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

Natural History of Microperimetry and Optical Coherence Tomography in USH2A-Retinopathy: A Structure-Function Association Study

PURPOSE

To describe the natural history of optical coherence tomography (OCT) and mesopic microperimetry (MP) parameters in the Rate of Progression of USH2A-related Retinal Degeneration (RUSH2A) study.

DESIGN

Multi-center, international, prospective, longitudinal natural history study.

METHODS

STUDY POPULATION: 105 participants with biallelic disease-causing variants in USH2A with a clinical diagnosis of Usher Syndrome or autosomal recessive retinitis pigmentosa who underwent annual testing over 4 years.

MAIN OUTCOME MEASURE(S)

Ellipsoid zone (EZ) area and central sub-field thickness (CST) on OCT. Mean sensitivity (MS) and mean pointwise sensitivity at predefined functional transition points (MSFTP) on MP.

RESULTS

102 and 94 participants met criteria for OCT and MP analysis, respectively. The average EZ area was 3.9 ± 5.3 mm2 at baseline which decreased to 3.3 ± 4.1 mm2 at 4 years [rate of change (ROC) (-0.18 mm2/year)]. The average CST decreased from 249.7 ± 35.6 to 244.1 ± 39.3 microns over 4 years (-2.14 microns/year). The average MP MS declined from 6.0 ± 5.1 dB (baseline) to 4.5 ± 4.2 (4 years) (-0.39 dB/year). The MSFTP significantly decreased over time [17.9 dB (baseline) to 10.8 dB (4 years)]. Notably, at 4 years, there was a meaningful decrease (≥ 7dB) in MSFTP in 46% of study eyes.

CONCLUSIONS

This study establishes the natural history of key structural and functional parameters in USH2A-retinopathy. The MSFTP is a novel, robust parameter that showed clinically meaningful change over time and is a promising tool to monitor treatment efficacy in clinical trials.

Test-retest variability of mesopic microperimetry-associated parameters in patients with retinitis pigmentosa: REPEAT Study Report No. 2

PURPOSE

Understanding test-retest variability (TRV) of mesopic microperimetry is critical for defining meaningful treatment effects in retinitis pigmentosa (RP) trials. This study uniquely evaluates intra- and intervisit TRV and coefficients of repeatability (CoRs) for microperimetry parameters in RP patients with varying best-corrected visual acuity (BCVA) levels.

METHODS

In this single-centre prospective cohort study, RP patients were assessed on two visits, 14.0 days apart. Patients were grouped by BCVA: low (≤20/50 Snellen; ≥0.4 logMAR) or moderate (>20/50 Snellen; <0.4 logMAR). Using Bland-Altman analyses, the CoRs for intra- and intervisit variability were determined for pointwise (dB), mean (dB), and volume sensitivity (dB*deg2) on mesopic microperimetry.

RESULTS

Intravisit CoRs for mean, volume, and pointwise sensitivity were 1.7 dB, 353.2 dB*deg2, and 8.6 dB, respectively, in the low-BCVA group (n = 32), and 0.9 dB, 254.5 dB*deg2, and 7.3 dB in the moderate-BCVA group (n = 15). Intervisit CoRs for mean, volume, and pointwise sensitivity were 2.4 dB, 355.2 dB*deg2, and 10.2 dB in the low-BCVA group (n = 31). The moderate-BCVA group (n = 16) showed smaller CoRs of 1.6 dB, 386.8 dB*deg2, and 7.7 dB for mean, volume, and pointwise sensitivity. BCVA and mean sensitivity, but not fixation stability, are predictors of TRV for volume sensitivity.

CONCLUSIONS

Due to significant TRV, pointwise sensitivity is an unreliable endpoint for RP patients, irrespective of BCVA. Mean sensitivity is suitable as an endpoint when BCVA is relatively preserved. Volume sensitivity provides additional spatial information, and shows promise as a clinical endpoint for assessing macular sensitivity changes on mesopic microperimetry in patients with RP.

Visual Function Benefit After Treatment With Pegcetacoplan: Microperimetry Analysis From the Phase 3 Oaks Trial

PURPOSE

To evaluate the impact of pegcetacoplan on its ability to slow the loss of visual function using microperimetry endpoints in eyes with geographic atrophy secondary to age-related macular degeneration (AMD).

DESIGN

Post hoc analysis of phase 3 randomized controlled trial data.

METHODS

Utilizing data from the OAKS study, which evaluated pegcetacoplan monthly (PM) or every other month (PEOM) vs sham for the treatment of GA secondary to AMD, microperimetry endpoints were assessed at baseline and every 6 months until 24 months, using a 10-2 grid composed of 68 points with a 4-2 threshold strategy. Main outcome measures included the time to development of absolute scotomas in the 4 and 16 central macular points. The number of absolute scotomatous points and mean retinal sensitivity (dB) within the junctional zone extending to 250 µm on either side of autofluorescence-determined GA border was analyzed for change from baseline.

RESULTS

Among 605 patients with subfoveal or nonsubfoveal GA, treatment with pegcetacoplan delayed time to development of absolute scotomas of all 4 central macular points compared to sham at 24 months (PM: hazard ratio [HR]: 0.66 [34% risk reduction]; 95% confidence interval [CI]: 0.46, 0.96; P = .0282; PEOM: HR: 0.64 [36% risk reduction]; 95% CI: 0.44, 0.92; P = .0164). Similarly, PM and PEOM treatment delayed time to development of absolute scotomas of all 16 central points (PM: HR: 0.57 [43% risk reduction]; 95% CI: 0.33, 0.96; P = .0361; PEOM: HR: 0.52 [48% risk reduction]; 95% CI: 0.32, 0.85; P = .0084). Across the junctional zone of GA, pegcetacoplan-treated eyes developed fewer absolute scotomatous points (PM difference vs sham pooled: -0.68 points, P = .1444; PEOM difference vs sham pooled: -1.14 points, P = .0140) and experienced decreased loss of mean retinal sensitivity (PM difference vs sham pooled: 0.56 dB, P = .0650; PEOM difference vs sham pooled: 0.71 dB, P = .0202) compared with sham at 24 months.

CONCLUSIONS

Microperimetry demonstrates a reduced rate of visual function loss in the central macula and junctional zone with pegcetacoplan treatment in GA due to AMD.

Assessing structure - Function relationships in non-neovascular age-related macular degeneration

Age-related macular degeneration (AMD), a neurodegenerative disease, is the leading cause of visual impairment in industrialized countries. Challenges in defining structural/functional relationships at various stages of disease especially with non-neovascular AMD, have slowed therapeutic development. Development of such sensitive and specific markers associated with AMD progression could provide the basis necessary for future regulatory outcome variables that will be useful in assessing new, innovative AMD therapies. Advanced imaging technologies such as high-resolution optical coherence tomography, fundus autofluorescence and near infrared imaging; and functional tests including rod-mediated dark adaptation, microperimetry, fluorescence lifetime imaging ophthalmoscopy and others will be important in the evaluation of these structure/function correlations. Development of more advanced methods to study structure such as high-resolution OCT and en face OCT offer further opportunities to better correlate structure and function in clinical trials, and to better define useful biomarkers of visual outcome endpoints. Dark adaptation, although correlated with AMD stage, is difficult to incorporate as endpoint in clinical trials because dark adaptation changes slowly and the technique is time consuming. Microperimetry has become a useful outcome variable in many clinical trials and new methodology may improve its utility in structure-function correlation. These and other newer techniques will require further prospective studies to determine their clinical utility in early AMD detection, prediction of disease progression from intermediate to late stages, and the ability to monitor the advancement of non-neovascular AMD.

Characterizing the Preferred Retinal Locus and Fixation Stability in Diabetic Macular Ischemia: A One-Year Study

Eyes with maculopathy usually have poor fixation stability (FS) and develop a new preferred retinal locus (PRL). The exact FS and PRL have never been studied in diabetic macular ischemia (DMI). In this one-year observational study, we recruited 79 patients (145 eyes) with evidence of DMI on optical coherence tomography angiography (OCTA). Microperimetry (MP) was performed at baseline and 52 weeks. Overall, DMI eyes demonstrated relatively stable FS without evolving into eccentric fixation over one year. When comparing the better-seeing eye (BSE) with the worse-seeing eye (WSE) in eyes with bilateral DMI, the latter presented with a larger bivariate contour ellipse area (BCEA) initially but gradually aligned with the one in the BSE at the end of the study. Conversely, the foveolar retinal sensitivity (RS) worsened significantly alongside the extension of disorganization of the retinal inner layers (DRIL) in the WSE at one year despite the best-corrected visual acuity (BCVA) being maintained. This suggests that foveolar RS might reflect the start of DMI deterioration more sensitively than BCVA.

