The Association Between Metformin Use and New-Onset ICD Coding of Geographic Atrophy

Purpose

Metformin has been suggested to protect against the development of age-related macular degeneration (AMD) in multiple observational studies. However, the association between metformin and geographic atrophy (GA), a debilitating subtype of AMD, has not been analyzed.

Methods

We conducted a case-control study of patients ages 60 years and older with new-onset International Classification of Diseases (ICD) coding of GA in the Merative MarketScan Commercial and Medicare Databases between 2017 and 2021. Cases were matched with propensity scores estimated by age, region, hypertension, and Charlson Comorbidity Index to a control without GA of the same year. Exposure to metformin was assessed for cases and controls in the year prior to their index visit. Conditional multivariable logistic regression, adjusting for AMD risk factors, was used to calculate odd ratios and 95% confidence intervals (CIs). This study design and analysis were repeated in a sample of patients without diabetes.

Results

In the full sample, we identified 10,505 cases with GA and 10,502 matched controls without GA. In total, 1149 (10.9%) cases and 1277 (12.2%) controls were exposed to metformin, and in multivariable regression, metformin decreased the odds of new-onset ICD coding of GA by 12% (95% CI, 0.79-0.99). In the sample of patients without diabetes, we identified 7611 cases with GA and 7608 matched controls without GA. Twenty-nine (0.4%) cases and 63 (0.8%) controls were exposed to metformin, and in multivariable regression, metformin decreased the odds of new-onset ICD coding of GA by 47% (95% CI, 0.33-0.83).

Conclusions

Metformin may hold promise as a noninvasive, alternative agent to prevent the development of GA. This finding is notable due to shortcomings in recently approved therapeutics for GA and metformin's overall ease of use and few adverse effects. Additional studies are required to explore our findings further and motivate a clinical trial.

FULL-THICKNESS MACULAR HOLE CLOSURE WITH TOPICAL MEDICAL THERAPY

PURPOSE

To examine the efficacy and clinical characteristics of successful full-thickness macular hole closure with topical therapy.

METHODS

Retrospective case series of full-thickness macular holes managed by a single retinal physician (DS) diagnosed and treated from 2017 to 22.

RESULTS

Of 168 patients with full-thickness macular holes, 71 patients were started on steroid, carbonic anhydrase inhibitor, and nonsteroidal antiinflammatory (NSAID) drops. 49 patients (mean 67 years, 59% women) were included in the analysis, and 22 patients were excluded for poor follow-up. In total, 7/49 were secondary post-PPV holes and 42/49 were idiopathic. In addition, 18/49 eyes (36.7%) achieved closure on topical therapy, of which 13 were idiopathic. Hole size was directly correlated with odds of closure: for every 10 μm decrease in size and odds of closure increased by 1.2× ( P = 0.001, CI 1.1-1.4). Average time to closure was 107.2 days (range 20-512 days) and was not correlated with hole size ( P = 0.217, CI -0.478 to +1.938). The presence of VMT was found to be inversely related to successful closure (OR 6.1, P = 0.029, CI 1.2-31.3). There was no significant difference in final best-corrected visual acuity for eyes undergoing primary pars plana vitrectomy versus those trialing drops before undergoing pars plana vitrectomy ( P = 0.318, CI -0.094 to +0.112).

CONCLUSION

In the first study to date to report the overall efficacy and clinical characteristics of successful macular hole closure with topical therapy, drops achieved an overall closure rate of 36.7%, with higher efficacy in smaller holes and those without VMT. Rates of MH narrowing and reduction in central foveal thickness acted as predictors of effectiveness of drop therapy.

INTERACTIONS OF METFORMIN AND OTHER MEDICATIONS IN REDUCING THE ODDS OF AGE-RELATED MACULAR DEGENERATION IN A COHORT OF PATIENTS WITH DIABETES

PURPOSE

A previous study from our group demonstrated protective effects of the use of metformin in the odds of developing age-related macular degeneration (AMD). This is a subgroup analysis in a cohort of patients with diabetes to assess the interaction of metformin and other medications in protecting diabetic patients against developing AMD.

METHODS

This is a case-control analysis using data from the Merative MarketScan Commercial and Medicare databases. Patients were 55 years and older with newly diagnosed AMD and matched to controls. We performed multivariable conditional logistic regressions, which adjusted for known risk factors of AMD and tested multiple interaction effects between metformin and 1) insulin, 2) sulfonylureas, 3) glitazones, 4) meglitinides, and 5) statins.

RESULTS

The authors identified 81,262 diabetic cases and 79,497 diabetic controls. Metformin, insulin, and sulfonylureas demonstrated independent protective effects against AMD development. Sulfonylureas in combination with metformin demonstrated further decreased odds of AMD development compared with metformin alone. The other medication group (exenatide, sitagliptin, and pramlintide) slightly increased the odds of developing AMD when taken alone, but the combination with metformin alleviated this effect.

CONCLUSION

The authors believe that their results bring them one step closer to finding an optimal effective hypoglycemic regimen that also protects against AMD development in diabetic patients.

Racial Differences in Choroidal Vascularity Index in Healthy Patients: Novel Insights

BACKGROUND AND OBJECTIVE

Choroidal vascularity index (CVI) measures the ratio of blood vessels in the choroid to the total choroidal area. We aimed to compare CVI between young Black and White patients without a history of ocular or systemic disease.

PATIENTS AND METHODS

We used a previously validated algorithm for shadow compensation and choroidal vessel binarization to measure CVI across the Early Treatment of Diabetic Retinopathy Study grid.

RESULTS

Black patients had a lower CVI (ß = -0.05, P < 0.001) compared to White patients. Choroidal volume or luminal volume did not significantly differ with respect to race, whereas there was a trend for Black patients to have a greater stromal volume (ß = 3.08, P = 0.01).

CONCLUSIONS

Black patients have a lower CVI than do White patients, likely due to a greater proportion of stromal volume. Further study of this parameter is warranted to validate the findings of this exploratory study. [Ophthalmic Surg Lasers Imaging Retina 2024;55:30-38.].

Metformin Use and Age-Related Macular Degeneration in Patients Without Diabetes

Importance

Metformin use may protect against the development of age-related macular degeneration (AMD) based on results from observational studies. However, its potential effectiveness among patients without diabetes remains unclear.

Objective

To assess the association between metformin use and the development of AMD in patients without diabetes.

Design, Setting, and Participants

This case-control study used data from 2006 to 2017 in the Merative MarketScan Research Database, a nationwide insurance claims database that includes between 27 and 57 million patients in the US with primary or Medicare supplemental health insurance. Cases with AMD and controls without AMD aged 55 years or older were matched 1:1 by year, age, anemia, hypertension, region, and Charlson Comorbidity Index score. Then, cases and matched controls without a diagnosis of diabetes were selected. In subgroup analyses, cases with dry AMD and their matched controls were identified to explore the association between metformin use and AMD staging in patients without diabetes. Data were analyzed between March and September 2023.

Exposures

Exposure to metformin in the 2 years prior to the index date (ie, date of AMD diagnosis in cases and date of a randomly selected eye examination for controls) was assessed from the claims database and categorized into quartiles based on cumulative dose (1-270, 271-600, 601-1080, and >1080 g/2 y). Exposure to other antidiabetic medications was also noted.

