July 2023

Rare missense and nonsense variants in the Angiopoietin-like 7 (ANGPTL7) gene confer protection from primary open-angle glaucoma (POAG), though the functional mechanism remains uncharacterized. Interestingly, a larger variant effect size strongly correlates with in silico predictions of increased protein instability (r = -0.98), suggesting that protective variants lower ANGPTL7 protein levels. Here, we show that missense and nonsense variants cause aggregation of mutant ANGPTL7 protein in the endoplasmic reticulum (ER) and decreased levels of secreted protein in human trabecular meshwork (TM) cells; a lower secreted:intracellular protein ratio strongly correlates with variant effects on intraocular pressure (r = 0.81). Importantly, accumulation of mutant protein in the ER does not increase expression of ER stress proteins in TM cells (P > 0.05 for all variants tested). Cyclic mechanical stress, a glaucoma-relevant physiologic stressor, also significantly lowers ANGPTL7 expression in primary cultures of human Schlemm's canal (SC) cells (-2.4-fold-change, P = 0.01). Collectively, these data suggest that the protective effects of ANGPTL7 variants in POAG stem from lower levels of secreted protein, which may modulate responses to physiologic and pathologic ocular cell stressors. Downregulation of ANGPTL7 expression may therefore serve as a viable preventative and therapeutic strategy for this common, blinding disease.

PURPOSE: Genetic variants in regions that include the mitochondrial genes TXNRD2 and ME3 are associated with primary open-angle glaucoma (POAG) in genome-wide association studies (GWAS). To assess their clinical impact, we investigated whether TXNRD2 and ME3 genetic risk scores (GRSs) are associated with specific glaucoma phenotypes. DESIGN: Cross-sectional study PARTICIPANTS: 2617 POAG cases and 2634 controls from the NEIGHBORHOOD consortium. METHODS: All POAG-associated single nucleotide polymorphisms (SNPs) in the TXNRD2 and ME3 loci were identified using GWAS data (p<0.05). Of these, 20 TXNRD2 and 24 ME3 SNPs were selected after adjusting for linkage disequilibrium. The correlation between SNP effect size and gene expression levels was investigated using the Gene-Tissue Expression (GTEx) database. GRSs were constructed for each individual using the unweighted sum of TXNRD2, ME3, and TXNRD2+ME3 combined risk alleles. Age and gender-adjusted odds ratios (ORs) for POAG diagnosis were calculated per decile for each GRS. Additionally, the clinical features of POAG cases in the top 1, 5, and 10% of each GRS were compared to the bottom 1, 5, and 10%, respectively. MAIN OUTCOME MEASURES: POAG OR per GRS decile; maximal treated intraocular pressure (IOP) and prevalence of paracentral visual field loss among POAG cases with high vs. low GRSs. RESULTS: Increased SNP effect size strongly correlated with higher TXNRD2 and lower ME3 expression levels (r=0.95 and -0.97, respectively, p<0.05 for both). Individuals in decile 10 of TXNRD2+ME3 GRS had the highest odds of POAG diagnosis (OR=1.79 compared to decile 1, p<0.001). POAG cases in the top 1% of TXNRD2 GRS had higher mean maximal treated IOP compared to the bottom 1% (19.9 mmHg vs 15.6 mmHg, adjusted p=0.03). POAG cases in the top 1% of ME3 and TXNRD2+ME3 GRS had a higher prevalence of paracentral field loss compared to the bottom 1% (72.7-88.9% vs 14.3-33.3%; adjusted p=0.03 for both). CONCLUSIONS: POAG patients with higher TXNRD2 and ME3 GRSs had higher treated IOP and a greater prevalence of paracentral field loss. Functional studies exploring how these variants impact mitochondrial function in glaucoma patients are warranted.