Addressing Multiplicity in Retinal Sensitivity Analysis: An Alternative Approach to Assessing Gene Therapy Efficacy in Inherited Retinal Diseases

Purpose

The purpose of this study was to propose an alternative statistical approach that addresses the issue of multiplicity in microperimetry data analysis, offering a more balanced and sensitive measure of the efficacy of gene therapy in inherited retinal diseases (IRDs).

Methods

We analyzed microperimetry data from a phase II trial of AGTC-501 in patients with X-linked retinitis pigmentosa (XLRP). The Macular Integrity Assessment (MAIA; CenterVue, Padova, Italy) device was used to evaluate test-retest repeatability. A binomial model was used to calculate the probability of ≥7 decibel (dB) improvements due to chance alone across a 68-locus grid. We proposed an alternative approach to detect changes using a threshold of ≥7 loci with ≥7 dB mean improvement.

Results

Test-retest repeatability analysis showed a probability of < 5% for observing pointwise improvements ≥7 dB between 2 baseline visits. Applying the binomial distribution model, we found that the probability of observing improvements ≥7 dB in at least 7 unspecified loci purely by chance was 5.3%.

Conclusions

The proposed approach provides a balanced way to address multiplicity while maintaining reasonable statistical significance. Using ≥7 unspecified loci as the criterion for assessing sensitivity changes, offers a comprehensive assessment that can detect genuine treatment effects without being overly conservative.

Translational Relevance

This alternative statistical method has the potential to improve the evaluation of retinal sensitivity changes in gene therapy trials for IRDs, providing a more accurate measure of therapeutic efficacy and enhancing clinical decision making.

Assessment of CRB1-Associated Retinopathies Using the S-MAIA Fast Protocol and Spectral-Domain Optical Coherence Tomography

Background: A cross-sectional study was conducted at Moorfields Eye Hospital, UK, involving patients with CRB1-associated retinopathies: macular dystrophy (MD), cone-rod dystrophy (CORD), and early-onset severe retinal dystrophy/Leber congenital amaurosis (EOSRD/LCA). The study aimed to evaluate CRB1-associated retinopathies using microperimetry (macular integrity assessment (S-MAIA) fast protocol) and spectral domain optical coherence tomography (SD-OCT). Methods: Data quality and participant attrition were assessed in 18 patients (10 MD, 5 EOSRD/LCA, 3 CORD), aged 10-52 years, with a median best corrected visual acuity (BCVA) of 0.41 logMAR. Results: Microperimetry and SD-OCT data were obtained from 14 and 18 patients, respectively, but eccentric fixation hindered structure-function analysis. All participants showed overall abnormal sensitivity on the S-MAIA fast protocol. Parafoveal volume was significantly increased, while foveal thickness and volume were reduced compared to normative data (p < 0.01). Conclusions: This study highlights the challenges of participant attrition and the need for alternative functional metrics to complement traditional evaluations. It also reinforces previous findings of abnormal retinal architecture in CRB1-associated retinopathies, providing further insights into S-MAIA and SD-OCT assessments for this patient population.

Rethinking Clinical Trials in Age-Related Macular Degeneration: How AI-Based OCT Analysis Can Support Successful Outcomes

Age-related macular degeneration (AMD) is a leading cause of blindness in the developed world. Due to an aging population, its prevalence is expected to increase, making novel and optimized therapy options imperative. However, both late-stage forms of the disease, neovascular AMD (nAMD) and geographic atrophy (GA), exhibit considerable variability in disease progression and treatment response, complicating the evaluation of therapeutic efficacy and making it difficult to design clinical trials that are both inclusive and statistically robust. Traditional trial designs frequently rely on generalized endpoints that may not fully capture the nuanced benefits of treatment, particularly in diseases like GA, where functional improvements can be gradual or subtle. Artificial intelligence (AI) has the potential to address these issues by identifying novel, condition-specific biomarkers or endpoints, enabling precise patient stratification and improving recruitment strategies. By providing an overview of the advances and application of AI-based optical coherence tomography analysis in the context of AMD clinical trials, this review highlights the transformative potential of AI in optimizing clinical trial outcomes for patients with nAMD or GA secondary to AMD.

Retinal Disease Variability in Female Carriers of RPGR Variants Associated with Retinitis Pigmentosa: Clinical and Genetic Parameters

Objectives: We sought to investigate the visual function, retinal features, and genotype-phenotype correlations of an Australian cohort of RPGR carriers. Methods: In this cross-sectional study, we evaluated RPGR carriers seen in Melbourne and Perth between 2013 and 2023 and healthy women seen between 2022 and 2023 in Melbourne. Visual acuity tests, fundus-tracked microperimetry, and retinal imaging were performed. RPGR carriers were classified into four retinal phenotypes (normal, radial, focal pigmentary retinopathy, and male pattern phenotype) and compared against healthy controls. Genotype-phenotype relationships in the RPGR carriers were investigated. Results: Thirty-five female RPGR carriers and thirty healthy controls were included in this study. The median ages were 40 and 48.5 years for RPGR carriers and controls, respectively (p = 0.26). Most RPGR carriers (89%) had a genetic diagnosis. Best-corrected visual acuity (BCVA), low luminance visual acuity, retinal sensitivity, central inner retinal thickness (IRT, 1°), and photoreceptor complex (PRC) thickness across the central 1-7° of the retina differed between phenotypes of RPGR carriers. On average, RPGR carriers with ORF15 variants (n = 25 carriers) had reduced LLVA, a greater IRT at 1°, and thinner PRC thickness at 7° from the fovea (all p < 0.05) compared to those with exon 1-14 variants. Conclusions: Female RPGR carriers with severe retinal phenotypes had significantly decreased visual function and changes in retinal structure in comparison to both the controls and carriers with mild retinal disease. BCVA, LLVA, retinal sensitivity, and retinal thickness are biomarkers for detecting retinal disease in RPGR carriers. The genetic variant alone did not influence retinal phenotype; however, RPGR carriers with ORF15 variants exhibited reduced retinal and visual measurements compared to those with exon 1-14 variants.

Structure-Function Relationships in Geographic Atrophy Based on Mesopic Microperimetry, Fundus Autofluorescence, and Optical Coherence Tomography

Purpose

To examine relationships between retinal structure and visual function in geographic atrophy (GA) by analyzing spatial agreement between absolute scotomas and macular structure, focusing on (1) choroidal hypertransmission, a key feature of complete retinal pigment epithelium and outer retinal atrophy (cRORA), and (2) fundus autofluorescence (FAF)-defined GA.

Methods

Mesopic microperimetry (using a novel T-shaped pattern) and multimodal imaging were recorded longitudinally in a phase II GA trial. Horizontal and vertical optical coherence tomography (OCT) line scans (corresponding to the T axes) were graded for choroidal hypertransmission; FAF images were graded for GA. Spatial concordance between zones of absolute scotoma and atrophy was quantified by the Dice similarity coefficient (DSC).

Results

The analysis population comprised 24 participants (mean follow-up 26.8 months). For concordance between absolute scotoma and choroidal hypertransmission, estimated mean DSC was 0.70 (95% confidence interval [CI], 0.64-0.77). This was significantly higher than for FAF-defined GA (0.67; 95% CI, 0.61-0.74; estimated mean difference = 0.03, 95% CI, 0.02-0.05, P < 0.001). Mean OCT choroidal reflectivity was strongly associated with likelihood and severity of scotoma.

Conclusions

Spatial concordance between absolute scotomas and GA structural features is moderately high and slightly higher for choroidal hypertransmission than FAF-defined GA. This supports choroidal hypertransmission, a key cRORA feature, as an outcome measure in interventional trials. OCT provides more information to explain visual function than FAF alone. However, given some discordance for both structural features, performing microperimetry alongside imaging remains important.

Translational Relevance

These findings provide insights into the complex relationship between retinal structure and visual function and contribute to a nuanced understanding of outcome measures.

Longitudinal assessment of female carriers of choroideremia using multimodal retinal imaging

BACKGROUND/AIMS

Female choroideremia carriers present with a spectrum of disease severity. Unlike in men, the rate of disease progression has not been well characterised in carriers. This longitudinal study aimed to determine the rate of retinal degeneration in choroideremia carriers, using multimodal imaging and microperimetry.