Main Outcomes and Measures

Odds of new-onset AMD development as assessed by multivariable conditional logistic regression after adjusting for known risk factors for AMD, including female sex, hyperlipidemia, smoking, and exposures to other antidiabetic medications. Asymptotic Cochran-Armitage tests for trend were also performed.

Results

We identified 231 142 patients with any AMD (mean [SD] age, 75.1 [10.4] years; 140 172 females [60.6%]) and 232 879 matched controls without AMD (mean [SD] age, 74.9 [10.5] years; 133 670 females [57.4%]), none of whom had a diagnosis of diabetes. The sample included 144 147 cases with dry AMD that were matched to 144 530 controls. In all, 2268 (1.0%) cases and 3087 controls (1.3%) were exposed to metformin in the 2 years before their index visit. After data adjustment, exposure to any metformin was associated with reduced odds of any AMD development (adjusted odds ratio [AOR], 0.83; 95% CI, 0.74-0.87), specifically in the dosing quartiles of 1 to 270, 271 to 600, and 601 to 1080 g/2 y. Any metformin use was also associated with a reduced odds of developing dry AMD (AOR, 0.85; 95% CI, 0.79-0.92), specifically in the dosing quartiles of 1 to 270 and 271 to 600 g/2 y. Adjusted odds ratios for any AMD and dry AMD development did not differ across the dosing quartiles. Asymptotic Cochran-Armitage tests for trend revealed 2-sided P = .51 and P = .66 for the any and dry AMD samples, respectively.

Conclusions and Relevance

In this case-control study of a population without a diagnosis of diabetes, metformin use was associated with reduced odds of developing AMD. This association does not appear to be dose dependent. These findings provide further impetus to study metformin's usefulness in protecting against AMD in prospective clinical trials.

Associations Between Autoimmune Disease and the Development of Age-Related Macular Degeneration

Purpose

The pathogenesis of age-related macular degeneration (AMD) likely implicates the dysregulation of immune response pathways. Several studies demonstrate that the pathogenic elements of AMD resemble those of autoimmune diseases, yet the association between AMD development and most autoimmune diseases remain unexplored.

Methods

We conducted a case-control analysis of patients ages 55 and older with new-onset International Classification of Diseases (ICD) coding of dry, wet, or unspecified AMD between 2005 and 2019 in the Merative MarketScan Commercial and Medicare Databases. The diagnosis of an autoimmune disease was defined by an outpatient or inpatient claim with a relevant ICD code in the 12 months before the index visit. Conditional multivariable logistic regression, adjusted for AMD risk factors, was used to calculate odd ratios and 95% confidence intervals.

Results

We identified 415,027 cases with new-onset ICD coding for AMD matched with propensity scores to 414,853 controls. In total, 16.1% of cases and 15.9% of controls were diagnosed with any autoimmune disease. The diagnosis of any autoimmune disease did not affect the odds of new-onset ICD coding for AMD in multivariable regression (OR = 1.01; 95% CI, 0.999-1.02). Discoid lupus erythematosus (OR = 1.29; 95% CI, 1.12-1.48), systemic lupus erythematosus (SLE) (OR = 1.21; 95% CI, 1.15-1.27), giant cell arteritis (OR = 1.19; 95% CI, 1.09-1.30), Sjogren's syndrome (OR = 1.17; 95% CI, 1.09-1.26), and Crohn's disease (OR = 1.13; 95% CI, 1.06-1.22) increased the odds of a new-onset ICD coding for AMD.

Conclusions

Most autoimmune diseases do not affect the odds of developing AMD but several common autoimmune disorders such as SLE and Crohn's disease were associated with modestly increased odds of AMD. Further studies are needed to validate and investigate the underlying mechanisms of these associations.

Oral Metformin Inhibits Choroidal Neovascularization by Modulating the Gut-Retina Axis

Purpose

Emerging data indicate that metformin may prevent the development of age-related macular degeneration (AMD). Whereas the underlying mechanisms of metformin's anti-aging properties remain undetermined, one proposed avenue is the gut microbiome. Using the laser-induced choroidal neovascularization (CNV) model, we investigate the effects of oral metformin on CNV, retinal pigment epithelium (RPE)/choroid transcriptome, and gut microbiota.

Methods

Specific pathogen free (SPF) male mice were treated via daily oral gavage of metformin 300 mg/kg or vehicle. Male mice were selected to minimize sex-specific differences to laser induction and response to metformin. Laser-induced CNV size and macrophage/microglial infiltration were assessed by isolectin and Iba1 immunostaining. High-throughput RNA-seq of the RPE/choroid was performed using Illumina. Fecal pellets were analyzed for gut microbiota composition/pathways with 16S rRNA sequencing/shotgun metagenomics, as well as microbial-derived metabolites, including small-chain fatty acids and bile acids. Investigation was repeated in metformin-treated germ-free (GF) mice and antibiotic-treated/GF mice receiving fecal microbiota transplantation (FMT) from metformin-treated SPF mice.

Results

Metformin treatment reduced CNV size (P < 0.01) and decreased Iba1+ macrophage/microglial infiltration (P < 0.005). One hundred forty-five differentially expressed genes were identified in the metformin-treated group (P < 0.05) with a downregulation in pro-angiogenic genes Tie1, Pgf, and Gata2. Furthermore, metformin altered the gut microbiome in favor of Bifidobacterium and Akkermansia, with a significant increase in fecal levels of butyrate, succinate, and cholic acid. Metformin did not suppress CNV in GF mice but colonization of microbiome-depleted mice with metformin-derived FMT suppressed CNV.

Conclusions

These data suggest that oral metformin suppresses CNV, the hallmark lesion of advanced neovascular AMD, via gut microbiome modulation.

NODULAR EPIRETINAL MÜLLER CELL GLIOSIS IN THE FOVEA

PURPOSE

The purpose of this study was to report the findings of a hyperreflective nodular epiretinal gliosis observed with optical coherence tomography presumed to be due to subclinical hyaloidal traction causing Mϋller cell cone gliosis.

METHODS

Retrospective, observational case series.

RESULTS

Six eyes of six patients (mean age: 57 years, range 35-81 years) presented with a nodular epiretinal gliosis and had an average follow-up interval of 26 months (range 1-82 months). The mean baseline best-corrected visual acuity was 0.25 ± 0.17 (Snellen equivalent 20/38.3 ± 16.9). Fundus photography demonstrated a yellowish lesion overlying the fovea. Optical coherence tomography imaging revealed a hyperreflective preretinal lesion with a mean vertical length of 267 μ m (range 185-497) and a mean greatest linear diameter of 312 µ m (range 124-640). There was no vitreoretinal abnormality including vitreomacular traction or epiretinal membrane noted in any eye, and two of six eyes displayed a definitive posterior vitreous detachment. These nodules may have occurred before and persisted even after a posterior vitreous detachment or may have been acquired after the posterior vitreous detachment. The nodules typically remained stable with minimal change although in one eye, a posterior vitreous detachment occurred 6 months after initial presentation and lifted the gliosis off of the retinal surface where it remained attached to the posterior hyaloid.

CONCLUSION

Foveal nodular epiretinal gliosis may occur due to subclinical hyaloidal traction on the Müller cell cone even without obvious vitreoretinal interface abnormality on optical coherence tomography.

