Ultra-Widefield Fluorescein Angiography as a Biomarker for Response to Switch in Therapy in Persistent DME.

BACKGROUND AND OBJECTIVE: To explore the effect of peripheral ischemia identified on ultra-widefield fluorescein angiography (UWFA) as a biomarker of response to a switch in therapy from bevacizumab to aflibercept in persistent diabetic macular edema (DME). PATIENTS AND METHODS: Prospective clinical trial of 38 eyes from 38 patients previously treated with bevacizumab and persistent DME. Patients subsequently received aflibercept per protocol and were followed up for 48 weeks. UWFA was obtained for all patients at baseline and 48 weeks. Images were graded and used to calculate an overall ischemic index (II) and macular ischemic index (MII). II was compared with visual and central macular thickness (CMT) outcomes. Paired and independent samples t-tests and Fisher's exact tests were used to assess change and associations. RESULTS: Patients with an II greater than or equal to 50% at baseline had a poorer baseline visual acuity (VA) (60.1 +/- 10.2 vs. 70.7 +/- 9.0 letters: P = .005) and a worse MII (6.9 +/- 25 vs. 56 +/- 52%: P < .001). These patients gained significantly more vision at 48 weeks (8.3 +/- 9.3 vs. 2.6 +/- 5.9 letters; P = .03). At 48 weeks, there was no significant difference in VA of patients with an II greater or less than 50% (68.4 +/- 6.0 vs. 73.3 +/- 9.6 letters; P = .16). CONCLUSIONS: Patients with persistent DME treated with bevacizumab and worse II had poorer baseline VA, potentially due to worse macular ischemia. These patients had greater visual gain with similar final visual outcomes of those without marked peripheral ischemia subsequent to switching to aflibercept.