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Br J Ophthalmol 2003;87:1268-1271 Aims: To determine the interocular amplitude response difference of the electroretinogram (ERG) in normal subjects. Methods: 79 subjects, without retinal changes of clinical significance, underwent ERG [...]

Purpose: To evaluate peripapillary retinal nerve fiber layer (RNFL) thickness using spectral-domain optical coherence tomography in patients with autosomal recessive cone-rod dystrophy (CRD).Design: Cross-sectional study.Methods: Eleven patients (22 eyes) with CRD were studied, including 4 patients with identified ABCA4 gene mutations. Peripapillary RNFL thickness was measured in 16 segments from 4 quadrants. The analyses were based on age and disc size-adjusted normative data. An abnormal thinning was considered when RNFL thickness measurements were less than the fifth percentile in at least 2 of 4 segments in a quadrant. Mean RNFL thickness was compared quantitatively with normative data obtained from 134 subjects.Results: Eight patients (73%) had peripapillary RNFL thinning in at least 1 quadrant of at least 1 eye, including 3 of 4 patients with known ABCA4 gene mutations. Peripapillary RNFL thinning in the temporal quadrant was seen most commonly in 11 (79%) of 14 eyes with thinning in at least 1 quadrant. Significant thinning of the overall peripapillary RNFL was observed in CRD patients compared with controls (P = .0002). Subgroup analysis showed that 8 (89%) of 9 patients who were older than 40 years had thinning in at least 1 quadrant of at least 1 eye.Conclusions: Peripapillary RNFL thinning was observed commonly in our patients with autosomal recessive CRD. The results confirm that the inner retinal structures can be affected in outer retinal disease. Careful evaluation of the inner retina may be important in determining the success rate of potential treatments for predominantly outer retinal diseases. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate spatial and temporal integration across the visual field in individuals with juvenile X-linked retinoschisis (XLRS)., Methods: Nine subjects with XLRS and 10 visually normal individuals participated. Luminance thresholds were measured at 15 locations along the horizontal visual field meridian. Locations were grouped into four regions for analysis: foveal, parafoveal (2°), perifoveal (5°-10°), and peripheral (10°-60°). For spatial integration measurements, stimulus duration was 100 ms, and size ranged from 0.01 to 2.32 deg2 (Goldmann I-V). For temporal integration measurements, stimulus size was 0.15 deg2 (Goldmann III), and duration ranged from 12 to 800 ms. The effect of stimulus size and duration on the subjects' threshold was described using integration models., Results: Luminance thresholds for the XLRS group were more elevated for small targets (2.0×-12.6×) than for large targets (1.25×-3.2×) compared to controls for all locations. Likewise, thresholds for the XLRS group were more elevated for short durations (6.3×) than for long durations (4.0×) in the fovea and parafovea but were similarly elevated at all durations (2.0×-2.5×) in the perifovea and periphery. For both the size and duration experiments, thresholds measured in the fovea, parafovea, and perifovea of XLRS subjects were highly similar to those measured from the peripheral field of the controls., Conclusions: Spatial and temporal integration characteristics of the XLRS fovea, parafovea, and perifovea are similar to those of the normal periphery. The results also indicate that scaling stimulus size equates thresholds for the XLRS and control subjects throughout the visual field, but scaling duration does not.

Over 1,500 variants in the ABCA4 locus cause phenotypes ranging from severe, early-onset retinal degeneration to very late-onset maculopathies. The resulting ABCA4/Stargardt disease is the most prevalent Mendelian eye disorder, although its underlying clinical heterogeneity, including penetrance of many alleles, are not well-understood. We hypothesized that a share of this complexity is explained by trans-modifiers, i.e., variants in unlinked loci, which are currently unknown. We sought to identify these by performing exome sequencing in a large cohort for a rare disease of 622 cases and compared variation in seven genes known to clinically phenocopy ABCA4 disease to cohorts of ethnically matched controls. We identified a significant enrichment of variants in 2 out of the 7 genes. Moderately rare, likely functional, variants, at the minor allele frequency (MAF) <0.005 and CADD>25, were enriched in ROM1, where 1.3% of 622 patients harbored a ROM1 variant compared to 0.3% of 10,865 controls (p = 2.41E04; OR 3.81 95% CI [1.77; 8.22]). More importantly, analysis of common variants (MAF>0.1) identified a frequent haplotype in PRPH2, tagged by the p.Asp338 variant with MAF = 0.21 in the matched general population that was significantly increased in the patient cohort, MAF 0.25, p = 0.0014. Significant differences were also observed between ABCA4 disease subgroups. In the late-onset subgroup, defined by the hypomorphic p.Asn1868Ile variant and including c.4253+43G>A, the allele frequency for the PRPH2 p.Asp338 variant was 0.15 vs 0.27 in the remaining cohort, p = 0.00057. Known functional data allowed suggesting a mechanism by which the PRPH2 haplotype influences the ABCA4 disease penetrance. These associations were replicated in an independent cohort of 408 patients. The association was highly statistically significant in the combined cohorts of 1,030 cases, p = 4.00E-05 for all patients and p = 0.00014 for the hypomorph subgroup, suggesting a substantial trans-modifying role in ABCA4 disease for both rare and common variants in two unlinked loci., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: SHT has received support from Abeona Therapeutics and is a board member of Emendo Biotherapeutics, Nanoscope Therapeutics, and Rejuvitas, Inc. The other authors declare that no competing interests exist.

Purpose: To define relationships among contrast sensitivity (CS), equivalent intrinsic noise (Neq; a measure of noise within the visual pathway), and retinal thickness in X-linked retinoschisis (XLRS)., Methods: Nine XLRS and 10 visually-normal subjects participated. CS was measured in the presence and absence of luminance noise. These data were fit with a standard model to estimate Neq and sampling efficiency (an estimate of the ability to use stimulus information). Optical coherence tomography images were obtained to quantify outer nuclear layer (ONL+) and outer segment (OS+) thickness. A linear structure-function model was used to describe the relationship between CS and the product of ONL+ and OS+ thickness., Results: CS in the absence of noise (CS0) for the XLRS subjects ranged from normal to as much as 1.5× below the lower limit of normal. Four of the nine subjects with XLRS had abnormally high Neq, whereas two others had sampling efficiency that was borderline abnormal. Log CS0 for the subjects with XLRS was correlated significantly with log Neq (r = -0.78, P = 0.01), but not with log efficiency (r = 0.19, P = 0.63). CS0 and Neq, but not efficiency, conformed to the linear ONL+ × OS+ structure-function model., Conclusions: The XLRS subjects in this study who had elevated internal noise had abnormally low CS; both internal noise and CS fell within the predicted limits of a structure-function model., Translational Relevance: Internal noise measurements can provide insight into a source of CS loss in some individuals with XLRS.

Purpose: To provide a comprehensive analysis of light- and dark-adapted luminance thresholds and their associations with retinal structure in X-linked retinoschisis (XLRS)., Methods: Nine subjects with XLRS and 10 visually-normal individuals participated. Threshold was measured at 15 locations along the horizontal meridian of the visual field at several adaptation levels (5 × 10-5 to 50 cd/m2) after dark-adaptation. The relationship between threshold and adaptation level across the field was described using a standard "threshold-versus-illuminance" model. Optical coherence tomography images were obtained and segmented to quantify outer nuclear layer (ONL+) and outer segment (OS+) thickness. A linear structure-function model was used to describe the relationship between threshold and the product of ONL+ and OS+ thickness., Results: For peripheral field measurements, thresholds were generally normal for most subjects with XLRS. All subjects had perifoveal and parafoveal threshold elevations under dark-adapted and high illuminance conditions, with thresholds at moderate illuminances being closer to normal. For foveal measurements, seven of nine subjects with XLRS had normal dark-adapted thresholds, and all had abnormally elevated high illuminance thresholds. Threshold-versus-illuminance curves in the fovea, parafovea, and perifovea were abnormally steep for subjects with XLRS, appearing similar to the normal peripheral field shape. Under both dark- and light-adapted conditions, threshold was predicted by ONL+ × OS+ thickness at nearly all field locations., Conclusions: Threshold elevation in XLRS is complex, depending on both the adaptation level and the visual field location. The pattern of threshold-versus-illuminance suggests that macular function in XLRS is similar to the periphery of controls.