METHODS

Choroideremia carriers previously seen at Oxford Eye Hospital (United Kingdom) between 2012 and 2017 returned for testing between 2015 and 2023, providing up to 11 years' follow-up data. Participants had optical coherence tomography, fundus-tracked microperimetry and fundus autofluorescence (FAF) imaging performed.

RESULTS

Thirty-four eyes of 17 choroideremia carriers were examined using multimodal imaging. Median age was 44 (range: 15-73) years at baseline and median follow-up duration was 7 (range: 1-11) years. At baseline, phenotype was classified as fine (n=5 eyes), coarse (n=13 eyes), geographic (n=12 eyes) or male pattern (n=4 eyes). Thirteen patients showed no change in phenotype classification, four showed slight changes associated with choroideremia-related retinal degeneration. Despite this, carriers with severe retinal phenotypes had a statistically significant decline in average retinal sensitivity (-0.7 dB and -0.8 dB per year, respectively, p<0.001), area of geographic loss defined by FAF (+2.5 mm2 and +3.7 mm2 per year, respectively, p<0.001) and thinning of the photoreceptor complex (up to -2.8 microns and -10.3 microns per year, p<0.001).

CONCLUSION

Choroideremia carriers, particularly those with severe retinal phenotypes, exhibit progressive retinal degeneration, as evident by multimodal imaging biomarkers and functional testing. Clinicians should not rely on retinal severity classification alone to assess disease progression.

Expert CONsensus on Visual Evaluation in Retinal disease manaGEment: the CONVERGE study

BACKGROUND/AIMS

Recent decades have seen significant advances in both structural and functional testing of retinal disease. However, the current clinical value of specific testing modalities, as well as future trends, need to be clearly identified in order to highlight areas for further development in routine care and clinical trials.

METHODS

We designed a modified two-round Delphi study to obtain the opinion of a multidisciplinary group of 33 international experts involved in the field of retinal disease management/research to determine the level of agreement and consensus regarding the value and performance of specific structural and functional testing methods for retinal disease. On a Likert scale, a median of 1-2 indicated disagreement with the statement, and 5-6 indicated agreement with the statement. An IQR of ≤2 indicated consensus in the responses. Several questions also allowed comments on responses.

RESULTS

There was overall agreement that structural testing currently predominates for detection and monitoring. There was moderate agreement that functional testing remains important and will continue to do so in the future because it provides complementary information. Certain respondents considered that properly designed and applied psychophysical tests are as reliable and repeatable as structural observations and that functional changes are the most important in the long run. Respondents considered future care and research to require a combination of structural and functional testing with strong consensus that the relative importance will depend on disease type and stage.

CONCLUSION

The study obtained important insights from a group of international experts regarding current and future needs in the management of retinal disease using a mix of quantitative and qualitative approaches. Responses provide a rich range of opinions that will be of interest to researchers seeking to design tests for future patient care and clinical trials.

Retinal Sensitivity in KCNV2-Associated Retinopathy

Purpose

The purpose of this study was to analyze the retinal sensitivity under photopic, mesopic, and scotopic conditions in a cohort of patients affected with KCNV2-associated retinopathy.

Methods

Cross-sectional evaluation of molecularly confirmed individuals was conducted. Data were obtained prospectively. The main microperimetry parameters analyzed were mean sensitivity (MS) and number of floor effects (noF) in the central macular zone (CMZ; central 6 degrees) and peripheral macular zone (PMZ; 6 to 10 degrees). Interocular symmetry was also assessed.

Results

The MS under photopic, mesopic, and scotopic conditions were, respectively, 20.2 (6.3-29.5, ±6.5), 16.2 (3.7-23.1, ±5.3), and 1.3 (0-13.3, ±3.8) in the right eyes, and 21.1 (9.8-28.9, ±6.1), 16.8 (9.6-23.5, ±4.0), and 1.1 (0-12.4, ±3.5) in the left eyes. MS was highly symmetric between eyes (Pearson correlation coefficient) in photopic (r = 0.96, P < 0.0001), mesopic (r = 0.9, P < 0.0001), and scotopic (r = 0.98, P < 0.0001) testing conditions. MS was also highly symmetric (Pearson coefficient) in the photopic CMZ (r = 0.97, P = 0.0001) and PMZ (r = 0.95, P = 0.0002), mesopic CMZ (r = 0.94, P = 0.0003), and PMZ (r = 0.92, P = 0.0009), and scotopic CMZ (r = 0.99, P < 0.0001) and PMZ (r = 0.99, P < 0.0001).The mean noF (± standard deviation [SD]; range) was 4.6 (SD = ±5.3, range = 0-16) in photopic, 5.0 (SD = ±5.4, range = 0-15) in mesopic, and 23.2 (SD = ±8.6, range = 0-28) in scotopic conditions. Subject 01-041 was the only affected individual in which no floor effect was found. Simple linear regression revealed a significant inverse relationship between age and MS, and a direct relationship between age and noF.

Conclusions

KCNV2-associated retinopathy is a largely symmetric disease from a functional perspective. Despite the early decrease in scotopic retinal sensitivity, our data suggests a large window for photoreceptor rescue with novel treatments, such as gene therapy.

Retinal Characteristics of Female Choroideremia Carriers: Multimodal Imaging, Microperimetry, and Genetics

PURPOSE

To describe visual function and retinal features of female carriers of choroideremia (CHM), using multimodal imaging and microperimetry.

DESIGN

Cross-sectional cohort study.

PARTICIPANTS AND CONTROLS

Choroideremia carriers seen in Australia (Melbourne or Perth) or the United Kingdom (Oxford or Cambridge) between 2012 and 2023. Healthy age-matched controls seen in Melbourne, Australia, between 2022 and 2023.

METHODS

Participants had visual acuity, fundus-tracked microperimetry, OCT, and fundus autofluorescence imaging performed. Choroideremia carriers were either genetically or clinically confirmed (i.e., obligate carriers). Choroideremia carriers were grouped according to their retinal phenotype and compared with healthy controls. Statistical analyses were performed on StataBE (v18.0).

MAIN OUTCOME MEASURES

Best-corrected visual acuity (BCVA), low-luminance visual acuity (LLVA), average retinal sensitivity, volume of macular hill of vision (HoV), inner retinal thickness, and photoreceptor complex (PRC) thickness.

RESULTS

Eighty-six eyes of 43 CHM carriers and 60 eyes of 30 healthy controls were examined using multimodal imaging and microperimetry. Median age was 54 and 48.5 years for CHM carriers and controls, respectively (P = 0.18). Most CHM carriers (86%) were genetically confirmed. Choroideremia carriers and controls had strong intereye correlation between eyes for BCVA and average retinal sensitivity (P < 0.001). Low-luminance visual acuity and macular HoV tests were sensitive tests to detect changes in CHM carriers with mild phenotypes (i.e., fine and coarse). Choroideremia carriers with geographic or male-pattern phenotypes had reduced BCVA, LLVA, retinal sensitivity, and retinal thinning, compared with healthy controls. Retinal thickening of the inner retina was observed in the central 1°, despite generalized thinning of the PRC in the central 7°, indicating retinal remodeling in CHM carriers, compared with controls. There were no genotype-phenotype correlations observed.

CONCLUSIONS

Female carriers of CHM with severe retinal phenotypes (i.e., geographic or male pattern) have significantly decreased visual function and retinal structural changes when compared with age-matched controls and those carriers with milder phenotypes. Low-luminance visual acuity and volumetric measures of the macular HoV were found to be the most sensitive functional tests to detect milder retinal disease (fine and coarse phenotypes) in CHM carriers.

FINANCIAL DISCLOSURE(S)

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

Key challenges in developing a gene therapy for Usher syndrome: machine-assisted scoping review

Despite compelling empirical evidence demonstrating its efficacy, gene therapies for usher syndrome (USH) are not yet available for the patient's usage. This scoping review assessed the current scenario and analysed the challenges in implementing gene therapies for USH. A literature search was conducted using PubMed and Google Scholar through an artificial intelligence (AI) tool, MaiA, focusing on relevant publications from the last 10 years. We followed the methodological guidance of the Joanna Briggs Institute (JBI) and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews (PRISMA-ScR) checklist. Of 517 records, 51 reports were considered for final analysis. It identified and categorized challenges across four key areas: preclinical, clinical, economic, and regulatory. Of all, many reports (30) highlighted the preclinical challenges where the USH gene development process encountered roadblocks. Specifically, preclinical challenges included the lack of suitable in-vivo models and effective delivery methods. Clinical challenges focused on establishing clear endpoints and long-term safety and efficacy. Economic challenges addressed diagnostic issues and manufacturing hurdles, while regulatory challenges focused on expedited evaluation processes and guidance for clinical development. Our analysis uncovered key barriers to clinical translation of USH gene therapy and strategies to address them. Researchers are employing innovative approaches, including novel delivery methods such as minigenes and nanoparticles, inventive clinical trial designs, cohesive regulatory frameworks, strategic market assessments, and collaborative research initiatives. These efforts hold promise for impactful disease-cure and modifying interventions ultimately enhancing the quality of life for USH patients.

