Quantification of Fundus Autofluorescence Features in a Molecularly Characterized Cohort of More Than 3000 Inherited Retinal Disease Patients from the United Kingdom

Purpose

To quantify relevant fundus autofluorescence (FAF) image features cross-sectionally and longitudinally in a large cohort of inherited retinal diseases (IRDs) patients.

Design

Retrospective study of imaging data (55-degree blue-FAF on Heidelberg Spectralis) from patients.

Participants

Patients with a clinical and molecularly confirmed diagnosis of IRD who have undergone FAF 55-degree imaging at Moorfields Eye Hospital (MEH) and the Royal Liverpool Hospital (RLH) between 2004 and 2019.

Methods

Five FAF features of interest were defined: vessels, optic disc, perimacular ring of increased signal (ring), relative hypo-autofluorescence (hypo-AF) and hyper-autofluorescence (hyper-AF). Features were manually annotated by six graders in a subset of patients based on a defined grading protocol to produce segmentation masks to train an AI model, AIRDetect, which was then applied to the entire imaging dataset.

Main Outcome Measures

Quantitative FAF imaging features including area in mm 2 and vessel metrics, were analysed cross-sectionally by gene and age, and longitudinally to determine rate of progression. AIRDetect feature segmentation and detection were validated with Dice score and precision/recall, respectively.

Results

A total of 45,749 FAF images from 3,606 IRD patients from MEH covering 170 genes were automatically segmented using AIRDetect. Model-grader Dice scores for disc, hypo-AF, hyper-AF, ring and vessels were respectively 0.86, 0.72, 0.69, 0.68 and 0.65. The five genes with the largest hypo-AF areas were CHM , ABCC6 , ABCA4 , RDH12 , and RPE65 , with mean per-patient areas of 41.5, 30.0, 21.9, 21.4, and 15.1 mm 2 . The five genes with the largest hyper-AF areas were BEST1 , CDH23 , RDH12 , MYO7A , and NR2E3 , with mean areas of 0.49, 0.45, 0.44, 0.39, and 0.34 mm 2 respectively. The five genes with largest ring areas were CDH23 , NR2E3 , CRX , EYS and MYO7A, with mean areas of 3.63, 3.32, 2.84, 2.39, and 2.16 mm 2 . Vessel density was found to be highest in EFEMP1 , BEST1 , TIMP3 , RS1 , and PRPH2 (10.6%, 10.3%, 9.8%, 9.7%, 8.9%) and was lower in Retinitis Pigmentosa (RP) and Leber Congenital Amaurosis genes. Longitudinal analysis of decreasing ring area in four RP genes ( RPGR, USH2A, RHO, EYS ) found EYS to be the fastest progressor at -0.18 mm 2 /year.

Conclusions

We have conducted the first large-scale cross-sectional and longitudinal quantitative analysis of FAF features across a diverse range of IRDs using a novel AI approach.

IQCB1 (NPHP5)-retinopathy: Clinical and Genetic Characterization and Natural History

PURPOSE

To describe the clinical and genetic features, and explore the natural history of retinopathy associated with IQCB1 variants in children and adults with retinopathy.

DESIGN

Retrospective cohort study at a single tertiary care referral center.

METHODS

The study recruited 19 patients with retinopathy, harboring likely disease-causing variants in IQCB1. Demographic data and clinical presentation, best corrected visual acuity (BCVA), fundus appearance, optical coherence tomography (OCT) and autofluorescence features, electroretinography (ERG) and molecular genetics are reported.

RESULTS

Ten patients had BCVA better than 1.0 LogMAR, and BCVA remained stable till the last review. Seven patients had a vision of hand movements or worse in at least one eye at presentation. There was no correlation found between age of onset and severity of vision loss. Nine patients (47.4%) had a diagnosis of end-stage renal failure at presentation. The other 10 patients (52.6%) had a diagnosis of non-syndromic IQCB1-retinopathy and maintained normal renal function until the last follow-up. The mean age at diagnosis of renal failure was 26.3 ±19.8 years. OCT showed ellipsoid zone (EZ) disruption with foveal sparing in 8/13 patients. All patients had stable OCT findings. Full-field ERGs in four adults revealed a severe cone-rod dystrophy and three children had extinguished ERGs. We identified 17 IQCB1 variants, all predicted to cause loss of function.

CONCLUSION

IQCB1-retinopathy is a severe early-onset cone-rod dystrophy. The dissociation between severely decreased retinal function and relative preservation of retinal structure over a wide age window makes the disease a candidate for gene therapy.

"Congenital Stationary Night Blindness: Structure, Function and Genotype - Phenotype Correlations in a cohort of 122 patients."

OBJECTIVE

To examine the molecular causes of Schubert-Bornschein (S-B) congenital stationary night blindness (CSNB), clinically characterize in detail, and assess genotype-phenotype correlations for retinal function and structure.

DESIGN

Retrospective, longitudinal, single center case series.

PARTICIPANTS

122 patients with S-B CSNB attending Moorfields Eye Hospital, United Kingdom.

METHODS

All case notes, results of molecular genetic testing, and optical coherence tomography (OCT) were reviewed.

MAIN OUTCOME MEASURES

Molecular genetics, presenting complaints, rates of nystagmus, nyctalopia, photophobia, strabismus, color vision defects and spherical error of refraction (SER). Retinal thickness, outer nuclear layer thickness (ONL) and ganglion cell layer + inner plexiform layer (GCL+IPL) thickness from OCT imaging.

RESULTS

X-linked (CACNA1F and NYX) and autosomal recessive (TRPM1, GRM6, GPR179 and CABP4) genotypes were identified. The mean reported age of onset was 4.94 ± 8.99 years. Over the follow-up period, 95.9% of patients reported reduced visual acuity (VA), half had nystagmus and 64.7% reported nyctalopia. Incomplete CSNB (iCSNB) patients more frequently had nystagmus and photophobia. Nyctalopia was similar for iCSNB and complete CSNB (cCSNB). Color vision data was limited but more defects were found in iCSNB. None of these clinical differences met statistical significance. There was no significant difference between groups in VA, with a mean of 0.46 LogMAR, and remained stable over the course of follow-up. cCSNB patients, specifically those with NYX and TRPM1 variants, were more myopic. CACNA1F patients showed the largest refractive variability and the CABP4 patient was hyperopic. No significant differences were found in OCT structural analysis during the follow-up period.

CONCLUSIONS

Retinal structure in CSNB is stationary and no specific genotype - structure correlates were identified. VA appears to be relatively stable, with rare instances of progression.

Stargardt macular dystrophy and therapeutic approaches

Stargardt macular dystrophy (Stargardt disease; STGD1; OMIM 248200) is the most prevalent inherited macular dystrophy. STGD1 is an autosomal recessive disorder caused by multiple pathogenic sequence variants in the large ABCA4 gene (OMIM 601691). Major advances in understanding both the clinical and molecular features, as well as the underlying pathophysiology, have culminated in many completed, ongoing and planned human clinical trials of novel therapies.The aims of this concise review are to describe (1) the detailed phenotypic and genotypic characteristics of the disease, multimodal imaging findings, natural history of the disease, and pathogenesis, (2) the multiple avenues of research and therapeutic intervention, including pharmacological, cellular therapies and diverse types of genetic therapies that have either been investigated or are under investigation and (3) the exciting novel therapeutic approaches on the translational horizon that aim to treat STGD1 by replacing the entire 6.8 kb ABCA4 open reading frame.

PREVALENCE AND CLINICAL FEATURES OF RADIAL FUNDUS AUTOFLUORESCENCE IN HIGH MYOPIC WOMEN

PURPOSE

To determine the prevalence and characteristics of radial fundus autofluorescence (FAF) in highly myopic women.

METHODS

This was a retrospective, observational case study to determine the prevalence of radial FAF in the ultra-widefield FAF images in women. The clinical characteristics of these patients were evaluated.

RESULTS

Fifteen of 1,935 (0.78%) highly myopic women were found to have radial FAF. Their mean age was 36.6 ± 25.6 years, and their mean best-corrected visual acuity was 0.3 ± 0.42 logMAR units. The mean axial length (AL) was 28.8 ± 2.8 mm. Among the 15 cases, eight did not have pigmentary changes and seven had pigmentary changes in the ultra-widefield FAF images. The women with the pigmentary changes were significantly older ( P = 0.021), had poorer BCVA ( P = 0.001), and had longer ALs ( P = 0.002). The visual fields and electroretinograms were worse in the eyes with pigmentary changes.

CONCLUSION

The prevalence of radial FAF was 0.78% in women with high myopia. These patients might have mutations in the RPGR or RP2 genes and can develop high myopia and retinitis pigmentosa. Ultra-widefield FAF images should be examined in all highly myopic patients for early detection of radial FAF, and myopia prevention and genetic counseling for possible genetic therapy are recommended.

Genetics, Clinical Characteristics, and Natural History of PDE6B-Associated Retinal Dystrophy

PURPOSE

To analyze the clinical characteristics, natural history, and genetics of PDE6B-associated retinal dystrophy.

DESIGN

Retrospective, observational cohort study.

METHODS

Review of medical records and retinal imaging, including fundus autofluorescence (FAF) imaging and spectral-domain optical coherence tomography (SD-OCT) of patients with molecularly confirmed PDE6B-associated retinal dystrophy in a single tertiary referral center. Genetic results were reviewed, and the detected variants were assessed.

