Secondary and Exploratory Outcomes of the Subthreshold Nanosecond Laser Intervention Randomized Trial in Age-Related Macular Degeneration: A LEAD Study Report

Deep Learning Approaches for Detecting of Nascent Geographic Atrophy in Age-Related Macular Degeneration

Purpose

Nascent geographic atrophy (nGA) refers to specific features seen on OCT B-scans, which are strongly associated with the future development of geographic atrophy (GA). This study sought to develop a deep learning model to screen OCT B-scans for nGA that warrant further manual review (an artificial intelligence [AI]-assisted approach), and to determine the extent of reduction in OCT B-scan load requiring manual review while maintaining near-perfect nGA detection performance.

Design

Development and evaluation of a deep learning model.

Participants

One thousand eight hundred and eighty four OCT volume scans (49 B-scans per volume) without neovascular age-related macular degeneration from 280 eyes of 140 participants with bilateral large drusen at baseline, seen at 6-monthly intervals up to a 36-month period (from which 40 eyes developed nGA).

Methods

OCT volume and B-scans were labeled for the presence of nGA. Their presence at the volume scan level provided the ground truth for training a deep learning model to identify OCT B-scans that potentially showed nGA requiring manual review. Using a threshold that provided a sensitivity of 0.99, the B-scans identified were assigned the ground truth label with the AI-assisted approach. The performance of this approach for detecting nGA across all visits, or at the visit of nGA onset, was evaluated using fivefold cross-validation.

Main Outcome Measures

Sensitivity for detecting nGA, and proportion of OCT B-scans requiring manual review.

Results

The AI-assisted approach (utilizing outputs from the deep learning model to guide manual review) had a sensitivity of 0.97 (95% confidence interval [CI] = 0.93-1.00) and 0.95 (95% CI = 0.87-1.00) for detecting nGA across all visits and at the visit of nGA onset, respectively, when requiring manual review of only 2.7% and 1.9% of selected OCT B-scans, respectively.

Conclusions

A deep learning model could be used to enable near-perfect detection of nGA onset while reducing the number of OCT B-scans requiring manual review by over 50-fold. This AI-assisted approach shows promise for substantially reducing the current burden of manual review of OCT B-scans to detect this crucial feature that portends future development of GA.

Financial Disclosures

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

Retinal sensitivity changes in early/intermediate AMD: a systematic review and meta-analysis of visual field testing under mesopic and scotopic lighting

Visual fields under mesopic and scotopic lighting are increasingly being used for macular functional assessment. This review evaluates its statistical significance and clinical relevance, and the optimal testing protocol for early/intermediate age-related macular degeneration (AMD). PubMed and Embase were searched from inception to 14/05/2022. All quality assessments were performed according to GRADE guidelines. The primary outcome was global mean sensitivity (MS), further meta-analysed by: AMD classification scheme, device, test pattern, mesopic/scotopic lighting, stimuli size/chromaticity, pupil dilation, testing radius (area), background luminance, adaptation time, AMD severity, reticular pseudodrusen presence, and follow-up visit. From 1489 studies screened, 42 observational study results contributed to the primary meta-analysis. Supported by moderate GRADE certainty of the evidence, global MS was significantly reduced across all devices under mesopic and scotopic lighting with large effect size (-0.9 [-1.04, -0.75] Hedge's g, P < 0.0001). The device (P < 0.01) and lighting (P < 0.05) used were the only modifiable factors affecting global MS, whereby the mesopic MP-1 and MAIA produced the largest effect sizes and exceeded test-retest variabilities. Global MS was significantly affected by AMD severity (intermediate versus early AMD; -0.58 [-0.88, -0.29] Hedge's g or -2.55 [3.62, -1.47] MAIA-dB) and at follow-up visit (versus baseline; -0.62 [-0.84, -0.41] Hedge's g or -1.61[-2.69, -0.54] MAIA-dB). Magnitudes of retinal sensitivity changes in early/intermediate AMD are clinically relevant for the MP-1 and MAIA devices under mesopic lighting within the central 10° radius. Other factors including pupil dilation and dark adaptation did not significantly affect global MS in early/intermediate AMD.

Microperimetry and Structural Risk Factors on OCT in Intermediate Age-Related Macular Degeneration

PURPOSE

To determine the relationship between structural biomarkers on OCT that increase the risk of disease progression and microperimetric retinal sensitivity in patients with intermediate age-related macular degeneration (iAMD).

DESIGN

Prospective cross-sectional, observational study.

PARTICIPANTS

Forty-five eyes of 23 patients with iAMD.

METHODS

Patients underwent OCT and microperimetry. OCT scans were evaluated for the risk factors intraretinal hyperreflective foci (HRF), hyporeflectivity within drusenoid lesions (HRDL), subretinal drusenoid deposits, double-layer sign (DLS), and drusen volume. Microperimetric retinal sensitivity was analyzed with a 33-point grid covering the macula. With a novel method of determining what part of the retina corresponded to each microperimetry point, a Voronoi diagram was constructed, dividing the macula in cells consisting of the region nearer to each point than any other. The Voronoi diagram was superimposed on the OCT, making it possible to determine the point-to-point location of the OCT risk factors. Univariable and multivariable linear mixed-effect models were used for analysis.

MAIN OUTCOME MEASURES

Association between microperimetric retinal sensitivity and OCT risk factors at individual measuring points.

