James Shaffer

Successful arrest of photoreceptor and vision loss expands the therapeutic window of retinal gene therapy to later stages of disease.

Significance Corrective gene therapies for inherited retinal degenerations are being developed with the expectation that even patients in later stages of the disease will benefit from such intervention. Evidence in animal models for a rescue after the onset of photoreceptor loss is scarce, and recent results from patients enrolled in two of the gene therapy clinical trials for a congenital form of blindness (RPE65-LCA) show that, despite transient improvement in visual function, photoreceptor cell death remains unabated. Here we show in a canine model for a common and severe form of X-linked retinal degeneration that gene therapy successfully stops photoreceptor cell death, improves the structure of retinal cells, and prevents vision loss for more than 2 y. Inherited retinal degenerations cause progressive loss of photoreceptor neurons with eventual blindness. Corrective or neuroprotective gene therapies under development could be delivered at a predegeneration stage to prevent the onset of disease, as well as at intermediate-degeneration stages to slow the rate of progression. Most preclinical gene therapy successes to date have been as predegeneration interventions. In many animal models, as well as in human studies, to date, retinal gene therapy administered well after the onset of degeneration was not able to modify the rate of progression even when successfully reversing dysfunction. We evaluated consequences of gene therapy delivered at intermediate stages of disease in a canine model of X-linked retinitis pigmentosa (XLRP) caused by a mutation in the Retinitis Pigmentosa GTPase Regulator (RPGR) gene. Spatiotemporal natural history of disease was defined and therapeutic dose selected based on predegeneration results. Then interventions were timed at earlier and later phases of intermediate-stage disease, and photoreceptor degeneration monitored with noninvasive imaging, electrophysiological function, and visual behavior for more than 2 y. All parameters showed substantial and significant arrest of the progressive time course of disease with treatment, which resulted in long-term improved retinal function and visual behavior compared with control eyes. Histology confirmed that the human RPGR transgene was stably expressed in photoreceptors and associated with improved structural preservation of rods, cones, and ON bipolar cells together with correction of opsin mislocalization. These findings in a clinically relevant large animal model demonstrate the long-term efficacy of RPGR gene augmentation and substantially broaden the therapeutic window for intervention in patients with RPGR-XLRP.

Outcomes in Eyes with Retinal Angiomatous Proliferation in the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT).

PURPOSE To compare baseline characteristics, visual acuity (VA), and morphologic outcomes between eyes with retinal angiomatous proliferation (RAP) and all other eyes among patients with neovascular age-related macular degeneration (NVAMD) treated with anti-vascular endothelial growth factor (VEGF) drugs. DESIGN Prospective cohort study within the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT). PARTICIPANTS Patients with NVAMD. METHODS Reading center staff evaluated digital color fundus photographs, fluorescein angiography (FA) images, and optical coherence tomography (OCT) scans of eyes with NVAMD treated with either ranibizumab or bevacizumab over a 2-year period. Retinal angiomatous proliferation was identified by the intense intra-retinal leakage of fluorescein in combination with other associated features. MAIN OUTCOME MEASURES Visual acuity; fluorescein leakage; scar; geographic atrophy (GA) on FA; retinal thickness, fluid, and subretinal hyperreflective material (SHRM) on OCT; and the number of intravitreal anti-VEGF injections at 1 and 2 years. RESULTS Retinal angiomatous proliferation was present in 126 of 1183 (10.7%) study eyes at baseline. Mean VA improvement from baseline was greater (10.6 vs. 6.9 letters; P = 0.01) at 1 year, but similar at 2 years (7.8 vs. 6.2 letters; P = 0.34). At 1 year, eyes with RAP were more likely to have no fluid (46% vs. 26%; P < 0.001) on OCT, no leakage on FA (61% vs. 50%; P = 0.03), and greater reduction in foveal thickness (-240 μm vs. -161 μm; P < 0.001). They were more likely to demonstrate GA (24% vs. 15%; P = 0.01) and less likely to have scarring (17% vs. 36%; P < 0.001) or SHRM (36% vs. 48%; P = 0.01). These results were similar at 2 years. The mean change in lesion size at 1 year differed (-0.27 DA vs. 0.27 DA; P = 0.02), but was similar at 2 years (0.49 DA vs. 0.79 DA; P = 0.26). Among eyes treated PRN, eyes with RAP received a lower mean number of injections in year 1 (6.1 vs. 7.4; P = 0.003) and year 2 (5.4 vs. 6.6; P = 0.025). CONCLUSIONS At both 1 and 2 years after initiation of anti-VEGF treatment in CATT, eyes with RAP were less likely to have fluid, FA leakage, scar, and SHRM and more likely to have GA than eyes without RAP. Mean improvement in VA was similar at 2 years.