PURPOSE: To determine the effect of combined macular optical coherence tomography (SD-OCT) and ultrawide field retinal imaging (UWFI) within a telemedicine program. METHODS: Comparative cohort study of consecutive patients with both UWFI and SD-OCT. UWFI and SD-OOCT were independently evaluated for diabetic macular edema (DME) and non-diabetic macular pathology. Sensitivity and specificity were calculated with SD-OCT as gold standard. RESULTS: 422 eyes from 211 diabetic patients were evaluated. DME severity by UWFI: no DME 93.4%, non-center involved DME (nonciDME) 5.1%, ciDME 0.7%, ungradable DME 0.7%. SD-OCT was ungradable in 0.5%. Macular pathology was identified in 34 (8.1%) eyes by UWFI and in 44 (10.4%) eyes by SD-OCT. DME represented only 38.6% of referable macular pathology identified by SD-OCT imaging. Sensitivity/specificity of UWFI compared to SD-OCT was 59%/96% for DME and 33%/99% for ciDME. Sensitivity/specificity of UWFI compared to SDOCT was 3%/98% for ERM. CONCLUSIONS: Addition of SD-OCT increased the identification of macular pathology by 29.4%. Over 58.3% of the eyes thought to have any DME on UWF imaging alone were false positives by SD-OCT. The integration of SD-OCT with UWFI markedly increased detection and reduced false positive assessments of DME and macular pathology in a teleophthalmology program.

PURPOSE: To evaluate the retinal vasculature in pediatric patients with X-linked retinoschisis (XLRS). DESIGN: Retrospective consecutive case series. SUBJECTS: Pediatric patients with a diagnosis of XLRS who had undergone widefield fluorescein angiography (FA). METHODS: The electronic medical records of pediatric patients with XLRS at a tertiary referral eye center were reviewed from January 2015 to December 2021. Fluorescein angiography images were reviewed for anomalies of the retinal vasculature. MAIN OUTCOMES MEASURES: Vascular anomalies on FA were recorded, including capillary dropout/ischemia, terminal supernumerary vessels, vascular leakage, abnormal vascular loops, straightening of vessels, aberrant circumferential vessels, and neovascularization. RESULTS: In total, 29 eyes of 15 patients were included in the study (1 patient had a phthisical eye). On FA, the most common findings were capillary dropout/ischemia (21 of 29 eyes, 72.4%), terminal supernumerary vessels (21 eyes, 72.4%), abnormal vascular loops (20 eyes, 69%), and vascular leakage (17 eyes, 58.6%). Of the 17 eyes with leakage, the most posterior zone of involvement was zone 1 in 11 eyes (64.7%) and zone 2 in 6 eyes (35.3%). All eyes demonstrated ≥ 1 vascular anomaly on FA. Among the 29 eyes, 23 (79.3%) demonstrated peripheral bullous schisis or retinal detachment (RD) with a mean of 5.6 clock hours of involvement. The presence of either RD or bullous retinal schisis was associated with the incidence of capillary dropout (91.3% in schisis/RD eyes vs. 0% in nonschisis/RD eyes, P < 0.001). Among those with RD or bullous schisis, a higher degree of involvement correlated with more severe capillary dropout (Pearson 0.49, P = 0.025). CONCLUSION: The present study demonstrates consistent vascular changes in pediatric patients with XLRS using widefield FA. Although the presence of capillary ischemia was associated with the severity of bullous schisis or RD, other vascular anomalies were observed in patients both with and without peripheral schisis. Although further research is needed to understand the etiology of these vascular anomalies, FA should be considered in the evaluation of these patients. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

PURPOSE: Utilization of antibiotics for endoscopic dacryocystorhinostomy (endo-DCR) is largely dependent on individual surgeon preference. This study aimed to investigate prescribing practices of pre-, peri-, and postoperative antibiotics and effects on postoperative infection rates in patients who underwent endo-DCR. METHODS: A retrospective chart review of institutional data at two academic centers of endo-DCR cases from 2015-2020 was performed. Postoperative infection rates for patients who received pre-, peri-, and postoperative antibiotics, individually or in combination, and those who did not, were compared via odds ratio and ANOVA linear regression. RESULTS: 331 endo-DCR cases were included; 22 cases (6.6%) had a postoperative infection. There was no significant difference in the infection rates between patients without an active preoperative dacryocystitis who received different permutations of peri- and postoperative antibiotics. Patients who received preoperative antibiotics within two weeks of surgery for preexisting acute dacryocystitis, but did not receive peri- or postoperative antibiotics, had a higher rate of postoperative infections (p = 008). CONCLUSIONS: Our data suggest antibiotics may be beneficial only when patients have a recent or active dacryocystitis prior to surgery. Otherwise, our data do not support the routine use of antibiotic prophylaxis in endo-DCR.