A pathognomonic macular ripple sign has been reported with scanning laser ophthalmoscopy images in patients with foveal hypoplasia, though the optical basis of this sign is presently unknown. Here we present a case series of seven individuals with foveal hypoplasia (based on spectral domain optical coherence tomography). Each patient underwent infrared scanning laser ophthalmoscopy retinal imaging in both eyes, acquired with and without a polarization filter and assessment for a ripple-like effect in the fovea. On imaging, macular ripples were present in all eyes with foveal hypoplasia when using a polarization filter, but not when imaged without the filter. We conclude that the macular ripple sign is an imaging artifact attributable to the unique pattern of phase retardation of the Henle fiber layer in the setting of foveal hypoplasia. By utilizing a polarization filter with retinal photography, this feature can be exploited to promptly identify foveal hypoplasia in settings where OCT is not possible due to nystagmus.

Over 1200 variants in the ABCA4 gene cause a wide variety of retinal disease phenotypes, the best known of which is autosomal recessive Stargardt disease (STGD1). Disease-causing variation encompasses all mutation categories, from large copy number variants to very mild, hypomorphic missense variants. The most prevalent disease-causing ABCA4 variant, present in ~ 20% of cases of European descent, c.5882G > A p.(Gly1961Glu), has been a subject of controversy since its minor allele frequency (MAF) is as high as ~ 0.1 in certain populations, questioning its pathogenicity, especially in homozygous individuals. We sequenced the entire ~140Kb ABCA4 genomic locus in an extensive cohort of 644 bi-allelic, i.e. genetically confirmed, patients with ABCA4 disease and analyzed all variants in 140 compound heterozygous and 10 homozygous cases for the p.(Gly1961Glu) variant. A total of 23 patients in this cohort additionally harbored the deep intronic c.769-784C > T variant on the p.(Gly1961Glu) allele, which appears on a specific haplotype in ~ 15% of p.(Gly1961Glu) alleles. This haplotype was present in 5/7 of homozygous cases, where the p.(Gly1961Glu) was the only known pathogenic variant. Three cases had an exonic variant on the same allele with the p.(Gly1961Glu). Patients with the c.[769-784C > T;5882G > A] complex allele exhibit a more severe clinical phenotype, as seen in compound heterozygotes with some more frequent ABCA4 mutations, e.g. p.(Pro1380Leu). Our findings indicate that the c.769-784C > T variant is major cis-acting modifier of the p.(Gly1961Glu) allele. The absence of such additional allelic variation on most p.(Gly1961Glu) alleles largely explains the observed paucity of affected homozygotes in the population., (© The Author(s) 2021. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Purpose: Adaptive optics scanning light ophthalmoscopy (AOSLO) imaging in patients with achromatopsia (ACHM) and albinism is not always successful. Here, we tested whether optical coherence tomography (OCT) measures of foveal structure differed between patients for whom AOSLO images were either quantifiable or unquantifiable., Methods: The study included 166 subjects (84 with ACHM; 82 with albinism) with previously acquired OCT scans, AOSLO images, and best-corrected visual acuity (BCVA, if available). Foveal OCT scans were assessed for outer retinal structure, outer nuclear layer thickness, and hypoplasia. AOSLO images were graded as quantifiable if a peak cone density could be measured and/or usable if the location of peak density could be identified and the parafoveal mosaic was quantifiable., Results: Forty-nine percent of subjects with ACHM and 57% of subjects with albinism had quantifiable AOSLO images. Older age and better BCVA were found in subjects with quantifiable AOSLO images for both ACHM (P = 0.0214 and P = 0.0276, respectively) and albinism (P = 0.0073 and P < 0.0004, respectively). There was a significant trend between ellipsoid zone appearance and ability to quantify AOSLO (P = 0.0028). In albinism, OCT metrics of cone structure did not differ between groups., Conclusions: Previously reported AOSLO-based cone density measures in ACHM may not necessarily reflect the degree of remnant cone structure in these patients., Translational Relevance: Until AOSLO is successful in all patients with ACHM and albinism, the possibility of the reported data from a particular cohort not being representative of the entire population remains an important issue to consider when interpreting results from AOSLO studies.

Purpose: Despite the extensive use of next-generation sequencing (NGS) technology to identify disease-causing genomic variations, a major gap in our understanding of Mendelian diseases is the unidentified molecular lesion in a significant portion of patients. For inherited retinal degenerations (IRDs), although currently close to 300 disease-associated genes have been identified, the mutations in approximately one-third of patients remain unknown. With mounting evidence that noncoding mutations might contribute significantly to disease burden, we aimed to systematically investigate the contributions of noncoding regions in the genome to IRDs., Methods: In this study, we focused on RPGRIP1 , which has been linked to various IRD phenotypes, including Leber congenital amaurosis (LCA), retinitis pigmentosa (RP), and macular dystrophy (MD). As several noncoding mutant alleles have been reported in RPGRIP1, and we observed that the mutation carrier frequency of RPGRIP1 is higher in patient cohorts with unsolved IRDs, we hypothesized that mutations in the noncoding regions of RPGRIP1 might be a significant contributor to pathogenicity. To test this hypothesis, we performed whole-genome sequencing (WGS) for 25 patients with unassigned IRD who carry a single mutation in RPGRIP1 ., Results: Three noncoding variants in RPGRIP1 , including a 2,890 bp deletion and two deep-intronic variants (c.2710+233G>A and c.1468-263G>C), were identified as putative second hits of RPGRIP1 in three patients with LCA. The mutant alleles were validated with direct sequencing or in vitro assays., Conclusions: The results highlight the significance of the contribution of noncoding pathogenic variants to unsolved IRD cases., (Copyright © 2021 Molecular Vision.)

Purpose: To determine whether artifacts in optical coherence tomography (OCT) images are associated with the success or failure of adaptive optics scanning light ophthalmoscopy (AOSLO) imaging in subjects with achromatopsia (ACHM)., Methods: Previously acquired OCT and non-confocal, split-detector AOSLO images from one eye of 66 subjects with genetically confirmed achromatopsia (15 CNGA3 and 51 CNGB3 ) were reviewed along with best-corrected visual acuity (BCVA) and axial length. OCT artifacts in interpolated vertical volumes from CIRRUS macular cubes were divided into four categories: (1) none or minimal, (2) clear and low frequency, (3) low amplitude and high frequency, and (4) high amplitude and high frequency. Each vertical volume was assessed once by two observers. AOSLO success was defined as sufficient image quality in split-detector images at the fovea to assess cone quantity., Results: There was excellent agreement between the two observers for assessing OCT artifact severity category (weighted kappa = 0.88). Overall, AOSLO success was 47%. For subjects with OCT artifact severity category 1, AOSLO success was 65%; for category 2, 47%; for category 3, 11%; and for category 4, 0%. There was a significant association between OCT artifact severity category and AOSLO success ( P = 0.0002). Neither BCVA nor axial length was associated with AOSLO success ( P = 0.07 and P = 0.75, respectively)., Conclusions: Artifacts in OCT volumes are associated with AOSLO success in ACHM. Subjects with less severe OCT artifacts are more likely to be good candidates for AOSLO imaging, whereas AOSLO was successful in only 7% of subjects with category 3 or 4 OCT artifacts. These results may be useful in guiding patient selection for AOSLO imaging., Translational Relevance: Using OCT to prescreen patients could be a valuable tool for clinical trials that utilize AOSLO to reduce costs and decrease patient testing burden., Competing Interests: Disclosure: K.M. Litts, None; E.N. Woertz, None; M. Georgiou, MeiraGTx (C); E.J. Patterson, None; B.L. Lam, AGTC (F), G.A. Fishman, AGTC (F); M.E. Pennesi, AGTC (F); C.N. Kay, AGTC (F); W.W. Hauswirth, AGTC (I, R); M. Michaelides, MeiraGTx (C); J. Carroll, MeiraGTx (C, F), OptoVue (F), AGTC (F), Translational Imaging Innovations (I), (Copyright 2021 The Authors.)

