Mean macular intercapillary area in eyes with diabetic macular oedema after anti-vascular endothelial growth factor therapy and its association with treatment response.

BACKGROUND: To evaluate the changes in the mean macular intercapillary area (ICA) from sequential enface optical coherence tomography angiography (OCTA) images following intravitreal anti-vascular endothelial growth factor (VEGF) therapy in initially treatment-naïve eyes with diabetic macular oedema (DME). METHODS: In this multicentre retrospective study, 6 × 6 and 3 × 3 mm customised, total retinal projection enface OCTA images were collected and processed for quantitative assessment of ICA by a customised MATLAB software. Measurements were done in concentric regions centred on the fovea-with the exclusion of foveal avascular zone (FAZ)-in 0.5 mm diameter increments as well as within the intervening rings. RESULTS: In this study, 6 × 6 mm OCTA images from 46 eyes of 29 patients, and 3 × 3 mm OCTA images from 23 eyes of 15 patients were included. There was no significant change in mean ICA after treatment in either scan size or in any measurement regions (all p > 0.05). Multivariate analysis revealed that baseline BCVA was significantly correlated with the visual outcome (p = 0.039). Additionally, after correction for age, baseline central retinal thickness (CRT), baseline BCVA, and retinopathy severity, mean ICA in the 1.5 mm circle was found to be a significant predictor of post treatment CRT, (p = 0.006). CONCLUSIONS: Absence of significant change in mean ICA after a minimum of three intravitreal anti-VEGF injections, may indicate that, in the short term, anti-VEGF injections neither impair nor improve macular perfusion in DME. Baseline BCVA was found to be a robust predictor of functional outcome, while inner mean ICA was a significant predictor for macular thickness outcomes.

Chronic sildenafil citrate use decreases retinal vascular endothelial growth factor expression in diabetic rats: a pilot study.

BACKGROUND: Sildenafil citrate (SC) attenuates endothelial dysfunction. However, its effects on diabetic retinopathy (DR), which is mainly a microvascular disease, remain unclear. Vascular endothelial growth factor (VEGF) is known to be a critical mediator of DR. Therefore, we investigated the effects of SC on diabetic retina by measuring VEGF levels. METHODS: In this study, twenty-eight rats were divided into the following groups: group I, the control group; group II, rats with streptozotocin-induced diabetes; group III, rats with streptozotocin-induced diabetes receiving daily oral sildenafil at 1 mg/kg; and group IV, rats with streptozotocin-induced diabetes receiving high-dose daily sildenafil at 2.5 mg/kg. After 3 months, VEGF was measured in the retina specimen in one eye and the vitreous body in the other eye by immunohistochemistry and enzyme-linked immunosorbent assay, respectively. RESULTS: We found that VEGF expression in the retina was low in all rats from groups I and IV and in 30% of rats from group III; 80% of rats in group II demonstrated high VEGF expression in the retinae (P < 0.001). VEGF concentrations in the vitreous body samples were 32 ± 2, 61 ± 4, 44 ± 5, and 36 ± 3 pg/l in groups I-IV, respectively (P < 0.001). CONCLUSION: VEGF decreased significantly in the eyes of diabetic rats after chronic oral sildenafil citrate treatment. SC may have a modifying/attenuating effect on DR. However, further studies are needed to evaluate its use as an adjunctive treatment.

Evaluation of Urgent Retinal Practice and Safety Measures for Physicians and Patients During COVID-19 Pandemic.

Purpose: To assess the impact of the COVID-19 pandemic on urgent retina practice and factors influencing adherence of physicians and patients to safety measures. Methods: In this clinical audit, urgent or emergent vitreoretinal surgical disorders that presented to our hospital during the period of 15th March-15th May 2020 were compared with the period just before the pandemic declaration (15th December 2019-15th February 2020). Additionally, two questionnaires assessing the adherence to safety measures were circulated to the medical personnel and a sample of patients. The collected data were analyzed, and accordingly, recommendations were proposed to the hospital administration and specific corrective measures were applied. The outcome of applying these corrective measures was assessed in the re-audit cycle during the period of 15th June-15th August 2020. Results: There was a significant decrease in the number of urgent or emergent vitreoretinal surgical disorders that presented to our hospital during the pandemic (161 versus 302 cases in a similar period before the pandemic; p = 0.022). Just with the pandemic recession, there was a significant increase in the number of urgent cases (391 versus 161 cases during the pandemic; p = 0.006), also there was an increased number of complex cases. Residents and fellows were less compliant than attending physicians in adherence to safety measures. Conclusion: Delayed presentation of urgent retinal cases during the pandemic highlights the importance of public awareness of urgent conditions that need immediate medical or surgical care. Attention to young physicians during the pandemic is crucial as they are less adherent to safety measures due to work overload.

Visual and anatomic outcomes of sustained single agent anti-VEGF treatment versus double anti-VEGF switching in the treatment of persistent diabetic macular edema.

BACKGROUND: To compare the anatomical and visual outcomes in eyes with persistent diabetic macular edema (DME) after initial anti-VEGF therapy that were retreated continuously with the same anti-VEGF drug versus those that underwent two successive cycles of medication change in anti-VEGF drugs (double anti-VEGF switch). METHODS: Retrospective review of eyes with persistent DME after 3 initial consecutive monthly anti-VEGF injections. This cohort was divided into two groups: Group 1 continued to receive the same initial anti-VEGF drug for at least 18 months while group 2 eyes were switched to different anti-VEGF medications twice. Group 1 was further subdivided into: Group 1A composed of eyes with less than 20% reduction in central subfield thickness (CRT) at month 3; and group 1B eyes with greater than or equal to 20% reduction in CRT. The percentage of eyes that achieved greater than 10 letters visual acuity (VA) gain or loss was recorded as the primary end point (through month 18 in group 1 and month 6 after 2nd switch in group 2). RESULTS: Group 1A, 1B and group 2 were composed of 24, 18, and 14 eyes respectively. 34.7%, 56.2% and 36.3% of eyes achieved > 10 letters gain, while 4.3%, 6.2% and 27.2% of eyes lost > 10 letters in groups 1A, 1B, and 2, respectively. Analysis of the visual acuity (VA) letter change in this time interval revealed no significant difference between all groups (p = 0.11). Mean VA and CRT measurements at the primary endpoint in all groups were 0.5, 0.39, and 0.47 logMAR (p = 0.44), and 369.7, 279.9, 321 µm, (p = 0.01) respectively. CONCLUSIONS: There was no difference in the visual outcomes between the two treatment strategies in eyes with persistent DME after 3 consecutive anti-VEGF injections. This may indicate that anti-VEGF switching-even if it is done twice-may have comparable clinical outcomes to sustained treatment with one agent.