RESULTS

Forty patients (80 eyes) were identified and evaluated longitudinally. The mean age (±SD, range) was 42.1 years (± 19.0, 10-86) at baseline, with a mean follow-up time of 5.2 years. Twenty-nine (72.5%) and 27 (67.5%) patients had no or mild visual acuity impairment at baseline and last visit, respectively. Best-corrected visual acuity (BCVA) was 0.56 ± 0.72 LogMAR (range -0.12 to 2.80) at baseline and 0.63 ± 0.73 LogMAR (range 0.0-2.80) at the last visit. BCVA was symmetrical in 87.5% of patients. A hyperautofluorescent ring was observed on FAF in 48 and 46 eyes at baseline and follow-up visit, respectively, with a mean area of 7.11 ± 4.13 mm2 at baseline and mean of 6.13 ± 3.62 mm2 at the follow-up visit. Mean horizontal ellipsoid zone width at baseline was 1946.1 ± 917.2 µm, which decreased to 1763.9 ± 827.9 µm at follow-up. Forty-four eyes had cystoid macular edema at baseline (55%), and 41 eyes (51.3%) at follow-up. There were statistically significant changes during the follow-up period in terms of BCVA and the ellipsoid zone width. Genetic analysis identified 43 variants in the PDE6B gene, including 16 novel variants.

CONCLUSIONS

This study details the natural history of PDE6B-retinopathy in the largest cohort to date. Most patients had mild to no BCVA loss, with slowly progressive disease, based on FAF and OCT metrics. There is a high degree of disease symmetry and a wide window for intervention.

ISCEV and IPS guideline for the full-field stimulus test (FST)

The full-field stimulus test (FST) is a psychophysical technique designed for the measurement of visual function in low vision. The method involves the use of a ganzfeld stimulator, as used in routine full-field electroretinography, to deliver full-field flashes of light. This guideline was developed jointly by the International Society for Clinical Electrophysiology of Vision (ISCEV) and Imaging and Perimetry Society (IPS) in order to provide technical information, promote consistency of testing and reporting, and encourage convergence of methods for FST. It is intended to aid practitioners and guide the formulation of FST protocols, with a view to future standardisation.

RBP3-Retinopathy-Inherited High Myopia and Retinal Dystrophy: Genetic Characterization, Natural History, and Deep Phenotyping

PURPOSE

To examine the genetic and clinical features and the natural history of RBP3-associated retinopathy.

DESIGN

Multi-center international, retrospective, case series of adults and children, with moleculraly confirmed RBP3-asociated retinopathy.

METHODS

The genetic, clinical, and retinal imaging findings, including optical coherence tomography (OCT) and fundus autofluorescence (FAF), were investigated both cross-sectionally and longitudinally. The results of international standard full-field electroretinography (ERG) and pattern electroretinography (PERG) were reviewed.

RESULTS

We ascertained 12 patients (5 female and 7 male) from 10 families (4 patients previously reported). Ten novel disease-causing RBP3 variants were identified. Ten patients were homozygous. The mean age (±SD, range) of the group was 21.4 years (±19.1, 2.9-60.5 years) at baseline evaluation. All 12 patients were highly myopic, with a mean spherical equivalent of -16.0D (range, -7.0D to -33.0D). Visual acuity was not significantly different between eyes, and no significant anisometropia was observed. Mean best-corrected visual acuity (BCVA) was 0.48 logMAR (SD, ±0.29; range, 0.2-1.35 logMAR); at baseline. Eleven patients had longitudinal BCVA assessment, with a mean BCVA of 0.46 logMAR after a mean follow-up of 12.6 years. All patients were symptomatic with reduced VA and myopia by the age of 7 years old. All patients had myopic fundi and features in keeping with high myopia on OCT, including choroidal thinning. The 4 youngest patients had no fundus pigmentary changes, with the rest of the patients presenting with a variable degree of mid-peripheral pigmentation and macular changes. FAF showed variable phenotypes, ranging from areas of increased signal to advanced atrophy in older patients. OCT showed cystoid macular edema at presentation in 3 patients, which persisted during follow-up in 2 patients and resolved to atrophy in the third patient. The ERGs were abnormal in 9 of 9 cases, revealing variable relative involvement of rod and cone photoreceptors with additional milder dysfunction post-phototransduction in some. All but 1 patient had PERG evidence of macular dysfunction, which was severe in most cases.

CONCLUSIONS

This study details the clinical and functional phenotype of RBP3-retinopathy in the largest cohort reported to date. RBP3-retinopathy is a disease characterized by early onset, slow progression over decades, and high myopia. The phenotypic spectrum and natural history as described herein has prognostic and counseling implications. RBP3-related disease should be considered in children with high myopia and retinal dystrophy.

Phenotyping and genotyping inherited retinal diseases: Molecular genetics, clinical and imaging features, and therapeutics of macular dystrophies, cone and cone-rod dystrophies, rod-cone dystrophies, Leber congenital amaurosis, and cone dysfunction syndromes

Inherited retinal diseases (IRD) are a leading cause of blindness in the working age population and in children. The scope of this review is to familiarise clinicians and scientists with the current landscape of molecular genetics, clinical phenotype, retinal imaging and therapeutic prospects/completed trials in IRD. Herein we present in a comprehensive and concise manner: (i) macular dystrophies (Stargardt disease (ABCA4), X-linked retinoschisis (RS1), Best disease (BEST1), PRPH2-associated pattern dystrophy, Sorsby fundus dystrophy (TIMP3), and autosomal dominant drusen (EFEMP1)), (ii) cone and cone-rod dystrophies (GUCA1A, PRPH2, ABCA4, KCNV2 and RPGR), (iii) predominant rod or rod-cone dystrophies (retinitis pigmentosa, enhanced S-Cone syndrome (NR2E3), Bietti crystalline corneoretinal dystrophy (CYP4V2)), (iv) Leber congenital amaurosis/early-onset severe retinal dystrophy (GUCY2D, CEP290, CRB1, RDH12, RPE65, TULP1, AIPL1 and NMNAT1), (v) cone dysfunction syndromes (achromatopsia (CNGA3, CNGB3, PDE6C, PDE6H, GNAT2, ATF6), X-linked cone dysfunction with myopia and dichromacy (Bornholm Eye disease; OPN1LW/OPN1MW array), oligocone trichromacy, and blue-cone monochromatism (OPN1LW/OPN1MW array)). Whilst we use the aforementioned classical phenotypic groupings, a key feature of IRD is that it is characterised by tremendous heterogeneity and variable expressivity, with several of the above genes associated with a range of phenotypes.

Best Vitelliform Macular Dystrophy Natural History Study Report 1: Clinical Features and Genetic Findings

PURPOSE

To analyze the genetic findings, clinical spectrum, and natural history of Best vitelliform macular dystrophy (BVMD) in a cohort of 222 children and adults.

DESIGN

Single-center retrospective, consecutive, observational study.

PARTICIPANTS

Patients with a clinical diagnosis of BVMD from pedigrees with a likely disease-causing monoallelic sequence variant in the BEST1 gene.

METHODS

Data were extracted from electronic and physical case notes. Electrophysiologic assessment and molecular genetic testing were analyzed.

MAIN OUTCOME MEASURES

Molecular genetic test findings and clinical findings including best-corrected visual acuity (BCVA), choroidal neovascularization (CNV) rates, and electrophysiologic parameters.

RESULTS

Two hundred twenty-two patients from 141 families were identified harboring 69 BEST1 variants. Mean age at presentation was 26.8 years (range, 1.3-84.8 years) and most patients (61.5%) demonstrated deterioration of central vision. Major funduscopic findings included 128 eyes (30.6%) with yellow vitelliform lesions, 78 eyes (18.7%) with atrophic changes, 49 eyes (11.7%) with fibrotic changes, 48 eyes (11.5%) with mild pigmentary changes, and 43 eyes (10.3%) showing a vitelliruptive appearance. Mean BCVA was 0.37 logarithm of the minimum angle of resolution (logMAR; Snellen equivalent, 20/47) for the right eye and 0.33 logMAR (Snellen equivalent, 20/43) for the left eye at presentation, with a mean annual loss rate of 0.013 logMAR and 0.009 logMAR, respectively, over a mean follow-up of 9.7 years. Thirty-seven patients (17.3%) received a diagnosis of CNV over a mean follow-up of 8.0 years. Eyes with CNV that received treatment with an anti-vascular endothelial growth factor (VEGF) agent showed better mean BCVA compared with eyes that were not treated with an anti-VEGF agent (0.28 logMAR [Snellen equivalent, 20/38] vs. 0.62 logMAR [Snellen equivalent, 20/83]). Most eyes exhibited a hyperopic refractive error (78.7%), and 13 patients (6.1%) received a diagnosis of amblyopia. Among the 3 most common variants, p.(Ala243Val) was associated with a later age of onset, better age-adjusted BCVA, and less advanced Gass stages compared with p.(Arg218Cys) and p.(Arg218His).

CONCLUSIONS

BVMD shows a wide spectrum of phenotypic variability. The disease is very slowly progressive, and the observed phenotype-genotype correlations allow for more accurate prognostication and counselling.

FINANCIAL DISCLOSURE(S)

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

Distinct Clinical Effects of Two RP1L1 Hotspots in East Asian Patients With Occult Macular Dystrophy (Miyake Disease): EAOMD Report 4

Purpose

To characterize the clinical effects of two RP1L1 hotspots in patients with East Asian occult macular dystrophy (OMD).

