Abnormal Visual Function Outside the Area of Atrophy Defined by Short-Wavelength Fundus Autofluorescence in Stargardt Disease

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

Purpose

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

Design

Cohort study.

Subjects

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

Methods

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

Main Outcome Measures

Microperimetry grid parameters at baseline and progression rates.

Results

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

Conclusions

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

Financial Disclosures

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

Informing Endpoints for Clinical Trials of Geographic Atrophy

Geographic atrophy (GA), the non-neovascular advanced form of age-related macular degeneration, remains an important disease area in which treatment needs are currently unmet. Recent clinical trials using drugs that target the complement pathway have shown modest yet consistent reductions in GA expansion but without commensurate changes in measures of visual function. In this review, we summarize information from the wide range of studies describing the characteristics of GA morphology and enumerate the factors influencing the growth rates of lesions and the directionality of expansion. In addition, we review the relationship between GA growth and the various measures of vision that reflect changes in function. We consider the reasons for the discordance between the anatomical and functional endpoints in current use and discuss methods to align these key outcomes.

Retinal Imaging Findings in Inherited Retinal Diseases

Inherited retinal diseases (IRDs) represent one of the major causes of progressive and irreversible vision loss in the working-age population. Over the last few decades, advances in retinal imaging have allowed for an improvement in the phenotypic characterization of this group of diseases and have facilitated phenotype-to-genotype correlation studies. As a result, the number of clinical trials targeting IRDs has steadily increased, and commensurate to this, the need for novel reproducible outcome measures and endpoints has grown. This review aims to summarize and describe the clinical presentation, characteristic imaging findings, and imaging endpoint measures that are being used in clinical research on IRDs. For the purpose of this review, IRDs have been divided into four categories: (1) panretinal pigmentary retinopathies affecting rods or cones; (2) macular dystrophies; (3) stationary conditions; (4) hereditary vitreoretinopathies.

Local progression kinetics of macular atrophy in recessive Stargardt disease

BACKGROUND

To determine the effect of lesion topography on progression in Stargardt disease (STGD1).

METHODS

Fundus autofluoresence (excitation 488 nm) images of 193 eyes in patients with proven ABCA4 mutation were semi-automatically segmented for autofluoresence changes: (DDAF) and questionably decreased autofluoresence (QDAF), which are proxies for retinal pigment epithelial (RPE) atrophy. We calculated topographic incidence of DDAF and DDAF + QDAF, as well as velocity of progression of the border of lesions using Euclidean distance mapping.

RESULTS

Incidence of atrophy was highest near the fovea, then decreased in incidence with increased foveal eccentricity. However, the rate of atrophy progression followed the opposite pattern; rate of atrophy increased with distance from foveal center. The mean growth rate 500 microns from the foveal center for DDAF + QDAF was 39 microns per year (95% CI = 28-49), whereas the mean growth rate 3000 microns from the foveal center was 342 microns per year (95% CI = 194-522). No difference in growth rate was noted by axis around the fovea.

CONCLUSIONS

Incidence and progression of atrophy by fundus autofluorescence follow opposite patterns in STGD1. Further, atrophy progression increases significantly with distance from foveal center, which should be taken into consideration in clinical trials.

Monitoring Lesion Area Progression in Stargardt Disease: A Comparison of En Face Optical Coherence Tomography and Fundus Autofluorescence

Purpose

To compare longitudinal changes in en face spectral domain-optical coherence tomography (SD-OCT) measurements of ellipsoid zone (EZ) and retinal pigment epithelium (RPE) loss to changes in the hypoautofluorescent and hyperautofluorescent (AF) areas detected with short-wavelength (SW)-AF in ABCA4-associated retinopathy.