Parafoveal Microperimetric Retinal Sensitivity as a Key Parameter Associated with Vision Loss in Retinitis Pigmentosa

Background: Although optical coherence tomography (OCT) is useful in determining outer retinal architecture, it may be suboptimal when monitoring subtle changes in retinitis pigmentosa (RP) patients. The aim of this study is to investigate precise microperimetric parameters for disease severity identification in RP patients. Methods: A cross-sectional and retrospective study. Thirty-nine eyes of 39 RP patients were included. Associations between logMAR visual acuity (VA), spectral-domain OCT, fundus autofluorescence imaging (FAF), and various microperimetric measures were evaluated. Microperimetric test locations were grouped into "foveal", parafoveal "inner ring", and perifoveal "outer ring". Independent variables were analyzed based on logistic regression, then assessed using area under the receiver operating characteristic curve (AUROC). Results: Among all microperimetric measures, linear regression analysis indicated that mean retinal sensitivity and deep scotoma count at the parafoveal inner ring were the principal parameters associated with decreased VA. The AUROC was highest for deep scotoma count at the inner ring at a value of 0.829, with the cut-off point at 3.5. A visual function index was then established according to the number of parafoveal deep scotoma points, in order of mild (0 points), moderate (1-3 points), and severe (4 or more points). Our microperimetric visual function index also correlated significantly to logMAR VA and previously established FAF patterns. Conclusions: Our study discovered deep scotoma count at the parafoveal inner ring to be a key microperimetric parameter in evaluating vision loss in RP patients. Those with four or more deep scotoma points at the parafoveal inner ring are more likely to have functional low vision.

A pilot study : retinal sensitivity change in neovascular age-related macular degeneration patients with better baseline visual acuity

This study evaluated changes in retinal sensitivity (RS) during aflibercept treatment in neovascular age-related macular degeneration (nAMD) patients with good vision. Treatment-naive nAMD patients with visual acuity better than 20/40 were treated with an aflibercept loading regiment, and RS was measured using the MAIA microperimetry device. The study examined RS differences based on visit, region, adjacent local pathology, outer retinal changes and optical coherence tomography angiography (OCTA) data were investigated. Twelve patients completed the protocol. Mean RS improved from 17.9 (3.9) µm at baseline to 20.4 (4.7) µm at final visit, while best-corrected visual acuity (BCVA) did not change. (P = 0.041) RS at baseline is worst in the presence of intraretinal fluid (IRF) and improved after treatment for all retinal pathologies except IRF. RS improvement occurred even with initial outer retinal damage. A Linear mixed model showed subretinal hyperreflective material, baseline IRF height, outer retinal integrity, fibrovascular pigment epithelial detachment height, and local choroidal vascular index as factors associated with RS. In conclusion, RS improved with aflibercept treatment in nAMD eyes with good initial visual acuity, despite no change in BCVA, except when IRF was present.

Comparison of Microperimetry and Static Perimetry for Evaluating Macular Function and Progression in Retinitis Pigmentosa

Purpose

To compare the usefulness of microperimetry and static automated perimetry in patients with retinitis pigmentosa (RP), using macular anatomical metrics as a reference.

Design

Prospective observational study.

Participants

Forty-eight eyes of 48 patients with RP in Kyushu University Hospital who underwent microperimetry-3 (MP-3) and Humphrey Field Analyzer (HFA) 10-2 testing ≥3 times during ≥2 years were included.

Methods

Macular anatomy (ellipsoid zone [EZ] length) was assessed by OCT, and macular function was assessed by MP-3 (mean retinal sensitivity at radii 2°, 4°, and 8°) and HFA10-2 program (mean retinal sensitivity at radii 2°, 4°, and 8°). Correlations between functional and anatomical parameters were analyzed cross sectionally at baseline and longitudinally by comparing the rate of progression.

Main Outcome Measures

Correlation coefficients between anatomical and functional metrics.

Results

The mean age at baseline was 50.1 ± 12.3 years, and the mean follow-up period was 2.8 ± 0.7 years. At baseline, EZ length was significantly correlated with MP-3 mean retinal sensitivity at radii 2°, 4°, and 8° (Spearman's ρ = 0.65, 0.84, 0.89; all P < 0.005) and HFA10-2 mean retinal sensitivity at radii 2°, 4°, and 8° (Spearman's ρ = 0.61, 0.73, 0.78; all P < 0.005). Longitudinal analysis showed that the slope of EZ length (-88.92 μm/year) was significantly correlated with the slope of MP-3 retinal sensitivity at 8° radius (-0.62 decibels [dB]/year; Spearman's ρ = 0.31, P=0.03) and the slope of HFA retinal sensitivity at 8° radius (-0.60 dB/year; Spearman's ρ = 0.43, P < 0.005).

Conclusions

Both MP-3 and HFA values were cross sectionally well-correlated with EZ length in patients with patients; however, these associations became weaker in the longitudinal analysis. This highlights the need for researchers to explore additional or more sensitive parameters to better monitor RP progression.

Financial Disclosures

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

Diabetic retinopathy: New concepts of screening, monitoring, and interventions

The science of diabetes care has progressed to provide a better understanding of the oxidative and inflammatory lesions and pathophysiology of the neurovascular unit within the retina (and brain) that occur early in diabetes, even prediabetes. Screening for retinal structural abnormalities, has traditionally been performed by fundus examination or color fundus photography; however, these imaging techniques detect the disease only when there are sufficient lesions, predominantly hemorrhagic, that are recognized to occur late in the disease process after significant neuronal apoptosis and atrophy, as well as microvascular occlusion with alterations in vision. Thus, interventions have been primarily oriented toward the later-detected stages, and clinical trials, while demonstrating a slowing of the disease progression, demonstrate minimal visual improvement and modest reduction in the continued loss over prolonged periods. Similarly, vision measurement utilizing charts detects only problems of visual function late, as the process begins most often parafoveally with increasing number and progressive expansion, including into the fovea. While visual acuity has long been used to define endpoints of visual function for such trials, current methods reviewed herein are found to be imprecise. We review improved methods of testing visual function and newer imaging techniques with the recommendation that these must be utilized to discover and evaluate the injury earlier in the disease process, even in the prediabetic state. This would allow earlier therapy with ocular as well as systemic pharmacologic treatments that lower the and neuro-inflammatory processes within eye and brain. This also may include newer, micropulsed laser therapy that, if applied during the earlier cascade, should result in improved and often normalized retinal function without the adverse treatment effects of standard photocoagulation therapy.

Update on Clinical Trial Endpoints in Gene Therapy Trials for Inherited Retinal Diseases

Inherited retinal diseases (IRDs) encompass a wide spectrum of rare conditions characterized by diverse phenotypes associated with hundreds of genetic variations, often leading to progressive visual impairment and profound vision loss. Multiple natural history studies and clinical trials exploring gene therapy for various IRDs are ongoing. Outcomes for ophthalmic trials measure visual changes in three main categories-structural, functional, and patient-focused outcomes. Since IRDs may range from congenital with poor central vision from birth to affecting the peripheral retina initially and progressing insidiously with visual acuity affected late in the disease course, typical outcome measures such as central visual acuity and ocular coherence tomography (OCT) imaging of the macula may not provide adequate representation of therapeutic outcomes including alterations in disease course. Thus, alternative unique outcome measures are necessary to assess loss of peripheral vision, color vision, night vision, and contrast sensitivity in IRDs. These differences have complicated the assessment of clinical outcomes for IRD therapies, and the clinical trials for IRDs have had to design novel specialized endpoints to demonstrate treatment efficacy. As genetic engineering and gene therapy techniques continue to advance with growing investment from industry and accelerated approval tracks for orphan conditions, the clinical trials must continue to improve their assessments to demonstrate safety and efficacy of new gene therapies that aim to come to market. Here, we will provide an overview of the current gene therapy approaches, review various endpoints for measuring visual function, highlight those that are utilized in recent gene therapy trials, and provide an overview of stage 2 and 3 IRD trials through the second quarter of 2024.