In autosomal dominant conditions with haploinsufficiency, a single functional allele cannot maintain sufficient dosage for normal function. We hypothesized that pharmacologic induction of the wild-type allele could lead to gene dosage compensation and mitigation of the disease manifestations. The paired box 6 ( PAX6 ) gene is crucial in tissue development and maintenance particularly in eye, brain, and pancreas. Aniridia is a panocular condition with impaired eye development and limited vision due to PAX6 haploinsufficiency. To test our hypothesis, we performed a chemical screen and found mitogen-activated protein kinase kinase (MEK) inhibitors to induce PAX6 expression in normal and mutant corneal cells. Treatment of newborn Pax6 -deficient mice ( Pax6 Sey-Neu/+ ) with topical or systemic MEK inhibitor PD0325901 led to increased corneal PAX6 expression, improved corneal morphology, reduced corneal opacity, and enhanced ocular function. These results suggest that induction of the wild-type allele by drug repurposing is a potential therapeutic strategy for haploinsufficiencies, which is not limited to specific mutations., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Best disease (BD), also known as vitelliform macular dystrophy, is an inherited disease of the central retina caused by more than 300 pathogenic variants in the BEST1 gene. The phenotype of BD is variable, and there are just a few reports on the histopathology of eyes from donors with BD. Here, we describe the histopathological comparison of donor's eyes from two patients with BD. Eyes obtained from 85-year-old (donor 1) and 65-year-old (donor 2) donors were fixed within 25 h postmortem. Perifoveal and peripheral retinal regions were processed for histology and immunocytochemistry using retinal-specific and retinal pigment epithelium (RPE)-specific antibodies. Three age-matched normal eyes were used as controls. DNA was obtained from donor blood samples. Sequence analysis of the entire BEST1 coding region was performed and identified a c.886A > C (p.Asn296His) variant in donor 1 and a c.602T > C (p.Ile201Thr) variant in donor 2; both mutations were heterozygous. Fundus examination showed that donor 1 displayed a macular lesion with considerable scarring while donor 2 displayed close to normal macular morphology. Our studies of histology and molecular pathology in the perifovea and periphery of these two BD donor eyes revealed panretinal abnormalities in both photoreceptors and RPE cellular levels in the periphery; donor 1 also displayed macular lesion. Our findings confirm the phenotypic variability of BD associated with BEST1 variants., (Copyright © 2020 Bonilha, Bell, DeBenedictis, Hagstrom, Fishman and Hollyfield.)

We report two unrelated male patients presenting at a young age with decreased vision from a macular dystrophy due to biallelic CRB1 mutations. In addition to a previously-described pathogenic variant, Ile167&#95;Gly169del, two new pathogenic missense variants in CRB1, Thr745Met, and Cys948Tyr are reported here. While CRB1 mutations have been more commonly described in retinitis pigmentosa (RP) and Leber's congenital amaurosis (LCA), we demonstrate that mutations in CRB1 can cause a maculopathy whose initial features can resemble juvenile X-linked retinoschisis (JXLRS). We show that the accompanying macular edema is responsive to carbonic anhydrase inhibitors. With long-term follow-up for each case, we illustrate the natural history of CRB1 maculopathy based on clinical examination and diagnostic imaging., Competing Interests: Financial disclosure and competing interest statement: Each author warrants that he or she has no commercial associations that might pose a conflict of interest in connection with the submitted article. We hereby declare that none of the authors have a proprietary interest.

Purpose : To determine the interocular symmetry of foveal cone topography in achromatopsia (ACHM) using non-confocal split-detection adaptive optics scanning light ophthalmoscopy (AOSLO). Methods : Split-detector AOSLO images of the foveal cone mosaic were acquired from both eyes of 26 subjects (mean age 24.3 years; range 8-44 years, 14 females) with genetically confirmed CNGA3 - or CNGB3 -associated ACHM. Cones were identified within a manually delineated rod-free zone. Peak cone density (PCD) was determined using an 80 × 80 μm sampling window within the rod-free zone. The mean and standard deviation (SD) of inter-cell distance (ICD) were calculated to derive the coefficient of variation (CV). Cone density difference maps were generated to compare cone topography between eyes. Results : PCD (mean ± SD) was 17,530 ± 9,614 cones/mm 2 and 17,638 ± 9,753 cones/mm 2 for right and left eyes, respectively ( p = .677, Wilcoxon test). The mean (± SD) for ICD was 9.05 ± 2.55 µm and 9.24 ± 2.55 µm for right and left eyes, respectively ( p = .410, paired t -test). The mean (± SD) for CV of ICD was 0.16 ± 0.03 µm and 0.16 ± 0.04 µm for right and left eyes, respectively ( p = .562, paired t -test). Cone density maps demonstrated that cone topography of the ACHM fovea is non-uniform with local variations in cone density between eyes. Conclusions : These results demonstrate the interocular symmetry of the foveal cone mosaic (both density and packing) in ACHM. As cone topography can differ between eyes of a subject, PCD does not completely describe the foveal cone mosaic in ACHM. Nonetheless, these findings are of value in longitudinal monitoring of patients during treatment trials and further suggest that both eyes of a given subject may have similar therapeutic potential and non-study eye can be used as a control.

Purpose: To compare electrophysiological and pupillometric responses in subjects with cone-rod dystrophy due to autosomal recessive (AR) PROM1 mutations., Methods: Four subjects with AR PROM1 dystrophy and 10 visually normal, age-similar controls participated in this study. Full-field, light- and dark-adapted electroretinograms (ERGs) were obtained using conventional techniques. Full-field, light- and dark-adapted measures of the pupillary light reflex (PLR; pupil constriction elicited by a flash of light) were obtained across a range of stimulus luminance using long- and short-wavelength light. Pupil size as a function of stimulus luminance was described using Naka-Rushton functions to derive P max (maximum response) and s (pupil response sensitivity)., Results: Light-adapted ERGs were non-detectable in all four PROM1 subjects, whereas dark-adapted ERGs were non-detectable in three subjects and markedly attenuated in the fourth. By contrast, each PROM1 subject had light- and dark-adapted PLRs. P max ranged from normal to slightly attenuated under all conditions. Light-adapted s was generally normal, with the exception of two subjects who had abnormal s for the long-wavelength stimulus. Dark adapted s was abnormal for each PROM1 subject for the long-wavelength stimulus and ranged from the upper limit of normal to substantially abnormal for the short-wavelength stimulus., Conclusions: ERG and PLR comparison showed an unanticipated dichotomy: ERGs were generally non-detectable, whereas PLRs were normal for all PROM1 subjects under select conditions. Differences between the measures may be attributed to distinct spatiotemporal summation/gain characteristics., Translational Relevance: These data highlight the potential usefulness of pupillometry in cases where the ERG is non-detectable., Competing Interests: Disclosure: J.C. Park, None; F.T. Collison, None; G.A. Fishman, None; J.J. McAnany, None, (Copyright 2020 The Authors.)