Methods

SD-OCT volume scans were obtained from 20 patients (20 eyes) over 2.6 ± 1.2 years (range 1-5 years). The EZ, and RPE/Bruch's membrane boundaries were segmented, and en face slab images generated. SubRPE and EZ slab images were used to measure areas of atrophic RPE and EZ loss. These were compared to longitudinal measurements of the hypo- and abnormal AF (hypoAF and surrounding hyperAF) areas.

Results

At baseline, the en face area of EZ loss was significantly larger than the subRPE atrophic area, and the abnormal AF area was significantly larger than the hypoAF area. The median rate of EZ loss was significantly greater than the rate of increase in the subRPE atrophic area (1.2 mm2/yr compared to 0.5 mm2/yr). The median rate of increase in the abnormal AF area was significantly greater than the increase in the hypoAF area (1.6 mm2/yr compared to 0.6 mm2/yr).

Conclusions

En face SD-OCT can be used to quantify changes in RPE atrophy and photoreceptor integrity. It can be a complementary or alternative technique to SW-AF with the advantage of monitoring EZ loss. The SW-AF results emphasize the importance of measuring changes in the hypo- and abnormal AF areas.

Translational Relevance

The findings are relevant to the selection of outcome measures for monitoring ABCA4-associated retinopathy.

Evaluating the quality and readability of online information on keratoconus treatment

OBJECTIVE

This study aims to evaluate the quality and readability of online resources on keratoconus treatment.

METHODS

A Google.com search was conducted on August 9, 2020; 32 web sites were selected for analysis. Popularity was assessed by Google and Alexa rank. The quality of web sites was analyzed using the quality criteria for consumer health information (DISCERN) tool, the Journal of the American Medical Association (JAMA) benchmark, and the Health On the Net Code of Conduct Certification (HONcode). The readability of the web sites was assessed using the Fleschwebr hea Reading Ease, the Automated Readability Index, and the Fleschted Readability RESULTS: The JAMA benchmark scores, unlike the DISCERN scores, were correlated with the Google and Alexa rank. One web site (3.1%) met all the JAMA benchmark criteria, and 3 (9.3%) others had HONcode certification. The median DISCERN score was 33 (range, 29.6-43.1; maximum possible, 80). Rnib.org.uk scored the highest at 57 (71.0%). The mean Flesch-Kincaid Reading Ease score (52.9 ± 7.1) corresponded to uk" n DIdifficult to read." Thirty-one web sites (96.8%) had a Flesch-Kincaid Grade higher than the American Medical Association recommendation of sixth grade level. The median Automated Readability Index score was 7 (range, 6.2-7.3).

CONCLUSION

The majority of online information currently available on keratoconus treatment is complex and highly variable. Rnib.org.uk is the best currently available source. Clinicians should inform patients on how to assess the credibility of online information and recommend suitable information sources.

Longitudinal Analysis of a Resolving Foveomacular Vitelliform Lesion in ABCA4 Disease

PURPOSE

To describe the longitudinal progression and phenotypic association of bilateral foveomacular vitelliform lesions in the setting of ABCA4 disease.

DESIGN

Case report and cross-sectional cohort study.

PARTICIPANTS

Nineteen patients with confirmed ABCA4 disease exhibiting an optical gap phenotype.

METHODS

Multimodal retinal imaging across multiple visits included autofluorescence imaging, spectral-domain OCT (SD-OCT), and OCT angiography. Electro-oculogram (EOG) and full-field electroretinogram testing results were analyzed. Exome sequencing was performed for diagnostic confirmation and the verification of other variations.

MAIN OUTCOME MEASURES

Light-peak-to-dark-trough ratio (Arden ratio) on EOG; thickness and en face maps of various retinal layers on SD-OCT; area measurements on 488- and 787-nm autofluorescence images; and the presence of variation in vitelliform-associated genes identified using exome sequencing.