The Emerging Role of Gut Microbiota in Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a progressive, degenerative retinal disease that is a leading cause of blindness globally. Although multiple risk factors have been identified regarding disease incidence and progression, including smoking, genetics, and diet, the understanding of AMD pathogenesis remains unclear. As such, primary prevention is lacking, and current treatments have limited efficacy. More recently, the gut microbiome has emerged as an influential player in various ocular pathologies. As mediators of metabolism and immune regulation, perturbations in gut microbiota may impart significant effects distally on the neuroretina and its adjacent tissues, termed the gut-retina axis. In this review, key studies over the past several decades are summarized, both in humans and in animal models, which shed insight on the relationships between the gut microbiome and retinal biology and their implications for AMD. The literature linking gut dysbiosis with AMD is examined, along with preclinical animal models and techniques apt for studying the role of gut microbiota in AMD pathogenesis, which include interactions with systemic inflammation, immune regulation, chorioretinal gene expression, and diet. As understanding of the gut-retina axis continues to advance, so too will the possibility for more accessible and effective prevention and therapy of this vision-threatening condition.

Association of metformin use with risk of newly onset neovascular age-related macular degeneration development

PURPOSE

To investigate if metformin use reduces the odds of developing new neovascular AMD (nAMD).

METHODS

This is a case-control study of 86,930 subjects with new diagnoses of nAMD and 86,918 matched controls using the Merative™ Marketscan® Research Databases. Subjects were analyzed using multivariable conditional logistic regression to identify the risks of various exposures on developing nAMD. A subgroup analysis of 22,117 diabetic cases and 21,616 diabetic controls was also performed.

RESULTS

Metformin use was associated with reduced odds ratio (OR) of developing nAMD (OR 0.95, 95% confidence interval 0.91-0.98) in full sample and diabetic cohort particularly in patients without any diabetic retinopathy (DR) -an effect that persisted after Bonferroni correction. In the diabetic cohort without DR, reduced OR was observed at 24-month cumulative doses of 1 to 300g, 301 to 630g, and 631 to 1080g.

CONCLUSIONS

Metformin use was associated with reduced OR of nAMD, particularly in patients without DR. The protective effect was noted for 24-month cumulative doses below 1080g. Metformin may be a novel preventive strategy for nAMD.

The Association of Antibiotic Use and the Odds of a New-Onset ICD Code Diagnosis of Age-Related Macular Degeneration: A Large National Case-Control Study

Purpose

The widespread use of antibiotics has many well-documented impacts on the human microbiome, which may be associated with the development of various inflammatory diseases. Despite age-related macular degeneration (AMD) featuring an inflammatory pathogenesis, the relationship between antibiotics and AMD has remained unexplored. We conducted the first study to determine the association between antibiotic exposure and a new-onset International Classification of Diseases (ICD) diagnosis of AMD.

Methods

We performed a case-control analysis of patients aged 55 and older with new-onset AMD between 2008 and 2017 from a nationwide commercial health insurance claims database. Exposure to antibiotics in the two years before the index date was determined for cases and controls matched one-to-one by age, year, region, anemia, hypertension, and a comorbidity index. Conditional multivariable logistic regression, adjusted for AMD risk factors, was performed to calculate odd ratios (OR) and 95% confidence intervals (CI).

Results

Among the antibiotic classes, exposure to aminoglycosides (OR = 1.24; 95% CI, 1.22-1.26) and fluoroquinolones (OR = 1.13; 95% CI, 1.12-1.14) was associated with the greatest odds of a new-onset ICD code diagnosis of AMD. Broad-spectrum antibiotics were associated with nearly three times greater odds of a new-onset ICD code diagnosis of AMD (OR = 1.15; 95% CI, 1.13-1.16) compared to narrow-spectrum antibiotics (OR = 1.05; 95% CI, 1.03-1.07). We also identified a frequency- and duration-dependent association, with a greater cumulative number of antibiotic prescriptions or day supply of antibiotics conferring increased odds of a new-onset ICD code diagnosis of AMD.

Conclusions

Greater cumulative exposure to antibiotics, particularly fluoroquinolones, aminoglycosides, and those with broader-spectrum coverage, may be associated with the development of AMD, a finding that requires further investigation using prospective studies.

Levodopa Is Associated with Reduced Development of Neovascular Age-Related Macular Degeneration

OBJECTIVE

To determine whether levodopa (L-DOPA) is associated with a reduced likelihood of developing neovascular age-related macular degeneration (AMD).

DESIGN

Three studies were performed: retrospective analyses in the Vestrum Health Retina Database (#1-2) and case-control analysis in the Merative MarketScan Research Databases (#3).

PARTICIPANTS

Eyes with neovascular AMD and 2 years of follow-up (#1). Eyes with non-neovascular AMD and 1 to 5 years of follow-up (#2). Patients aged ≥ 55 years with newly diagnosed neovascular AMD matched to controls without neovascular AMD (#3).

METHODS

Eyes were divided into 2 groups (#1-2): exposed to L-DOPA before or on the date of neovascular (#1) or nonneovascular (#2) AMD diagnosis, and eyes not exposed to L-DOPA. We extracted AMD risk factors, number of intravitreal injections (#1), and conversion rate to neovascular AMD (#2). We calculated the percentage of newly diagnosed neovascular AMD cases and matched controls exposed to any L-DOPA and determined the cumulative 2-year dose in grams by tertiles (< 100 mg, approximately 100-300 mg, and approximately > 300 mg per day, #3).

MAIN OUTCOME MEASURES

Number of intravitreal injections (#1) and detection of new-onset neovascular AMD (#2-3) after adjusting for AMD risk factors.

RESULTS

In the Vestrum database, eyes with neovascular AMD that were exposed to L-DOPA underwent 1 fewer intravitreal injection over 2 years (N = 84 088 control vs. 530 L-DOPA eyes, P = 0.006). In eyes with nonneovascular AMD (N = 42 081-203 155 control vs. 314-1525 L-DOPA eyes), L-DOPA exposure was associated with a reduced risk of conversion to neovascular AMD by 21% at year 2 (P = 0.029), 35% at years 3 to 4 (P < 0.001), and 28% at year 5 (P = 0.024). In the MarketScan databases (N = 86 900 per group), cumulative 2-year doses of L-DOPA between approximately 100 to 300 mg per day and approximately > 300 mg were associated with decreased odds of developing neovascular AMD by 15% (odds ratio [OR], 0.85; 95% confidence interval [CI], 0.75-0.97) and 23% (OR, 0.77; 95% CI, 0.67-0.87), respectively.

CONCLUSIONS

Levodopa use was associated with reduced detection of new-onset neovascular AMD. A prospective, randomized clinical trial should be considered to investigate whether low-dose L-DOPA reduces neovascular AMD conversion.

FINANCIAL DISCLOSURE(S)

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

EXUDATIVE MACULAR DETACHMENT FOLLOWING UNCOMPLICATED PARS PLANA VITRECTOMY FOR DIABETIC VITREOUS HEMORRHAGE

BACKGROUND/PURPOSE

To describe diagnostic characteristics and management of exudative macular detachment, a rare complication of pars plana vitrectomy and endolaser for diabetic vitreous hemorrhage.

METHODS

Case report including multimodal imaging.