Amniotic bands can lead to eyelid colobomas contiguous with facial clefts, resulting in severe and highly variable eyelid malformations. There is no known underlying genetic cause of amniotic band sequence. Here, the authors review the case of an infant born with large, 4-eyelid colobomatous defects in the setting of facial clefts, amniotic bands and an underlying SMOC1 mutation, which has not previously been linked to amniotic band sequence or eyelid colobomas. Reconstructive technique and the postoperative course are described, and underlying etiologic theories of amniotic band sequence are reviewed and expanded upon. Although amblyopia prevention in this patient with poor visual potential was not a consideration, the goals of improving the patient's ocular surface and maintaining eye contact were achieved.

PURPOSE OF REVIEW: Optical coherence tomography angiography (OCTA) is a novel, noninvasive imaging technique, which provides depth resolved visualization of microvasculature of the retina and choroid. Although OCTA has been widely used for the evaluation of a number of retinal diseases, its use in the field of neuro-ophthalmology has been less studied. In this review, we provide an update on the utility of OCTA in neuro-ophthalmic conditions. RECENT FINDINGS: Peripapillary and macular microvasculature analyses have indicated that OCTA can be a promising tool for early detection of a number of neuro-ophthalmic diseases, differential diagnosis, and monitoring of disease progression. Recent studies have demonstrated that structural and functional impairment can develop at early stages in some conditions such as in multiple sclerosis and Alzheimer's disease even in the absence of overt clinical symptoms. Furthermore, this dye-less technique can be a valuable adjunct tool in the detection of complications commonly seen in some congenital entities such optic disc drusen. SUMMARY: Since its introduction, OCTA has emerged as an important imaging approach shedding light on unrevealed pathophysiological mechanisms of several ocular diseases. The use of OCTA as a biomarker in the field of neuro-ophthalmology has recently gained considerable attention with studies supporting its role in clinical setting while larger studies are warranted for correlating these findings with traditional diagnostic procedures and clinical features and outcomes.

PURPOSE: The Paul glaucoma implant (PGI, Advanced Ophthalmic Innovations, Singapore, Republic of Singapore) is a recently developed novel non-valved glaucoma drainage device (GDD) designed to effectively reduce the intraocular pressure (IOP) in glaucoma patients with a theoretically reduced risk of postoperative complications such as hypotony, endothelial cell loss, strabismus, and diplopia. Limited literature has evaluated its use in adult glaucoma; however, its use in pediatric glaucoma has not been reported to date. We present our early experience with PGI in refractory childhood glaucoma. PATIENTS AND METHODS: This study was retrospective single-surgeon case series in a single tertiary center. RESULTS: Three eyes of 3 patients with childhood glaucoma were enrolled in the study. During nine months of follow-up, postoperative IOP and number of glaucoma medications were significantly lower than preoperative values in all the enrolled patients. None of the patients developed postoperative complications including postoperative hypotony, choroidal detachment, endophthalmitis, or corneal decompensation. CONCLUSION: PGI is an efficient and relatively safe surgical treatment option in patients with refractory childhood glaucoma. Further studies with larger number of participants and longer follow-up period are required to confirm our encouraging results.

Clinical staging systems for diagnosis and treatment of diabetic retinopathy (DR) must closely relate to endpoints that are both relevant for patients and feasible for physicians to implement. Current DR staging systems for clinical eye care and research provide detailed phenotypic characterization to predict patient outcomes in diabetes but have limitations. Biochemical biomarkers provide a rich pool of potential candidates for new DR staging systems that can be readily measured in accessible fluids. Circulating biomarkers that are specific to the retina and relate to angiogenesis and inflammation have been suggested as relevant for DR. Although there is a lack of multi-ethnic studies evaluating circulatory biomarkers in DR, variability in circulatory biomarkers have been reported in people from different ethnic and racial backgrounds. Therefore, there is a need for future studies to evaluate individual or combinations of biomarkers in diverse populations with DR from different ethnic and racial backgrounds.