Purpose: Retinitis pigmentosa (RP) is an inherited pigmentary retinal dystrophy where patients experience poor peripheral, night, and eventually central vision. There are statements in the literature which suggest visual acuity loss can progress to total blindness in these patients. This study sought to examine these statements by performing a retrospective analysis of the visual acuity measured in a large cohort of RP patients., Methods: The charts of 1,095 RP patients were reviewed in this retrospective cross-sectional analysis. They included all of the RP patients examined by one of the authors (G.A.F.). Patients with sector RP or a delimited form of this disease were not included. The review was focused on the analysis of patients with 20/200 or worse vision in the better-seeing eye (N = 215)., Results: We determined that 0.46% of the enrolled patients progressed to no light perception in each eye. Ninety-two percent of the 1,095 patients examined were able to read a visual acuity chart. There were 6.8% who saw only hand motion, count fingers, or light perception., Conclusion: No light perception was measured in only 0.46% of patients. Thus, only a very small number of the RP patients in our cohort progressed to total blindness.

Purpose: To evaluate the nature and extent of functional abnormality in X-linked retinoschisis (XLRS) by comparing three dark-adapted, full-field measures: the electroretinogram (ERG), pupillary light reflex (PLR), and luminance threshold., Methods: ERGs, PLRs (pupil constriction due to light stimulation), and luminance thresholds were measured from seven XLRS subjects and from 10 normally sighted, age-similar controls. ERGs and PLRs were obtained for a range of flash strengths, and these data were fit with Naka-Rushton functions to derive the maximum saturated b-wave (Vmax) and PLR (Pmax) amplitudes. Additionally, semi-saturation constants were obtained for the b-wave (σ) and PLR (s). Values of 1/σ and 1/s provide sensitivity measures. Full-field, dark-adapted luminance thresholds were measured using 465-nm and 642-nm flash stimuli., Results: Vmax and 1/σ were significantly reduced in XLRS compared to the controls (both t ≥ 5.33, P < 0.001). In comparison, Pmax was normal in the XLRS subjects (t = 1.39, P = 0.19), but 1/s was reduced (t = 7.84, P < 0.001). Luminance thresholds for the control and XLRS groups did not differ significantly (F = 3.57, P = 0.08). Comparisons among measures indicated that pupil sensitivity was correlated with luminance threshold for the long- and short-wavelength stimuli (both, r ≥ 0.77, P ≤ 0.04). Correlations among all other measures were not statistically significant., Conclusions: The results indicate that the presumed bipolar cell dysfunction in XLRS, indicated by b-wave abnormalities, has complex downstream effects: Dark-adapted luminance threshold and maximum pupil responses are not significantly affected, but pupil sensitivity is reduced.

Purpose: To investigate the Stargardt disease phenotype associated with an unusually common and "extremely hypomorphic" ABCA4 variant, p.N1868I., Methods: The charts of 27 patients with p.N1868I on one allele and a severe/deleterious mutation on the other allele were reviewed. Subjective age of onset, best-corrected visual acuity, and stage of disease were recorded for all 27 patients, 18 of whom had multiple visits. When available, fundus photography, spectral domain optical coherence tomography, fundus autofluorescence, full-field electroretinograms, Goldmann visual fields, and fluorescein angiography were included. Five families with multiple affected members were analyzed., Results: The median age at symptom onset was 41.5 years, and 3 p.N1868I patients had not developed visual symptoms as of the most recent eye examination. Median best-corrected visual acuity in the better-seeing eye at baseline was 20/25, and the median duration from symptom onset to legal blindness was 25 years. The five families described in this study demonstrated clinically significant intrafamilial variability, and affected family members who did not share the p.N1868I variant had relatively more severe phenotypes., Conclusion: This study demonstrates the consistency of foveal sparing, the variation in age at onset, the intrafamilial variability, and the prognosis with regard to visual acuity in p.N1868I-associated Stargardt disease.

Purpose: To investigate receptor and post-receptor function in KCNV2 retinopathy [cone dystrophy with supernormal rod electroretinogram (ERG)], using the pupillary light reflex (PLR) and the ERG., Methods: Two unrelated patients (1 male and 1 female) with molecularly confirmed KCNV2 retinopathy underwent full-field two-color pupillometry testing in one eye, with monitoring of the stimulated eye by an infrared digital camera. Pupillometry stimuli consisted of 1-s duration, short-wavelength (465-nm, blue) and long-wavelength (642-nm, red) stimuli. Pupillometry intensity series were performed under both a dark-adapted condition and a light-adapted condition (on a 0.76-log cd m -2 blue background). The transient PLR, defined as the maximum constriction following flash onset, was measured under all conditions. The melanopsin-mediated sustained constriction was measured 5-7 s following flash offset for the highest flash luminance presented in the dark. Both patients were also tested in one eye with the full-field ERG, including a dark-adapted intensity series and ISCEV standard stimuli., Results: Dark-adapted PLRs were markedly attenuated or extinguished for low-luminance stimuli, but the responses to higher-luminance blue stimuli were within normal limits. Light-adapted PLRs to blue stimuli were generally within normal limits, exceeding the responses to photopically matched red stimuli. Thus, light-adapted responses were consistent with either rod or S-cone mediation of the PLR. Melanopsin-mediated sustained PLRs were within normal limits. ERG showed the characteristic findings previously reported in this condition. Cone-mediated ERG responses were markedly decreased in amplitude. Rod-mediated ERG responses were absent for low-luminance stimuli (- 3 log cd s m -2 ), but had normal amplitude for stimuli of - 2 log cd s m -2 and above (although none were "supernormal"). The b-wave for the dark-adapted ISCEV standard - 2 log cd s m -2 stimulus was markedly delayed, whereas the b-wave timing was generally normal for higher flash luminances., Conclusions: The abnormalities measured by pupillometry have a similar pattern to the outer-retinal abnormalities measured by ERG in KCNV2 retinopathy. These findings as well as the normal sustained PLR suggest that inner-retinal function may be preserved in KCNV2 retinopathy and highlight the potential for therapies designed to restore outer-retinal function in these individuals.

Purpose: To define characteristic ocular features in a group of patients with autosomal recessive (AR) PROM1 cone-rod dystrophy (CRD)., Methods: Three males and one female from three unrelated families were first seen at the ages of 15 to 22 years and diagnosed with CRD. Clinical testing available for review included full-field electroretinogram (ERG) in three patients, as well as near-infrared autofluorescence (NIR-AF), spectral-domain optical coherence tomography (SD-OCT), and color fundus photography in all four patients. Whole exome sequencing (WES) was performed on all cases, and whole genome sequencing (WGS) was performed in two families., Results: WES found compound heterozygous PROM1 variants in one isolated male, plus heterozygous variants in the remaining patients. WGS uncovered deleterious PROM1 variants in these two families. ERG showed markedly reduced cone-isolated amplitudes and variably reduced rod-isolated amplitudes. The dark-adapted combined rod and cone responses demonstrated notably reduced a-wave amplitudes and moderately reduced b-waves, and the resultant waveform resembled the normal rod-isolated response. On fundus examination, oval-shaped macular lesions were observed, as were several small, circular hypoautofluorescent lesions within the posterior pole on NIR-AF. Three patients showed extramacular circular atrophic lesions., Conclusions: The autofluorescence changes, peripheral retinal abnormalities, and ERG findings have not been emphasized in previous reports of AR PROM1, but they became a recognizable phenotype in this cohort of patients. A similar constellation of findings may be observed in CRD due to CDHR1, a functionally related gene. The pattern of abnormalities reported herein may help to focus genetic screening in patients with these findings.