RESULTS

Forty-seven-year-old man with diabetes mellitus Type 2 and proliferative diabetic retinopathy underwent uncomplicated 23-gauge pars plana vitrectomy, Triesence-assisted hyaloid peeling, fill-in endolaser, and intravitreal bevacizumab injection in the left eye for nonclearing visually significant vitreous hemorrhage. On the first postoperative day, patient developed significant macular subretinal fluid. Multimodal imaging revealed numerous pigment epithelial detachments around optic nerve, and subretinal fluid throughout the macula on optical coherence tomography in the absence of retinal breaks on widefield raster, late deep leakage on fluorescein angiography, and corresponding hyperautofluorescence in the same region. Diagnosed with macular exudative retinal detachment, patient was treated with topical and systemic corticosteroids, with gradual resolution of subretinal fluid and visual acuity improvement.

DISCUSSION

Exudative retinal detachment following diabetic pars plana vitrectomy with endolaser has been described in as many as 8.78% of cases, however may be missed in the early postoperative period. Multimodal imaging including multiple pigment epithelial detachments on optical coherence tomography, hyperautofluorescence, and late deep leakage on fluorescein angiography can help differentiate this condition from rhegmatogenous retinal detachment and central serous chorioretinopathy, and guide management to include corticosteroids.

Association of Metformin and Other Diabetes Medication Use and the Development of New-Onset Dry Age-Related Macular Degeneration: A Case-Control Study

Purpose

To investigate if metformin use is associated with decreased odds of developing new non-neovascular ("dry") age-related macular degeneration (AMD).

Methods

Case-control study examining 194,135 cases with diagnoses of new-onset AMD between 2008 and 2017 and 193,990 matched controls in the Merative MarketScan Research Databases. The diabetic subgroup included 49,988 cases and 49,460 controls. Multivariable conditional logistic regressions identified the risks of exposures on the development of dry AMD. Main outcome measures were odds ratios (ORs) of developing dry AMD with metformin use.

Results

In multivariable conditional logistic regression, any metformin use was associated with decreased odds of developing dry AMD (OR = 0.97; 95% confidence interval [CI], 0.95-0.99). This protective effect was noted for cumulative 2-year doses of metformin of 1 to 270 g (OR = 0.93; 95% CI, 0.90-0.97) and 271 to 600 g (OR = 0.92; 95% CI, 0.89-0.96). In a diabetic subgroup, metformin use below 601 g per 2 years decreased the odds of developing dry AMD (1-270 g: OR = 0.95; 95% CI, 0.91-0.99; 271-600 g: OR = 0.92; 95% CI, 0.89-0.96). Unlike in diabetic patients with diabetic retinopathy, diabetic patients without diabetic retinopathy had decreased odds of developing dry AMD with any metformin use (OR = 0.97; 95% CI, 0.94-0.998) and cumulative two-year doses of 1 to 270 g (OR 0.96; 95% CI, 0.91-0.998) and 271 to 600 g (OR = 0.92; 95% CI, 0.88-0.96).

Conclusions

Metformin use was associated with decreased odds of developing dry AMD. The protective effect was observed for cumulative 2-year doses below 601 g. In diabetics, this association persisted, specifically in those without diabetic retinopathy. Therefore, metformin may be a strategy to prevent development of dry AMD.

Identifying novel candidate compounds for therapeutic strategies in retinopathy of prematurity via computational drug-gene association analysis

Purpose

Retinopathy of prematurity (ROP) is the leading cause of preventable childhood blindness worldwide. Although interventions such as anti-VEGF and laser have high success rates in treating severe ROP, current treatment and preventative strategies still have their limitations. Thus, we aim to identify drugs and chemicals for ROP with comprehensive safety profiles and tolerability using a computational bioinformatics approach.

Methods

We generated a list of genes associated with ROP to date by querying PubMed Gene which draws from animal models, human studies, and genomic studies in the NCBI database. Gene enrichment analysis was performed on the ROP gene list with the ToppGene program which draws from multiple drug-gene interaction databases to predict compounds with significant associations to the ROP gene list. Compounds with significant toxicities or without known clinical indications were filtered out from the final drug list.

Results

The NCBI query identified 47 ROP genes with pharmacologic annotations present in ToppGene. Enrichment analysis revealed multiple drugs and chemical compounds related to the ROP gene list. The top ten most significant compounds associated with ROP include ascorbic acid, simvastatin, acetylcysteine, niacin, castor oil, penicillamine, curcumin, losartan, capsaicin, and metformin. Antioxidants, NSAIDs, antihypertensives, and anti-diabetics are the most common top drug classes derived from this analysis, and many of these compounds have potential to be readily repurposed for ROP as new prevention and treatment strategies.

Conclusion

This bioinformatics analysis creates an unbiased approach for drug discovery by identifying compounds associated to the known genes and pathways of ROP. While predictions from bioinformatic studies require preclinical/clinical studies to validate their results, this technique could certainly guide future investigations for pathologies like ROP.

Central Serous Chorioretinopathy: An Update on the Current State of Management

Central serous chorioretinopathy (CSCR) is a relatively common retinal disorder that leads to central vision impairment, often with a high recurrence rate. The exact etiology and pathogenetic mechanisms have not been fully elucidated but are likely to be associated with hyperpermeability of the choroidal capillaries and failure of the retinal pigment epithelium (RPE), leading to serous detachment of the neurosensory retina. Multimodal imaging plays a critical role in the diagnostic approach and monitoring of CSCR. Fortunately, the natural course of the disease is usually self-limiting, with spontaneous resolution and total fluid reabsorption. However, some patients may exhibit recurrences or persistent subretinal fluid (chronic CSCR), leading to progressive and irreversible RPE atrophy or photoreceptor damage. Thus, to prevent permanent visual loss, individualized treatment should be considered. Recent developments in the diagnostic and therapeutic approach have contributed to better outcomes in patients with CSCR. More studies are required to improve our understanding of epidemiology, pathogenesis, diagnosis, and treatment, with a significant impact on the management of this challenging clinical entity. The purpose of this review is to summarize the current knowledge about the clinical features, diagnostic workup, and therapeutic approach of CSCR.

Repurposing medications for treatment of age-related macular degeneration: Insights from novel approaches to data mining

The economic and visual burdens associated with age-related macular degeneration (AMD) are expected to significantly increase in the coming years. As of now, interventions to delay or prevent AMD are limited. Hence, there is an urgent and unmet need to expand our therapeutic tools for AMD in a manner, that is, both efficient and cost-effective. In this review, we consider the idea of drug repurposing, in which existing medications with other indications can be re-imagined for treating AMD. We detail the results of several population-level studies that have shown associations between several candidates and decreased risk of AMD development or progression. Such candidates include the more extensively studied metformin and statins, in addition to recently identified candidates fluoxetine and l-DOPA (levodopa) that show promise. We then briefly explore results from an advanced bioinformatics study, which provides further evidence that existing medications are associated with AMD risk genes. Many of these candidates warrant further study in prospective, clinical trials, where their potential causal relationships with AMD can be thoroughly assessed.

Using Advanced Bioinformatics Tools to Identify Novel Therapeutic Candidates for Proliferative Vitreoretinopathy

Purpose

Proliferative vitreoretinopathy (PVR) is the dreaded cause of failure following retinal detachment repair; however, no cures or preventative therapies exist to date. The purpose of this study was to use bioinformatics tools to identify drugs or compounds that interact with biomarkers and pathways involved in PVR pathogenesis that could be eligible for further testing for the prevention and treatment of PVR.