RESULTS

One thousand four hundred seventy-nine points of retinal sensitivity and corresponding structural area on OCT were included in this study. Retinal sensitivity was significantly decreased with presence of the OCT risk factors HRF, HRDL, DLS, and drusen volume (all P < 0.001) when analyzed with the univariable linear mixed-effect model. The multivariable model showed a significant decrease of retinal sensitivity with presence of HRF (P < 0.001), DLS (P = 0.025), and greater drusen volume (P < 0.001).

CONCLUSIONS

Presence of HRF, DLS, and greater drusen volume, all of which increase the risk of disease progression, is significantly and independently associated with decreased microperimetric retinal sensitivity in patients with iAMD.

FINANCIAL DISCLOSURE(S)

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

Targeted High-Density Microperimetry Testing of Nascent Geographic Atrophy in Age-Related Macular Degeneration

Purpose

To examine the effectiveness of a targeted high-density microperimetry testing strategy for detecting visual sensitivity abnormalities in eyes with nascent geographic atrophy (nGA) when compared with standard central microperimetry testing.

Design

Observational study.

Participants

Three-hundred and twenty-one eyes from 176 individuals with nonneovascular age-related macular degeneration (AMD).

Methods

Thirty-five eyes from 33 participants underwent targeted high-density microperimetry testing of atrophic lesions (either nGA or geographic atrophy [GA]) within a 1.75° radius (or approximately 1000 μm diameter) region. Another cohort of 286 eyes from 143 participants with bilateral large drusen at baseline underwent standard microperimetry testing of the central 6° radius region at 6-monthly intervals for up to 36 months and thus included eyes that developed nGA and GA over the follow-up. All eyes underwent 2 tests at each visit to evaluate intrasession measurement repeatability.

Main Outcome Measures

Magnitude of visual sensitivity abnormalities based on mean sensitivity (MS), pointwise sensitivity standard deviation (PSD), and the number of test locations with a threshold of ≤ 10 decibels (dB; or deep defects) in eyes with nGA, compared between eyes that underwent targeted high-density microperimetry testing and standard central microperimetry testing.

Results

The magnitude of visual sensitivity abnormalities based on MS, PSD and the number of deep defects were all significantly greater in eyes with nGA using targeted, high-density microperimetry testing compared with eyes with nGA using standard central microperimetry testing (all P < 0.001) and were all significantly less than eyes with GA using targeted, high-density microperimetry testing (all P ≤ 0.004). The intrasession coefficient of repeatability, where 95% of the test-retest differences are expected to occur, for MS in eyes with atrophic changes was 0.9 dB with the targeted, high-density microperimetry testing, and 1.8 dB with standard central microperimetry testing.

Conclusions

Targeted, high-density microperimetry testing enabled the detection of a significantly greater magnitude of visual sensitivity abnormalities in eyes with nGA than standard microperimetry testing.

Financial Disclosures

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

Choroidal signal hypertransmission on optical coherence tomography imaging: Association with development of geographic atrophy in age-related macular degeneration

BACKGROUND

To examine the association between large choroidal signal hypertransmission ≥250 μm (LHyperT) on optical coherence tomography (OCT) with the risk of developing geographic atrophy (GA) and compare this risk with those associated with nascent geographic atrophy (nGA).

METHODS

Two hundred and eighty eyes from 140 participants with bilateral large drusen and without late age-related macular degeneration (AMD) or nGA at baseline underwent OCT imaging and colour fundus photography (CFP) at 6-monthly intervals up to 5 years. OCT scans were graded for the presence of LHyperT and nGA, and CFPs were graded for the presence of GA.

RESULTS

The five-year incidence of LHyperT and nGA were 37% and 27% respectively (p = 0.003), and the two-year probability of their progression to GA were 17% and 40%, respectively (p = 0.002). LHyperT and nGA explained 81% and 91% of the variance in the time to develop GA, respectively (p = 0.032), and they were both associated with a significantly higher rate of GA development compared to eyes without these lesions (adjusted hazard ratio = 110.8 and 183.2, respectively; p < 0.001 for both).

CONCLUSIONS

LHyperT and nGA were both high-risk features for GA development, but the latter showed a higher rate of GA progression and explained a significantly greater proportion of the variance in the time to develop GA. As such, nGA may be a more robust surrogate endpoint than LHyperT for the conventional clinical endpoint of CFP-defined GA for intervention trials in the early stages of AMD.

Subthreshold laser treatment in retinal diseases: a mini review

PURPOSE

To summarize the mechanism and the clinical applications of subthreshold laser (STL) in retinal practice. Subthreshold or "non-destructive" laser includes all types of laser treatments that produce minimal or no damage to the tissues and no visible signs after application.

METHODS

A descriptive review of articles from literature databases (PubMed, Medline, Embase, Cochrane, Web of Science) published before August 2023, which discuss current STL treatments of retinal diseases.

RESULTS

This review provides evidence for STL as a treatment option for central serous chorioretinopathy, diabetic retinopathy, age-related macular degeneration, macular edema due to retinal vein occlusion, and other maculopathies. In most published reports, STL has shown a therapeutic effect without damage to the underlying tissue.