Methods

Fifty-one patients diagnosed with OMD harboring monoallelic pathogenic RP1L1 variants (Miyake disease) from Japan, South Korea, and China were enrolled. Patients were classified into two genotype groups: group A, p.R45W, and group B, missense variants located between amino acids (aa) 1196 and 1201. The clinical parameters of the two genotypes were compared, and deep learning based on spectral-domain optical coherence tomographic (SD-OCT) images was used to distinguish the morphologic differences.

Results

Groups A and B included 29 and 22 patients, respectively. The median age of onset in groups A and B was 14.0 and 40.0 years, respectively. The median logMAR visual acuity of groups A and B was 0.70 and 0.51, respectively, and the survival curve analysis revealed a 15-year difference in vision loss (logMAR 0.22). A statistically significant difference was observed in the visual field classification, but no significant difference was found in the multifocal electroretinographic classification. High accuracy (75.4%) was achieved in classifying genotype groups based on SD-OCT images using machine learning.

Conclusions

Distinct clinical severities and morphologic phenotypes supported by artificial intelligence-based classification were derived from the two investigated RP1L1 hotspots: a more severe phenotype (p.R45W) and a milder phenotype (1196-1201 aa). This newly identified genotype-phenotype association will be valuable for medical care and the design of therapeutic trials.

Rationale and protocol paper for the Asia Pacific Network for inherited eye diseases

PURPOSE

There are major gaps in our knowledge of hereditary ocular conditions in the Asia-Pacific population, which comprises approximately 60% of the world's population. Therefore, a concerted regional effort is urgently needed to close this critical knowledge gap and apply precision medicine technology to improve the quality of lives of these patients in the Asia-Pacific region.

DESIGN

Multi-national, multi-center collaborative network.

METHODS

The Research Standing Committee of the Asia-Pacific Academy of Ophthalmology and the Asia-Pacific Society of Eye Genetics fostered this research collaboration, which brings together renowned institutions and experts for inherited eye diseases in the Asia-Pacific region. The immediate priority of the network will be inherited retinal diseases (IRDs), where there is a lack of detailed characterization of these conditions and in the number of established registries.

RESULTS

The network comprises 55 members from 35 centers, spanning 12 countries and regions, including Australia, China, India, Indonesia, Japan, South Korea, Malaysia, Nepal, Philippines, Singapore, Taiwan, and Thailand. The steering committee comprises ophthalmologists with experience in consortia for eye diseases in the Asia-Pacific region, leading ophthalmologists and vision scientists in the field of IRDs internationally, and ophthalmic geneticists.

CONCLUSIONS

The Asia Pacific Inherited Eye Disease (APIED) network aims to (1) improve genotyping capabilities and expertise to increase early and accurate genetic diagnosis of IRDs, (2) harmonise deep phenotyping practices and utilization of ontological terms, and (3) establish high-quality, multi-user, federated disease registries that will facilitate patient care, genetic counseling, and research of IRDs regionally and internationally.

Gene Therapy for Inherited Retinal Diseases: From Laboratory Bench to Patient Bedside and Beyond

This comprehensive review provides a thorough examination of inherited retinal diseases (IRDs), encompassing their classification, genetic underpinnings, and the promising landscape of gene therapy trials. IRDs, a diverse group of genetic conditions causing vision loss through photoreceptor cell death, are explored through various angles, including inheritance patterns, gene involvement, and associated systemic disorders. The focal point is gene therapy, which offers hope for halting or even reversing the progression of IRDs. The review highlights ongoing clinical trials spanning retinal cell replacement, neuroprotection, pharmacological interventions, and optogenetics. While these therapies hold tremendous potential, they face challenges like timing optimization, standardized assessment criteria, inflammation management, vector refinement, and raising awareness among vision scientists. Additionally, translating gene therapy success into widespread adoption and addressing cost-effectiveness are crucial challenges to address. Continued research and clinical trials are essential to fully harness gene therapy's potential in treating IRDs and enhancing the lives of affected individuals.

KCNV2-associated retinopathy: genotype-phenotype correlations - KCNV2 study group report 3

BACKGROUND/AIMS

To investigate genotype-phenotype associations in patients with KCNV2 retinopathy.

METHODS

Review of clinical notes, best-corrected visual acuity (BCVA), molecular variants, electroretinography (ERG) and retinal imaging. Subjects were grouped according to the combination of KCNV2 variants-two loss-of-function (TLOF), two missense (TM) or one of each (MLOF)-and parameters were compared.

RESULTS

Ninety-two patients were included. The mean age of onset (mean±SD) in TLOF (n=55), TM (n=23) and MLOF (n=14) groups was 3.51±0.58, 4.07±2.76 and 5.54±3.38 years, respectively. The mean LogMAR BCVA (±SD) at baseline in TLOF, TM and MLOF groups was 0.89±0.25, 0.67±0.38 and 0.81±0.35 for right, and 0.88±0.26, 0.69±0.33 and 0.78±0.33 for left eyes, respectively. The difference in BCVA between groups at baseline was significant in right (p=0.03) and left eyes (p=0.035). Mean outer nuclear layer thickness (±SD) at baseline in TLOF, MLOF and TM groups was 37.07±15.20 µm, 40.67±12.53 and 40.38±18.67, respectively, which was not significantly different (p=0.85). The mean ellipsoid zone width (EZW) loss (±SD) was 2051 µm (±1318) for patients in the TLOF, and 1314 µm (±965) for MLOF. Only one patient in the TM group had EZW loss at presentation. There was considerable overlap in ERG findings, although the largest DA 10 ERG b-waves were associated with TLOF and the smallest with TM variants.

CONCLUSIONS

Patients with missense alterations had better BCVA and greater structural integrity. This is important for patient prognostication and counselling, as well as stratification for future gene therapy trials.

CERKL-Associated Retinal Dystrophy: Genetics, Phenotype, and Natural History

PURPOSE

To analyze the clinical characteristics, natural history, and genetics of CERKL-associated retinal dystrophy in the largest series to date.

DESIGN

Multicenter retrospective cohort study.

SUBJECTS

Forty-seven patients (37 families) with likely disease-causing CERKL variants.

METHODS

Review of clinical notes, ophthalmic images, and molecular diagnosis from 2 international centers.

MAIN OUTCOME MEASURES

Visual function, retinal imaging, and characteristics were evaluated and correlated.

RESULTS

The mean age at the first visit was 29.6 ± 13.9 years, and the mean follow-up time was 9.1 ± 7.4 years. The most frequent initial symptom was central vision loss (40%), and the most common retinal feature was well-demarcated areas of macular atrophy (57%). Seventy-seven percent of the participants had double-null genotypes, and 64% had electrophysiological assessment. Among the latter, 53% showed similar severity of rod and cone dysfunction, 27% revealed a rod-cone, 10% a cone-rod, and 10% a macular dystrophy dysfunction pattern. Patients without double-null genotypes tended to have fewer pigment deposits and included a higher proportion of older patients with a relatively mild electrophysiological phenotype. Longitudinal analysis showed that over half of the cohort lost 15 ETDRS letters or more in ≥ 1 eye during the first 5 years of follow-up.

CONCLUSIONS

The phenotype of CERKL-retinal dystrophy is broad, encompassing isolated macular disease to severe retina-wide involvement, with a range of functional phenotypes, generally not fitting in the rod-cone/cone-rod dichotomy. Disease onset is often earlier, with more severe retinal degenerative changes and photoreceptor dysfunction, in nullizygous cases.

FINANCIAL DISCLOSURE(S)

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

Occult Macular Dysfunction Syndrome: Identification of Multiple Pathologies in a Clinical Spectrum of Macular Dysfunction with Normal Fundus in East Asian Patients: EAOMD Report No. 5

Occult macular dystrophy (OMD) is the most prevalent form of macular dystrophy in East Asia. Beyond RP1L1, causative genes and mechanisms remain largely uncharacterised. This study aimed to delineate the clinical and genetic characteristics of OMD syndrome (OMDS). Patients clinically diagnosed with OMDS in Japan, South Korea, and China were enrolled. The inclusion criteria were as follows: (1) macular dysfunction and (2) normal fundus appearance. Comprehensive clinical evaluation and genetic assessment were performed to identify the disease-causing variants. Clinical parameters were compared among the genotype groups. Seventy-two patients with OMDS from fifty families were included. The causative genes were RP1L1 in forty-seven patients from thirty families (30/50, 60.0%), CRX in two patients from one family (1/50, 2.0%), GUCY2D in two patients from two families (2/50, 4.0%), and no genes were identified in twenty-one patients from seventeen families (17/50, 34.0%). Different severities were observed in terms of disease onset and the prognosis of visual acuity reduction. This multicentre large cohort study furthers our understanding of the phenotypic and genotypic spectra of patients with macular dystrophy and normal fundus. Evidently, OMDS encompasses multiple Mendelian retinal disorders, each representing unique pathologies that dictate their respective severity and prognostic patterns.

Functional Characteristics of Diverse PAX6 Mutations Associated with Isolated Foveal Hypoplasia

The human fovea is a specialized pit structure in the central retina. Foveal hypoplasia is a condition where the foveal pit does not fully develop, and it is associated with poor vision. Autosomal dominant isolated foveal hypoplasia (FVH1) is a rare condition of foveal hypoplasia (FH) that lacks any other ocular manifestations. FVH1 is associated with hypomorphic mutations in the PAX6 gene that encodes a sequence-specific DNA-binding transcription factor for morphogenesis and evolution of the eye. We report our findings in 17 patients with PAX6 mutations associated with FVH1 or FH with aniridia and corneal opacities. Patients with three mutations, p.V78E, p.V83F and p.R128H, in the C-terminal subdomain of the paired domain (CTS) consistently have severe FH. Luciferase assays for a single reporter containing a representative PAX6 binding site indicated that the transcriptional activities of these mutations were significantly reduced, comparable to that of the truncation mutation of p.G65Rfs*5. Patients with p.P20S in the N-terminal subdomain of the paired domain, and a patient with p.N365K in the proline-serine-threonine-rich domain (PSTD) had mild FH. A patient with p.Q255L in the homeodomain had severe FH. The P20S and Q255L mutants did not affect the transcriptional activity. Mutant N365K has a retained DNA-binding activity but a reduced transcriptional activity, due to a low PSTD transactivation. These findings demonstrated that mutations associated with FVH1 underlie a functional divergence between DNA-binding ability and transcriptional activity. We conclude that a wide range of mutations in the PAX6 gene is not limited to the CST region and are responsible for FVH1.

