Quantitative Ultra-Widefield Angiography and Diabetic Retinopathy Severity: An Assessment of Panretinal Leakage Index, Ischemic Index and Microaneurysm Count.

PURPOSE: To investigate the relationship between the diabetic retinopathy (DR) severity and quantitative ultra-widefield angiographic metrics, including leakage index, ischemic index, and microaneurysm count. DESIGN: Retrospective image analysis study. METHODS: Eyes with DR that had undergone ultra-widefield fluorescein angiography (UWFA) with associated color photography were identified. All eyes were laser-naive and had not received any intravitreal pharmacotherapy within 6 months of UWFA. Each eye was graded for DR severity. Quantitative angiographic parameters were evaluated with a semiautomated analysis platform with expert reader correction, as needed. Angiographic parameters included panretinal leakage index, ischemic index, and microaneurysm count. Clinical characteristics analyzed included age, gender, race, hemoglobin A1C level, hypertension, systolic blood pressure, diastolic blood pressure, and smoking history. MAIN OUTCOME MEASURES: Association of DR severity with panretinal leakage index, ischemic index, and microaneurysm count. RESULTS: Three hundred thirty-nine eyes were included with mean age of 62±13 years. Forty-two percent of eyes were from women and 57.5% were from men. Distribution of DR severity was as follows: mild NPDR in 11.2%, moderate NPDR in 23.9%, severe NPDR in 40.1%, and PDR with 24.8%. Panretinal leakage index [mild NPDR (mean = 0.51%), moderate NPDR mean = 1.20%, severe NPDR (mean = 2.75%), and PDR (mean = 5.84%); P<2×10-16], panretinal ischemic index [mild NPDR (mean = 0.95%, moderate NPDR (mean = 1.37%), severe NPDR (mean = 2.80%), and PDR (mean = 9.53%); P<2×10-16], and panretinal microaneurysm count [mild NPDR (mean = 36), moderate NPDR (mean = 129), severe NPDR (mean = 203), and PDR (mean = 254); P<5×10-7] were strongly associated with DR severity. Multivariate analysis demonstrated that ischemic index and leakage index were the parameters associated most strongly with level of DR severity. CONCLUSIONS: Panretinal leakage index, panretinal ischemic index, and panretinal microaneurysm count are associated with DR severity. Additional research is needed to understand the clinical implications of these parameters related to progression risk, prognosis, and implications for therapeutic response.

Controlled Release of Vancomycin From a Thermoresponsive Hydrogel System for the Prophylactic Treatment of Postoperative Acute Endophthalmitis.

PURPOSE: To investigate the efficacy of a poly(ethylene glycol) diacrylate and poly(N-isopropylacrylamide) based thermo-responsive hydrogel drug delivery system (DDS) to deliver prophylactic vancomycin (VAN) following ocular surgery. METHODS: VAN was encapsulated in a hydrogel DDS and characterized in terms of initial burst, release kinetics, bioactivity, and cytotoxicity. Long-Evans rats received an intravitreal injection of Staphylococcus aureus to produce acute endophthalmitis in four experimental groups. One of four treatments were then applied: (1) bolus subconjunctival injection of VAN, (2) blank DDS, (3) saline treatment, and (4) subconjunctival injection of VAN DDS. Animals were scored for infection (0-3) at 12, 24, 48, and 72 hours, and eyes were harvested at 24 and 48 hours for histology. RESULTS: Following a 36% initial burst, VAN release from the DDS continued at a steady rate for 2 weeks plateauing at 84% after 504 hours. Bioactivity was maintained for all release samples and cytotoxicity analysis for the DDS revealed cell viability >90%. Not until after 12 hours did any of the groups show evidence of infection; however, at 24 hours, animals that received the VAN DDS had significantly lower infection scores (0 ± 0) than those that received a bolus VAN injection, blank DDS, or saline (1.5 ±1.5, 2.3 ± 0.87, and 2.9 ± 0.25; respectively). At 48 and 72 hours, the VAN DDS and bolus VAN treatment groups performed comparably and showed significantly better infection scores than the control groups. CONCLUSIONS: This DDS appears to have promise as a vehicle for short term, prophylactic antibiotic delivery. TRANSLATIONAL RELEVANCE: This DDS may prevent the development of postoperative endophthalmitis.