Ocular Complications in Children with Diabetes Mellitus

PURPOSE The effectiveness of annual eye examinations in diabetic children is unclear. We sought to determine the prevalence and onset of ocular pathology in children with diabetes mellitus (DM), identify risk factors for ocular disease, and recommend a screening regimen for asymptomatic children. DESIGN Retrospective, consecutive cohort study. PARTICIPANTS Children aged less than 18 years with type 1 or 2 DM examined over a 4-year period. METHODS All children underwent a complete eye examination, including dilated fundoscopy and cycloplegic refraction. A literature review was performed, identifying the youngest reported age and shortest reported duration of DM before the diagnosis of diabetic retinopathy (DR). MAIN OUTCOME MEASURES Prevalence of DR, cataract, high refractive error, and strabismus. RESULTS A total of 370 children (mean age, 11.2 years; range, 1-17.5 years) had 693 examinations, with a mean DM duration of 5.2 years (range, 0.1-16.2 years) and a mean hemoglobin A1c (HbA1c) of 8.6 (range, 5-≥14). No children had DR. A total of 12 children had cataract; 5 required extraction but were identified by decreased vision, not diabetic screening. A total of 19 children had strabismus; only 1 was microvascular paralytic strabismus. A total of 41 children had high refractive error. There were no associations between these conditions and duration or control of DM. In the literature, the youngest age at diagnosis of severe DR was 15 years, and the shortest duration of disease was 5 years. CONCLUSIONS Diabetic retinopathy is rare in children regardless of duration and control of DM. On the basis of our study and literature review, screening examinations for type 1 diabetes could begin at age 15 years or at 5 years after the diagnosis of DM, whichever occurs later, unless the child is judged by the endocrinologist as being at unusually high risk. Other ocular complications are identifiable through existing amblyopia screening methods.

Development of Experimental Myopia in Chicks in a Natural Environment.

Purpose The hypothesis that outdoor exposure might protect against myopia has generated much interest, although available data find only modest clinical efficacy. We tested the effect of outdoor rearing on form-deprivation myopia in chicks, a myopia model markedly inhibited by high-intensity indoor laboratory lighting. Methods Unilaterally goggled cohorts of White Leghorn chicks were maintained in a species-appropriate, outdoor rural setting during daylight hours to the extent permitted by weather. Control chicks were reared indoors with incandescent lighting. Besides ocular refraction and ultrasound, we determined dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) content in retina and vitreous and measured mRNA expression levels of selected clock and circadian rhythm-related genes in the retina/RPE. Results Myopia developed in the goggled eyes of all cohorts. Whereas outdoor rearing lessened myopia by 44% at 4 days, a protective effect was no longer evident at 11 days. Outdoor rearing had no consistent effect on retinal or vitreous content of dopamine or DOPAC. Conforming to prior data on form-deprivation myopia, retina and vitreous levels of DOPAC were reduced in goggled eyes. Compared with contralateral eyes, the retinal expression of clock and circadian rhythm-related genes was modestly altered in myopic eyes of chicks reared indoors or outdoors. Conclusions Outdoor rearing of chicks induces only a partial decrease of goggle-induced myopia that is not maintained, without evidence that retinal dopamine metabolism accounts for the partial myopia inhibition under these outdoor conditions. Although modest, alterations in retinal gene expression suggest that studying circadian signals might be informative for understanding refractive mechanisms.