Methods

We queried PubMed to compile a comprehensive list of genes described in PVR to date from human studies, animal models, and genomic studies found in the National Center for Biotechnology Information database. Gene enrichment analysis was performed using ToppGene on PVR-related genes against drug-gene interaction databases to construct a pharmacome and estimate the statistical significance of overrepresented compounds. Compounds with no clinical indications were filtered out from the resulting drug lists.

Results

Our query identified 34 unique genes associated with PVR. Out of 77,146 candidate drugs or compounds in the drug databases, our analysis revealed multiple drugs and compounds that have significant interactions with genes involved in PVR, including antiproliferatives, corticosteroids, cardiovascular agents, antioxidants, statins, and micronutrients. Top compounds, including curcumin, statins, and cardiovascular agents such as carvedilol and enalapril, have well-established safety profiles and potentially could be readily repurposed for PVR. Other significant compounds such as prednisone and methotrexate have shown promising results in ongoing clinical trials for PVR.

Conclusions

This bioinformatics approach of studying drug-gene interactions can identify drugs that may affect genes and pathways implicated in PVR. Predicted bioinformatics studies require further validation by preclinical or clinical studies; however, this unbiased approach could identify potential candidates among existing drugs and compounds that could be repurposed for PVR and guide future investigations.

Translational Relevance

Novel repurposable drug therapies for PVR can be found using advanced bioinformatics models.

Clinical variations of polypoidal choroidal vasculopathy: A cohort study from Japan and the USA

We describe the clinical characteristics of treatment-naïve polypoidal choroidal vasculopathy (PCV) in three tertiary clinic settings in 2 cities (Chicago in the USA and Nishinomiya in Japan). This cohort study was a retrospective, multicenter, consecutive case series. A total of 126 patients with treatment-naïve PCV-46 in Chicago and 80 in Nishinomiya-were identified. The proportion of PCV in patients with neovascular age-related macular degeneration was lower in Chicago (10.8% vs. 36.9%). Patients in Chicago had a significantly higher prevalence of soft drusen (50.0% vs 25.0%, p = 0.006) and intra-retinal cyst (37.0% vs 15.0%, p = 0.008), and a significantly lower prevalence of pachyvessels (41.3% vs 62.5%, p = 0.03). At baseline, presenting vision for patients in Chicago was worse than in Nishinomiya (mean log MAR: 0.609 vs. 0.312, p < 0.001). Ninety-five eyes were followed for more than one year. The Nishinomiya group received a higher rate of combination therapy (61.0%) compared to the Chicago group (5.3%). Vision and central foveal thickness at month 12 were significantly improved from baseline in both Chicago (p = 0.009 and p = 0.01) and Nishinomiya groups (both p < 0.001). Our study highlights interesting differences in the proportion of PCV, clinical findings and treatment responses of PCV, that need to be further evaluated in larger, epidemiologic cohorts.

Effects of systemic drugs on the development and progression of age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of severe loss of central vision among people over 50. The pathophysiology of the disease is multifactorial and can be attributed to genetics, aging, inflammation, environmental factors, and lifestyle factors including smoking, diet, obesity, and alcohol consumption. While there is no treatment for dry AMD, the current standard treatment for wet AMD is an intraocular injection of anti-vascular endothelial growth factor-an effective, yet expensive, therapy that requires ongoing treatment. As the aging population continues to grow, and AMD diagnoses continue to rise, new treatments should be explored to reduce vision complications and decrease treatment burdens. Many systemic conditions have progressive pathological changes that may affect AMD, particularly those affecting systemic vasculature like diabetes and cardiovascular status. Consequently, systemic drugs used to treat coexistent systemic diseases may influence some of the pathogenic mechanisms of AMD and lead its progression or delay. In this review we explore the current literature to summarize the findings of the reported effects of antihypertensive, immunosuppressants, cholesterol lowering agents, nonsteroidal anti-inflammatory drugs, dopamine precursors, hypoglycemic agents, and anticoagulants on AMD.

Racial differences in quantitative optical coherence tomography angiography findings between older non-diabetics with co-morbidities

This cross-sectional study compared optical coherence tomography angiography (OCTA) parameters between older Black and White adults with systemic comorbidities in an effort to further understand racial differences in the retinal microvasculature. We analyzed vessel density at the superficial (SCP), intermediate (ICP), and deep capillary plexuses (DCP), foveal avascular zone (FAZ) parameters, and blood flow area (BFA) at the choriocapillaris. We used a mixed-effects linear regression model, controlling for hypertension and two eyes from the same subject, to compare OCTA parameters. Black subjects had lower foveal vessel density at the SCP and ICP, while no differences were observed at the parafovea or 3x3 mm macular area of any capillary layer. Black subjects had greater FAZ area, perimeter, and FD-300, a measurement of vessel density in a 300 μm wide ring around the FAZ. Black subjects also had lower BFA at the choriocapillaris. Within a cohort of subjects without hypertension, these differences remained statistically significant, with the exception of foveal vessel density at the SCP and foveal BFA of the choriocapillaris. These findings suggest that normative databases of OCTA parameters must strive to be diverse in nature to adequately capture differences across patient populations. Further study is required to understand if baseline differences in OCTA parameters contribute to epidemiological disparities in ocular diseases.

Gonioscopy-assisted transluminal trabeculotomy in neovascular glaucoma: Salvaging the conventional outflow pathway

Purpose

To report a case of acute neovascular glaucoma with partial synechial angle closure secondary to central retinal vein occlusion that underwent gonioscopy-assisted transluminal trabeculotomy as well as near-monthly anti-vascular endothelial growth factor (VEGF) injections and panretinal photocoagulation (PRP) treatments.

Observations

Nine months after GATT, the patient had achieved intraocular pressure control on no medications. However, she was lost to follow up for 4 months and received no anti-VEGF or PRP during that time; she re-presented with acute NVG and complete synechial closure, and ultimately underwent aqueous shunt implantation.

Conclusions and Importance

To our knowledge, this is the first reported attempt of an ab interno angle surgery to successfully restore aqueous outflow through the conventional outflow pathway in an eye with acute NVG and partial synechial angle closure. We posit that this can be an effective approach to achieve IOP control in NVG with at least partially open angles, as long as sufficient anti-neovascular treatments are administered until the underlying neovascular drive achieves quiescence.

Using Computational Drug-Gene Analysis to Identify Novel Therapeutic Candidates for Retinal Neuroprotection

Retinal cell death is responsible for irreversible vision loss in many retinal disorders. No commercially approved treatments are currently available to attenuate retinal cell loss and preserve vision. We seek to identify chemicals/drugs with thoroughly-studied biological functions that possess neuroprotective effects in the retina using a computational bioinformatics approach. We queried the National Center for Biotechnology Information (NCBI) to identify genes associated with retinal neuroprotection. Enrichment analysis was performed using ToppGene to identify compounds related to the identified genes. This analysis constructs a Pharmacome from multiple drug-gene interaction databases to predict compounds with statistically significant associations to genes involved in retinal neuroprotection. Compounds with known deleterious effects (e.g., asbestos, ethanol) or with no clinical indications (e.g., paraquat, ozone) were manually filtered. We identified numerous drug/chemical classes associated to multiple genes implicated in retinal neuroprotection using a systematic computational approach. Anti-diabetics, lipid-lowering medicines, and antioxidants are among the treatments anticipated by this analysis, and many of these drugs could be readily repurposed for retinal neuroprotection. Our technique serves as an unbiased tool that can be utilized in the future to lead focused preclinical and clinical investigations for complex processes such as neuroprotection, as well as a wide range of other ocular pathologies.