Can artificial intelligence accelerate the diagnosis of inherited retinal diseases? Protocol for a data-only retrospective cohort study (Eye2Gene)

INTRODUCTION

Inherited retinal diseases (IRD) are a leading cause of visual impairment and blindness in the working age population. Mutations in over 300 genes have been found to be associated with IRDs and identifying the affected gene in patients by molecular genetic testing is the first step towards effective care and patient management. However, genetic diagnosis is currently slow, expensive and not widely accessible. The aim of the current project is to address the evidence gap in IRD diagnosis with an AI algorithm, Eye2Gene, to accelerate and democratise the IRD diagnosis service.

METHODS AND ANALYSIS

The data-only retrospective cohort study involves a target sample size of 10 000 participants, which has been derived based on the number of participants with IRD at three leading UK eye hospitals: Moorfields Eye Hospital (MEH), Oxford University Hospital (OUH) and Liverpool University Hospital (LUH), as well as a Japanese hospital, the Tokyo Medical Centre (TMC). Eye2Gene aims to predict causative genes from retinal images of patients with a diagnosis of IRD. For this purpose, 36 most common causative IRD genes have been selected to develop a training dataset for the software to have enough examples for training and validation for detection of each gene. The Eye2Gene algorithm is composed of multiple deep convolutional neural networks, which will be trained on MEH IRD datasets, and externally validated on OUH, LUH and TMC.

ETHICS AND DISSEMINATION

This research was approved by the IRB and the UK Health Research Authority (Research Ethics Committee reference 22/WA/0049) 'Eye2Gene: accelerating the diagnosis of IRDs' Integrated Research Application System (IRAS) project ID: 242050. All research adhered to the tenets of the Declaration of Helsinki. Findings will be reported in an open-access format.

Progression of Stargardt Disease as Determined by Fundus Autofluorescence Over a 24-Month Period (ProgStar Report No. 17)

PURPOSE

To estimate the progression rate of atrophic lesions in Stargardt disease derived from fundus autofluorescence (FAF).

DESIGN

International, multicenter, prospective cohort study.

METHODS

A total of 259 participants aged ≥6 years with disease-causing variants in the ABCA4 gene were enrolled from 9 centers and followed over a 24-month period. FAF images were obtained every 6 months, and areas of definitely decreased autofluorescence (DDAF) and decreased autofluorescence (DAF) were quantified. Progression rates were estimated from linear mixed models with time as the independent variable.

RESULTS

A total of 488 study eyes of 259 participants (88.8% with both eyes) were enrolled and images from 432 eyes were followed for 24 months. The overall estimated progression of DDAF was 0.74 mm²/y (95% CI 0.64-0.85, P < .0001) and that of DAF was 0.64 mm²/y (95% CI 0.57-0.71) over a 24-month period in univariate analysis. Growth rates were strongly dependent on baseline lesion area. After square root transformation, the DDAF growth rate was not dependent on baseline lesion radius (P = .11), whereas the DAF growth rate was dependent (P < .0001). Genotype was not found to significantly impact the growth rate of DDAF or DAF lesions.

CONCLUSIONS

FAF may serve as a convenient monitoring tool and suitable end point for interventional clinical trials that aim to slow disease progression. DDAF and DAF lesion sizes at baseline are strong predicting factors for lesion area growth and can be partially accounted for by square root transformation.

CRB1-Associated Retinal Dystrophies: Genetics, Clinical Characteristics, and Natural History

PURPOSE

To analyze the clinical characteristics, natural history, and genetics of CRB1-associated retinal dystrophies.

DESIGN

Multicenter international retrospective cohort study.

METHODS

Review of clinical notes, ophthalmic images, and genetic testing results of 104 patients (91 probands) with disease-causing CRB1 variants. Macular optical coherence tomography (OCT) parameters, visual function, fundus characteristics, and associations between variables were the main outcome measures.

RESULTS

The mean age of the cohort at the first visit was 19.8 ± 16.1 (median 15) years, with a mean follow-up of 9.6 ± 10 years. Based on history, imaging, and clinical examination, 26 individuals were diagnosed with retinitis pigmentosa (RP; 25%), 54 with early-onset severe retinal dystrophy / Leber congenital amaurosis (EOSRD/LCA; 52%), and 24 with macular dystrophy (MD; 23%). Severe visual impairment was most frequent after 40 years of age for patients with RP and after 20 years of age for EOSRD/LCA. Longitudinal analysis revealed a significant difference between baseline and follow-up best-corrected visual acuity in the 3 subcohorts. Macular thickness decreased in most patients with EOSRD/LCA and MD, whereas the majority of patients with RP had increased perifoveal thickness.

CONCLUSIONS

A subset of individuals with CRB1 variants present with mild, adult-onset RP. EOSRD/LCA phenotype was significantly associated with null variants, and 167_169 deletion was exclusively present in the MD cohort. The poor OCT lamination may have a degenerative component, as well as being congenital. Disease symmetry and reasonable window for intervention highlight CRB1 retinal dystrophies as a promising target for trials of novel therapeutics.

A Japanese boy with Bardet-Biedl syndrome caused by a novel homozygous variant in the ARL6 gene who was initially diagnosed with retinitis punctata albescens: A case report

PURPOSE

Bardet-Biedl Syndrome (BBS) is an autosomal recessive systemic disorder characterized by retinitis pigmentosa, polydactyly, obesity, intellectual disability, renal impairments, and hypogonadism. The purpose of this study was to determine the ocular characteristics of a boy with BBS caused by a novel homozygous variant in the ARL6 (alternative named BBS3) gene who had been originally diagnosed with retinitis punctata albescens.

METHODS

This was an observational case study. The patient underwent ophthalmological examinations, electroretinography, and genetic analyses using whole-exome sequencing.

RESULTS

A 7-year-old boy was examined in our hospital with complaints of a progressive reduction of his visual acuity and night blindness in both eyes. There was no family history of eye diseases and no consanguineous marriage. Fundus examinations showed numerous white spots in the deep retina and retinal pigment epithelium. Fundus autofluorescence showed hypofluorescence consistent with these spots. Both the scotopic and photopic components of the full-field electroretinographies were non-detectable. Based on these clinical findings, this boy was suspected to have retinitis punctata albescens. Subsequent genetic testing using whole-exome sequencing revealed a novel homozygous variants in the ARL6/BBS3 gene (NM_001278293.3:c.528G>A, (p.Trp176Ter)). A systemic examination by the pediatric department revealed that this boy had a history of a surgical excision of polydactyly on his left foot when he was born, and that he was mildly obese. There were no prominent intellectual or gonadal dysfunctions, no craniofacial or dental abnormalities, no congenital heart disease, and no hearing impairment. He was then clinically and genetically diagnosed with BBS.

CONCLUSION AND IMPORTANCE

In children with night blindness and progressive visual dysfunction, it is important for ophthalmologists to consult clinical geneticists and pediatricians to rule out the possibility of systemic diseases such as BBS.

Genetic characterization of 1210 Japanese pedigrees with inherited retinal diseases by whole-exome sequencing

Inherited retinal diseases (IRDs) comprise a phenotypically and genetically heterogeneous group of ocular disorders that cause visual loss via progressive retinal degeneration. Here, we report the genetic characterization of 1210 IRD pedigrees enrolled through the Japan Eye Genetic Consortium and analyzed by whole exome sequencing. The most common phenotype was retinitis pigmentosa (RP, 43%), followed by macular dystrophy/cone- or cone-rod dystrophy (MD/CORD, 13%). In total, 67 causal genes were identified in 37% (448/1210) of the pedigrees. The first and second most frequently mutated genes were EYS and RP1, associated primarily with autosomal recessive (ar) RP, and RP and arMD/CORD, respectively. Examinations of variant frequency in total and by phenotype showed high accountability of a frequent EYS missense variant (c.2528G>A). In addition to the two known EYS founder mutations (c.4957dupA and c.8805C>G) of arRP, we observed a frequent RP1 variant (c.5797C>T) in patients with arMD/CORD.

A recurrent variant in LIM2 causes an isolated congenital sutural/lamellar cataract in a Japanese family

Background

Genetically determined cataract is both clinically and molecularly highly heterogeneous. Here, we have identified a heterozygous variant in the lens integral membrane protein LIM2, the second most abundant protein in the lens, responsible for congenital sutural/lamellar cataract in a three-generation Japanese family.

Methods

Whole exome sequencing (WES) was undertaken in one affected and one unaffected individual from a family with autosomal dominant congenital cataract to establish the underlying genetic basis.

Results

A recurrent missense variant LIM2: c.388C>T; p.R130C was identified and found to co-segregate with disease. In addition, one variant COL11A1:c.3788C>T of unknown significance (VUS) was also identified.