Serious Adverse Events with Bevacizumab or Ranibizumab for Age-Related Macular Degeneration: Meta-analysis of Individual Patient Data

TOPIC A comparison between ranibizumab and bevacizumab of the incidence of systemic serious adverse events (SAEs) among patients with neovascular age-related macular degeneration (nAMD) who participated in a large-scale randomized trial. Use of individual patient data, rather than aggregate data, allowed adjustment for strong predictors of SAEs. CLINICAL RELEVANCE Relative safety of ranibizumab and bevacizumab is important in choosing an anti-VEGF drug for the hundreds of thousands of patients with nAMD treated each year worldwide. METHODS Results of a Cochrane aggregate meta-analysis of the relative efficacy and safety of bevacizumab and ranibizumab that used searches of bibliographic databases and clinical trial registries as of March 14, 2014 and hand searching were reviewed to identify 6 large-scale, multicenter clinical trials. Individual patient data on SAEs, assigned drug and dosing regimen, and baseline prognostic factors were requested from the leaders of the 6 trials. A two-stage approach was used to estimate relative risks and 95% confidence intervals (CIs) from Cox proportional hazards models adjusting for baseline prognostic factors. The primary outcome measure was development of ≥1 SAE; secondary outcome measures were death, arteriothrombotic events, events associated with systemic anti-VEGF therapy, and events not associated with systemic anti-VEGF therapy. RESULTS Individual patient data were received from 5 trials to provide information on 3052 patients. There were no large imbalances between drug groups on baseline factors. The adjusted relative risk (95% CI) for bevacizumab relative to ranibizumab was 1.06 [(0.84, 1.35); p=0.61] for ≥1 SAEs. For secondary outcomes, adjusted relative risks were 0.99 [ (0.69, 1.43); p=0.97] for death, 0.89 [ (0.62, 1.28); p=0.53] for arteriothrombotic events, 1.10 [ (0.81, 1.50); p=0.54] for events related to anti-VEGF treatment, and 1.11 [ (0.87, 1.40); p=0.40] for events not related to anti-VEGF treatment. CONCLUSION Our findings support the absence of large differences in risk of systemic serious adverse events between these two anti-VEGF drugs; i.e., relative risks of ≥1.5 are unlikely. Because additional head-to-head trials are unlikely, any further investigation of differential risk between anti-VEGF agents will only be achieved though post-marketing surveillance or through the interrogation of healthcare databases.

Angiographic Cystoid Macular Edema and Outcomes in the Comparison of Age-Related Macular Degeneration Treatments Trials.

PURPOSE To describe morphologic and visual outcomes in eyes with angiographic cystoid macular edema (CME) treated with ranibizumab or bevacizumab for neovascular age-related macular degeneration (nAMD). DESIGN Prospective cohort study within a randomized clinical trial. PARTICIPANTS A total of 1185 CATT study subjects. METHODS Baseline fluorescein angiography (FA) images of all CATT study eyes were evaluated for CME. Grading of other characteristics on optical coherence tomography (OCT) and photographic images at baseline and during 2-year follow-up was completed by readers at the CATT Reading Centers. Three groups were created on the basis of baseline CME and intraretinal fluid (IRF) status: (1) CME, (2) IRF without CME, (3) neither CME nor IRF. MAIN OUTCOME MEASURES Visual acuity (VA) and total central retinal thickness (CRT) on OCT at baseline, year 1, and year 2. RESULTS Among 1131 participants with images of sufficient quality for determining CME and IRF at baseline, 92 (8.1%) had CME, 766 (67.7%) had IRF without CME, and 273 (24.1%) had neither. At baseline, eyes with CME had worse mean VA (letters) than eyes with IRF without CME and eyes with neither CME nor IRF (52 vs. 60 vs. 66 letters, P < 0.001); higher mean total CRT (μm) on OCT (514 vs. 472 vs. 404, P < 0.001); and greater hemorrhage, retinal angiomatous proliferation (RAP) lesions, and classic choroidal neovascularization (CNV). All groups showed improvement in VA at follow-up; however, the CME group started and ended with the worst VA among the 3 groups. Central retinal thickness, although higher at baseline for the CME group, was similar at 1 and 2 years follow-up for all groups. More eyes with CME (65.3%) developed scarring during 2 years of follow-up compared with eyes with IRF without CME (43.8%) and eyes with neither CME nor IRF (32.5%; P < 0.001). CONCLUSIONS In CATT, eyes with CME had worse baseline and follow-up VA, although all groups showed similar rates of improvement in VA during 2 years of follow-up. Cystoid macular edema seems to be a marker for poorer visual outcomes in nAMD because of underlying baseline retinal dysfunction and subsequent scarring.

SYSTEMIC BETA-BLOCKERS IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION.