RESULTS

A 25-year-old White man presented with bilateral central vision loss due to foveal lesions consisting of vitelliform fluid. The result of EOG testing was inconsistent with bestrophinopathy (Arden ratio = 1.62), and no generalized rod or cone dysfunction was detected on full-field electroretinogram. Exome sequencing identified the pathogenic variants c.5882G>A (p.(Gly1961Glu)) and c.4139C>T (p.(Pro1380Leu)) in ABCA4 and no other vitelliform-associated genes. Significant thinning and abnormal reflectivity of photoreceptor-attributable layers as well as near-infrared autofluorescence abnormalities were found in lesion-adjacent areas. Complete resorption of the vitelliform fluid occurred after 30 months, after which the optical gap lesions exhibited an enlarged and "cavitated" appearance. Phenotypic screening for additional cases from a large ABCA4 disease database (n = 602) identified 18 additional patients at various stages of optical gap lesion formation, most of whom harbored the c.5882G>A (p.(Gly1961Glu)) variant (P < 0.001), although none had apparent vitelliform fluid. At least 5 of the 18 (31.6%) patients exhibited optical gap lesions with the distinct "cavitated" appearance, whereas the lesions remained unperturbed in the other patients over the course of examination.

CONCLUSIONS

Foveomacular vitelliform deposition is a mechanistically congruent but rare manifestation of ABCA4 disease. Specifically, this disease phenotype may be clinically associated with the c.5882G>A (p.(Gly1961Glu)) allele and optical gap lesions.

Photoreceptor degeneration in ABCA4-associated retinopathy and its genetic correlates

BACKGROUND

Outcome measures sensitive to disease progression are needed for ATP-binding cassette, sub-family A, member 4–associated (ABCA4-associated) retinopathy. We aimed to quantify ellipsoid zone (EZ) loss and photoreceptor degeneration beyond EZ-loss in ABCA4-associated retinopathy and investigate associations between photoreceptor degeneration, genotype, and age.

METHODS

We analyzed 132 eyes from 66 patients (of 67 enrolled) with molecularly confirmed ABCA4-associated retinopathy from a prospective natural history study with a median [IQR] follow-up of 4.2 years [3.1, 5.1]. Longitudinal spectral-domain optical coherence tomography volume scans (37 B-scans, 30° × 15°) were segmented using a deep learning (DL) approach. For genotype-phenotype analysis, a model of ABCA4 variants was applied with the age of criterion EZ-loss (6.25 mm²) as the dependent variable.

RESULTS

Patients exhibited an average (square-root-transformed) EZ-loss progression rate of [95% CI] 0.09 mm/y [0.06, 0.11]. Outer nuclear layer (ONL) thinning extended beyond the area of EZ-loss. The average distance from the EZ-loss boundary to normalization of ONL thickness (to ±2 z score units) was 3.20° [2.53, 3.87]. Inner segment (IS) and outer segment (OS) thinning was less pronounced, with an average distance from the EZ-loss boundary to layer thickness normalization of 1.20° [0.91, 1.48] for the IS and 0.60° [0.49, 0.72] for the OS. An additive model of allele severity explained 52.7% of variability in the age of criterion EZ-loss.

CONCLUSION

Patients with ABCA4-associated retinopathy exhibited significant alterations of photoreceptors outside of EZ-loss. DL-based analysis of photoreceptor laminae may help monitor disease progression and estimate the severity of ABCA4 variants.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01736293.

FUNDING

National Eye Institute Intramural Research Program and German Research Foundation grant PF950/1-1.

Comparisons Among Optical Coherence Tomography and Fundus Autofluorescence Modalities as Measurements of Atrophy in ABCA4-Associated Disease

Purpose

In ABCA4-associated retinopathy, central atrophy was assessed by spectral domain optical coherence tomography (SD-OCT) and by short-wavelength (SW-AF) and near-infrared (NIR-AF) autofluorescence.