CONCLUSION

Subthreshold laser treatment has shown safety and efficacy in the management of some retinal and macular diseases. Stimulation of the retinal pigment epithelium without destroying adjacent neuroretina has been shown to be sufficient in inducing retinal repair in many clinical cases. Recent research and clinical studies continue to explore the mechanisms and improving therapeutic benefits of this technology as well as extend the range of retinal disorders treatable by this modality.

Biomarkers for the Progression of Intermediate Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a leading cause of severe vision loss worldwide, with a global prevalence that is predicted to substantially increase. Identifying early biomarkers indicative of progression risk will improve our ability to assess which patients are at greatest risk of progressing from intermediate AMD (iAMD) to vision-threatening late-stage AMD. This is key to ensuring individualized management and timely intervention before substantial structural damage. Some structural biomarkers suggestive of AMD progression risk are well established, such as changes seen on color fundus photography and more recently optical coherence tomography (drusen volume, pigmentary abnormalities). Emerging biomarkers identified through multimodal imaging, including reticular pseudodrusen, hyperreflective foci, and drusen sub-phenotypes, are being intensively explored as risk factors for progression towards late-stage disease. Other structural biomarkers merit further research, such as ellipsoid zone reflectivity and choriocapillaris flow features. The measures of visual function that best detect change in iAMD and correlate with risk of progression remain under intense investigation, with tests such as dark adaptometry and cone-specific contrast tests being explored. Evidence on blood and plasma markers is preliminary, but there are indications that changes in levels of C-reactive protein and high-density lipoprotein cholesterol may be used to stratify patients and predict risk. With further research, some of these biomarkers may be used to monitor progression. Emerging artificial intelligence methods may help evaluate and validate these biomarkers; however, until we have large and well-curated longitudinal data sets, using artificial intelligence effectively to inform clinical trial design and detect outcomes will remain challenging. This is an exciting area of intense research, and further work is needed to establish the most promising biomarkers for disease progression and their use in clinical care and future trials. Ultimately, a multimodal approach may yield the most accurate means of monitoring and predicting future progression towards vision-threatening, late-stage AMD.

Spatial Cluster Patterns of Retinal Sensitivity Loss in Intermediate Age-Related Macular Degeneration Features

Purpose

To examine spatial patterns of retinal sensitivity loss in the three key features of intermediate age-related macular degeneration (iAMD).

Methods

One-hundred individuals (53 iAMD, 47 normal) underwent 10-2 mesopic microperimetry testing in one eye. Pointwise sensitivities (dB) were corrected for age, sex, iAMD status, and co-presence of co-localized key iAMD features: drusen load, pigmentary abnormalities, and reticular pseudodrusen (RPD). Clusters (labeled by ranks of magnitude C-2, C-1, C0) were derived from pointwise sensitivities and then assessed by quadrants and eccentricity/rings.

Results

Two clusters of decreased sensitivities were evident in iAMD versus normal: C-2, -1.67 dB (95% CI (confidence intervals), -2.36 to -0.98; P < 0.0001); C-1, -0.93 dB (95% CI, -1.5 to -0.36; P < 0.01). One cluster of decreased sensitivity was independently associated each with increased drusen load (13.57 µm increase per -1 dB; P < 0.0001), pigmentary abnormalities (C-1: -2.23 dB; 95% CI, -3.36 to -1.1; P < 0.01), and RPD (C-1: -1.07 dB; 95% CI, -2 to -0.14; P < 0.01). Sensitivity loss in iAMD was biased toward the superior and central macula (P = 0.16 to <0.0001), aligning with structural distributions of features. However, sensitivity loss associated with drusen load also extended to the peripheral macula (P < 0.0001) with paracentral sparing, which was discordant with the central distribution of drusen.

Conclusions

Drusen load, pigmentary abnormalities, and RPD are associated with patterns of retinal sensitivity loss commonly demonstrating superior and central bias. Results highlighted that a clinical focus on these three key iAMD features using structural measures alone does not capture the complex, spatial extent of vision-related functional impairment in iAMD.

Translational Relevance

Defining the spatial patterns of retinal sensitivity loss in iAMD can facilitate a targeted visual field protocol for iAMD assessment.

Comparison of Novel Volumetric Microperimetry Metrics in Intermediate Age-Related Macular Degeneration: PINNACLE Study Report 3

Purpose

To investigate and compare novel volumetric microperimetry (MP)-derived metrics in intermediate age-related macular degeneration (iAMD), as current MP metrics show high variability and low sensitivity.

Methods

This is a cross-sectional analysis of microperimetry baseline data from the multicenter, prospective PINNACLE study (ClinicalTrials.gov NCT04269304). The Visual Field Modeling and Analysis (VFMA) software and an open-source implementation (OSI) were applied to calculate MP-derived hill-of-vison (HOV) surface plots and the total volume (VTOT) beneath the plots. Bland-Altman plots were used for methodologic comparison, and the association of retinal sensitivity metrics with explanatory variables was tested with mixed-effects models.

Results

In total, 247 eyes of 189 participants (75 ± 7.3 years) were included in the analysis. The VTOT output of VFMA and OSI exhibited a significant difference (P < 0.0001). VFMA yielded slightly higher coefficients of determination than OSI and mean sensitivity (MS) in univariable and multivariable modeling, for example, in association with low-luminance visual acuity (LLVA) (marginal R2/conditional R2: VFMA 0.171/0.771, OSI 0.162/0.765, MS 0.133/0.755). In the multivariable analysis, LLVA was the only demonstrable predictor of VFMA VTOT (t-value, P-value: -7.5, <0.001) and MS (-6.5, <0.001).