Conclusions

We report a variant in LIM2 causing an isolated autosomal-dominant congenital sutural/lamellar cataract in a Japanese family. This is the first report of a LIM2 variant in the Japanese population. Hence, we expand the mutation spectrum of LIM2 variants in different ethnic groups.

Clinical course of a Japanese girl with Leber congenital amaurosis associated with a novel nonsense pathogenic variant in NMNAT1: a case report and mini review

   Leber congenital amaurosis (LCA), although rare, is one of the most severe forms of early-onset inherited retinal dystrophy (IRD). Here, we review the molecular genetics and phenotypic characteristics of patients with NMNAT1-associated IRD. The longitudinal clinical and molecular findings of a Japanese girl diagnosed with LCA associated with pathogenic variants in NMNAT1 c.648delG, (p.Trp216Ter*) and c.709C>T (p.Arg237Cys) have been described to highlight the salient clinical features of NMNAT1-associated IRD.

Visual Field Characteristics in East Asian Patients With Occult Macular Dystrophy (Miyake Disease): EAOMD Report No. 3

Purpose

The purpose of this study was to investigate the perimetric features and their associations with structural and functional features in patients with RP1L1-associated occult macular dystrophy (OMD; i.e. Miyake disease).

Methods

In this international, multicenter, retrospective cohort study, 76 eyes of 38 patients from an East Asian cohort of patients with RP1L1-associated OMD were recruited. Visual field tests were performed using standard automated perimetry, and the patients were classified into three perimetric groups based on the visual field findings: central scotoma, other scotoma (e.g. paracentral scotoma), and no scotoma. The association of the structural and functional findings with the perimetric findings was evaluated.

Results

Fifty-four eyes (71.1%) showed central scotoma, 14 (18.4%) had other scotomata, and 8 (10.5%) had no scotoma. Central scotoma was mostly noted in both eyes (96.3%) and within the central 10 degrees (90.7%). Among the three perimetric groups, there were significant differences in visual symptoms, best-corrected visual acuity (BCVA), and structural phenotypes (i.e. severity of photoreceptor changes). The central scotoma group showed worse BCVA often with severe structural abnormalities (96.3%) and a pathogenic variant of p.R45W (72.2%). The multifocal electroretinogram (mfERG) groups largely corresponded with the perimetric groups; however, 8 (10.5%) of 76 eyes showed mfERG abnormalities preceding typical central scotoma.

Conclusions

The patterns of scotoma with different clinical severity were first identified in occult macular dystrophy, and central scotoma, a severe pattern, was most frequently observed. These perimetric patterns were associated with the severity of BCVA, structural phenotypes, genotype, and objective functional characteristics which may precede in some cases.

Longitudinal Changes of Fixation Stability and Location Within 24 Months in Stargardt Disease: ProgStar Report No. 16

PURPOSE

Stargardt disease type 1 (STGD1) is the most common macular dystrophy. The assessment of fixation describes an important dimension of visual function, but data on its progression over time are limited. We present longitudinal changes and investigate its usefulness for clinical trials.

DESIGN

International, multicenter, prospective cohort study.

METHODS

Included were 239 individuals with genetically confirmed STGD1 (one or more disease-causing ATP binding cassette subfamily A member 4 [ABCA4] variant). We determined the fixation stability (FS) using 1 SD of the bivariate contour ellipse area (1 SD-BCEA) and fixation location (FL) using the eccentricity of fixation from the fovea during five study visits every 6 months.

RESULTS

At baseline, 239 patients (105 males [44%]) and 459 eyes, with a median age of 32 years, were included. The baseline mean logBCEA was 0.70 ± 1.41 log deg² and the mean FL was 6.25° ± 4.40°. Although the mean logBCEA did not monotonically increase from visit to visit, the overall yearly increase in the logBCEA was 0.124 log deg² (95% CI, 0.063-0.185 log deg²). The rate of change was not different between the 2 years but increased faster in eyes without flecks outside of the vascular arcades and depended on baseline logBCEA. FL did not change statistically significantly over time.

CONCLUSIONS

Fixation parameters are unlikely to be sensitive outcome measures for clinical trials in STGD1 but may provide useful ancillary information in selected cases to longitudinally describe and understand an eye's visual function.

A Japanese boy with double diagnoses of 2p15p16.1 microdeletion syndrome and RP2-associated retinal disorder

2p15p16.1 microdeletion syndrome is a recently recognized congenital disorder characterized by developmental delay and dysmorphic features. RP2-associated retinal disorder (RP2-RD) is an X-linked inherited retinal disease with a childhood onset caused by a loss-of-function variant in the RP2 gene. Here, we describe a 14-year-old boy with double diagnoses of 2p15p16.1 microdeletion syndrome and RP2-RD. The recurrence risk of each condition and the indication for potential therapeutic options for RP2-RD are discussed.

Machine Learning Algorithms to Detect Subclinical Keratoconus: Systematic Review

BACKGROUND

Keratoconus is a disorder characterized by progressive thinning and distortion of the cornea. If detected at an early stage, corneal collagen cross-linking can prevent disease progression and further visual loss. Although advanced forms are easily detected, reliable identification of subclinical disease can be problematic. Several different machine learning algorithms have been used to improve the detection of subclinical keratoconus based on the analysis of multiple types of clinical measures, such as corneal imaging, aberrometry, or biomechanical measurements.

OBJECTIVE

The aim of this study is to survey and critically evaluate the literature on the algorithmic detection of subclinical keratoconus and equivalent definitions.

METHODS

For this systematic review, we performed a structured search of the following databases: MEDLINE, Embase, and Web of Science and Cochrane Library from January 1, 2010, to October 31, 2020. We included all full-text studies that have used algorithms for the detection of subclinical keratoconus and excluded studies that did not perform validation. This systematic review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) recommendations.

RESULTS

We compared the measured parameters and the design of the machine learning algorithms reported in 26 papers that met the inclusion criteria. All salient information required for detailed comparison, including diagnostic criteria, demographic data, sample size, acquisition system, validation details, parameter inputs, machine learning algorithm, and key results are reported in this study.

CONCLUSIONS

Machine learning has the potential to improve the detection of subclinical keratoconus or early keratoconus in routine ophthalmic practice. Currently, there is no consensus regarding the corneal parameters that should be included for assessment and the optimal design for the machine learning algorithm. We have identified avenues for further research to improve early detection and stratification of patients for early treatment to prevent disease progression.

X-Linked Retinoschisis: Deep Phenotyping and Genetic Characterization

PURPOSE

To examine the genetic and clinical features in children and adults with X-linked retinoschisis (XLRS).

DESIGN

Single-center consecutive, retrospective, observational study.

PARTICIPANTS

Adults and children with molecularly confirmed XLRS followed up between 1999 and 2020.

METHODS

Analysis of genetic, clinical, and retinal imaging findings, including OCT and fundus autofluorescence (FAF), cross-sectionally and longitudinally, was performed.

MAIN OUTCOMES MEASURES

RS1, variants, type of variants and phenotype correlations, age of onset, complications rates and types, fundoscopy findings, OCT metrics, FAF patterns, correlations including between best corrected visual acuity (BCVA) and age, and OCT characteristics.

RESULTS

One hundred thirty-two male patients were identified harboring 66 retinoschisin 1 variants, with 7 being novel. The mean age at onset was 16.5 years (range, 0-58 years). Seventy-one patients (71/75 [94.7%]) were symptomatic at presentation; all had decreased best-corrected visual acuity (BCVA). Funduscopy findings were symmetric in 104 patients (104/108 [96.3%]), with the most common finding being macular schisis (82.4%), whereas peripheral retinoschisis was present in 38.9% and macular atrophy was present in 11.1%. Twenty patients (18.5%) demonstrated complications (vitreous hemorrhage, retinal detachment, or both). Mean BCVA was 0.65 logarithm of the minimum angle of resolution (logMAR; Snellen equivalent, 20/89) in the right eye and 0.64 logMAR (Snellen equivalent, 20/87) in the left eye. Mean BCVA change over a mean interval of 6.7 years was 0.04 and 0.01 logMAR for right and left eyes, respectively. A normal FAF pattern was identified in 16 of 106 eyes (15.1%); 45 eyes (42.5%) showed a spoke-wheel pattern, 13 eyes (12.3%) showed foveal hyperautofluorescence, and 18 eyes (17.0%) showed a central reduction in signal. In total, 14 patients demonstrated evidence of progression on FAF over time. On OCT, foveoschisis was observed in 172 eyes (172/215 [80%]), parafoveal schisis was observed in 171 eyes (171/215 [79.5%]), and foveal atrophy was observed in 44 eyes (44/215 [20.5%]). Cystoid changes were localized to the inner nuclear layer (172/181 eyes [95%]), the outer nuclear layer (97/181 [53.6%]), and the ganglion cell layer (92/181 [50.8%]). Null variants were associated with worse final BCVA and aforementioned complications.

CONCLUSIONS

X-linked retinoschisis is highly phenotypically variable, but with relative foveal and BCVA preservation until late adulthood, allowing more accurate prognostication. The slowly (often minimally) progressive disease course may pose a challenge in identification of early end points for therapeutic trials aimed at altering the kinetics of degeneration.

The Progression of Stargardt Disease Using Volumetric Hill of Vision Analyses Over 24 Months: ProgStar Report No.15

PURPOSE

To report the yearly rate of change in macular function in patients with Stargardt disease type 1 (STGD1) over 24 months and to establish a new volumetric visual function index for use in clinical trials investigating the efficacy on retinal sensitivity.

METHODS

Design: International, multicenter, prospective cohort study with 5 study visits every 6 months over 24 months.

