years) with intermediate AMD were enrolled. Retinal sensitivity and bivariate contour ellipse area (BCEA) were obtained by microperimetry MP-1 (Humphrey 10-2 68-loci grid) under mesopic conditions. Drusen type, drusenoid pigment epithelial detachment, hyperreflective foci (HF), integrity of external limiting membrane (ELM), inner ellipsoid zone (ISel), RPE/Bruch's membrane complex (RPE/B) and subfoveal choroidal thickness were analyzed in the foveal region and compared with RS and BCEA. Spearman's rank correlation coefficient was used to evaluate the relationship between variables. Logistic regression analysis was also used to assess morphological predictor influencing RS or BCEA.

RESULTS

RS was strongly and inversely related with the presence of HF (r = -0.66, P = 0.001), integrity of ELM (r = -0.70, P < 0.001), ellipsoid zone (r = -0.45, P = 0.03). Instead, BCEA is positively related to the ellipsoid zone integrity (r = 0.45, P = 0.03). Logistic regression analysis confirmed that disruption of ISel influenced fixation stability (ExpB: 9.69, P = 0.04) but not RS. Instead, the presence of HF and disruption of ELM predicted RS reduction (ExpB: 0.55, P = 0.02 and ExpB: 0.29, P = 0.04, respectively).

CONCLUSIONS

The integrity of ELM and the presence of HF are both predictors of RS. The ELM status may be considered a new biomarker of retinal function together with HF. Instead, the integrity of ISel band seems to be a more selective predictor of BCEA than RS.

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.