Conclusions

The HOV-derived metric of VTOT exhibits favorable characteristics compared to MS in evaluating retinal sensitivity. The output of VFMA and OSI is not exactly interchangeable in this cross-sectional analysis. Longitudinal analysis is necessary to assess their performance in ability-to-detect change.

Translational Relevance

This study explores new volumetric MP endpoints for future application in therapeutic trials in iAMD and reports specific characteristics of the available HOV software applications.

Incomplete Retinal Pigment Epithelial and Outer Retinal Atrophy: Longitudinal Evaluation in Age-Related Macular Degeneration

PURPOSE

To examine the association between incomplete retinal pigment epithelial and outer retinal atrophy (iRORA) on OCT imaging and the subsequent risk of developing geographic atrophy (GA) defined on conventional color fundus photography (CFP) and to compare this with the specific features that define nascent GA (nGA).

DESIGN

Retrospective analysis of data from a longitudinal study.

PARTICIPANTS

A total of 280 eyes from 140 participants with bilateral large drusen without specific nGA-defining features or late age-related macular degeneration (AMD) at baseline.

METHODS

OCT imaging and CFP were performed at baseline and then at 6-month intervals for up to 36 months. Eyes that developed neovascular AMD were censored on the day it was detected. OCT volume scans were graded for the presence of iRORA and nGA separately, and CFP images were graded for the presence of GA.

MAIN OUTCOME MEASURES

Association with and variance explained in time to GA development.

RESULTS

A total of 58 eyes (21%) from 46 participants (33%) had iRORA at baseline, and a further 87 eyes (31%) developed iRORA over the follow-up period. Time-to-event analyses demonstrated that prevalent or incident iRORA was associated with an increased rate of GA development (adjusted hazard ratio [HR], 12.1; P = 0.021), as was incident nGA (adjusted HR, 78.6; P < 0.001). However, only the specific nGA features (adjusted P < 0.001), and not iRORA (adjusted P = 0.520), were associated with an increased rate of GA development when both features were included in the same multivariable model. The proportion of variance explained in the time to GA development by iRORA itself (R² = 43%) was significantly lower than explained by nGA alone (R² = 91%; P = 0.010).

CONCLUSIONS

In this cohort, iRORA is a significant risk factor for GA development, but its association with GA development appears to be accounted for by the development of the specific features that define nGA. Although requiring replication, these findings provide useful guidance on the relative utility of nGA and iRORA as risk factors for GA and as potential surrogate end points for future interventional studies in the early stages of AMD.

Reticular Pseudodrusen on the Risk of Progression in Intermediate Age-Related Macular Degeneration

PURPOSE

To examine the association between reticular pseudodrusen (RPD) and progression to late age-related macular degeneration (AMD) in individuals with intermediate AMD.

DESIGN

Prospective cohort study.

METHODS

Two hundred eighty eyes from 140 participants with bilateral large drusen underwent multimodal imaging (MMI), including optical coherence tomography (OCT), near-infrared reflectance (NIR), fundus autofluorescence, and color fundus photography (CFP), at 6-monthly intervals up over a 36-month follow-up period. The presence of RPD per eye was determined based on either a combined MMI criterion, or each individual imaging modality, and their extent measured on combined OCT and NIR imaging. The association between the presence of RPD on different imaging modalities, and their extent, with the development of late AMD (including OCT-defined atrophy) was evaluated.

RESULTS

The presence of RPD on MMI, or any of its individual modalities, at baseline was not significantly associated with an increased rate of developing late AMD, with or without adjusting for risk factors for AMD progression (age, drusen volume on OCT, and pigmentary abnormalities on CFP; all P ≥ 0.205). The extent of RPD present was also not significantly associated with an increased rate of developing late AMD, with or without adjustment for risk factors for AMD progression (both P ≥ 0.522).

CONCLUSIONS

In this cohort with bilateral large drusen, the presence of RPD was not significantly associated with an increased risk of developing late AMD. Additional longitudinal studies in all stages of AMD are needed to understand the implications of RPD on vision loss in this condition.

Subretinal drusenoid deposits: An update

A wide spectrum of phenotypic manifestations characterizes age-related macular degeneration (AMD). Drusen is considered the hallmark of AMD and is located underneath the retinal pigment epithelium (RPE). In contrast, subretinal drusenoid deposits (SDDs), also known as reticular pseudodrusens, are located in the subretinal space, on top of the RPE. SDDs are poorly detected by clinical examination and color fundus photography. Multimodal imaging is required for their proper diagnosis. SDDs are topographically and functionally related to rods. SDDs cause a deep impairment in retinal sensitivity and dark adaptation. SDDs are dynamic structures that may grow, fuse with each other, or regress over time. An intermediate step in some eyes is the development of an acquired vitelliform lesion. The presence of SDD confers an eye a high risk for the development of late AMD. SDD leads to macular neovascularization, particularly type 3, geographic atrophy, and outer retinal atrophy.

Subthreshold Nanosecond Laser in Age-Related Macular Degeneration: Observational Extension Study of the LEAD Clinical Trial

PURPOSE

To evaluate the long-term effect of subthreshold nanosecond laser (SNL) treatment on progression to late age-related macular degeneration (AMD).