Customized Visual Discrimination Digital Therapy According to Visual Field Defects in Chronic Stroke Patients

BACKGROUND AND PURPOSE

Visual perceptual learning (VPL) may improve visual field defects (VFDs) after chronic stroke, but the optimal training duration and location remain unknown. This prospective study aimed to determine the efficacy of 8 weeks of VFD-customized visual discrimination training in improving poststroke VFDs.

METHODS

Prospectively enrolled patients with poststroke VFDs initially received no training for 8 weeks (no-training phase). They subsequently underwent our customized VPL program that included orientation-discrimination tasks in individualized blind fields and central letter-discrimination tasks three times per week for 8 weeks (training phase). We analyzed the luminance detection sensitivity and deviation as measured using Humphrey visual field tests before and after the no-training and training phases. The vision-related quality of life was assessed at baseline and at a 16-week follow-up using the National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25).

RESULTS

Changes in mean total deviation (MTD) scores were greater during the training phase than during the no-training phase (defective hemifield, p=0.002; whole field, p=0.004). The MTD scores improved during the training phase (defective hemifield, p=0.004; whole field, p=0.016), but not during the no-training phase (defective hemifield, p=0.178; whole field, p=0.178). The difference between the improved and worsened areas (≥6 dB changes in luminance detection sensitivity) was greater during the training phase than during the no-training phase (p=0.009). The vision-specific social functioning subscore of the NEI-VFQ-25 improved after the 16-week study period (p=0.040).

CONCLUSIONS

Our 8-week VFD-customized visual discrimination training protocol may effectively improve VFDs and vision-specific social functioning in chronic stroke patients.

Correlations between the Michigan Retinal Degeneration Questionnaire and visual function parameters in patients with retinitis pigmentosa

PURPOSE

To validate the use of best-corrected visual acuity (BCVA), low-luminance visual acuity (LLVA), low-luminance deficit (LLD; the difference between BCVA and LLVA), mean macular sensitivity and fixation stability as parameters of vision-related quality of life based on the novel Michigan Retinal Degeneration Questionnaire (MRDQ) in retinitis pigmentosa (RP) patients.

METHODS

In this prospective cross sectional study, 30 patients with RP (47% female) were included with a median age of 41.0 years (interquartile range: 24.1-58.3 years). BCVA, LLVA and LLD were measured with Early Treatment Diabetic Retinopathy Study (ETDRS) charts. Mesopic microperimetry was performed to measure mean macular sensitivity and fixation stability. Patients completed a Dutch translation of the MRDQ which results in an experienced disability (Θ-)score of seven domains. Spearman's rank correlation was used.

RESULTS

BCVA correlated significantly to the MRDQ domain of central vision (r = 0.657; p < 0.001) and colour vision (r = 0.524; p = 0.003). Lower LLVA significantly correlated to higher experienced disability in the MRDQ domains for central vision (=0.550; p = 0.002) and contrast sensitivity (r = 0.502; p = 0.005). LLD was significantly correlated to the MRDQ domains of scotopic function (r = -0.484; p = 0.007) and mesopic peripheral function (r = -0.533; p = 0.002). Lower mean macular sensitivity was significantly associated with high experienced disability in all domains except for photosensitivity.

CONCLUSIONS

The majority of the MRDQ domains is strongly associated with visual function parameters. These findings show that visual function measurements, especially LLVA, LLD and mean macular sensitivity on microperimetry, reflect vision-related quality of life and can be used as relevant outcome measures in clinical trials for RP.

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.

Current Status of Clinical Trials Design and Outcomes in Retinal Gene Therapy

With the rapid expansion of methods encompassed by the term gene therapy, new trials exploring the safety and efficacy of these methods are initiated more frequently. As a result, important questions arise pertaining the design of these trials and patient participation. One of the most important aspects of any clinical trial is the ability to measure the trial's outcome in a manner that will reflect the effect of the treatment and allow its quantification, whether the trial is aimed at preservation or restoration of retinal cells (photoreceptors and others), vision, or both. Here we will review the existing methods for quantification of trial outcomes, stressing the importance of assessing the participant's visual function and not just visual acuity. We will also describe the key considerations in trial design. Finally, as patient safety remains the primary concern in any trial participation, we will outline the key principles in that regard.

A Long-Term Retrospective Natural History Study of EFEMP1-Associated Autosomal Dominant Drusen

Purpose

To analyze the natural history of EFEMP1-associated autosomal dominant drusen (ADD).

Methods

In this retrospective observational study of molecularly confirmed patients with ADD, data and retinal imaging were extracted from an in-house database. The main outcome measurements were best-corrected visual acuity (BCVA), refraction, and retinal imaging, including quantitative analyses of the outer nuclear layer (ONL) thickness and pigmented epithelium detachment area, as well as qualitative analyses.

Results

The study included 44 patients (34 females and 10 males). The mean ± SD age of symptom onset was 40.1 ± 6.59 years of age (range, 25-52). Fourteen patients were asymptomatic during their entire follow-up. The most common symptoms at presentation were reduced vision (70%) and distortion in central vision (53%). Most subjects were emmetropic. The mean BCVA (logMAR) at baseline was 0.27 ± 0.41 (range, -0.1 to 2.1) in right eyes and was 0.19 ± 0.32 (range, -0.2 to 1.3) in left eyes. After a mean follow-up of 7.9 years, BCVA was reduced to 0.59 ± 0.66 (range, -0.1 to 2.1) in right eyes and 0.5 ± 0.72 (range, -0.1 to 2.4) in left eyes, values that were significantly different than baseline (P < 0.0001 and P < 0.0014, respectively). Fifteen eyes showed active or inactive choroidal neovascularization (CNV). BCVA differed significantly (P = 0.0004) between eyes with and without CNV at a comparable mean age. The ONL had a slow rate of thinning longitudinally, which significantly correlated with BCVA.

Conclusions

Despite the late onset and relatively good prognosis of ADD, CNVs are more frequent than previously reported and are associated with a worse prognosis. Further research is necessary to elucidate gender associations.

ASSOCIATION OF MACULAR STRUCTURE WITH MICROPERIMETRY SENSITIVITY FOLLOWING VITRECTOMY FOR PROLIFERATE DIABETIC RETINOPATHY

PURPOSE

To evaluate macular sensitivity using microperimetry in patients with proliferate diabetic retinopathy following vitrectomy and to investigate the relationship between the sensitivity and foveal microstructures with optical coherence tomography/angiography.

METHODS

Eighty-four eyes of 84 patients with proliferative diabetic retinopathy, who were indicated for vitrectomy, had no intraocular surgery history 3 months preoperatively, and were able to ensure fundus examination after the vitrectomy, were included. A logMAR best-corrected visual acuity, macular sensitivity of microperimetry, macular retinal thickness, and macular vessel perfusion using optical coherence tomography/angiography were examined at 1 week, 1 month, and 3 months postoperatively.

RESULTS

The logMAR best-corrected visual acuity and mean macular sensitivity of patients with proliferative diabetic retinopathy improved postoperatively (P < 0.05). There was a significant correlation between best-corrected visual acuity and mean sensitivity (P < 0.05). Postoperative mean macular sensitivity was significantly correlated with outer retinal thickness in the 0 to 6 mm macular area (P < 0.05) and also significantly correlated with deep capillary plexus perfusion (P < 0.05). Fixation stability and mean macular sensitivity did not show any correlation with glycated hemoglobin, triglyceride, serum total cholesterol, carbamide, and creatinine and duration of diabetes mellitus (P > 0.05).

CONCLUSION

Postoperative mean macular sensitivity was significantly correlated with outer retinal thickness and deep capillary plexus perfusion for patients with proliferative diabetic retinopathy. The authors found that the visual performance of patients can be evaluated by the outer retinal thickness and deep capillary plexus perfusion, so optical coherence tomography/angiography examination can be an important prognostic factor for visual performance in patients.Clinical Trial Registration: This trial is registered with the Chinese Clinical Trial Registry (http://www.chictr.org.cn; Registration No.: ChiCTR2100043399).

Morphological and Functional Correlations in Acute Central Serous Chorioretinopathy

PURPOSE

We evaluate morphological and functional correlations in patients with acute central serous chorioretinopathy (CSC).

METHODS

A prospective study was conducted on 50 patients with an acute CSC episode lasting less than 3 months. At baseline, assessments included optical coherence tomography (OCT), best-corrected visual acuity (BCVA), contrast sensitivity (CS), microperimetry (MP), and multifocal electroretinography (mfERG). A correlation analysis between OCT morphological parameters (maximal subretinal fluid height (SRF), central retinal thickness (CRT), and macular volume (MV)) and functional parameters was conducted on the affected eye for each patient.