PARTICIPANTS

A total of 233 individuals with genetically confirmed STGD1 (≥1 disease-causing ABCA4 variant).

MAIN OUTCOME MEASURES

The total volume (V_TOT) beneath the sensitivity surface of a 3-D model of the hill of vision and mean sensitivity (MS) derived from mesopic microperimetry performed with a white stimulus. Changes of V_TOT over time and its correlation with the ABCA4 genotype and baseline features.

RESULTS

At baseline, 440 eyes (233 patients) with a mean (SD) age of 33.7 (15.0) years, mean (SD) visual acuity of 46.08 (16.03) ETDRS letters were analyzed with an average V_TOT of 0.91 decibel-steradian (dB-sr) and an MS of 10.73 dB. The overall mean rate of decrease in sensitivity [95% confidence interval] was 0.077 [0.064, 0.090] dB-sr/y for V_TOT and 0.87 [0.72, 1.02] dB/year for MS. The progression rate of V_TOT depended on baseline visual function (0.029 dB-sr/year for low and 0.120 dB-sr/year for high baseline V_TOT; P < .001) and exhibited a difference in the first vs second year of follow-up (0.065 dB-sr/year vs 0.089 dB-sr/year, respectively; P < .001). The absence of pigmentary abnormalities of the retinal pigment epithelium at baseline was found to be associated with a faster progression rate (P < .001), whereas a significant association with the genotype was not detected (P = .7).

CONCLUSION

In STGD1, both microperimetric outcomes demonstrate statistically significant and clinically meaningful changes after relatively short follow-up periods. Volumetric modeling may be useful in future interventional clinical trials that aim to improve retinal sensitivity or to slow down its decline and for structure-function correlations.

KCNV2-Associated Retinopathy: Detailed Retinal Phenotype and Structural Endpoints-KCNV2 Study Group Report 2

PURPOSE

To describe the detailed retinal phenotype of KCNV2-associated retinopathy.

STUDY DESIGN

Multicenter international retrospective case series.

METHODS

Review of retinal imaging including fundus autofluorescence (FAF) and optical coherence tomography (OCT), including qualitative and quantitative analyses.

RESULTS

Three distinct macular FAF features were identified: (1) centrally increased signal (n = 35, 41.7%), (2) decreased autofluorescence (n = 27, 31.1%), and (3) ring of increased signal (n = 37, 44.0%). Five distinct FAF groups were identified based on combinations of those features, with 23.5% of patients changing the FAF group over a mean (range) follow-up of 5.9 years (1.9-13.1 years). Qualitative assessment was performed by grading OCT into 5 grades: (1) continuous ellipsoid zone (EZ) (20.5%); (2) EZ disruption (26.1%); (3) EZ absence, without optical gap and with preserved retinal pigment epithelium complex (21.6%); (4) loss of EZ and a hyporeflective zone at the foveola (6.8%); and (5) outer retina and retinal pigment epithelium complex loss (25.0%). Eighty-six patients had scans available from both eyes, with 83 (96.5%) having the same grade in both eyes, and 36.1% changed OCT grade over a mean follow-up of 5.5 years. The annual rate of outer nuclear layer thickness change was similar for right and left eyes.

CONCLUSIONS

KCNV2-associated retinopathy is a slowly progressive disease with early retinal changes, which are predominantly symmetric between eyes. The identification of a single OCT or FAF measurement as an endpoint to determine progression that applies to all patients may be challenging, although outer nuclear layer thickness is a potential biomarker. Findings suggest a potential window for intervention until 40 years of age.

RETINAL SURFACE WRINKLING AS AN INDICATOR FOR INTERNAL LIMITING MEMBRANE PEELING DURING VITRECTOMY FOR RETINAL DETACHMENT

PURPOSE

To assess the validity of retinal surface wrinkling (RSW) as an indicator to select patients relevant for internal limiting membrane peeling during vitrectomy for rhegmatogenous retinal detachment, to prevent postoperative visual decline due to epiretinal membrane growth.

METHODS

This was a prospective, interventional case series of 78 consecutive eyes that underwent initial vitrectomy to repair rhegmatogenous retinal detachments and were followed for 6 months. The presence/absence of RSW was evaluated presurgically on en face optical coherence tomographic images. The internal limiting membrane was peeled if RSW was identified. The main outcome measure was the prevalence of postsurgical epiretinal membrane growth that caused a visual decline of 0.2 or more in logarithm of the minimum angle of resolution unit.

RESULTS

The internal limiting membrane was peeled for RSW appearance in 22 eyes (28.2%). Mild epiretinal membranes developed in 8 of the 56 internal limiting membrane-unpeeled eyes (10.3% of total, 6 eyes at stage 1 in the classification of Govetto); however, visual decline occurred in none of them with the mean visual acuity of these 8 eyes maintained at -0.08 ± 0.11 in logarithm of the minimum angle of resolution (≈20/16).

CONCLUSION

Visual decline due to epiretinal membrane growth after rhegmatogenous retinal detachment repair was entirely prevented by peeling the internal limiting membrane in about 30% of cases selected for the presence of RSW.

Ocular findings in Japanese patients with hydroxychloroquine retinopathy developing within 3 years of treatment

PURPOSE

To describe the characteristics of Japanese patients with hydroxychloroquine (HCQ) retinopathy developing within 3 years of treatment outset.

STUDY DESIGN

Retrospective case series METHODS: Three patients with HCQ retinopathy developing within 3 years of treatment outset have been identified in Japan since HCQ became available in 2015. Their medical charts, containing optical coherence tomography (OCT), fundus autofluorescence imaging, and visual field tests, were reviewed.

RESULTS

The treatment durations and cumulative doses until onset were 29-36 months and 182-326 g, respectively. The first patient had possible pre-existing maculopathy, although the abnormalities were ambiguous. The second and third patients had impaired renal function. The patients did not complain of severe visual disturbance at diagnosis, but visual field loss and disruption of the outer retinal segments consisting of a parafoveal pattern in the first case and a pericentral pattern (localized, 8 or more degrees from the center of the fovea) in the second and third cases were clearly observed on OCT. Even after HCQ discontinuation, their retinopathy showed slight progression on the visual field tests and OCT images. A blood sample was obtained from 1 patient on the day after HCQ discontinuation, and the whole blood level of HCQ was measured using validated liquid chromatography-tandem mass spectrometry. The HCQ level 27 h after the last dose was high, at 2240 ng/mL (suggested threshold > 1733 ng/mL).

CONCLUSION

Ophthalmologic screening from the initiation of HCQ treatment detected 3 cases of HCQ retinopathy developing within 3 years of treatment outset, including a patient with a high blood level of HCQ.

KCNV2-Associated Retinopathy: Genetics, Electrophysiology, and Clinical Course-KCNV2 Study Group Report 1

PURPOSE

To investigate genetics, electrophysiology, and clinical course of KCNV2-associated retinopathy in a cohort of children and adults.

STUDY DESIGN

This was a multicenter international clinical cohort study.

METHODS

Review of clinical notes and molecular genetic testing. Full-field electroretinography (ERG) recordings, incorporating the international standards, were reviewed and quantified and compared with age and recordings from control subjects.

RESULTS

In total, 230 disease-associated alleles were identified from 117 patients, corresponding to 75 different KCNV2 variants, with 28 being novel. The mean age of onset was 3.9 years old. All patients were symptomatic before 12 years of age (range, 0-11 years). Decreased visual acuity was present in all patients, and 4 other symptoms were common: reduced color vision (78.6%), photophobia (53.5%), nyctalopia (43.6%), and nystagmus (38.6%). After a mean follow-up of 8.4 years, the mean best-corrected visual acuity (BCVA ± SD) decreased from 0.81 ± 0.27 to 0.90 ± 0.31 logarithm of minimal angle of resolution. Full-field ERGs showed pathognomonic waveform features. Quantitative assessment revealed a wide range of ERG amplitudes and peak times, with a mean rate of age-associated reduction indistinguishable from the control group. Mean amplitude reductions for the dark-adapted 0.01 ERG, dark-adapted 10 ERG a-wave, and LA 3.0 30 Hz and LA3 ERG b-waves were 55%, 21%, 48%, and 74%, respectively compared with control values. Peak times showed stability across 6 decades.

CONCLUSION

In KCNV2-associated retinopathy, full-field ERGs are diagnostic and consistent with largely stable peripheral retinal dysfunction. Report 1 highlights the severity of the clinical phenotype and established a large cohort of patients, emphasizing the unmet need for trials of novel therapeutics.

Prediction of causative genes in inherited retinal disorder from fundus photography and autofluorescence imaging using deep learning techniques

BACKGROUND/AIMS

To investigate the utility of a data-driven deep learning approach in patients with inherited retinal disorder (IRD) and to predict the causative genes based on fundus photography and fundus autofluorescence (FAF) imaging.

METHODS

Clinical and genetic data from 1302 subjects from 729 genetically confirmed families with IRD registered with the Japan Eye Genetics Consortium were reviewed. Three categories of genetic diagnosis were selected, based on the high prevalence of their causative genes: Stargardt disease (ABCA4), retinitis pigmentosa (EYS) and occult macular dystrophy (RP1L1). Fundus photographs and FAF images were cropped in a standardised manner with a macro algorithm. Images for training/testing were selected using a randomised, fourfold cross-validation method. The application program interface was established to reach the learning accuracy of concordance (target: >80%) between the genetic diagnosis and the machine diagnosis (ABCA4, EYS, RP1L1 and normal).