DESIGN

Observational extension study of a randomized, sham-controlled trial.

PARTICIPANTS

Two hundred twelve participants with bilateral large drusen.

METHODS

The Laser Intervention in the Early Stages of AMD (LEAD) study was a 36-month trial where participants were randomized to receive SNL or sham treatment in 1 eye at 6-monthly intervals up to 30 months. After the completion of the LEAD study, the 2 largest recruiting sites offered remaining participants an opportunity to enroll in a 24-month observational extension study. This study thus examined all participants from these 2 sites who were enrolled in the LEAD study at baseline, including the additional observational data.

MAIN OUTCOME MEASURES

Time to develop late AMD, defined on multimodal imaging, between those randomized the SNL or sham treatment.

RESULTS

Overall, no significant difference was found in the rate of progression over a 60-month period in those randomized to the SNL compared with the sham group (adjusted hazard ratio [HR], 0.63; 95% confidence interval [CI], 0.36-1.09; P = 0.098), similar to the findings at 36 months in the LEAD Study. However, evidence of treatment effect modification continued to emerge based on the coexistence of reticular pseudodrusen (RPD; P = 0.007, adjusted interaction). Namely, progression was slowed significantly with SNL treatment for those without coexistent RPD (adjusted HR, 0.34; 95% CI, 0.16-0.71; P = 0.004), but it was not significantly different for those with RPD (adjusted HR, 1.81; 95% CI, 0.67-4.88; P = 0.239).

CONCLUSIONS

A 24-month observational extension study to the LEAD Study confirmed that SNL treatment did not significantly reduce the overall rate of progression to late AMD in a cohort with intermediate AMD. However, the persistence of a potential beneficial treatment effect in those without coexistent RPD over a longer follow-up duration of an additional 24 months without additional treatment is encouraging. These findings provide further justification for future trials to examine the potential value of SNL treatment for slowing progression in intermediate AMD.

Reticular pseudodrusen: A critical phenotype in age-related macular degeneration

Reticular pseudodrusen (RPD), or subretinal drusenoid deposits (SDD), refer to distinct lesions that occur in the subretinal space. Over the past three decades, their presence in association with age-related macular degeneration (AMD) has become increasingly recognized, especially as RPD have become more easily distinguished with newer clinical imaging modalities. There is also an increasing appreciation that RPD appear to be a critical AMD phenotype, where understanding their pathogenesis will provide further insights into the processes driving vision loss in AMD. However, key barriers to understanding the current evidence related to the independent impact of RPD include the heterogeneity in defining their presence, and failure to account for the confounding impact of the concurrent presence and severity of AMD pathology. This review thus critically discusses the current evidence on the prevalence and clinical significance of RPD and proposes a clinical imaging definition of RPD that will help move the field forward in gathering further key knowledge about this critical phenotype. It also proposes a putative mechanism for RPD formation and how they may drive progression to vision loss in AMD, through examining current evidence and presenting novel findings from preclinical and clinical studies.

Dose Response in the Subthreshold Nanosecond Laser Trial in Early Stages of AMD: A LEAD Study Report

BACKGROUND AND OBJECTIVE

To examine the association between treatment parameters and the progression to late age-related macular degeneration (AMD) in the Laser Intervention in Early Stages of Age-Related Macular Degeneration (LEAD) study, a randomized, controlled trial of a subthreshold nanosecond laser (SNL) for slowing disease progression in the early stages of AMD.

PATIENTS AND METHODS

The association between treatment parameters early in the trial period for participants in the SNL arm of the LEAD study and time to develop late AMD during the 3-year trial duration was examined. Parameters included treatment energy at the baseline and 6-month visits and the number of laser spots visible on fundus autofluorescence (FAF) imaging taken at 6 and 12 months (taken as a proxy measure of early, adequate delivery of the laser treatment at the baseline and 6-month visits, respectively).

RESULTS

A multivariable analysis revealed there were no significant associations between time to develop late AMD and number of FAF-visible laser spots at 6-months (adjusted P = .537) nor laser energy used at baseline (adjusted P = .910). No significant associations were also observed when evaluating FAF-visible spots at 12-months (adjusted P = .107) and the average laser energy used at baseline and 6 months (adjusted P = .558).

CONCLUSIONS

This study did not find any evidence to suggest that there was a dose response for the effect of laser treatment using these treatment parameters on the progression of AMD. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:380-386.].

Subthreshold Nanosecond Laser, from Trials to Real-Life Clinical Practice: A Cohort Study

Background

Age-related macular degeneration (AMD), a degenerative disorder, is a major cause of irreversible severe visual deterioration in the older Western population. Thus, treatments that resolve drusen may prove helpful in limiting the progression of AMD. The study aimed to evaluate the clinical outcome of sub-threshold nanosecond laser therapy (SNL) using a double-frequency nanosecond-pulsed laser with discontinuous energy beam distribution in the early stages of age-related macular degeneration (AMD).

Methods

In a single-center cohort study, 64 eyes with early or intermediate AMD were treated using SNL and then compared to 77 untreated, control eyes. The primary outcome measures included the area and amount of drusen, and the secondary outcome measures included change in visual acuity and rate of drusen progression within 6 months of follow-up.