OBJECTIVES: The Coronavirus Disease 2019 (COVID-19) pandemic led to the expansion of virtual medicine as a method to provide patient care. We aimed to determine the impact of pediatric and young adult virtual medicine use on fossil fuel consumption, greenhouse gas and non-greenhouse traffic-related air pollutant emissions. METHODS: We conducted a retrospective analysis of all virtual medicine patients at a single quaternary-care children's hospital with a geocoded address in the Commonwealth of Massachusetts prior to (3/16/2019-3/15/2020) and during the COVID-19 pandemic (3/16/2020-3/15/2021). Primary outcomes included patient travel distance, gasoline consumption, carbon dioxide and fine particulate matter emissions as well as savings in main hospital energy use. RESULTS: There were 3,846 and 307,273 virtual visits performed with valid Massachusetts geocoded addresses prior to and during the COVID-19 pandemic, respectively. During one year of the pandemic, virtual medicine services resulted in a total reduction of 620,231 gallons of fossil fuel use and $1,620,002 avoided expenditure as well as 5,492.9 metric tons of carbon dioxide and 186.3 kilograms of fine particulate matter emitted. There were 3.1 million fewer kilowatt hours used by the hospital intra-pandemic compared to the year prior. Accounting for equipment emissions, the combined intra-pandemic emission reductions are equivalent to the electricity required by 1,234 homes for one year. CONCLUSIONS: Widespread pediatric institutional use of virtual medicine provided environmental benefits. The true potential of virtual medicine for decreasing the environmental footprint of healthcare lies in scaling this mode of care to patient groups across the state and nation when medically feasible.

PURPOSE: To describe a novel technique for cataract surgery in patients with iris coloboma. METHODS: The technique involves 1) creation of an inferiorly displaced capsulorrhexis and 2) amputation of one intraocular lens (IOL) haptic, thus allowing for controlled IOL decentration in the direction of an inferior iris defect. RESULTS: We report favorable outcomes in two eyes (one patient) where eccentric capsulorrhexis and haptic amputation were employed during one-piece IOL repositioning in one eye and cataract surgery with three-piece IOL implantation in the contralateral eye. CONCLUSION: In coloboma patients who are asymptomatic from their iris defect and do not have a cosmetic desire for repair, eccentric capsulorrhexis and IOL haptic amputation is a viable surgical option that allows for the preservation of a clear visual axis without the need for iris repair.

BACKGROUND AND OBJECTIVE: Bilastine is a nonsedating second-generation antihistamine for the symptomatic treatment of allergic rhinoconjunctivitis and urticaria. Our study aimed to evaluate the optimal dose, efficacy, and safety of a newly developed once-daily preservative-free ophthalmic formulation of bilastine for allergic conjunctivitis. METHODS: Our phase 2, single-center, double-masked, randomized trial compared the efficacy of 3 doses of a bilastine ophthalmic formulation (0.2%, 0.4%, and 0.6%) with that of vehicle for the treatment of allergic conjunctivitis. The primary efficacy endpoint was the reduction in ocular itching. The Ora-CAC Conjunctival Allergen Challenge model was used to assess ocular and nasal symptoms at the onset of action (15 minutes) and at 8- and 16-hours after treatment. Tolerance and safety were also evaluated. RESULTS: A total of 121 adults with seasonal and/or perennial ocular allergy were randomized. Bilastine ophthalmic formulations 0.2%, 0.4%, and 0.6% were significantly superior (P>.001) to vehicle for the treatment of ocular itching at 3, 5, and 7 minutes after challenge at onset of action (15 minutes) and at 8 hours after treatment. Bilastine 0.6% was also effective at 16 hours after treatment. Treatment differences for bilastine 0.6% were statistically significant (P<.001) compared to vehicle at all timepoints for tearing, eyelid swelling, and nasal symptoms. No relevant adverse events were observed. CONCLUSION: All the tested ophthalmic bilastine doses were efficacious for rapid reduction of ocular itching. The 0.6% formulation was effective up to 16 hours after treatment, making it suitable for once-daily administration. The new formulation was safe and well tolerated.