Purpose: To evaluate whether oral beta-blockers (BBs) are associated with a decreased number of intravitreal injections in patients with incident neovascular age-related macular degeneration. Methods: A retrospective cohort study of subjects with a new diagnosis of neovascular age-related macular degeneration was conducted using a medical claims database from a large national US insurer. Two cohorts were created for comparison consisting of patients with regular use of BBs or calcium channel blockers. The main outcome measured was the difference in the mean number of intravitreal injections administered between the two cohorts. Results: After inclusion and exclusion criteria, 239 BB and 155 calcium channel blocker subjects remained for analysis. Univariate analysis revealed that the mean number of injections in the BB cohort was 6.43 (95% confidence interval [CI] 5.90–6.95) versus 6.55 (95% CI 5.85–7.25) in the calcium channel blocker cohort (P = 0.78). After multivariate adjustment, the mean number of injections in the BB group was 6.32 (95% CI 5.77–6.87) versus 6.71 (95% CI 6.02–7.40) in the calcium channel blocker group. The overall difference between the 2 groups was −0.39 (95% CI difference −1.29 to 0.51; P = 0.40). Conclusion: The use of oral BBs is not associated with a decreased number of intravitreal injections in incident neovascular age-related macular degeneration patients.

Pseudodrusen in the Fellow Eye of Patients with Unilateral Neovascular Age-Related Macular Degeneration: A Meta-Analysis

Importance The fellow eye of patients with unilateral neovascular age-related degeneration (nAMD) is at increased risk of developing late AMD. Several cohort studies have evaluated the prevalence of pseudodrusen and the association between pseudodrusen and late AMD in the fellow eye of patients with unilateral nAMD. However, these studies have limited sample sizes and their results are inconsistent. Objective To evaluate the prevalence rate of pseudodrusen, and the association between pseudodrusen and incidence of late AMD (nAMD and geographic atrophy (GA)) in the fellow eye of patients with unilateral nAMD. Data Sources The PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched up to July 2015, as well as other systematic reviews. Study Selection All cohort studies for pseudodrusen with late AMD in the fellow eye of patients with unilateral nAMD. Data Extraction and Synthesis The numbers of patients with and without pseudodrusen at baseline and the numbers of incident nAMD and GA during follow up among patients with and without pseudodrusen were independently extracted by 2 authors. The results were pooled using random-effects meta-analysis. Heterogeneity was assessed using the I2 test. Main Outcome Measures Prevalence rate of pseudodrusen, risk ratios (RRs) and their 95% confidence intervals (95% CIs) for associations between pseudodrusen and the incidence of nAMD and GA in the fellow eye. Results Five cohort studies (N = 677 patients) from 8 countries across 4 continents were included. The pooled prevalence rate of pseudodrusen in the fellow eye was 48.1% (95% Cl: 36.7–59.5%, I2 = 87%). Pseudodrusen were associated with an increased risk of nAMD (RR = 1.54, 95% Cl: 1.10–2.16, I2 = 42%), GA (RR = 4.70, 95% Cl: 1.22–18.1, I2 = 64%), and late AMD (RR = 2.03, 95% Cl: 1.35–3.06, I2 = 60%). Conclusions For patients with unilateral nAMD, pseudodrusen were present in about half of the fellow eyes. The presence of pseudodrusen was associated with a 1.5 times higher risk of developing nAMD, a 4.7 times higher risk of developing GA, and a 2 times higher risk of developing late AMD. Pseudodrusen should be considered in evaluating the risk of late AMD development; however, due to considerable heterogeneity across these studies, a larger study is needed to validate these findings.

Development of Modified Screening Criteria for Retinopathy of Prematurity: Primary Results From the Postnatal Growth and Retinopathy of Prematurity Study