Results

A total of 64 patients’ eyes following SNL treatment showed a significant reduction in the area and amount of drusen after 6 months in comparison to the corresponding values in the control group (p<0.001, respectively). There was no significant difference in visual acuity change after 6 months in both groups (p\documentclass[12pt]{minimal} \usepackage{wasysym} \usepackage[substack]{amsmath} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage[mathscr]{eucal} \usepackage{mathrsfs} \DeclareFontFamily{T1}{linotext}{} \DeclareFontShape{T1}{linotext}{m}{n} {linotext }{} \DeclareSymbolFont{linotext}{T1}{linotext}{m}{n} \DeclareSymbolFontAlphabet{\mathLINOTEXT}{linotext} \begin{document} $$ \ge $$ \end{document}0.59, respectively). Within the 6-month follow-up, the rate of progression in drusen size and number was significantly lower in the SNL group (26%) than in the control group (69%; p<0.001).

Discussion

SNL therapy is a novel, promising approach for improving the macular morphology in patients with early and intermediate AMD. Further studies are necessary to reveal the potential to reduce the risk of transformation into advanced or wet AMD and to retain vision.

USING MICROPERIMETRY AND LOW-LUMINANCE VISUAL ACUITY TO DETECT THE ONSET OF LATE AGE-RELATED MACULAR DEGENERATION: A LEAD Study Report

PURPOSE

To evaluate the performance of microperimetry and low-luminance visual acuity for detecting late age-related macular degeneration (AMD) onset.

METHODS

Two hundred ninety-two individuals with bilateral large drusen in the Laser Intervention in the Early Stages of AMD study underwent best-corrected visual acuity, low-luminance visual acuity, and microperimetry testing as well as multimodal imaging to detect late (neovascular or atrophic) AMD onset. The performance of the change in the measurement from baseline of each of visual function test for detecting late AMD onset was compared.

RESULTS

The area under the receiver operating characteristic curve for detecting neovascular and atrophic AMD onset was not significantly different for low-luminance visual acuity (area under the receiver operating characteristic curve = 0.71 and 0.56, respectively) and microperimetry (area under the receiver operating characteristic curve = 0.82 and 0.62, respectively) compared with best-corrected visual acuity (area under the receiver operating characteristic curve = 0.57 and 0.56, respectively; P ≥ 0.126 for all). There was also only a fair degree of agreement between the three visual function measures for detecting the onset of neovascular and atrophic AMD (κ ≥ 0.24).

CONCLUSION

Microperimetry, low-luminance visual acuity, and best-corrected visual acuity demonstrate limited performance for detecting the earliest onset of late AMD. It remains to be established whether they perform better than current methods designed to enable self-detection of neovascular AMD onset, such as Amsler grid testing.

Longitudinal Analysis of Retinal Thickness and Retinal Function in Eyes with Large Drusen Secondary to Intermediate Age-Related Macular Degeneration

PURPOSE

To assess the longitudinal association between outer retinal microstructure and mesopic as well as scotopic retinal sensitivity in patients with drusen secondary to intermediate age-related macular degeneration (iAMD).

DESIGN

Prospective, longitudinal natural history study.

PARTICIPANTS

Fifty-nine eyes of 54 patients with large drusen (> 125 μm) associated with iAMD and 27 age-matched healthy control eyes.

METHODS

Participants underwent spectral-domain OCT and both mesopic and scotopic fundus-controlled perimetry (FCP). Annual follow-up visits were performed over a 3-year period.

MAIN OUTCOME MEASURES

Pointwise correlation of retinal sensitivity stimuli to corresponding standardized (Z score) pointwise retinal thickness. Linear mixed-effect models were applied to analyze longitudinally the association of pointwise retinal thickness changes, follow-up time, or both with retinal function.

RESULTS

At baseline, mean pointwise sensitivity in patients was reduced by -1.67 dB (95% confidence interval [CI], -2.22 to -1.12) for mesopic and by -2.34 dB (95% CI, -2.85 to -1.84) for scotopic testing compared with controls with a pointwise sensitivity change of -0.35 dB/year (95% CI, -0.43 to -0.28) for mesopic and +0.20 dB/year (95% CI, 0.12-0.29) for scotopic testing, respectively (P < 0.001). Retinal thickness analysis in patients revealed a significantly thinner outer nuclear layer (ONL) by -0.49 standard deviation (SD; 95% CI, -0.70 to -0.28 SD) and a significant thicker retinal pigment epithelium-drusen complex (RPEDC) by +3.22 SD (95% CI, 2.27-4.17 SD) at baseline, respectively (P < 0.001). During follow-up, retinal thickness thickened further by +0.51 SD/year (RPEDC) and thinned by -0.03 SD/year (ONL; P = 0.045) and -0.34 SD/year (inner and outer photoreceptor segments) in patients, respectively (P < 0.001). Structure-function analysis showed a significant association of the ONL and the RPEDC thickness change with both types of FCP sensitivity testing (P < 0.001). Besides, follow-up time had a significant (independent) effect on mesopic and scotopic retinal sensitivity (P < 0.001).

CONCLUSIONS

The longitudinal structure-function correlation demonstrated a progressive quantifiable degeneration of the outer retina in iAMD associated with photoreceptor dysfunction. Because longitudinal sensitivity changes could not be explained by structural changes alone, an unmet need remains for additional refined parameters on retinal structure to predict retinal function.

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.