Update on Current Microbiological Techniques for Pathogen Identification in Infectious Endophthalmitis

Infectious endophthalmitis is a vision-threatening medical emergency that requires prompt clinical diagnosis and the initiation of treatment. However, achieving precision in endophthalmitis management remains challenging. In this review, we provide an updated overview of recent studies that are representative of the current trends in clinical microbiological techniques for infectious endophthalmitis.

Using Advanced Bioinformatics Tools to Identify Novel Therapeutic Candidates for Age-Related Macular Degeneration

Purpose

Age-related macular degeneration (AMD) is the most common cause of aging-related blindness in the developing world. Although medications can slow progressive wet AMD, currently, no drugs to treat dry-AMD are available. We use a systems or in silico biology analysis to identify chemicals and drugs approved by the Food and Drug Administration for other indications that can be used to treat and prevent AMD.

Methods

We queried National Center for Biotechnology Information to identify genes associated with AMD, wet AMD, dry AMD, intermediate AMD, and geographic atrophy to date. We combined genes from various AMD subtypes to reflect distinct stages of disease. Enrichment analysis using the ToppGene platform predicted molecules that can influence AMD genes. Compounds without clinical indications or with deleterious effects were manually filtered.

Results

We identified several drug/chemical classes that can affect multiple genes involved in AMD. The drugs predicted from this analysis include antidiabetics, lipid-lowering agents, and antioxidants, which could theoretically be repurposed for AMD. Metformin was identified as the drug with the strongest association with wet AMD genes and is among the top candidates in all dry AMD subtypes. Curcumin, statins, and antioxidants are also among the top drugs correlating with AMD-risk genes.

Conclusions

We use a systematic computational process to discover potential therapeutic targets for AMD. Our systematic and unbiased approach can be used to guide targeted preclinical/clinical studies for AMD and other ocular diseases.

Translational Relevance

Advanced bioinformatics models identify novel chemicals and approved drug candidates that can be efficacious for different subtypes of AMD.

Gut microbiome and retinal diseases: an updated review

PURPOSE OF REVIEW

The gut microbiome, trillions of microorganisms residing in our digestive tract, is now believed to play a significant role in retinal diseases. Breakthroughs in computational biology and specialized animal models have allowed researchers not only to characterize microbes associated with retinal diseases, but also to provide early insights into the function of the microbiome in relation to biological processes in the retinal microenvironment. This review aims to provide an update on recent advances in the current knowledge on the relationship between the gut microbiome and retinal disorders.

RECENT FINDINGS

Recent work demonstrates distinct gut microbial compositions associated with retinal diseases such as agerelated macular degeneration and retinopathy of prematurity. Currently, it is believed that gut dysbiosis leads to increased gut permeability, elevated circulation of bacterial products, microbial metabolites and inflammatory mediators that result in immune dysregulation at distant anatomic sites including the retina.

SUMMARY

Emerging evidence for the gut-retina axis can elucidate previously unknown pathways involved in retinal diseases and also presents an exciting potential therapeutic avenue. Further preclinical and clinical studies are necessary to establish causation and delineate the precise relationship of the gut microbiome with retinal disorders.

Metformin and retinal diseases in preclinical and clinical studies: Insights and review of literature

Metformin is one of the most prescribed drugs in the world giving potential health benefits beyond that of type 2 diabetes (T2DM). Emerging evidence suggests that it may have protective effects for retinal/posterior segment diseases including diabetic retinopathy (DR), age-related macular degeneration (AMD), inherited retinal degeneration such as retinitis pigmentosa (RP), primary open angle glaucoma (POAG), retinal vein occlusion (RVO), and uveitis. Metformin exerts potent anti-inflammatory, antiangiogenic, and antioxidative effects on the retina in response to pathologic stressors. In this review, we highlight the broad mechanism of action of metformin through key preclinical studies on animal models and cell lines used to simulate human retinal disease. We then explore the sparse but promising retrospective clinical data on metformin's potential protective role in DR, AMD, POAG, and uveitis. Prospective clinical data is needed to clarify metformin's role in management of posterior segment disorders. However, given metformin's proven broad biochemical effects, favorable safety profile, relatively low cost, and promising data to date, it may represent a new therapeutic preventive and strategy for retinal diseases.

Evaluation of flow of chorioretinal capillaries in healthy black and white subjects using optical coherence tomography angiography

This study compared macular capillary parameters between healthy black and white subjects using optical coherence tomography angiography (OCTA). We measured vessel density (VD) of superficial (SCP), intermediate (ICP), and deep (DCP) capillary plexuses and choriocapillaris blood flow area (BFA) of the fovea, parafovea and total 3 mm-diameter circular area centered on the fovea, as well as the foveal avascular zone (FAZ) parameters, controlling for axial length. Black subjects had lower foveal and parafoveal VD in the SCP (p = 0.043 and p = 0.014) and the ICP (p = 0.014 and p = 0.002). In the DCP, black subjects had a trend toward lower foveal and parafoveal VD. Black subjects had decreased choriocapillaris BFA in the total 3 mm area (p = 0.011) and the parafovea (p = 0.033), larger FAZ area (p = 0.006) and perimeter (p = 0.014), and a higher capillary density in a 300 μm wide region around the FAZ (FD-300) (p = 0.001). There was no significant difference in FAZ acircularity index. To our knowledge, this is the first report analyzing the three distinct retinal capillary plexuses and identifying differing baseline VD, choriocapillaris and FAZ parameters in healthy young black compared to white subjects. Larger studies are needed to validate these findings and better understand racial differences in vulnerability to ocular diseases.

High-Fat Diet Alters the Retinal Transcriptome in the Absence of Gut Microbiota

The relationship between retinal disease, diet, and the gut microbiome has shown increasing importance over recent years. In particular, high-fat diets (HFDs) are associated with development and progression of several retinal diseases, including age-related macular degeneration (AMD) and diabetic retinopathy. However, the complex, overlapping interactions between diet, gut microbiome, and retinal homeostasis are poorly understood. Using high-throughput RNA-sequencing (RNA-seq) of whole retinas, we compare the retinal transcriptome from germ-free (GF) mice on a regular diet (ND) and HFD to investigate transcriptomic changes without influence of gut microbiome. After correction of raw data, 53 differentially expressed genes (DEGs) were identified, of which 19 were upregulated and 34 were downregulated in GF-HFD mice. Key genes involved in retinal inflammation, angiogenesis, and RPE function were identified. Enrichment analysis revealed that the top 3 biological processes affected were regulation of blood vessel diameter, inflammatory response, and negative regulation of endopeptidase. Molecular functions altered include endopeptidase inhibitor activity, protease binding, and cysteine-type endopeptidase inhibitor activity. Human and mouse pathway analysis revealed that the complement and coagulation cascades are significantly affected by HFD. This study demonstrates novel data that diet can directly modulate the retinal transcriptome independently of the gut microbiome.