Age-related macular degeneration (AMD) is a leading cause of blindness in older adults. Investigating shared genetic components between metabolites and AMD can enhance our understanding of its pathogenesis. We conduct metabolite genome-wide association studies (mGWASs) using multi-ethnic genetic and metabolomic data from up to 28,000 participants. With bidirectional Mendelian randomization analysis involving 16,144 advanced AMD cases and 17,832 controls, we identify 108 putatively causal relationships between plasma metabolites and advanced AMD. These metabolites are enriched in glycerophospholipid metabolism, lysophospholipid, triradylcglycerol, and long chain polyunsaturated fatty acid pathways. Bayesian genetic colocalization analysis and a customized metabolome-wide association approach prioritize putative causal AMD-associated metabolites. We find limited evidence linking urine metabolites to AMD risk. Our study emphasizes the contribution of plasma metabolites, particularly lipid-related pathways and genes, to AMD risk and uncovers numerous putative causal associations between metabolites and AMD risk.

Glaucoma, a leading cause of irreversible blindness, is a highly heritable human disease. Previous genome-wide association studies have identified over 100 loci for the most common form, primary open-angle glaucoma. Two key glaucoma-associated traits also show high heritability: intraocular pressure and optic nerve head excavation damage quantified as the vertical cup-to-disc ratio. Here, since much of glaucoma heritability remains unexplained, we conducted a large-scale multitrait genome-wide association study in participants of European ancestry combining primary open-angle glaucoma and its two associated traits (total sample size over 600,000) to substantially improve genetic discovery power (263 loci). We further increased our power by then employing a multiancestry approach, which increased the number of independent risk loci to 312, with the vast majority replicating in a large independent cohort from 23andMe, Inc. (total sample size over 2.8 million; 296 loci replicated at P < 0.05, 240 after Bonferroni correction). Leveraging multiomics datasets, we identified many potential druggable genes, including neuro-protection targets likely to act via the optic nerve, a key advance for glaucoma because all existing drugs only target intraocular pressure. We further used Mendelian randomization and genetic correlation-based approaches to identify novel links to other complex traits, including immune-related diseases such as multiple sclerosis and systemic lupus erythematosus.

PURPOSE: To describe the 15-month baseline results and costs of the Manhattan Vision Screening and Follow-up Study, which aims to investigate whether innovative community-based eye health screening can improve early detection and management of glaucoma and other eye diseases among high-risk populations. DESIGN: 5-year prospective, cluster-randomized controlled trial. METHODS: Individuals age 40+ were recruited from public housing buildings in New York City for an eye health screening (visual acuity (VA) with correction, intraocular pressure measurements (IOP), and fundus photography). Participants with VA 20/40 or worse, IOP 23-29 mmHg, or an unreadable fundus image failed the screening and were scheduled for an optometric exam at the same location; those with an abnormal image were referred to ophthalmology. A cost analysis was conducted alongside the study. RESULTS: 708 participants were screened; mean age 68.6±11.9 years, female (65.1%), African American (51.8%) and Hispanic (42%). 78.4% (n = 555) failed the eye health screening; 35% (n= 250) had an abnormal image and were also referred to ophthalmology. 308 participants attended the optometric exam; 218 were referred to ophthalmology. Overall, 66.1% were referred to ophthalmology. The cost per participant to deliver the eye health screening and optometric exam was $180.88. The cost per case of eye disease detected was $273.64. CONCLUSIONS: This innovative study in public housing developments targeted high-risk populations, provided access to eye-care, and improved early detection of ocular diseases in New York City. The study has identified strategies to overcoming barriers to eye care to reduce eye health disparities.

PURPOSE: Postoperative endophthalmitis is a relatively uncommon, but potentially visually devastating, complication associated with cataract surgery. Specific microbial causes of endophthalmitis are characteristically associated with particular disease time courses. Though Cutibacterium acnes is typically associated with an indolent course of inflammation, we report a case of C. acnes endophthalmitis with onset on postoperative day (POD) 1 and a positive culture from POD 2. METHODS: Case report. RESULTS: A 56-year-old man underwent cataract extraction and posterior chamber intraocular lens placement in his left eye. On POD 1, he presented with severe discomfort, reduced visual acuity, and significant inflammation. On POD 2, his anterior chamber was tapped and injected with broad-spectrum antibiotics and steroids. The inflammation ultimately resolved, and his visual acuity improved to 20/20. CONCLUSIONS: C. acnes is a rare cause of hyperacute onset postoperative endophthalmitis. Maintaining a high clinical suspicion and initiating prompt treatment can help to optimize long-term visual outcomes.