Purpose: The Usher syndrome phenotype is comprised of ocular and audiologic anomalies. Patients characteristically experience congenital hearing loss, nyctalopia, reduced visual fields, and ultimately decreased visual acuity. However, diagnosis may initially be more difficult in cases with limited ocular findings. Here, we present a case in which an adult patient had neither subjective visual complaints nor ocular findings at the time of diagnosis aside from a moderate reduction in rod and cone function on electroretinogram testing. Nevertheless, 43 years after his initial examination, he showed severe degenerative changes in the retina., Methods: A 63-year-old man with Usher syndrome type 2 underwent ophthalmic examination that included visual acuity, optical coherence tomography (OCT), electroretinogram (ERG), fundus photography, and Goldmann visual field testing. The patient also had genetic testing performed. We additionally reviewed the ocular findings on two of his siblings also afflicted with Usher syndrome type 2., Results: Our findings documented the long-term progression of Usher syndrome in this patient. They showed that the patient was asymptomatic with only a moderate reduction on ERG testing at the time of diagnosis, but subsequently progressed to an advanced stage of retinal disease with severe visual loss., Conclusions: The patient demonstrated that the absence of visual symptoms and favorable findings on functional testing on initial presentation might yet belie a future for austere visual loss. Caution is thus warranted when predicting a visual prognosis in such a patient. Further, the value in electroretinographic testing for diagnosis is demonstrated.

Purpose: To better define visual acuity loss in patients with Stargardt disease later in life., Methods: The most recent best-corrected visual acuities in the better-seeing eye of 221 patients with Stargardt disease over 40 years of age were recorded. Also included were the age at subjective onset for symptoms and duration of symptoms. Juvenile onset was defined as onset before age 21; adult onset was defined as onset between 21 and 40 years; and late onset was defined as onset at age 41 or later., Results: The median age of the patients with Stargardt disease was 53.1 years. Twenty-four patients (10.9%) had worse than 20/400 best-corrected visual acuity, and none had either light perception or no light perception vision. Whereas 17 of the 52 juvenile onset patients had best-corrected visual acuity worse than 20/400, only 4 of 80 adult-onset patients and 1 of 70 late-onset patients reached this level of acuity loss., Conclusion: Although many patients with Stargardt disease lose visual acuity to the 20/200 to 20/400 range, and some lose visual acuity beyond 20/400, none of these patients reached either light perception or no light perception. The numbers found in this study will be valuable in counseling patients with Stargardt disease and could have value in planning treatment trials.

Background: Carbonic anhydrase inhibitors (CAIs) have been shown to have a beneficial effect on cystoid macular edema in X-linked retinoschisis (XLRS) and other inherited retinal conditions. The effect of CAIs outside the macula has been less well studied., Methods: Snellen visual acuity, spectral-domain optical coherence tomography (SD-OCT), kinetic visual field, and dark-adapted single-flash full-field electroretinogram (ERG) testing were all done at baseline and at least one follow-up visit. A 55-year-old male diagnosed with XLRS exhibited extensive macular and extramacular cystoid splitting in the right eye and was treated with oral extended-release acetazolamide 500 mg/day., Results: By 6 months of follow-up on acetazolamide treatment, SD-OCT demonstrated resolution of cystoid spaces both within the macula and out to the midperiphery. Visual acuity improved from 20/70 to 20/30. The full-field ERG was distinctly electronegative at both baseline and at a follow-up visit, with oscillatory potentials becoming more apparent at the follow-up visit. Peripheral visual field boundaries did not change significantly., Conclusion: This report demonstrates structural resolution of cystoid spaces throughout much of the retina in a patient with XLRS, adding to a published case report in which we first noted that extramacular cystoid spaces observed in XLRS may respond to CAI treatment. To our knowledge, this is the first reported study of follow-up functional studies (ERG and perimetry) in a CAI treatment responder with XLRS.

Autosomal recessive Stargardt disease (STGD1, MIM 248200) is caused by mutations in the ABCA4 gene. Complete sequencing of the ABCA4 locus in STGD1 patients identifies two expected disease-causing alleles in ∼75% of patients and only one mutation in ∼15% of patients. Recently, many possibly pathogenic variants in deep intronic sequences of ABCA4 have been identified in the latter group. We extended our analyses of deep intronic ABCA4 variants and determined that one of these, c.4253+43G>A (rs61754045), is present in 29/1155 (2.6%) of STGD1 patients. The variant is found at statistically significantly higher frequency in patients with only one pathogenic ABCA4 allele, 23/160 (14.38%), MAF = 0.072, compared to MAF = 0.013 in all STGD1 cases and MAF = 0.006 in the matching general population ( P < 1 × 10 -7 ). The variant, which is not predicted to have any effect on splicing, is the first reported intronic "extremely hypomorphic allele" in the ABCA4 locus; that is, it is pathogenic only when in trans with a loss-of-function ABCA4 allele. It results in a distinct clinical phenotype characterized by late onset of symptoms and foveal sparing. In ∼70% of cases the variant was allelic with the c.6006-609T>A (rs575968112) variant, which was deemed nonpathogenic. Another rare deep intronic variant, c.5196+1056A>G (rs886044749), found in 5/834 (0.6%) of STGD1 cases is, conversely, a severe allele. This study determines pathogenicity for three noncoding variants in STGD1 patients of European descent accounting for ∼3% of the disease. Defining disease-associated alleles in the noncoding sequences of the ABCA4 locus can be accomplished by integrated clinical and genetic analyses., (© 2018 Zernant et al.; Published by Cold Spring Harbor Laboratory Press.)

Purpose: Congenital achromatopsia is an autosomal recessive disease causing substantial reduction or complete absence of cone function. Although believed to be a relatively stationary disorder, questions remain regarding the stability of cone structure over time. In this study, the authors sought to assess the repeatability of and examine longitudinal changes in measurements of central cone structure in patients with achromatopsia., Methods: Forty-one subjects with CNGB3-associated achromatopsia were imaged over a period of between 6 and 26 months using optical coherence tomography and adaptive optics scanning light ophthalmoscopy. Outer nuclear layer (ONL) thickness, ellipsoid zone (EZ) disruption, and peak foveal cone density were assessed., Results: ONL thickness increased slightly compared with baseline (0.184 μm/month, P = 0.02). The EZ grade remained unchanged for 34/41 subjects. Peak foveal cone density did not significantly change over time (mean change 1% per 6 months, P = 0.126)., Conclusion: Foveal cone structure showed little or no change in this group of subjects with CNGB3-associated achromatopsia. Over the time scales investigated (6-26 months), achromatopsia seems to be a structurally stable condition, although longer-term follow-up is needed. These data will be useful in assessing foveal cone structure after therapeutic intervention.

Purpose: To evaluate changes in cystic-appearing macular lesions and visual acuity in patients with X-linked retinoschisis while being treated with a carbonic anhydrase inhibitor., Methods: A retrospective analysis of 68 eyes from 36 patients between the ages of 5 years and 61 years with X-linked retinoschisis were monitored while on a carbonic anhydrase inhibitor. Macular cystic-appearing lesions were monitored with optical coherence tomography. Snellen visual acuity measurements were converted to logarithm of the minimum angle of resolution equivalent Early Treatment Diabetic Retinopathy Study letters for analysis. Analyses for changes in both visual acuity and macular cysts included comparisons between treatment and pretreatment segments., Results: Forty-five eyes (66%) had a reduction of their cysts while on a carbonic anhydrase inhibitor. Twenty eyes (29%) showed no cystic change, whereas 3 eyes (4%) demonstrated worsening of their cysts with treatment when compared with pretreatment. There was a statistically significant improvement in logarithm of the minimum angle of resolution visual acuity while on treatment relative to pretreatment (P < 0.0001). The estimated average Early Treatment Diabetic Retinopathy Study equivalent improvement was 0.09 (slightly less than one line on the Early Treatment Diabetic Retinopathy Study chart) with a 95% confidence interval of 0.08 to 0.11., Conclusion: Considering the entire 36 patients in this cohort, while statistically significant, the average improvement in visual acuity was modest. Nonetheless, in individual patients, the improvement was more substantial. Improvement in the extent of cystic macular lesions was observed in a high percentage of cases.