RESULTS

A total of 417 images from 156 Japanese subjects were examined, including 115 genetically confirmed patients caused by the three prevalent causative genes and 41 normal subjects. The mean overall test accuracy for fundus photographs and FAF images was 88.2% and 81.3%, respectively. The mean overall sensitivity/specificity values for fundus photographs and FAF images were 88.3%/97.4% and 81.8%/95.5%, respectively.

CONCLUSION

A novel application of deep neural networks in the prediction of the causative IRD genes from fundus photographs and FAF, with a high prediction accuracy of over 80%, was highlighted. These achievements will extensively promote the quality of medical care by facilitating early diagnosis, especially by non-specialists, access to care, reducing the cost of referrals, and preventing unnecessary clinical and genetic testing.

Multisystem Inflammatory Syndrome in Adults after Mild SARS-CoV-2 Infection, Japan

In Japan, a 51-year-old man had minimally symptomatic severe acute respiratory syndrome coronavirus 2 infection. Multisystem inflammatory syndrome was diagnosed ≈5 weeks later; characteristics included severe inflammation, cardiac dysfunction, and IgG positivity. Clinicians should obtain detailed history and examine IgG levels for cases of inflammatory disease with unexplained cardiac decompensation.

Inherited retinal diseases: Therapeutics, clinical trials and end points-A review

Inherited retinal diseases (IRDs) are a clinically and genetically heterogeneous group of disorders characterised by photoreceptor degeneration or dysfunction. These disorders typically present with severe vision loss that can be progressive, with disease onset ranging from congenital to late adulthood. The advances in genetics, retinal imaging and molecular biology, have conspired to create the ideal environment for establishing treatments for IRDs, with the first approved gene therapy and the commencement of multiple clinical trials. The scope of this review is to familiarise clinicians and scientists with the current management and the prospects for novel therapies for: (1) macular dystrophies, (2) cone and cone-rod dystrophies, (3) cone dysfunction syndromes, (4) Leber congenital amaurosis, (5) rod-cone dystrophies, (6) rod dysfunction syndromes and (7) chorioretinal dystrophies. We also briefly summarise the investigated end points for the ongoing trials.

VALIDITY AND EFFICACY OF INTERNAL LIMITING MEMBRANE PEELING DURING INITIAL VITRECTOMY FOR RHEGMATOGENOUS RETINAL DETACHMENT: VISUAL OUTCOMES IN MACULA-SPARING CASES

PURPOSE

To compare the visual outcomes and prevalence of epiretinal membrane (ERM) growth postoperatively between eyes treated with and without internal limiting membrane peeling during vitrectomy for macula-sparing rhegmatogenous retinal detachment.

METHODS

Fifty-five consecutive cases who underwent vitrectomy for macula-sparing rhegmatogenous retinal detachment were reviewed retrospectively. The inclusion criteria were a minimal 6-month follow-up postoperatively and spectral domain optical coherence tomographic images available at follow-up. Cases with any pre-existing macular condition possibly affecting the visual prognosis were excluded. All cases were divided into two groups: 22 cases without internal limiting membrane peeling (Group 1) and 33 cases with internal limiting membrane peeling (Group 2). The two groups were compared using the Mann-Whitney U test and Fisher exact test in terms of the best-corrected visual acuity (BCVA) (logarithm of the minimum angle of resolution) before vitrectomy, postoperative BCVA, and the presence of postoperative ERM growth. Postoperative BCVA and ERM growth were determined at 6 months, 12 months, and the last visit. The visual outcomes were also analyzed between cases with and without postoperative symptomatic ERM growth, which caused visual impairment and required surgical removal.

RESULTS

The mean postoperative BCVAs were 0.00, -0.08, and -0.08 logarithm of the minimum angle of resolution in Group 1, and -0.08, -0.08, and -0.08 logarithm of the minimum angle of resolution in Group 2 at 6 months, 12 months, and the last visit, respectively, and did not differ significantly between the 2 groups at each time point except for at 12 months (P = 0.027). An ERM developed in 14 cases in Group 1, 7 of which were symptomatic. No cases in Group 2 had ERM growth. The prevalence of ERM growth was significantly (P < 0.001) higher in Group 1 than Group 2. The BCVA was significantly worse at 6 months (P = 0.011), 12 months (P = 0.003), and the last visit (P = 0.019) in 7 cases with symptomatic ERMs (median, 0.30, 0.15, and 0.10 logarithm of the minimum angle of resolution, respectively) than in 48 cases without symptomatic ERMs (median, -0.08, -0.08, and -0.08 logarithm of the minimum angle of resolution, respectively).

CONCLUSION

Internal limiting membrane peeling did not result in decreased visual acuity postoperatively in cases with a macula-sparing rhegmatogenous retinal detachment, and the procedure significantly prevented postsurgical ERM growth. Symptomatic ERMs led to decreased visual acuity even after surgical removal. These results support the validity and efficacy of internal limiting membrane peeling for preventing ERM growth after rhegmatogenous retinal detachment repair.

Genotype and Long-term Clinical Course of Bietti Crystalline Dystrophy in Korean and Japanese Patients

PURPOSE

To investigate the genotype and long-term clinical phenotype of patients with Bietti crystalline dystrophy (BCD) in Korea and Japan.

DESIGN

Retrospective case series.

PARTICIPANTS

We analyzed 62 patients with clinical features of BCD who harbor pathogenic biallelic CYP4V2 variants in their homozygote or compound heterozygote.

METHODS

Data were collected from patient charts, including age, best-corrected visual acuity (BCVA), Goldmann perimetry results, fundus photography, OCT findings, fundus autofluorescence results, and electroretinography findings. We compared the clinical course of the patients with homozygous c.802-8_810de117insGC [exon7del], the most common mutation in the East Asian population, with those of the patients with other genotypes.

MAIN OUTCOME MEASURES

Best-corrected visual acuity, visual field (VF), and their changes during follow-up.

RESULTS

The mean age at the first visit was 55.2 years, with a mean follow-up of 7.1 years. The mean BCVAs at the first and last visits were 0.28 logarithm of the minimum angle of resolution (logMAR) and 0.89 logMAR, respectively. In genetic testing, c.802-8_810de117insGC was detected in 86 of 124 alleles of the patients, and 36 patients were homozygous for this mutation. The age, BCVA, VF area, central foveal thickness, and abnormal hypoautofluorescent area at either the first or last visit were not different between the exon7del homozygotes and the others. The mean BCVA changes per year were 0.089 logMAR in the exon7del homozygotes and 0.089 logMAR in the others. An age- and gender-adjusted linear regression analysis showed no association between the exon7del homozygote status and the rate of vision loss. Characteristic crystalline deposits in the posterior pole were generally observed in younger patients and disappeared over time along with progressive retinochoroidal atrophy.

CONCLUSIONS

Patients with BCD and a homozygote for c.802-8_810de117insGC accounted for more than 50% of this cohort of Korean and Japanese patients, and the clinical effect of this deleterious variant was not severe in the spectrum of CYP4V2 retinopathy.

New variants and in silico analyses in GRK1 associated Oguchi disease

Biallelic mutations in G-Protein coupled receptor kinase 1 (GRK1) cause Oguchi disease, a rare subtype of congenital stationary night blindness (CSNB). The purpose of this study was to identify disease causing GRK1 variants and use in-depth bioinformatic analyses to evaluate how their impact on protein structure could lead to pathogenicity. Patients' genomic DNA was sequenced by whole genome, whole exome or focused exome sequencing. Disease associated variants, published and novel, were compared to nondisease associated missense variants. The impact of GRK1 missense variants at the protein level were then predicted using a series of computational tools. We identified twelve previously unpublished cases with biallelic disease associated GRK1 variants, including eight novel variants, and reviewed all GRK1 disease associated variants. Further structure-based scoring revealed a hotspot for missense variants in the kinase domain. In addition, to aid future clinical interpretation, we identified the bioinformatics tools best able to differentiate disease associated from nondisease associated variants. We identified GRK1 variants in Oguchi disease patients and investigated how disease-causing variants may impede protein function in-silico.

Sector Retinitis Pigmentosa: Extending the Molecular Genetics Basis and Elucidating the Natural History

Purpose

To determine the genetic background of sector retinitis pigmentosa (RP) natural history to better inform patient counseling.

Design

Retrospective case series.

Methods

Review of clinical notes, retinal imaging including color fundus photography (CFP), fundus autofluorescence (FAF), optical coherence tomography (OCT), electrophysiological assessment (ERG), and molecular genetic testing were performed in patients with sector RP from a single tertiary referral center. Main outcomes measured were demographic data, signs and symptoms, visual acuity, molecular genetics; and ERG, FAF, and OCT findings.

Results

Twenty-six molecularly confirmed patients from 23 different families were identified harboring likely disease-causing variants in 9 genes. The modes of inheritance were autosomal recessive (AR, n=6: USH1C, n=2; MYO7A, n=2; CDH3, n=1; EYS, n=1), X-linked (XL, n=4: PRPS1, n=1; RPGR, n=3), and autosomal dominant (AD, n=16: IMPDH1, n=3; RP1, n=3; RHO, n=10), with a mean age of disease onset of 38.5, 30.5, and 39.0 years old, respectively. Five of these genes have not previously been reported to cause sector RP (PRPS1, MYO7A, EYS, IMPDH1, and RP1). Inferior and nasal predilection was common across the different genotypes, and patients tended to maintain good central vision. Progression on serial FAF was observed in RPGR, MYO7A, CDH23, EYS, IMPDH1, RP1, and RHO-associated sector RP.

