The impact of Vitreo-Macular interface abnormalities on the response to Anti-VEGF therapy for centre involving diabetic macular oedema.

ABSTRACT

BACKGROUND: The influence of Vitreomacular Interface Abnormalities (VMIA) such as Epiretinal Membrane (ERM) and/or vitreomacular traction (VMT) on the response of patients with Centre Involving Diabetic Macular Edema (CIDME) to standard of care Anti-VEGF medications is under-researched. The aims of this study were 1) To determine the incidence of VMIA at baseline and 12 months amongst treatment naive patients commencing anti-VEGF treatment 2) To compare the response to Anti-VEGF medications at 3 monthly intervals for 12 months in a large cohort of patients with and without VMIA on their baseline OCT scan. Response was determined in terms of number of injections, central macular thickness and visual acuity. METHODS: A retrospective case notes review of treatment naïve patients with newly diagnosed CIDME. Included patients had been commenced on intravitreal Anti-VEGF injections (ranibizumab or aflibercept) at a single centre. Inclusion criteria were treatment naïve DME patients with a CMT of 400µ or more receiving anti-VEGF treatment with at least 12 months follow up and in whom macular OCT scans and visual acuity (VA) measurements were available within two weeks of baseline, 3, 6, 9 and 12 months. Exclusion criteria included previous intravitreal therapy, previous vitrectomy, cataract surgery during the follow-up period, concurrent eye conditions affecting vision or CMT. RESULTS: 119 eyes met the inclusion criteria and underwent analysis. Groups were comparable in their baseline demographics. Baseline CMT measurements were comparable at baseline (417µ and 430µ in the No-VMIA and VMIA groups respectively) and improved to approximately 300µ in both groups. From 6 months CMT continued to improve in the no-VMIA while progressively deteriorating in the VMIA group. Change in CMT was statistically different at 12 months between the 2 groups (108µ and 79µ, p= 0.04). There was a mean of 7 injections after 12 months. CONCLUSION: Our study has shown a 46% incidence of VMIA amongst patients newly diagnosed with centre involving DME undergoing treatment with anti-VEGF injections. We have also demonstrated a significant difference in CMT and VA response to anti-VEGF treatment in patients with and without VMIA. Initial response was similar between the 2 groups up until 6 months. From 6 to 12 months significant differences in treatment response emerged. Differences in clinical response between patients with and without VMIA may help guide further prospective controlled studies and optimise treatment strategies.