Methods

Patients exhibited a central atrophic lesion characterized by hypoautofluorescence (hypoAF) surrounded either by hyperautofluorescent (hyperAF) rings in both AF images (group 1, 4 patients); or a hyperAF ring in SW-AF but not in NIR-AF images (group 2, 11 patients); or hyperAF rings in neither AF images (group 3, 11 patients). Choroidal hypertransmission and widths of ellipsoid zone (EZ) loss were measured in foveal SD-OCT scans, and in AF images hypoAF and total hypo+hyperAF widths were measured along the same axis. Bland-Altman and repeated measures analysis of variance with Tukey post hoc were applied.

Results

For all groups, hypertransmission widths were significantly smaller than EZ loss widths. In Groups 1 and 2, hypertransmission width was not significantly different than SW-hypoAF width, but hypertransmission was narrower than the width of SW-hypo+hyperAF (groups 1, 2) and NIR-hypo+hyperAF (group 1). In group 3, the hypertransmission width was also significantly less than the width of SW-hypoAF and NIR-hypoAF. The EZ loss widths were not significantly different than measurements of total lesion size, the latter being the widths of SW-hypo+hyperAF and NIR-hypo+hyperAF (group 1); widths of NIR-hypoAF and SW-hypo+hyperAF (group 2); and widths of NIR-hypoAF and SW-hypoAF (group 3).

Conclusions

Hypertransmission and SW-hypoAF (except when reflecting total lesion width) underestimate lesion size detected by EZ loss, SW-hypoAF+hyperAF, and NIR-hypo+hyperAF.

Translational Relevance

The findings are significant to the selection of outcome measures in clinical studies.

Intraocular iron injection induces oxidative stress followed by elements of geographic atrophy and sympathetic ophthalmia

Iron has been implicated in the pathogenesis of age‐related retinal diseases, including age‐related macular degeneration (AMD). Previous work showed that intravitreal (IVT) injection of iron induces acute photoreceptor death, lipid peroxidation, and autofluorescence (AF). Herein, we extend this work, finding surprising chronic features of the model: geographic atrophy and sympathetic ophthalmia. We provide new mechanistic insights derived from focal AF in the photoreceptors, quantification of bisretinoids, and localization of carboxyethyl pyrrole, an oxidized adduct of docosahexaenoic acid associated with AMD. In mice given IVT ferric ammonium citrate (FAC), RPE died in patches that slowly expanded at their borders, like human geographic atrophy. There was green AF in the photoreceptor ellipsoid, a mitochondria‐rich region, 4 h after injection, followed later by gold AF in rod outer segments, RPE and subretinal myeloid cells. The green AF signature is consistent with flavin adenine dinucleotide, while measured increases in the bisretinoid all‐trans‐retinal dimer are consistent with the gold AF. FAC induced formation carboxyethyl pyrrole accumulation first in photoreceptors, then in RPE and myeloid cells. Quantitative PCR on neural retina and RPE indicated antioxidant upregulation and inflammation. Unexpectedly, reminiscent of sympathetic ophthalmia, autofluorescent myeloid cells containing abundant iron infiltrated the saline‐injected fellow eyes only if the contralateral eye had received IVT FAC. These findings provide mechanistic insights into the potential toxicity caused by AMD‐associated retinal iron accumulation. The mouse model will be useful for testing antioxidants, iron chelators, ferroptosis inhibitors, anti‐inflammatory medications, and choroidal neovascularization inhibitors.

Analysis of retinal sublayer thicknesses and rates of change in ABCA4-associated Stargardt disease