Conclusions

The genotypic spectrum of the disease is broader than previously reported. The longitudinal data provided will help to make accurate patient prognoses and counseling as well as inform patients' potential participation in the increasing numbers of trials of novel therapeutics and access to future treatments.

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This is the largest series and longitudinal study in sector retinitis pigmentosa.

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The genotypic spectrum of the disease is broader than previously reported.

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The longitudinal data provided more accurate patient prognosis and counseling.

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The study informed patients' potential participation in the increasing numbers of trials of novel therapeutics and access to future treatments.

Long-term follow-up of a Chinese patient with KCNV2-retinopathy

Purpose: To characterize and monitor the clinical and electrophysiological features of a Chinese patient with KCNV2 retinopathy.Methods: A 17-year-old Chinese male with the diagnosis of cone dystrophy with supernormal rod response (CDSRR) was followed-up for 5 years, with full ophthalmological examinations, including decimal best corrected visual acuity (BCVA), fundus photography, fundus autofluorescence (FAF) imaging, spectral-domain optical coherence tomography (SD-OCT), and full-field electroretinogram (ERG). Genetic screening was performed to detect the sequence variations in the retinal dystrophy associated genes in the patient and his parents.Results: The patient demonstrated the characteristic full-field electroretinography (ERG) features of CDSRR, namely a profound enlargement of the dark-adapted ERG b-wave amplitude with increasing flash strength and a broadened a-wave trough; this case also had undetectable light-adapted ERGs. A BCVA of 0.15 was maintained over 5 years in both eyes; while progressive macular atrophy was identified. Molecular genetic analyses revealed two novel disease-causing KCNV2 variants in compound heterozygous state: c.1408 G > C (p.Gly470Arg) and c.1500 C > G (p.Tyr500Ter).Conclusions: This is the first long-term case study of an East Asian patient with molecularly confirmed CDSRR. The progressive atrophy with maintained VA demonstrated in this case will be valuable for increasing the understanding of the natural course of KCNV2 retinopathy and it will help in counselling patients with this disease.

Fish oil supplementation and repeated macular hemorrhage without choroidal neovascularization: A case report

Macular hemorrhage can occur spontaneously and repeatedly without choroidal neovascularization or other known lesions associated with myopia. We report a case of repeated myopic macular hemorrhage following fish oil supplementation. A 32-year-old male was referred with newly acquired paracentral scotoma in the left eye. Serial retinal imaging, including fundus photography, fluorescein angiography, and spectral-domain optical coherence tomography were performed. Fundus photography and fluorescein angiography showed a subtle red-colored lesion nasal to the fovea. Optical coherence tomography showed a dome shaped elevation in the ellipsoid zone and interdigitation zone in the left eye. No known ocular risk factors for macular hemorrhage, such as choroidal neovascularization, lacquer cracks, Fuch’s spot or choroid thinning or keratoconus were observed. After 2 months without any treatment, the left eye lesion disappeared. However 2 weeks later, another newly developed red-colored lesion close to the left fovea was observed. At that moment, the detailed medical history revealed that the patient had been regularly taking a high dose of commercially available fish oil supplement beginning one month before the first macular hemorrhage. After discontinuation of the fish oil, the second left hemorrhage resolved gradually over the following 8 weeks. No recurrent hemorrhages have been detected at the 12 months follow-up visits. Our observations suggest that the relative value of nutritional supplementation with high doses of fish oil should be cautioned in patients with repetitive retinal hemorrhage.

Retinal imaging in inherited retinal diseases

Inherited retinal diseases (IRD) are a leading cause of blindness in the working age population. The advances in ocular genetics, retinal imaging and molecular biology, have conspired to create the ideal environment for establishing treatments for IRD, with the first approved gene therapy and the commencement of multiple therapy trials. The scope of this review is to familiarize clinicians and scientists with the current landscape of retinal imaging in IRD. Herein we present in a comprehensive and concise manner the imaging findings of: (I) macular dystrophies (MD) [Stargardt disease (ABCA4), X-linked retinoschisis (RS1), Best disease (BEST1), pattern dystrophy (PRPH2), Sorsby fundus dystrophy (TIMP3), and autosomal dominant drusen (EFEMP1)], (II) cone and cone-rod dystrophies (GUCA1A, PRPH2, ABCA4 and RPGR), (III) cone dysfunction syndromes [achromatopsia (CNGA3, CNGB3, PDE6C, PDE6H, GNAT2, ATF6], blue-cone monochromatism (OPN1LW/OPN1MW array), oligocone trichromacy, bradyopsia (RGS9/R9AP) and Bornholm eye disease (OPN1LW/OPN1MW), (IV) Leber congenital amaurosis (GUCY2D, CEP290, CRB1, RDH12, RPE65, TULP1, AIPL1 and NMNAT1), (V) rod-cone dystrophies [retinitis pigmentosa, enhanced S-Cone syndrome (NR2E3), Bietti crystalline corneoretinal dystrophy (CYP4V2)], (VI) rod dysfunction syndromes (congenital stationary night blindness, fundus albipunctatus (RDH5), Oguchi disease (SAG, GRK1), and (VII) chorioretinal dystrophies [choroideremia (CHM), gyrate atrophy (OAT)].

RP2-associated retinal disorder in a Japanese cohort: Report of novel variants and a literature review, identifying a genotype-phenotype association

The retinitis pigmentosa 2 (RP2) gene is one of the causative genes for X-linked inherited retinal disorder. We characterized the clinical/genetic features of four patients with RP2-associated retinal disorder (RP2-RD) from four Japanese families in a nationwide cohort. A systematic review of RP2-RD in the Japanese population was also performed. All four patients were clinically diagnosed with retinitis pigmentosa (RP). The mean age at examination was 36.5 (10-47) years, and the mean visual acuity in the right/left eye was 1.40 (0.52-2.0)/1.10 (0.52-1.7) in the logarithm of the minimum angle of resolution unit, respectively. Three patients showed extensive retinal atrophy with macular involvement, and one had central retinal atrophy. Four RP2 variants were identified, including two novel missense (p.Ser6Phe, p.Leu189Pro) and two previously reported truncating variants (p.Arg120Ter, p.Glu269CysfsTer3). The phenotypes of two patients with truncating variants were more severe than the phenotypes of two patients with missense variants. A systematic review revealed additional 11 variants, including three missense and eight deleterious (null) variants, and a statistically significant association between phenotype severity and genotype severity was revealed. The clinical and genetic spectrum of RP2-RD was illustrated in the Japanese population, identifying the characteristic features of a severe form of RP with early macular involvement.

Clinical and genetic characteristics of Stargardt disease in a large Western China cohort: Report 1

Stargardt disease 1 (STGD1) is the most prevalent retinal dystrophy caused by pathogenic biallelic ABCA4 variants. Forty-two unrelated patients mostly originating from Western China were recruited. Comprehensive ophthalmological examinations, including visual acuity measurements (subjective function), fundus autofluorescence (retinal imaging), and full-field electroretinography (objective function), were performed. Next-generation sequencing (target/whole exome) and direct sequencing were conducted. Genotype grouping was performed based on the presence of deleterious variants. The median age of onset/age was 10.0 (5-52)/29.5 (12-72) years, and the median visual acuity in the right/left eye was 1.30 (0.15-2.28)/1.30 (0.15-2.28) in the logarithm of the minimum angle of resolution unit. Ten patients (10/38, 27.0%) showed confined macular dysfunction, and 27 (27/37, 73.7%) had generalized retinal dysfunction. Fifty-eight pathogenic/likely pathogenic ABCA4 variants, including 14 novel variants, were identified. Eight patients (8/35, 22.8%) harbored multiple deleterious variants, and 17 (17/35, 48.6%) had a single deleterious variant. Significant associations were revealed between subjective functional, retinal imaging, and objective functional groups, identifying a significant genotype-phenotype association. This study illustrates a large phenotypic/genotypic spectrum in a large well-characterized STGD1 cohort. A distinct genetic background of the Chinese population from the Caucasian population was identified; meanwhile, a genotype-phenotype association was similarly represented.

Clinical and genetic characteristics of 10 Japanese patients with PROM1-associated retinal disorder: A report of the phenotype spectrum and a literature review in the Japanese population

Variants in the PROM1 gene are associated with cone (-rod) dystrophy, macular dystrophy, and other phenotypes. We describe the clinical and genetic characteristics of 10 patients from eight Japanese families with PROM1-associated retinal disorder (PROM1-RD) in a nationwide cohort. A literature review of PROM1-RD in the Japanese population was also performed. The median age at onset/examination of 10 patients was 31.0 (range, 10-45)/44.5 (22-73) years. All 10 patients showed atrophic macular changes. Seven patients (70.0%) had spared fovea to various degrees, approximately half of whom had maintained visual acuity. Generalized cone (-rod) dysfunction was demonstrated in all nine subjects with available electrophysiological data. Three PROM1 variants were identified in this study: one recurrent disease-causing variant (p.Arg373Cys), one novel putative disease-causing variant (p.Cys112Arg), and one novel variant of uncertain significance (VUS; p.Gly53Asp). Characteristic features of macular atrophy with generalized cone-dominated retinal dysfunction were shared among all 10 subjects with PROM1-RD, and the presence of foveal sparing was crucial in maintaining visual acuity. Together with the three previously reported variants [p.R373C, c.1551+1G>A (pathogenic), p.Asn580His (likely benign)] in the literature of Japanese patients, one prevalent missense variant (p.Arg373Cys, 6/9 families, 66.7%) detected in multiple studies was determined in the Japanese population, which was also frequently detected in the European population.