Background: Variation in the ABCA4 gene is causal for, or associated with, a wide range of phenotypes from early onset Mendelian retinal dystrophies to late-onset complex disorders such as age-related macular degeneration (AMD). Despite substantial progress in determining the causal genetic variation, even complete sequencing of the entire open reading frame and splice sites of ABCA4 identifies biallelic mutations in only 60%-70% of cases; 20%-25% remain with one mutation and no mutations are found in 10%-15% of cases with clinically confirmed ABCA4 disease. This study was designed to identify missing causal variants specifically in monoallelic cases of ABCA4 disease., Methods: Direct sequencing and analysis were performed in a large familial ABCA4 disease cohort of predominately European descent (n=643). Patient phenotypes were assessed from clinical and retinal imaging data., Results: We determined that a hypomorphic ABCA4 variant c.5603A>T (p.Asn1868Ile), previously considered benign due to high minor allele frequency (MAF) (~7%) in the general population, accounts for 10% of the disease, >50% of the missing causal alleles in monoallelic cases, ~80% of late-onset cases and distinguishes ABCA4 disease from AMD. It results in a distinct clinical phenotype characterised by late-onset of symptoms (4th decade) and foveal sparing (85%). Intragenic modifying effects involving this variant and another, c.2588G>C (p.Gly863Ala) allele, were also identified., Conclusions: These findings substantiate the causality of frequent missense variants and their phenotypic outcomes as a significant contribution to ABCA4 disease, particularly the late-onset phenotype, and its clinical variation. They also suggest a significant revision of diagnostic screening and assessment of ABCA4 variation in aetiology of retinal diseases., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Variants in the ABCA4 gene are the most common cause of juvenile-onset blindness affecting close to 1 in 10 000 people worldwide. Disease severity varies largely according to genotype, which can be specific to ethnic and racial groups. Here we investigate the spectrum of ABCA4 variation and its phenotypic expression in 38 patients of South Asian descent, notably from India, Pakistan, Bangladesh and Sri Lanka. Sequencing of all exons and flanking intronic sequences of ABCA4 revealed disease-causing variants in all patients: 3 in 2.6%, 2 in 81.6% and 1 in 15.8%. Altogether, 36 distinct variants were identified, including 9 previously not described. The most frequent variant c.5882G>A, p.(G1961E) was found in half the patients, the highest ever reported in a single study cohort. The South Asian founder variant c.859-9T>C was identified along with other founder variants ascribed to Danish, Chinese, Mexican and African patients. Patients carrying c.5882G>A, p.(G1961E) exhibited a consistently confined disease phenotype, normal quantitative autofluorescence (qAF) levels and preserved full-field ERG (ffERG) while c.859-9T>C resulted in widespread disease, significantly elevated qAF and reduced to non-detectable ffERG. South Asian patients present with a relatively unique ABCA4 profile comprised of various ethnic founder variants resulting in two or three major retinal phenotypes.

Purpose: To determine outcome measures for a clinical trial of Leber congenital amaurosis (LCA) associated with mutations in the GUCY2D gene., Design: Retrospective observational case series., Methods: Twenty-eight patients with GUCY2D-LCA (aged 2-59 years) were studied clinically and with chromatic full-field sensitivity testing (FST), optical coherence tomography (OCT), pupillometry, and the NEI Visual Function Questionnaire (VFQ)., Results: FST permitted quantitation of cone and rod sensitivity in these patients with severe visual impairment. For most patients, the degree of rod and cone sensitivity losses showed a relationship, thereby providing an opportunity to divide patients into cohorts by severity of rod and cone dysfunction. OCT analyses indicated that retinal structure could be used not only as an objective safety measure but also as an exploratory efficacy outcome. A foveal bulge was not present in 67% of patients. The intensity of inner segment/outer segment (ellipsoid zone line) reflectivity was reduced significantly at the fovea and in the rod-dense superior retina. Based on OCT and FST parameters, most patients had dissociation of structure and function. Abnormal pupillometry sensitivity in the majority of GUCY2D-LCA patients provided another objective efficacy outcome. NEI VFQ scores showed a similar range of findings to those of other severe retinal diseases., Conclusion: Conventional outcome measures, such as visual acuity and the NEI VFQ, will need to be complemented by methods more specific to this GUCY2D-LCA population. Any therapeutic strategy should determine if there is an effect on rod as well as cone function and structure. FST provides a photoreceptor-based subjective outcome; and OCT in 2 retinal regions, fovea and superior retina, can assess photoreceptor structure. A change in the relationship of structure and function away from baseline becomes evidence of efficacy., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: To determine efficacy outcome measures for clinical trials of Leber congenital amaurosis (LCA) associated with a common intronic mutation in the CEP290 gene., Methods: CEP290-LCA patients (ages 5-48) with the intronic mutation (c.2991+1655A>G) were studied as a retrospective observational case series using clinical methods and with full-field sensitivity testing (FST), optical coherence tomography (OCT), autofluorescence imaging (NIR-RAFI), transient pupillary light reflex (TPLR), oculomotor control and instability (OCI), a mobility course, and a questionnaire (NEI-VFQ). Patients were investigated cross-sectionally but a subset was able to be followed longitudinally., Results: With FST, there was no rod function; cone sensitivities had a wide range from not detectable to near normal. OCT analyses indicated retained central photoreceptors with abnormal distal laminae. Based on OCT and FST, most patients had dissociation of structure and function. TPLR was nondetectable in the majority of patients, with responders demonstrating severe losses in light sensitivity. OCI was abnormal in most patients. NEI-VFQ scores had a similar range to those of other severe retinopathies. Mobility scores were consistent with FST sensitivities. In patients examined with FST, OCT, and NIR-RAFI over long-term intervals (7-10 years), there was limited but detectable disease progression., Conclusions: Efficacy would be a quantitative change in foveal cone function and possibly distal laminar structure. FST provides a subjective photoreceptor-based outcome; OCT and NIR-RAFI can assess photoreceptor and RPE structure. TPLR and OCI can provide objective measures of postretinal transmission. Minimal change over a decade indicates that there is no practical value in natural history studies.

Purpose: Choroideremia is a progressive X-linked recessive dystrophy, characterized by degeneration of the retinal pigment epithelium (RPE), choroid, choriocapillaris, and photoreceptors. We examined photoreceptor structure in a series of subjects with choroideremia with particular attention to areas bordering atrophic lesions., Methods: Twelve males with clinically-diagnosed choroideremia and confirmed hemizygous mutations in the CHM gene were examined. High-resolution images of the retina were obtained using spectral domain optical coherence tomography (SD-OCT) and both confocal and non-confocal split-detector adaptive optics scanning light ophthalmoscope (AOSLO) techniques., Results: Eleven CHM gene mutations (3 novel) were identified; three subjects had the same mutation and one subject had two mutations. SD-OCT findings included interdigitation zone (IZ) attenuation or loss in 10/12 subjects, often in areas with intact ellipsoid zones; RPE thinning in all subjects; interlaminar bridges in the imaged areas of 10/12 subjects; and outer retinal tubulations (ORTs) in 10/12 subjects. Only split-detector AOSLO could reliably resolve cones near lesion borders, and such cones were abnormally heterogeneous in morphology, diameter and density. On split-detector imaging, the cone mosaic terminated sharply at lesion borders in 5/5 cases examined. Split-detector imaging detected remnant cone inner segments within ORTs, which were generally contiguous with a central patch of preserved retina., Conclusions: Early IZ dropout and RPE thinning on SD-OCT are consistent with previously published results. Evidence of remnant cone inner segments within ORTs and the continuity of the ORTs with preserved retina suggests that these may represent an intermediate state of retinal degeneration prior to complete atrophy. Taken together, these results supports a model of choroideremia in which the RPE degenerates before photoreceptors., Competing Interests: The authors have declared that no competing interests exist.