RESULTS

Among the morphological parameters, SRF showed the strongest correlations with functional parameters (r absolute value range = 0.10-0.70). Weak correlations were observed between BCVA and morphological parameters (r absolute value range = 0.14-0.26). Average retinal sensitivity (MP-A) was the functional parameter displaying the most robust negative correlation with morphological parameters (r absolute value range = 0.61-0.70). In contrast, average contrast sensitivity (CS-A) and mfERG average amplitude density in the first (mfERG-A1) and second (mfERG-A2) ring showed weak to moderate (r absolute value range = 0.35-0.56) yet statistically significantly nonzero correlations.

CONCLUSIONS

SRF and CRT could serve as the most representative morphological proxies for visual function deficit in acute CSC patients. Retinal sensitivity, as measured by MP, may be superior to BCVA in clinical research studies or when an in-depth visual function evaluation is needed.

Effectiveness of Mp-3 Microperimetric Biofeedback Fixation Training For Low Vision Rehabilitation in Patients Treated With Corticosteroid Ivt in Retinal Vein Occlusions

Background

The success of fixation training using microperimetric biofeedback (MP-3 MBFT) in the realm of visual rehabilitation for patients with central vision loss caused by macular pathologies is well established. This study aimed to assess the effectiveness and safety of visual rehabilitation with microperimetric biofeedback in consolidating the benefits obtained, with the goal of reducing the need for repeated intravitreal injections (IVT). Specifically, the focus is on the eyes of patients with central vision loss treated with slow-release corticosteroid IVT following retinal venous thrombosis (RVO), aiming to enhance and maintain postoperative efficacy.

Methods

This retrospective review involved the examination of 44 eyes affected by macular edema due to RVO associated with central vision loss. Patients were divided into two groups, with only one undergoing ten sessions of 10-minute visual rehabilitation with a microperimeter (MP-3 MBFT) after IVT over a period of 20 weeks.

Results

All the treated patients demonstrated good tolerance to the procedure, with no reported complications. A comparison of best-corrected visual acuity (BCVA), retinal sensitivity recorded with a microperimeter, and pre-IVT fixation stability revealed statistically significant improvements at the end of the first month after IVT. However, the treatment group continued to exhibit superior and more enduring results at four months post-IV.

Conclusion

The synergistic use of MP-3 MBFT rehabilitation after IVT with slow-release corticosteroids has proven particularly effective in improving BCVA and long-term fixation stability. This led to a significant reduction in the number of required IVTs, with no related adverse events. The authors argue that biofeedback utilization represents a noninvasive therapeutic option devoid of contraindications and easy to implement and that it positively contributes to the overall patient experience regarding quality of life in advanced stages of macular diseases.

The Natural History of Retinal Sensitivity Loss in Diabetic Macular Ischemia over One Year Evaluated by Microperimetry

Background/Objectives: This one-year prospective observational study, conducted at two centers, aimed to report the natural history of retinal sensitivity (RS) loss in diabetic macular ischemia (DMI). Methods: Patients with stable-treated proliferative diabetic retinopathy (PDR) were recruited if there was evidence of DMI on optical coherence tomography angiography, defined as a foveal avascular zone ≥ 0.5 mm2 or parafoveal capillary dropout ≥ 1 quadrant. The minimal visual acuity required for performing microperimetry (MP) was ≥54 Early Treatment Diabetic Retinopathy Study letters (Snellen equivalent 20/80). The overall RS (oRS) and pointwise sensitivity (PWS) within the 3 × 3 mm macula were assessed at baseline and twelve months. A value <25 decibels (dB) was defined as impaired RS, and a decrease of 2 and 7 dB was regarded as mild and severe loss, respectively. Results: A total of 88 patients (97 eyes) were included. No statistically significant MP changes were detected at one year. However, 10% of the cohort lost oRS ≥ 2 dB, and 73% lost ≥2 dB PWS in ≥5 loci, whereas 1% lost oRS ≥ 7 dB, and 4% lost ≥7 dB PWS in ≥5 loci. The foveola and temporal parafovea were the most vulnerable to severe RS loss. Compared to their counterpart, eyes with baseline oRS ≥ 25 dB had significantly more RS loss in the macula and superior parafovea (55% versus 32% and 53% versus 28%, both p = 0.01). Conclusions: Rather than oRS loss, ≥2 dB loss in PWS in ≥5 loci is a more feasible outcome measure for clinical trials in DMI.

In-Depth Retinal Sensitivity Assessment With the MP3 Type S Microperimeter: A Methods Study

Purpose

Retinal sensitivity is frequently listed as an end point in clinical trials, often with long working practices. The purpose of this methods study was to provide a new workflow and reduced test time for in-depth characterization of retinal sensitivity.

Methods

A workflow for the MP3-S microperimeter with detailed functional characterization of the retina under photopic, mesopic, and scotopic conditions was evaluated. Grids of 32 and 28 test positions for photopic/mesopic and scotopic, respectively, were tested in 12 healthy individuals and compared with an established 68-point grid for test time, mean sensitivity (MS), and bivariate contour ellipse area (BCEA).

Results

The mean test time (range; ±SD) was 10.5 minutes (8.4-14.9; ±2.0) in the 68-point grid and 4.3 minutes (3.8-5.0; ±0.4) in the 32-point grid, which was significantly different (P < 0.0001). The mean of difference in test time (±SD; 95% confidence interval) was 6.1 minutes (±2.0; 4.6-7.6). MS and BCEA were significantly correlated between grids (r = 0.89 and 0.74; P = 0.0005 and 0.014, respectively). Mean test time of subjects who underwent the full protocol (n = 4) was 2.15 hours.

Conclusions

The protocol suggested herein appears highly feasible with in-depth characterization of retinal function under different testing conditions and in a short test time.

Translational Relevance

The protocol described herein allows for characterization of the retina under different testing conditions and in a short test time, which is relevant due to its potential for patient prognostication and follow-up in clinical settings and also given its increasing role as a clinical trial end point.

ATXN7-Related Cone-Rod Dystrophy: The Integrated Functional Evaluation of the Cerebellum (CERMOI) Study

Importance

Reliable biomarkers with diagnostic and prognostic values are needed for upcoming gene therapy trials for spinocerebellar ataxias.

Objective

To identify ophthalmological biomarkers in a sample of spinocerebellar ataxia type 7 (SCA7) carriers.

Design, Setting, and Participants

This article presents baseline data from a cross-sectional natural history study conducted in Paris, France, reference centers for rare diseases from May 2020 to April 2021. Data were analyzed from September to December 2022. Fifteen adult ATXN7 pathogenic expansion carriers (9 with preataxia and 6 with ataxia) were included, all with a Scale for the Assessment and Rating of Ataxia (SARA) score of 15 of 40 or lower. Patients were recruited at the Paris Brain Institute, and all contacted patients accepted to participate in the study.

Main Outcomes and Measures

Three visits (baseline, 6 months, and 12 months) were planned, including neurological examination (SARA and Composite Cerebellar Functional Severity Score), ophthalmological examination (best-corrected visual acuity, microperimetry, full-field electroretinogram, optical coherence tomography, and fundus autofluorescence imaging), and neurofilament light chain (NfL) measurements. Here we report the baseline ophthalmic data from the cohort and determine whether there is a correlation between disease scores and ophthalmic results.

Results

Among the 15 included SCA7 carriers (median [range] age, 38 [18-60] years; 8 women and 7 men), 12 displayed cone or cone-rod dystrophy, with the number of CAG repeats correlating with disease severity (ρ, 0.73, 95% CI, 0.34 to 0.90; P < .001). Two patients with cone-rod dystrophy exhibited higher repeat numbers and greater ataxia scores (median [range] SARA score, 9 [7-15]) compared to those with only cone dystrophy (median [range] SARA score, 2 [0-5]). A correlation emerged for outer nuclear layer thickness with SARA score (ρ, -0.88; 95% CI, -0.96 to -0.59; P < .001) and NfL levels (ρ, -0.87; 95% CI, -0.86 to 0.96; P < .001). Moreover, ataxia severity was correlated with visual acuity (ρ: 0.89; 95% CI, 0.68 to 0.96; P < .001) and retinal sensitivity (ρ, -0.88; 95% CI, -0.96 to 0.59; P < .001).