Gnotobiotic Operations and Assembly for Development of Germ-Free Animal Model of Laser-Induced Choroidal Neovascularization

Purpose

Compelling new evidence reveals a close link between the gut microbiome and the pathogenesis of neovascular age-related macular degeneration (nAMD). Germ-free (GF) animal models are the current gold standard for studying host the microbe interactions in vivo; yet, no GF animal models of nAMD are available today. This protocol describes gnotobiotic operations and assembly for a laser-induced choroidal neovascularization (CNV) model in GF mice to study the gut microbiome in neovascular AMD.

Methods

We developed a step-wise approach to performing retinal laser photocoagulation in GF C57BL/6J mice that were bred and maintained at the gnotobiotic facility. Following a strict sterility protocol, we administered laser photocoagulation via an Argon 532-nm laser attached to a customized slit-lamp delivery system. Sterility was confirmed by weekly fecal cultures and reverse transcriptase-polymerase chain reaction.

Results

The experiment was repeated twice at different time points using seven mice (14 eyes). Stool cultures and RT-PCR remained negative for 14 days post-procedure in all mice. Lectin immunostaining performed on choroidal flatmounts confirmed the presence of CNV lesions 2 weeks after laser treatment.

Conclusions

We established a GF mouse model of nAMD with detailed guidelines to deliver retinal laser in GF mice maintaining sterility after the laser procedure.

Translational Relevance

To our knowledge, this is the first protocol that describes a GF murine model of laser-induced CNV. In addition to nAMD, this animal model can be used to investigate host-microbial interactions in other eye diseases with laser-induced mouse models such as glaucoma and retinal vein occlusion.

Management of severe epithelial versus fibrous downgrowth following trabeculectomy: Case report and literature review

Purpose

To describe the presentation and management of a patient with epithelial versus fibrous downgrowth following trabeculectomy surgery and review relevant literature regarding this complication after intraocular surgery.

Observations

A 52-year-old monocular African-American woman was referred for management of presumed epithelial versus fibrous downgrowth following trabeculectomy surgery. The patient was initially treated with intracameral injections of 5-fluorouracil (x2) and bevacizumab (x1). Cataract extraction, membranectomy, and a third intracameral 5-fluorouracil injection were performed. Intraocular pressure (IOP) elevation was subsequently managed with a superotemporal Ahmed FP7 glaucoma drainage device in the sulcus, followed by an inferonasal Baerveldt 350 glaucoma drainage device in the sulcus. The downgrowth has not progressed and the intraocular pressure remains controlled at the most recent follow-up.

Conclusions

This case underscores the risk of this complication following trabeculectomy, the role of a combined medical and surgical approach to management, and the possible need for multiple surgical interventions to control IOP. A review of the literature regarding epithelial and fibrous downgrowth after intraocular surgery was conducted, which highlighted the aggressive nature of these conditions and the range of therapeutic approaches that have been described.

Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immune checkpoint inhibitor-related adverse events

Immune checkpoint inhibitors (ICIs) are the standard of care for the treatment of several cancers. While these immunotherapies have improved patient outcomes in many clinical settings, they bring accompanying risks of toxicity, specifically immune-related adverse events (irAEs). There is a need for clear, effective guidelines for the management of irAEs during ICI treatment, motivating the Society for Immunotherapy of Cancer (SITC) to convene an expert panel to develop a clinical practice guideline. The panel discussed the recognition and management of single and combination ICI irAEs and ultimately developed evidence- and consensus-based recommendations to assist medical professionals in clinical decision-making and to improve outcomes for patients.

A Review of the Role of the Intestinal Microbiota in Age-Related Macular Degeneration

Blindness from age-related macular degeneration (AMD) is an escalating problem, yet AMD pathogenesis is incompletely understood and treatments are limited. The intestinal microbiota is highly influential in ocular and extraocular diseases with inflammatory components, such as AMD. This article reviews data supporting the role of the intestinal microbiota in AMD pathogenesis. Multiple groups have found an intestinal dysbiosis in advanced AMD. There is growing evidence that environmental factors associated with AMD progression potentially work through the intestinal microbiota. A high-fat diet in apo-E-/- mice exacerbated wet and dry AMD features, presumably through changes in the intestinal microbiome, though other independent mechanisms related to lipid metabolism are also likely at play. AREDS supplementation reversed some adverse intestinal microbial changes in AMD patients. Part of the mechanism of intestinal microbial effects on retinal disease progression is via microbiota-induced microglial activation. The microbiota are at the intersection of genetics and AMD. Higher genetic risk was associated with lower intestinal bacterial diversity in AMD. Microbiota-induced metabolite production and gene expression occur in pathways important in AMD pathogenesis. These studies suggest a crucial link between the intestinal microbiota and AMD pathogenesis, thus providing a novel potential therapeutic target. Thus, the need for large longitudinal studies in patients and germ-free or gnotobiotic animal models has never been more pressing.

Quantitative Optical Coherence Tomography Angiography (OCTA) Parameters in a Black Diabetic Population and Correlations with Systemic Diseases

This is a cross-sectional, prospective study of a population of black diabetic participants without diabetic retinopathy aimed to investigate optical coherence tomography angiography (OCTA) characteristics and correlations with systemic diseases in this population. These parameters could serve as novel biomarkers for microvascular complications; especially in black populations which are more vulnerable to diabetic microvascular complications. Linear mixed models were used to obtain OCTA mean values ± standard deviation and analyze statistical correlations to systemic diseases. Variables showing significance on univariate mixed model analysis were further analyzed with multivariate mixed models. 92 eyes of 52 black adult subjects were included. After multivariate analysis; signal strength intensity (SSI) and heart disease had statistical correlations to superficial capillary plexus vessel density in our population. SSI and smoking status had statistical correlations to deep capillary plexus vessel density in a univariate analysis that persisted in part of the imaging subset in a multivariate analysis. Hyperlipidemia; hypertension; smoking status and pack-years; diabetes duration; creatinine; glomerular filtration rate; total cholesterol; hemoglobin A1C; and albumin-to-creatinine ratio were not significantly associated with any OCTA measurement in multivariate analysis. Our findings suggest that OCTA measures may serve as valuable biomarkers to track systemic vascular functioning in diabetes mellitus in black patients.

Association of Metformin Use With Age-Related Macular Degeneration: A Case-Control Study

Importance

Age-related macular degeneration (AMD), the leading cause of irreversible blindness in older adults, appears to have no effective preventive measures. The common antidiabetic drug metformin has been shown to have protective outcomes in multiple age-associated diseases and may have the potential to protect against the development of AMD.

Objective

To determine whether metformin use is associated with reduced odds of developing AMD.

Design, Setting, and Participants

This case-control study of patients from a nationwide health insurance claims database included a population-based sample of patients. Those aged 55 years and older with newly diagnosed AMD from January 2008 to December 2017 were defined as cases and matched with control participants. Data analyses were completed from June 2019 to February 2020.

Exposures

Dosage of metformin and exposure to other prescribed medications, as identified from outpatient drug claims.

Main Outcomes and Measures

Risk of developing AMD.