Subthreshold Nano-Second Laser Treatment and Age-Related Macular Degeneration

The presence of drusen is an important hallmark of age-related macular degeneration (AMD). Laser-induced regression of drusen, first observed over four decades ago, has led to much interest in the potential role of lasers in slowing the progression of the disease. In this article, we summarise the key insights from pre-clinical studies into the possible mechanisms of action of various laser interventions that result in beneficial changes in the retinal pigment epithelium/Bruch's membrane/choriocapillaris interface. Key learnings from clinical trials of laser treatment in AMD are also summarised, concentrating on the evolution of laser technology towards short pulse, non-thermal delivery such as the nanosecond laser. The evolution in our understanding of AMD, through advances in multimodal imaging and functional testing, as well as ongoing investigation of key pathological mechanisms, have all helped to set the scene for further well-conducted randomised trials to further explore potential utility of the nanosecond and other subthreshold short pulse lasers in AMD.

Low luminance visual acuity as a clinical measure and clinical trial outcome measure: a scoping review

PURPOSE

The measurement of standard visual acuity (VA) is the most well-known part of any ophthalmic examination to indicate visual function. Despite this, it is insensitive in detecting early disease changes. Therefore, other visual function tests have been developed including low luminance VA (LLVA) and low luminance deficit (LLD). This scoping literature review aims to summarise the current published applications of LLVA and LLD assessments to evaluate their utility as clinical markers and research outcome measures in a variety of ophthalmic conditions.

RECENT FINDINGS

Sixty-five peer-reviewed publications were included. LLVA was pioneered for use in geographic atrophy, a subtype of age-related macular degeneration, which remains the mainstay of its clinical application. However, other studies have reported additional useful applications in inherited retinal diseases including rare maculopathies and rod-cone dystrophies. Although there are some variations in testing methodology, use of the standard Early Treatment Diabetic Retinopathy Study (ETDRS) chart with a 2.0 log unit neutral density filter is the most popular approach. The optimal testing luminance is still to be defined.

SUMMARY

Overall, LLVA is an earlier clinical marker of change in central retinal function than standard VA. It has been shown to be a risk factor for disease progression and a better indicator of a patient's level of everyday visual function. It is inexpensive and simple to implement using readily available standard ophthalmic equipment.

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.

One-Year Functional and Anatomical Outcomes After Selective Retina Therapy With Real-Time Feedback-Controlled Dosimetry in Patients With Intermediate Age-Related Macular Degeneration: A Pilot Study

BACKGROUND AND OBJECTIVES

This pilot study sought to evaluate changes in macular function and drusen volume (DV) after selective retina therapy (SRT) in patients with intermediate age-related macular degeneration (iAMD).

STUDY DESIGN/MATERIALS AND METHODS

Twenty participants with bilateral iAMD were included in this prospective interventional case series study. After titrating pulse energy by real-time feedback-controlled dosimetry, SRT with a wavelength of 527 nm was applied around the macula of one eye of each patient. Changes in best-corrected visual acuity (BCVA), DV within the central 5-mm ring (C5), and retinal sensitivity (RS) of the SRT-treated eyes (treated eyes) and untreated fellow eyes (untreated eyes) were evaluated at baseline and then at 3, 6, 9, and 12 months after treatment using linear mixed models.

RESULTS

The mean BCVA did not change significantly between baseline and 12 months in both treated and untreated eyes (P = 0.06, P = 0.24, respectively), whereas the BCVA increase rate was faster for treated than for untreated eyes at the 12-month visit (-0.072 logMAR; 95% confidence interval [CI], -0.085 to -0.059 logMAR; P = 0.006). The mean cube root transformation of DV (cube root DV) within C5 in the untreated eyes increased significantly from 0.278 ± 0.115 at baseline to 0.295 ± 0.132 mm (P = 0.027) at 12 months, whereas the cube root DV change in treated eyes was not significant (P = 0.553). The rate of increase in the cube root DV was lower in treated than in untreated eyes at the 12-month visit (-0.016 mm; 95% CI, -0.018 to -0.011 mm; P = 0.015). The mean RS was increased from 22.49 ± 2.40 dB to 24.09 ± 2.19 dB (P < 0.001) in the treated eyes, whereas the change of mean RS in the untreated eyes was not significant at the 12-month visit (P = 0.18). The treated eyes had a higher rate of increase in RS than untreated eyes at the 12-month visit (1.012 dB; 95% CI, 0.776-1.251 dB; P = 0.037). The RS change was significantly associated with the interaction between SRT treatment and time (P = 0.028), whereas it was not associated with cube root DV change (P = 0.106). No SRT-related adverse effects were observed in all participants during the 1-year follow-up.

CONCLUSION

Since SRT improved the mean RS and reduced the rate of change in drusen load in the treated eyes, as compared to the untreated eyes, SRT might slow the progression of iAMD. However, further large randomized clinical trials are necessary to confirm the efficacy of SRT for iAMD. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Multi-focal electro-retinogram response following sub-threshold nano-second laser intervention in age-related macular degeneration

IMPORTANCE

The effect of sub-threshold nano-second laser (SNL) treatment on retinal function remains unknown.

BACKGROUND

SNL treatment has been studied as a potential intervention in intermediate age-related macular degeneration (iAMD). This study investigated the longitudinal effect of SNL treatment on retinal function.