Conclusions and Relevance

In this cross-sectional study, retinal abnormalities were found at preataxic stages of the disease. Most of the carriers presented with cone dystrophy and preserved rod function. The outer nuclear layer thickness correlated with SARA score and plasma NfL levels suggesting nuclear layer thickness to be a biomarker of disease severity. These findings contribute to understanding the dynamics of SCA7-related retinal dystrophy and may help lay the groundwork for future therapeutic intervention monitoring and clinical trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT04288128.

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.

Morphological and functional parameters in X-linked retinoschisis patients-A multicentre retrospective cohort study

Introduction

X-linked retinoschisis (XLRS) is a potential target for gene supplementation approaches. To establish potential structural and functional endpoints for clinical trials, a comprehensive understanding of the inter-eye symmetry, relationship between structural and functional parameters, and disease progression is vital.

Methods

In this retrospective multicentre study, 118 eyes of 59 XLRS patients with RS1 mutations were assessed. Information from center databases included: RS1 variant; age at presentation; best-corrected visual acuity (BCVA), central retinal thickness (CRT), macular volume (MV) at presentation and at the last follow up; full-field electroretinogram (ERG) findings; presence of peripheral retinoschisis and complications (vitreous hemorrhage, retinal detachment); treatment with systemic or topical carbonic anhydrase inhibitors (CAI).

Results

Inter-eye symmetry revealed strong correlation in CRT (r = 0.77; p < 0.0001) and moderate correlations in MV (r = 0.51, p < 0.0001) and BCVA (r = 0.49; p < 0.0001). Weak or no correlations were observed between BCVA and structural parameters (CRT, MV). Peripheral retinoschisis was observed in 40 (68%), retinal detachment in 9 (15%), and vitreous hemorrhage in 5 (8%) patients, respectively. Longitudinal examinations (mean, 4.3 years) showed no BCVA changes; however, a reduction of the CRT (p = 0.02), and MV (p = 0.01) was observed. Oral and/or topical CAI treatment did not significantly alter the CRT (p = 0.34).

Discussion

The XLRS phenotype demonstrates a strong CRT symmetry between the eyes within individual patients and stable BCVA over several years. BCVA exhibits a weak correlation with the morphological parameters of retinal thickness (CRT MV). In our cohort, longitudinal functional changes were not significant, likely attributed to the short average follow-up period. Furthermore, CAI treatment didn't influence both morphological and functional outcomes.

Inter and intradevice assessment of microperimetry testing in aging eyes

Microperimetry (MP) is a psychometric examination combining retinal imaging and functional sensitivity testing with an increasing importance due to its potential use as clinical study outcome. We investigated the repeatability of pointwise retinal sensitivity (PWS) on the most advanced commercially available MP devices under their standard setting in a healthy aging population. Two successive MP examinations on both MP-3 (NIDEK CO., Ltd., Gamagori, Japan) and MAIA (CenterVue S.p.A. (iCare), Padova, Italy) were performed on healthy aging subjects in a randomized order. PWS repeatability was analysed for different macular regions and age groups using Bland-Altmann coefficients of repeatability (CoR). A total of 3600 stimuli from 20 healthy individuals with a mean age of 70 (11) years were included. Mean CoR in dB were ±4.61 for MAIA and ±4.55 for MP-3 examinations. A lower repeatability (p=0.005) was detected in the central millimetre on MAIA examinations. Higher subject age was associated with a lower repeatability of PWS on both devices (both p=0.003). Intra-device correlation was good (MAIA: 0.79 [0.76-0.81]; MP-3: 0.72 [0.68-0.76]) whereas a moderate mean inter-device correlation (0.6 [0.55-0.65]) could be detected. In conclusion, older subjects and the foveal region are associated with a worse pointwise repeatability.

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.

Validating Trend-Based End Points for Neuroprotection Trials in Glaucoma

Purpose

The purpose of this study was to evaluate the power of trend-based visual field (VF) progression end points against long-term development of event-based end points accepted by the US Food and Drug Administration (FDA).

Methods

One eye from 3352 patients with ≥10 24-2 VFs (median = 11 years) follow-up were analyzed. Two FDA-compatible criteria were applied to these series to label "true-progressed" eyes: ≥5 locations changing from baseline by more than 7 dB (FDA-7) or by more than the expected test-retest variability (GPA-like) in 2 consecutive tests. Observed rates of progression (RoP) were used to simulate trial-like series (2 years) randomly assigned (1000 times) to a "placebo" or a "treatment" arm. We simulated neuroprotective "treatment" effects by changing the proportion of "true progressed" eyes in the two arms. Two trend-based methods for mean deviation (MD) were assessed: (1) linear mixed model (LMM), testing average difference in RoP between the two arms, and (2) time-to-progression (TTP), calculated by linear regression as time needed for MD to decline by predefined cutoffs from baseline. Power curves with 95% confidence intervals were calculated for trend and event-based methods on the simulated series.

Results

The FDA-7 and GPA-like progression was achieved by 45% and 55% of the eyes in the clinical database. LMM and TTP had similar power, significantly superior to the event-based methods, none of which reached 80% power. All methods had a 5% false-positive rate.

Conclusions

The trend-based methods can efficiently detect treatment effects defined by long-term FDA-compatible progression.

Translational Relevance

The assessment of the power of trend-based methods to detect clinically relevant progression end points.

Subretinal timrepigene emparvovec in adult men with choroideremia: a randomized phase 3 trial

Choroideremia is a rare, X-linked retinal degeneration resulting in progressive vision loss. A randomized, masked, phase 3 clinical trial evaluated the safety and efficacy over 12 months of follow-up in adult males with choroideremia randomized to receive a high-dose (1.0 × 1011 vector genomes (vg); n = 69) or low-dose (1.0 × 1010 vg; n = 34) subretinal injection of the AAV2-vector-based gene therapy timrepigene emparvovec versus non-treated control (n = 66). Most treatment-emergent adverse events were mild or moderate. The trial did not meet its primary endpoint of best-corrected visual acuity (BCVA) improvement. In the primary endpoint analysis, three of 65 participants (5%) in the high-dose group, one of 34 (3%) participants in the low-dose group and zero of 62 (0%) participants in the control group had ≥15-letter Early Treatment Diabetic Retinopathy Study (ETDRS) improvement from baseline BCVA at 12 months (high dose, P = 0.245 versus control; low dose, P = 0.354 versus control). As the primary endpoint was not met, key secondary endpoints were not tested for significance. In a key secondary endpoint, nine of 65 (14%), six of 35 (18%) and one of 62 (2%) participants in the high-dose, low-dose and control groups, respectively, experienced ≥10-letter ETDRS improvement from baseline BCVA at 12 months. Potential opportunities to enhance future gene therapy studies for choroideremia include optimization of entry criteria (more preserved retinal area), surgical techniques and clinical endpoints. EudraCT registration: 2015-003958-41 .

MICROPERIMETRY IN FOVEAL-SPARING ATROPHIC LATE-ONSET RETINAL DEGENERATION

PURPOSE

To understand the baseline and longitudinal microperimetry characteristics in foveal-sparing atrophic late-onset retinal degeneration.

METHOD

Prospective, cross-sectional, longitudinal study in which patients from the retina clinics of two academic teaching hospitals were included. Mesopic microperimetry was performed using a Nidek MP-1 micro-perimeter. Mean total, foveal, inner ring, and outer ring sensitivities were analyzed.

RESULTS

A total of 20 eyes from 10 patients had baseline data. The subset of 10 eyes from five patients had follow-up data. The mean baseline macular sensitivity was 10.02 dB (± 5.26) with findings showing symmetry between both eyes. In the follow-up cohort, there was a significant loss of outer ring (0.83 dB per year; P = 0.0001), inner ring (0.67 dB per year; P = 0.034), and foveal sensitivity (0.92 dB loss per year; P = 0.015), whereas the mean sensitivity decreased significantly (0.66 dB per year; P = 0.0008) at 4-year follow-up. The drop in mean sensitivity was associated with significant increases in the number of deep scotoma points (6.20, P = 0.037) and a decrease in the number of normal points (-6.30, P = 0.022).

CONCLUSION

Microperimetry is a useful tool for macular function follow-up to measure disease progression in late-onset retinal degeneration.