Results

A total of 312 404 affected individuals were included (181 817 women [58.2%]). After matching, 312 376 control participants were included (172 459 women [55.2%]; age range, 55 to 107 years). The case group had a slightly higher percentage of participants with diabetes (81 262 participants [26.0%]) compared with the control group (79 497 participants [25.5%]). Metformin use was associated with reduced odds of developing AMD (odds ratio [OR], 0.94 [95% CI, 0.92-0.96]). This association was dose dependent, with low to moderate doses of metformin showing the greatest potential benefit (dosages over 2 years: 1-270 g, OR, 0.91 [95% CI, 0.88-0.94]; 271-600 g, OR, 0.90 [95% CI, 0.87-0.93]; 601-1080 g, OR, 0.95 [95% CI, 0.92-0.98]). Doses of more than 1080 g of metformin over 2 years did not have reduced odds of developing AMD. Both the reduction in odds ratio and the dose-dependent response were preserved in a cohort consisting only of patients with diabetes. Metformin use was associated with a decreased OR of AMD in patients with diabetes without coexisting diabetic retinopathy (OR, 0.93 [95% CI, 0.91-0.95]) but was a risk factor in patients with diabetic retinopathy (OR, 1.07 [95% CI, 1.01-1.15]).

Conclusion and Relevance

In this study, metformin use was associated with reduced odds of developing AMD. This association was dose dependent, with the greatest benefit at low to moderate doses. When looking only at patients with diabetes, we saw a preservation of the dose-dependent decrease in the odds of patients developing AMD. Metformin does not appear to be protective in patients with diabetes and coexisting diabetic retinopathy. This study suggests that metformin may be useful as a preventive therapy for AMD and provides the basis for potential prospective clinical trials.

Use of Short-wave Blue Fundus Autofluorescence to Detect and Monitor Acute Regional Outer Retinopathy in Punctate Inner Choroidopathy

Purpose: To describe the utility of fundus autofluorescence (FAF) for detection and monitoring of acute regional outer retinopathy in punctate inner choroidopathy (PIC).Design: Multimodal imaging case series.Methods: Patients with PIC and acute regional hyperautofluorescence were identified. Multimodal imaging, treatment, and clinical course were reviewed.Results: Six eyes of five patients were included (5 women, mean age 39 years, range 28-69). All endorsed new symptoms. Short-wave blue FAF revealed regional hyperautofluorescence in the symptomatic eye, corresponding to ellipsoid zone (EZ) loss on optical coherence tomography (OCT). All patients were treated with local or systemic corticosteroids or immunosuppression, with resolution of symptoms and acute imaging abnormalities.Conclusions: Symptomatic acute regional outer retinopathy in PIC, manifesting as hyperautofluorescence and EZ loss, is easily identifiable using widefield FAF imaging. Treatment resulted in resolution of symptoms and imaging findings in our cohort, and should be considered in this patient population.

The early gut microbiome could protect against severe retinopathy of prematurity

In this study, 6 infants with type 1 retinopathy of prematurity (ROP) were compared with 4 high-risk preterm neonates without any ROP but similar baseline neonatal comorbidities. The infants with type-1 ROP showed significant enrichment of Enterobacteriaceae at 28 weeks' postmenstrual age. Several metabolic pathways, including several amino acid metabolism pathways, were enriched in gut microbiota of infants without ROP. Based on these findings, we posit a possible association between early gut microbiome profile and ROP pathogenesis. Furthermore, it is possible that absence of Enterobacteriaceae overabundance, in addition to enrichment of amino acid biosynthesis pathways, may protect against severe ROP in high-risk preterm infants.

American Society of Retina Specialists Clinical Practice Guidelines on the Management of Nonproliferative and Proliferative Diabetic Retinopathy without Diabetic Macular Edema

Purpose

Nonproliferative (NPDR) and proliferative diabetic retinopathy (PDR) without diabetic macular edema (DME) affect millions of individuals living with diabetes throughout the world. There is increasing data on various management strategies for such patients, but there is limited consensus on how the data should be adopted into clinical practice.

Methods

This literature review and editorial presents and synthesizes the current evidence for various management paradigms for NPDR and PDR without DME.

Results

Retina specialists are an integral member of the diabetes management team, and should encourage patients on the importance of glycemic and cardiovascular optimization for both systemic and retinopathy risk factor reduction. The diabetic retinopathy severity scale (DRSS) is now an approvable endpoint for clinical trials in the United States, therefore becoming more clinically relevant. For PDR without DME, the Diabetic Retinopathy Study (DRS) and the Early Treatment Diabetic Retinopathy Study (ETDRS) established the standard of care with panretinal photocoagulation (PRP). Laser parameters have since evolved to include less intense and earlier intervention. Studies have recently demonstrated that anti-vascular endothelial growth factor (VEGF) treatment of PDR is effective at regressing neovascularization and improving DRSS levels in many patients. Further evidence is required to determine optimal treatment frequency, duration, and retreatment criteria, in the real world. There are concerns for adverse events in patients being lost to follow up during anti-VEGF treatment. For NPDR without DME, the standard of care has been a wait-and-watch approach. Data within the DRS and the ETDRS suggest that PRP for severe NPDR can be an option for select patients as well. Multiple clinical trials have now demonstrated that anti-VEGF treatment can improve the DRSS score in NPDR. Further studies are required to assess whether this positively affects long-term visual outcomes, and whether the benefits outweigh the risks in the real world for routine use.

Conclusions

There is cumulative evidence demonstrating the efficacy of various treatment options for NPDR and PDR without DME. Currently, patients would most likely benefit from thoughtful management strategies that are tailored to the individual patient.

Rapid pathogen identification and antimicrobial susceptibility testing in in vitro endophthalmitis with matrix assisted laser desorption-ionization Time-of-Flight Mass Spectrometry and VITEK 2 without prior culture

PURPOSE

Prompt clinical diagnosis and initiation of treatment are critical in the management of infectious endophthalmitis. Current methods used to identify causative agents of infectious endophthalmitis are mostly inefficient, owing to suboptimal sensitivity, length, and cost. Matrix Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) can be used to rapidly identity pathogens without a need for culture. Similarly, automated antimicrobial susceptibility test systems (AST, VITEK 2) provide accurate antimicrobial susceptibility profiles. In this proof-of-concept study, we apply these technologies for the direct identification and characterization of pathogens in vitreous samples, without culture, as an in vitro model of infectious endophthalmitis.

METHODS

Vitreous humor aspirated from freshly enucleated porcine eyes was inoculated with different inocula of Staphylococcus aureus (S. aureus) and incubated at 37°C. Vitreous endophthalmitis samples were centrifuged and pellets were directly analyzed with MALDI-TOF MS and VITEK 2 without prior culture. S. aureus colonies that were conventionally grown on culture medium were used as control samples. Time-to-identification, minimum concentration of bacteria required for identification, and accuracy of results compared to standard methods were determined.

RESULTS

MALDI-TOF MS achieved accurate pathogen identification from direct analysis of intraocular samples with confidence values of up to 99.9%. Time from sample processing to pathogen identification was <30 minutes. The minimum number of bacteria needed for positive identification was 7.889x106 colony forming units (cfu/μl). Direct analysis of intraocular samples with VITEK 2 gave AST profiles that were up to 94.4% identical to the positive control S. aureus analyzed per standard protocol.

CONCLUSION

Our findings demonstrate that the direct analysis of vitreous samples with MALDI-TOF MS and VITEK 2 without prior culture could serve as new, improved methods for rapid, accurate pathogen identification and targeted treatment design in infectious endophthalmitis. In vivo models and standardized comparisons against other microbiological methods are needed to determine the value of direct analysis of intraocular samples from infectious endophthalmitis with MALDI-TOF MS and VITEK 2.