Artificial intelligence (AI) applications in healthcare will have a potentially far-reaching impact on patient care, however issues regarding algorithmic bias and fairness have recently surfaced. There is a recognized lack of diversity in the available ophthalmic datasets, with 45% of the global population having no readily accessible representative images, leading to potential misrepresentations of their unique anatomic features and ocular pathology. AI applications in retinal disease may show less accuracy with underrepresented populations that may further widen the gap of health inequality if left unaddressed. Beyond disease symptomatology, social determinants of health must be integrated into our current paradigms of disease understanding, with the goal of more personalized care. AI has the potential to decrease global healthcare inequality, but it will need to be based on a more diverse, transparent and responsible use of healthcare data.

Oxidative stress plays a crucial role in aging-related eye diseases, including age-related macular degeneration (AMD), cataracts, and glaucoma. With age, antioxidant reparative capacity decreases, and excess levels of reactive oxygen species produce oxidative damage in many ocular cell types underling age-related pathologies. In AMD, loss of central vision in the elderly is caused primarily by retinal pigment epithelium (RPE) dysfunction and degeneration and/or choroidal neovascularization that trigger malfunction and loss of photo-sensing photoreceptor cells. Along with various genetic and environmental factors that contribute to AMD, aging and age-related oxidative damage have critical involvement in AMD pathogenesis. To this end, dietary intake of antioxidants is a proven way to scavenge free radicals and to prevent or slow AMD progression. This review focuses on AMD and highlights the pathogenic role of oxidative stress in AMD from both clinical and experimental studies. The beneficial roles of antioxidants and dietary micronutrients in AMD are also summarized.

OBJECTIVE: To describe the relationship between history of atopic disease on systemic and ocular manifestations of Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN). METHODS: Retrospective chart review of patients with SJS/TEN patients. Those with and without prior atopic diagnosis were compared. RESULTS: In total, 200 patients with SJS/TEN were identified. A total of 23 patients also had an atopic diagnosis. Four, 10, and 18 had atopic dermatitis, allergic rhinitis, and asthma respectively. Acute ocular severity was significantly worse in the atopic cohort. No significant differences in overall systemic severity of SJS or mortality were found between the atopic and non-atopic cohorts. Compared to our hospital system's general population, prevalence of an atopic diagnosis was significantly higher in those with SJS/TEN. CONCLUSION: Patients with a history of an atopic diagnosis appear to have more significant acute ocular involvement during their SJS/TEN hospitalization. Atopic conditions appear to occur more frequently in the SJS/TEN population compared to the general population.

PURPOSE: To investigate the prevalence and clinical characteristics of diabetic patients with retinal venous loops (RVLs) and to assess the association with retinal ischemia using widefield swept-source optical coherence tomography angiography (WF SS-OCTA). METHODS: In this retrospective, cross-sectional study, a total of 195 eyes of 132 diabetic patients (31 eyes with no diabetic retinopathy (DR), 76 eyes with nonproliferative DR (NPDR), and 88 eyes with proliferative DR (PDR)) were imaged with WF SS-OCTA using Angio 6 × 6 mm and Montage 15 × 15 mm scans. Quantitative ischemia-related parameters, including ischemia index (ratio of nonperfusion area to total retinal area), foveal avascular zone (FAZ), and neovascularization features, were evaluated. RVLs were classified as type I or type II according to the branching level of the feeder vessel. A multivariate generalized estimating equations (GEE) logistic regression model was used to analyze the association of systemic parameters and ischemia-related metrics with RVLs in PDR eyes. RESULTS: Forty-eight RVLs were identified in 22 eyes (11.28%). The prevalence of RVLs was higher in PDR compared to NPDR eyes (21.59% vs. 3.95%, P < 0.05). Type II RVLs accounted for a higher proportion than type I (89.58% vs. 10.42%, P < 0.001). RVLs were more likely to originate from superior (vs. inferior) and temporal (vs. nasal) veins (P < 0.05). The GEE model showed that neovascularization (NV) flow area and diastolic blood pressure were associated with RVLs in the PDR group (P < 0.05). CONCLUSION: WF SS-OCTA is useful for the identification of RVLs in patients with DR. NV flow area and diastolic blood pressure were associated with the presence of RVLs in eyes with PDR. Ischemia index, FAZ, and other WF SS-OCTA parameters were not associated with RVLs. Further longitudinal studies are needed to identify the role of RVLs in DR progression.