Importance Current retinopathy of prematurity (ROP) guidelines, which are based on studies of high-risk infants and expert opinion, have low specificity for disease requiring treatment. Postnatal weight gain–based models improve specificity but have been limited by complexity and small development cohorts, which results in model overfitting and resultant decreased sensitivity in validation studies. Objective To develop a birth weight (BW), gestational age (GA), and weight gain (WG) prediction model using data from a broad-risk cohort of premature infants. Design, Setting, and Participants The Postnatal Growth and ROP Study was a retrospective multicenter cohort study conducted in 29 hospitals in the United States and Canada from 2006 to 2012 that included 7483 premature infants at risk for ROP with a known ROP outcome. A hybrid modeling approach was used that combined BW/GA criteria, weight comparison with expected growth from infants without ROP, multiple growth-interval assessments, consideration of nonphysiological WG, and user-friendly screening criteria. Numerous BW/GA levels, postnatal age periods, time intervals, and WG percentile thresholds were evaluated to identify the most robust parameters. Main Outcome and Measures Sensitivity for Early Treatment of ROP Study type 1 ROP and potential reduction in infants who require examinations. Results Of 7483 infants, the median (SD) BW was 1099 (359) g, the median GA was 28 weeks (range, 22-35), 3575 (47.8%) were female, 3615 (48.4%) were white, 2310 (30.9%) were black, 233 (3.1%) were Asian, 93 (1.2%) were Pacific Islander, and 40 (0.5%) were American Indian/Alaskan Native. Infants who met any of 6 criteria would undergo examinations: (1) a GA of younger than 28 weeks; (2) a BW of less than 1051 g; a WG of less than 120 g, 180 g, or 170 g during ages 10 to 19, 20 to 29, or 30 to 39 days, respectively; or hydrocephalus. These criteria predicted 459 of 459 (100%) type 1 (sensitivity, 100%; 95% CI, 99.2%-100%), 524 of 524 (100%) treated, and 466 of 472 (98.7%) type 2 cases while reducing the number of infants who required examinations by 2269 (30.3%). Conclusions and Relevance This cohort study, broadly representative of infants who are undergoing ROP examinations, provides evidence-based screening criteria. With validation, the Postnatal Growth and ROP Study criteria could be incorporated into ROP screening guidelines to reduce the number of infants who require examinations in North America.

Visual and Morphologic Outcomes in Eyes with Hard Exudate in the Comparison of Age-Related Macular Degeneration Treatments Trials

PURPOSE To compare baseline characteristics, visual acuity (VA) and morphological outcomes between eyes with baseline hard exudates (HE) and all other eyes among patients with neovascular age-related macular degeneration (NVAMD) treated with anti-vascular endothelial growth factors (anti-VEGF). DESIGN Prospective cohort study within the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT). PARTICIPANTS Patients with NVAMD. METHODS Readers evaluated baseline and follow-up morphology on digital color images, fluorescein angiography (FA), and optical coherence tomography (OCT) in eyes with NVAMD that were randomly assigned to treatment with either ranibizumab or bevacizumab. Ophthalmologists identified HE on color images in the study eye. MAIN OUTCOME MEASURES VA; scar; geographic atrophy; retinal thickness, fluid; and number of anti-VEGF injections. RESULTS HE was present in 128 of 1185 (11%) study eyes at baseline, 77% within 1 disc diameter of the foveal center. Patients with study eye HE were more likely female (81% vs 60%; p<0.001) and non-smokers (53% vs 42%; p=0.004). Both groups had similar proportions of hypercholesterolemia and hypertriglyceridemia. At baseline, eyes with HE had worse VA (mean 57 vs 61 letters; p=0.003), larger total lesion size (3.3 vs 2.4 DA; p <0.001), greater total foveal thickness (522µm vs 452µm; p<0.001), more retinal angiomatous proliferation (18% vs 10%; p=0.009) and sub-RPE fluid (65% vs 47%; p<0.001). At 1 year, VA was similar in both groups; more eyes with baseline HE had no fluid (45% vs 29%; p<0.001) and greater reduction in total foveal thickness (-266µm vs -158u; p<0.001). VA at year 2 was similar but retinas of eyes with baseline HE were thinner (267µm vs 299µm; p=0.03) and fewer eyes had sub-retinal fluid (23% vs 36%; p=0.008). HE was present in 19% of eyes at 1 year and 5% of eyes at 2 years. LIPC promoter SNP rs10468017 was not associated with NVAMD HE. CONCLUSION Eyes with HE have larger CNV lesions and more RAP. Their initially thicker retina rapidly becomes thinner on anti-VEGF treatment. HE is not significantly associated with hyperlipidemia. HE at baseline does not significantly influence VA, scar and GA outcomes in eyes with NVAMD treated with anti-VEGF. Few eyes have HE at year 2.