Stargardt disease, the most common inherited macular dystrophy, is characterized by vision loss due to central retinal atrophy. Although clinical trials for Stargardt are currently underway, the disease is typically slowly progressive, and objective, imaging-based biomarkers are critically needed. In this retrospective, observational study, we characterize the thicknesses of individual retinal sublayers by macular optical coherence tomography (OCT) in a large cohort of patients with molecularly-confirmed, ABCA4-associated Stargardt disease (STGD1) relative to normal controls. Automated segmentation of retinal sublayers was performed with manual correction as needed, and thicknesses in various macular regions were compared using mixed effects models. Relative to controls (42 eyes, 40 patients), STGD1 patients (107 eyes, 63 patients) had slight thickening of the nerve fiber layer and retinal pigment epithelium-Bruch’s membrane, with thinning in other sublayers, especially the outer nuclear layer (ONL) (p < 0.0015). When comparing the rate of retinal sublayer thickness change over time (mean follow-up 3.9 years for STGD1, 2.5 years for controls), STGD1 retinas thinned faster than controls in the outer retina (ONL to photoreceptor outer segments). OCT-based retinal sublayer thickness measurements are feasible in STGD1 patients and may provide objective measures of disease progression or treatment response.

The Effect of Therapeutic Meibomian Glands Expression on Evaporative Dry Eye: A Prospective Randomized Controlled Trial

PURPOSE

To determine the clinical benefits of Meibomian gland expression therapy for the treatment of dry-eye disease caused by Meibomian gland dysfunction (MGD).

METHODS

In a prospective randomized controlled double-masked trial, 87 eyes of 44 patients with MGD and dry-eye symptoms were enrolled. Patients were randomly assigned into two groups; a study group that received therapeutic Meibomian gland expression once every month, and a control group that received sham treatment. All patients received treatment with artificial tears.

RESULTS

One week after the first treatment, the Ocular Surface Disease Index (OSDI) score improved significantly in the study group (mean change -18.5 ± 21.2, p = .01) but not in the control group (-3.8 ± 15.8, p = .16); after 1 month, both groups improved significantly (-20.5 ± 19 p = .001 in the study group and -6.5 ± 11, p = .016 in the control group). The improvement continued at 2 months in the study group (-28.4 ± 26.1, P < .0001) and in the control group (-9.6 ± 9.9, p = .007). The blepharitis questionnaire score improved in the study group compared to controls after 1 week (-9.95 ± 12.52 versus -1.77 ± 9.1, p = .03) 1 month (-11.5 ± 10.9 versus -1.1 ± 9.4, p = .02) and 2 months (-16.5 ± 8.0 versus -8.8 ± 11.7, p = .02). Burning sensation was significantly reduced only in the study group. Mean change after 2-month treatment was -2.00 ± 1.2583 (p < .0001) vs -0.67 ± 1.44 (p = .08). The trend was similar in Eyelid scales. Conjunctival hyperemia improved only in the study group 1 week after the treatment (-0.12 ± 0.32 p = .03).

CONCLUSION

Therapeutic Meibomian gland expression improves dry-eye symptoms in subjects with MGD, compared to conventional treatment with artificial tears.

Low-Intensity Laser Light Projection for Improved Reading Abilities in Low-Vision Patients

PURPOSE

To evaluate the efficacy of a new laser imaging device that projects images onto functioning macular areas, to improve visual acuity (VA) in low-vision patients with macular diseases.

METHODS

An interventional case series of consecutive patients with low vision in their right eyes (RE). RE VA was measured by showing the patients digits of various standard sizes and measuring their best-corrected VA (BCVA). Then, using the I.C.INSIDE device to project the same standard digits onto functioning macular areas. Patient's ability to recognize the digits with the I.C.INSIDE device was correlated with patient's performance using telescopic low-vision aids. The main outcome measure was change in VA with the different visual aids.

RESULTS

Eleven patients (6 males and 5 females) with an average age of 75 ± 6.7 years and low vision in their RE due to macular diseases were included in the study. Baseline BCVA was 1.554 ± 0.50 logMAR. Low-vision aids improved mean VA in 10 patients to 0.64 ± 0.40 logMAR (p < .0001), further improvement was noticed in 8 patients to 0.35 ± 0.16 logMAR (p < .0001) using the laser device, but, three patients did not recognize any digit using the laser device.

CONCLUSIONS

The I.C.INSIDE device significantly improved baseline VA in low-vision patients with macular diseases, using extra-foveal fixation.