Importance: In recent years, the treatment of patients with advanced cutaneous melanoma has undergone substantial changes. Patients can now be offered treatment with immune checkpoint inhibitors, which are capable of increasing patient survival. However, these new treatments are associated with immune-related adverse effects that can involve different organ systems, including the eye., Observations: We describe the case of a patient who received a diagnosis of metastatic cutaneous melanoma and developed melanoma-associated retinopathy with unanticipated fundus findings while receiving treatment with the immune checkpoint inhibitor pembrolizumab. Chorioretinal scars with pigment accumulations developed in the retinal periphery in both eyes., Conclusions and Relevance: Immune checkpoint inhibitors, which are now being used more commonly for patients with advanced stages of melanoma, can exacerbate autoimmune diseases in patients with underlying clinical or latent autoimmunity. Clinicians should be aware of atypical eye findings, including chorioretinal scars.

Purpose: Congenital achromatopsia (ACHM) is an autosomal recessive disorder in which cone function is absent or severely reduced. Gene therapy in animal models of ACHM have shown restoration of cone function, though translation of these results to humans relies, in part, on the presence of viable cone photoreceptors at the time of treatment. Here, we characterized residual cone structure in subjects with CNGB3-associated ACHM., Methods: High-resolution imaging (optical coherence tomography [OCT] and adaptive optics scanning light ophthalmoscopy [AOSLO]) was performed in 51 subjects with CNGB3-associated ACHM. Peak cone density and inter-cone spacing at the fovea was measured using split-detection AOSLO. Foveal outer nuclear layer thickness was measured in OCT images, and the integrity of the photoreceptor layer was assessed using a previously published OCT grading scheme., Results: Analyzable images of the foveal cones were obtained in 26 of 51 subjects, with nystagmus representing the major obstacle to obtaining high-quality images. Peak foveal cone density ranged from 7,273 to 53,554 cones/mm2, significantly lower than normal (range, 84,733-234,391 cones/mm2), with the remnant cones being either contiguously or sparsely arranged. Peak cone density was correlated with OCT integrity grade; however, there was overlap of the density ranges between OCT grades., Conclusions: The degree of residual foveal cone structure varies greatly among subjects with CNGB3-associated ACHM. Such measurements may be useful in estimating the therapeutic potential of a given retina, providing affected individuals and physicians with valuable information to more accurately assess the risk-benefit ratio as they consider enrolling in experimental gene therapy trials. (www.clinicaltrials.gov, NCT01846052.).

Purpose: To evaluate rod-isolated, cone-isolated, and combined rod and cone flicker electroretinograms (ERGs) as a possible means to identify electrophysiological abnormalities in carriers of X-linked retinoschisis (XLRS)., Methods: Full-field ERGs were recorded from six carriers of XLRS (aged 34-66 years) and eight normally sighted subjects (aged 27-59 years) under rod-isolated (ERGR), cone-isolated (ERGC), and combined rod and cone (ERGR+C) conditions. ERGs were obtained using a four-primary LED-based ganzfeld photostimulator and standard recording techniques. The four primaries were modulated sinusoidally in phase to achieve combined rod and cone activation (ERGR+C) or in different phases to achieve ERGR and ERGC by means of triple silent substitution. After 30 min of dark adaptation, 8- and 15-Hz ERGR, ERGC, and ERGR+C responses were obtained at a mean luminance level of 24 scot. cd/m(2). Standard ISCEV ERGs were also obtained from each subject., Results: The ISCEV and 15-Hz flicker ERGs were generally within the normal range for the carriers. The 8-Hz ERGR, ERGC, and ERGR+C amplitudes were also generally normal. In contrast, the carriers had ERGR, ERGC, and ERGR+C timing abnormalities, with phase advances beyond the range of normal for the ERGR (four carriers), ERGC (four carriers), and ERGR+C (three carriers). Only one carrier had normal 8-Hz responses under all conditions., Conclusions: The 8-Hz ERG timing abnormalities in five of six carriers indicate that retinal function is not necessarily normal in carriers of XLRS. The 8-Hz flicker ERG may be useful for studying retinal function in these individuals.

Purpose: The purpose of this study was to evaluate pupillary light reflexes (PLRs) mediated by rod, cone, and intrinsically photosensitive retinal ganglion cell pathways as indices of outer- and inner-retinal function in patients who have enhanced S-cone syndrome (ESCS) due to NR2E3 mutations., Methods: Four patients with ESCS (ages 16-23 years) participated in the study. Subjects were tested with long- and short-wavelength single-flash full-field ERG stimuli under light-adapted conditions. They were also tested with an established pupillometry protocol involving 1-s duration, long- and short-wavelength stimuli under dark- and light-adapted conditions. The PLR was measured as a function of stimulus luminance. Transient PLRs were measured under all conditions, and sustained PLRs were measured under the highest luminance dark-adapted condition., Results: Two-color light-adapted full-field ERGs demonstrated larger amplitude responses for short-wavelength stimuli relative to long-wavelength stimuli of the same photopic luminance, with three of four ESCS patients having super-normal a-wave amplitudes to the short-wavelength stimulus. b/a wave ratios were reduced in all four cases. Transient PLRs elicited by low-luminance stimuli under dark-adapted conditions (rod-mediated) were unrecordable, whereas the sustained PLRs elicited by high-luminance stimuli (melanopsin-mediated) were normal. Cone-mediated PLRs were recordable for all four patients, but generally lower than normal in amplitude. However, the cone-mediated PLR was larger for the short-wavelength stimulus compared to the photopically matched long-wavelength stimulus at high luminances, a pattern that was not observed for control subjects. None of the PLR conditions demonstrated "super-normal" responses., Conclusion: ESCS patients appear to have generally well-preserved cone- and melanopsin-mediated PLRs, indicating intact inner-retinal function. Two-color pupillometry demonstrates greater sensitivity to short-wavelength light under higher-luminance conditions and could complement the ERG as a tool for evaluating retinal function in ESCS.

Background: The goal of this study was to define the histopathology of the retina in donor eyes from a patient with Stargardt disease (STGD1) due to compound mutations in the ABCA4 gene., Materials and Methods: Eyes were obtained from a 66-year-old female and fixed within 18 hours postmortem. The fundi of the posterior globes were evaluated with macroscopic, SLO and OCT imaging. The perifoveal and peripheral regions were processed for electron microscopy and immunocytochemistry using cell specific antibodies. Two age-similar normal eyes were used as controls. Prior ophthalmic examinations and genetic test results were also reviewed., Results: All imaging modalities showed scattered bone spicules in the peripheral retina. Atrophy of the RPE was present around the optic nerve as evidenced by the absence of SLO autofluorescence. Histology analysis showed a severely degenerated fovea with little evidence of any retinal layering or remaining RPE. The fovea was severely degenerated, with little evidence of any retinal cell layer, including the RPE. In contrast, retinal nuclear layers were present in the periphery. The perifoveal region contained few cones labeled with cone-specific antibodies; some rhodopsin-labeled cells, reactive glia labeled with GFAP; and decreased autofluorescence of the RPE. The fovea was free of cone-specific labeling, contained a few disorganized rhodopsin-labeled cells and showed substantial GFAP labeling and no autofluorescent material in the retina. The periphery displayed stubby cells labeled with cone-specific antibodies, decreased rhodopsin-labeled cells, increased GFAP staining, and autofluorescent granules in the RPE., Conclusions: The histopathology of the retina in this patient with Stargardt disease displayed a highly degenerated fovea. In all retinal locations studied, cones were more severely affected than rods.