DESIGN

This was a sub-study of the LEAD trial; a 36-month, multi-centre, randomized and sham-controlled trial.

PARTICIPANTS

Subjects with iAMD.

METHODS

Eligible participants were assigned randomly to receive SNL or sham treatment to the study eye at 6-monthly visits. Multi-focal electro-retinography (mfERG) was performed at each study visit from a study site. The mfERG responses were grouped into three regions (central, middle and outer rings) and compared between the SNL and sham group.

MAIN OUTCOME MEASURES

mfERG P1 response amplitude and implicit time.

RESULTS

Data were collected from 50 subjects (26 in the SNL group, 24 in the sham group). At baseline, the P1 amplitudes of both the study eyes and the fellow eyes were similar between the groups at all rings. In the sham group, the P1 amplitude gradually decreased over time (P < .05). In the SNL group, there was an improvement in P1 amplitude which became statistically significant at the 36-month visit, detected in both the treated and fellow eyes at the central (P = .005) and middle ring (P = .007) but not at the outer ring (P = .070). No difference in P1 implicit time detected between the groups (P > .05).

CONCLUSIONS AND RELEVANCE

SNL treatment improved electro-physiological function. mfERG could be useful for monitoring AMD progression and evaluating the efficacy of SNL treatment.

Examining the added value of microperimetry and low luminance deficit for predicting progression in age-related macular degeneration

PURPOSE

To examine the added predictive value of microperimetric sensitivity and low luminance deficit (LLD; difference between photopic and low luminance visual acuity (VA)) to information from colour fundus photography (CFP) for progression to late age-related macular degeneration (AMD) in individuals with bilateral large drusen.

METHODS

140 participants with bilateral large drusen underwent baseline microperimetry testing, VA measurements and CFP. They were then reviewed at 6-monthly intervals to 36 months, to determine late AMD progression. Microperimetry pointwise sensitivity SD (PSD), LLD and the presence of pigmentary abnormalities on CFPs were determined. Predictive models based on these parameters were developed and examined.

RESULTS

Baseline microperimetry PSD and presence of pigmentary abnormalities were both significantly associated with time to develop late AMD (p≤0.004), but LLD was not (p=0.471). The area under the receiver operating characteristic curve (AUC) for discriminating between eyes that progressed to late AMD based on models using microperimetry PSD (AUC=0.68) and LLD (AUC=0.58) alone was significantly lower than that based on CFP grading for the presence of pigmentary abnormalities (AUC=0.80; both p<0.005). Addition of microperimetry and/or LLD information to a model that included CFP grading did not result in any improvement in its predictive performance (AUC=0.80 for all; all p≥0.66).

CONCLUSIONS

While microperimetry, but not LLD, was significantly and independently associated with AMD progression at the population level, this study observed that both measures were suboptimal at predicting progression at the individual level when compared to conventional CFP grading and their addition to the latter did not improve predictive performance.

Association between Patient-Reported Outcomes and Time to Late Age-Related Macular Degeneration in the Laser Intervention in Early Stages of Age-Related Macular Degeneration Study

PURPOSE

To investigate the relationship between patient-reported outcome (PRO) questionnaire responses and time to late age-related macular degeneration (AMD; neovascular AMD [nAMD] or multimodal imaging [MMI]-defined atrophy) among individuals with bilateral large drusen, and the prognostic value of baseline PROs for 36-month AMD status.

DESIGN

Exploratory analyses from a multicenter randomized controlled trial of an AMD intervention (Australian New Zealand Clinical Trials Registry identifier, ACTRN12612000704897).

PARTICIPANTS

Sham treatment group of the Laser Intervention in Early Stages of Age-Related Macular Degeneration (LEAD) Study (n = 141; age, 50-88 years; 77% female).

METHODS

The 28-item Impact of Vision Impairment (IVI-28) and 10-item Night Vision Questionnaire (NVQ-10) were administered at the baseline visit. The PRO scores were derived using rating scale models. Multivariate Cox regression adjusting for demographics and clinical measures of vision (low-luminance visual acuity, low-luminance deficit, and microperimetric sensitivity) from the poorer-performing eye was used to investigate the association between PRO scores and time to late AMD in either eye. Multivariate competing-risk regression was used to estimate cause-specific subhazard ratios for nAMD and atrophy in either eye. Cross-validated logistic lasso models were used to estimate the predicted probability of AMD at 36 months. The area under the receiver operating characteristic curve was assessed to compare prognostic accuracy between models with and without PROs.

MAIN OUTCOME MEASURE

Time until nAMD or atrophy in either eye.

RESULTS

The PRO scores were skewed toward higher functional vision. Higher IVI-28 scores were associated with a lower risk of progression to MMI-defined atrophy (20 events: adjusted hazard ratio, 0.65/logit increase; P = 0.002) but not nAMD (10 events; P = 0.562). Insufficient evidence was found of an association between NVQ-10 score and rate of progression to late AMD (P ≥0.149). Baseline IVI-28 scores were found to contribute to the prognosis of atrophy at the 36-month visit (P = 0.010).

CONCLUSIONS

On average, PROs were associated with an increased risk of progression from intermediate AMD to MMI-defined atrophy. Continuing development of instruments to record PROs in the early stages of AMD have the potential to produce inexpensive and efficient tools to assist in the assessment of disease severity and risk of AMD progression.