Female carriers of X-linked inherited retinal diseases - Genetics, diagnosis, and potential therapies

Inherited retinal diseases (IRDs) are a group of heterogeneous conditions that cause progressive vision loss, typically due to monogenic mutations. Female carriers of X-linked IRDs have a single copy of the disease-causing gene, and therefore, may exhibit variable clinical signs that vary from near normal retina to severe disease and vision loss. The relationships between individual genetic mutations and disease severity in X-linked carriers requires further study. This review summarises the current literature surrounding the spectrum of disease seen in female carriers of choroideremia and X-linked retinitis pigmentosa. Various classification systems are contrasted to accurately grade retinal disease. Furthermore, genetic mechanisms at the early embryonic stage are explored to potentially explain the variability of disease seen in female carriers. Future research in this area will provide insight into the association between genotype and retinal phenotypes of female carriers, which will guide in the management of these patients. This review acknowledges the importance of identifying which patients may be at high risk of developing severe symptoms, and therefore should be considered for emerging treatments, such as retinal gene therapy.

Microperimetry as an Outcome Measure in RPGR-associated Retinitis Pigmentosa Clinical Trials

Purpose

To explore which microperimetry sensitivity index (pointwise sensitivity, mean sensitivity, and volume sensitivity) is suitable as a microperimetry outcome measure in patients with X-linked RPGR-associated retinitis pigmentosa (RP).

Methods

Microperimetry data from patients with RPGR-associated RP were collected and analyzed retrospectively. Fourteen participants completed triplicate microperimetry testing, across 2 consecutive days for the repeatability analyses. Longitudinal data was obtained from 13 participants who completed microperimetry testing at two separate visits.

Results

The test-retest coefficients of repeatability (CoR) for pointwise sensitivity were ±9.5 dB and ±9.3 dB, in the right and left eyes, respectively. The mean sensitivity CoR for the right and left eyes was ±0.7 dB and ±1.3 dB. Volume sensitivity CoR was ±144.5 dB*deg2 and ±324.2 dB*deg2 for the right and left eyes, respectively. The mean sensitivities were positively skewed toward zero in those with a high number of nonseeing points (arbitrarily assigned to -1.0 dB) and just seen points (0.0 dB). Volume sensitivities were unaffected by the averaging effects of skewed data.

Conclusions

Clinical trials should report population-specific test-retest variability to determine a clinically significant change. Pointwise sensitivity indices should be used with caution as outcome measures in clinical trials owing to high levels of test-retest variability. Global indices seem to be less prone to variability. Volume sensitivity indices seem to be superior for use in RPGR-associated RP clinical trials compared with mean sensitivity because they are unaffected by the averaging effects of highly skewed data.

Translational Relevance

Careful selection of sensitivity indices (VA) is required when using microperimetry as a clinical trial outcome measure.

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.

The Importance of Natural History Studies in Inherited Retinal Diseases

Natural history studies of inherited retinal diseases (IRDs) play a critical role in the design and implementation of treatment trials. Study objectives ideally encompass (1) understanding the time course and pattern of disease progression, (2) within genotypic and phenotypic subtypes of patient populations, and (3) characterizing a range of measures of vision function, retinal structure, and functional vision that may serve as endpoints. In rare disease, data quality standards are paramount to optimizing smaller sample sizes, including a prospective, standardized, and longitudinal approach to data collection. Multicenter studies additionally facilitate strength in numbers and generalizability, and multidisciplinary collaboration ensures a holistic approach to study design and knowledge-building. Dissemination of natural history study results, data sets, and lessons learned will stimulate further innovation and progress in IRD therapeutic research, including setting up future trial designs for their best chance of success.

Repeatability and Discriminatory Power of Chart-Based Visual Function Tests in Individuals With Age-Related Macular Degeneration: A MACUSTAR Study Report

Question

Under multicenter, multiexaminer conditions, do simple chart-based assessments of visual function (VF) have sufficient repeatability and discrimination in people with age-related macular degeneration (AMD) to be considered as measures for future clinical trial end points?

Findings

In this cross-sectional study including 245 people with AMD and 56 healthy, age-similar control individuals, best-corrected visual acuity, low-luminance visual acuity, Moorfields Acuity Test, contrast sensitivity, and International Reading Speed Test had adequate repeatability but limited power to discriminate between no AMD and intermediate AMD (iAMD).

Meaning

The findings suggest that the chart-based tests included in this study perform sufficiently well to be considered as potential measures for clinical trial end points; their prognostic power to predict conversion from iAMD to late AMD needs to be examined with longitudinal data.

Importance

There is a need for validated clinical end points that are reliably able to quantify potential therapeutic effects of future treatments targeting age-related macular degeneration (AMD) before the onset of serious visual impairment.

Objective

To assess the reliability and discriminatory power of 5 simple chart-based visual function (VF) tests as potential measures for clinical trial end points with regulatory and patient-access intention in intermediate AMD (iAMD).

Design, Setting, and Participants

This international noninterventional study took place at 18 tertiary ophthalmology departments across Europe. Participants were recruited between April 2018 and March 2020 and were identified during routine clinical review. Participants with no AMD and early AMD were recruited from hospital staff, friends, and family of participants with AMD and via referrals from community ophthalmologists and optometrists. The repeatability and discriminatory power of 5 simple chart-based assessments of VF (best-corrected visual acuity [BCVA], low-luminance visual acuity [LLVA], Moorfields Acuity Test [MAT], Pelli-Robson Contrast Sensitivity [CS], and International Reading Speed Test [IReST]) were assessed in a repeated-measures design. VF assessments were performed on day 0 and day 14. Participants with early AMD, iAMD, late AMD, and no AMD were recruited.

Main Outcomes and Measures

Intraclass correlation coefficients (ICCs) and Bland-Altman 95% limits of agreement (LoA) were computed to assess repeatability. Area under the receiver operating characteristic curves (AUCs) determined the discriminatory ability of all measures to classify individuals as having no AMD or iAMD and to differentiate iAMD from its neighboring disease states.

Results

A total of 301 participants (mean [SD] age, 71 [7] years; 187 female participants [62.1%]) were included in the study. Thirty-four participants (11.3%) had early AMD, 168 (55.8%) had iAMD, 43 (14.3%) had late AMD, and 56 (18.6%) had no AMD. ICCs for all VF measures ranged between 0.88 and 0.96 when all participants were considered, indicating good to excellent repeatability. All measures displayed excellent discrimination between iAMD and late AMD (AUC, 0.92-0.99). Early AMD was indistinguishable from iAMD on all measures (AUC, 0.54-0.64). CS afforded the best discrimination between no AMD and iAMD (AUC, 0.77). Under the same conditions, BCVA, LLVA, and MAT were fair discriminators (AUC, 0.69-0.71), and IReST had poor discrimination (AUC, 0.57-0.61).

Conclusions and Relevance

BCVA, LLVA, MAT, CS, and IReST had adequate repeatability in this multicenter, multiexaminer setting but limited power to discriminate between no AMD and iAMD. The prognostic power of these variables to predict conversion from iAMD to late AMD is being examined in the ongoing longitudinal part of the MACUSTAR study.

Central Visual Function and Genotype-Phenotype Correlations in PDE6A-Associated Retinitis Pigmentosa

Purpose

Autosomal recessive retinitis pigmentosa (arRP) can be caused by mutations in the phosphodiesterase 6A (PDE6A) gene. Here, we describe the natural course of disease progression with respect to central retinal function (i.e., visual acuity, contrast sensitivity, and color vision) and establish a detailed genotype-–phenotype correlation.

Methods

Forty-four patients (26 females; mean age ± SD, 43 ± 13 years) with a confirmed genetic diagnosis of PDE6A-associated arRP underwent comprehensive ophthalmological examinations including best-corrected visual acuity (BCVA) with Early Treatment Diabetic Retinopathy Study charts, contrast sensitivity (CS) with Pelli–Robson charts at distances of 3 m and 1 m, and color vision testing using Roth 28-Hue and Panel D-15 saturated color cups.

Results

The most frequently observed variants were c.998+1G>A/p.?, c.304C>A/p.R102S, and c.2053G>A/p.V685M. Central retinal function in patients homozygous for variant c.304C>A/p.R102S was better when compared to patients homozygous for variant c.998+1G>A/p.?, although the former were older at baseline. Central retinal function was similar in patients homozygous for variant c.304C>A/p.R102S and patients heterozygous for variants c.304C>A/p.R102S and c.2053G>A/p.V685M, although the latter were younger at baseline. Annual decline rates in central retinal function were small.

Conclusions

We conclude that the severity of the different disease-causing PDE6A mutations in humans with respect to central visual function may be ranked as follows: c.2053G>A/p.V685M in homozygous state (most severe) > c.998+1G>A/p.? in homozygous state > c.304C>A/p.R102S and c.2053G>A/p.V685M in compound-heterozygous state > c.304C>A/p.R102S in homozygous state (mildest). The assessment of treatment efficacy in interventional trials will remain challenging due to small annual decline rates in central retinal function.