Purpose: To demonstrate a method for correlating photoreceptor mosaic structure with optical coherence tomography (OCT) and microperimetry findings in patients with Stargardt disease., Methods: A total of 14 patients with clinically diagnosed Stargardt disease were imaged using confocal and split-detection adaptive optics scanning light ophthalmoscopy. Cone photoreceptors were identified manually in a band along the temporal meridian. Resulting values were compared to a normative database ( n = 9) to generate cone density deviation (CDD) maps. Manual measurement of outer nuclear layer plus Henle fiber layer (ONL+HFL) thickness was performed, in addition to determination of the presence of ellipsoid zone (EZ) and interdigitation zone (IZ) bands on OCT. These results, along with microperimetry data, were overlaid with the CDD maps., Results: Wide variation in foveal structure and CDD maps was seen within this small group. Disruption of ONL+HFL and/or IZ band was seen in all patients, with EZ band preservation in regions with low cone density in 38% of locations analyzed. Normality of retinal lamellar structure on OCT corresponded with cone density and visual function at 50/78 locations analyzed. Outer retinal tubulations containing photoreceptor-like structures were observed in 3 patients., Conclusions: The use of CDD color-coded maps enables direct comparison of cone mosaic local density with other measures of retinal structure and function. Larger normative datasets and improved tools for automation of image alignment are needed., Translational Relevance: The approach described facilitates comparison of complex multimodal data sets from patients with inherited retinal degeneration, and can be expanded to incorporate other structural imaging or functional testing.

Purpose: To identify specific mutations causing North Carolina macular dystrophy (NCMD)., Design: Whole-genome sequencing coupled with reverse transcription polymerase chain reaction (RT-PCR) analysis of gene expression in human retinal cells., Participants: A total of 141 members of 12 families with NCMD and 261 unrelated control individuals., Methods: Genome sequencing was performed on 8 affected individuals from 3 families affected with chromosome 6-linked NCMD (MCDR1) and 2 individuals affected with chromosome 5-linked NCMD (MCDR3). Variants observed in the MCDR1 locus with frequencies <1% in published databases were confirmed using Sanger sequencing. Confirmed variants absent from all published databases were sought in 8 additional MCDR1 families and 261 controls. The RT-PCR analysis of selected genes was performed in stem cell-derived human retinal cells., Main Outcome Measures: Co-segregation of rare genetic variants with disease phenotype., Results: Five sequenced individuals with MCDR1-linked NCMD shared a haplotype of 14 rare variants spanning 1 Mb of the disease-causing allele. One of these variants (V1) was absent from all published databases and all 261 controls, but was found in 5 additional NCMD kindreds. This variant lies in a DNase 1 hypersensitivity site (DHS) upstream of both the PRDM13 and CCNC genes. Sanger sequencing of 1 kb centered on V1 was performed in the remaining 4 NCMD probands, and 2 additional novel single nucleotide variants (V2 in 3 families and V3 in 1 family) were identified in the DHS within 134 bp of the location of V1. A complete duplication of the PRDM13 gene was also discovered in a single family (V4). The RT-PCR analysis of PRDM13 expression in developing retinal cells revealed marked developmental regulation. Next-generation sequencing of 2 individuals with MCDR3-linked NCMD revealed a 900-kb duplication that included the entire IRX1 gene (V5). The 5 mutations V1 to V5 segregated perfectly in the 102 affected and 39 unaffected members of the 12 NCMD families., Conclusions: We identified 5 rare mutations, each capable of arresting human macular development. Four of these strongly implicate the involvement of PRDM13 in macular development, whereas the pathophysiologic mechanism of the fifth remains unknown but may involve the developmental dysregulation of IRX1., (Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Unlabelled: Restoring vision in inherited retinal degenerations remains an unmet medical need. In mice exhibiting a genetically engineered block of the visual cycle, vision was recently successfully restored by oral administration of 9-cis-retinyl acetate (QLT091001). Safety and visual outcomes of a once-daily oral dose of 40 mg/m2/day QLT091001 for 7 consecutive days was investigated in an international, multi-center, open-label, proof-of-concept study in 18 patients with RPE65- or LRAT-related retinitis pigmentosa. Eight of 18 patients (44%) showed a ≥20% increase and 4 of 18 (22%) showed a ≥40% increase in functional retinal area determined from Goldmann visual fields; 12 (67%) and 5 (28%) of 18 patients showed a ≥5 and ≥10 ETDRS letter score increase of visual acuity, respectively, in one or both eyes at two or more visits within 2 months of treatment. In two patients who underwent fMRI, a significant positive response was measured to stimuli of medium contrast, moving, pattern targets in both left and right hemispheres of the occipital cortex. There were no serious adverse events. Treatment-related adverse events were transient and the most common included headache, photophobia, nausea, vomiting, and minor biochemical abnormalities. Measuring the outer segment length of the photoreceptor layer with high-definition optical coherence tomography was highly predictive of treatment responses with responders having a significantly larger baseline outer segment thickness (11.7 ± 4.8 μm, mean ± 95% CI) than non-responders (3.5 ± 1.2 μm). This structure-function relationship suggests that treatment with QLT091001 is more likely to be efficacious if there is sufficient photoreceptor integrity., Trial Registration: ClinicalTrials.gov NCT01014052.

Purpose: To investigate visual function in patients with CEP290 Leber congenital amaurosis (LCA-CEP290), using three full-field tests that can be performed by patients with poor fixation., Methods: Six patients (age range, 9-39 years) with LCA-CEP290 participated in the study. Stimuli for all three tests (full-field stimulus test [FST], pupillometry, and light discomfort threshold [LDT] testing) were generated by the Diagnosys ColorDome ganzfeld, by using achromatic stimuli as well as long- and short-wavelength stimuli to target rod and cone photoreceptors with all three tests and, in the latter two tests, melanopsin photoreceptors., Results: Dark-adapted FST thresholds in LCA-CEP290 patients were cone mediated and elevated between 4.8 and 6.2 log units above the normal achromatic threshold. The FST threshold was not measurable in one patient. The rod-mediated transient pupillary light reflex (PLR) was absent in all but the youngest patient, where unreliable responses precluded PLR quantification. Cone-mediated transient PLRs were subnormal in five patients, and absent in another. Sustained melanopsin-mediated PLRs were measurable in all patients. Full-field LDT thresholds were elevated compared to normal controls, and were lower for short-wavelengh than for long-wavelength stimuli., Conclusions: The FST thresholds and transient PLRs were cone mediated in our cohort LCA-CEP290 patients. Rod-mediated PLRs were undetectable, whereas melanopsin-mediated sustained responses were detected in all patients, suggesting a relative preservation of inner-retina function. The LDT elevations for the patients are somewhat paradoxical, given their subjective perception of photoaversion. Relative aversion to short-wavelength light suggests influence from melanopsin on LDTs in these patients.

Purpose: To develop and apply an objective algorithm for analyzing outer retinal layers imaged by spectral-domain optical coherence tomography (SD-OCT) in patients with Stargardt disease (STGD1)., Methods: Horizontal macular B-scans were acquired from 20 visually normal controls and 20 genetically confirmed stage 1 STGD1 patients. The number of outer retinal bands was quantified using a semiautomated algorithm that detected bands using the second derivative of longitudinal reflectivity profiles. The present analysis focused on the three outermost bands, currently associated with the ellipsoid zone (EZ), cone outer segment interdigitation zone (IZ), and retinal pigment epithelium (RPE) complex., Results: The RPE complex and EZ bands were detected throughout the B-scan in all controls. The RPE complex was detected throughout the B-scan in all patients, but was atrophic appearing in some locations. The EZ band was detected only outside the central lesion. Interdigitation zone band detection varied as a function of eccentricity for both groups, with detection for controls being highest in the para- and perifovea and lowest in the fovea and near periphery. In patients, the IZ band was generally not present in the fovea or para- or perifovea due to the central lesion. Outside of the lesion, the IZ band was detected in 26% of patients (mean detection across the near periphery), which was approximately half of the detection in controls., Conclusions: An objective approach for quantifying the number of outer retinal OCT bands found reduced IZ detection in STGD1 patients. This occurred even outside the central lesion, demonstrating an inability to image the IZ, possibly due to enhanced RPE reflectivity or abnormal outer retinal structure.