Treatment outcomes of intravitreal ranibizumab for diabetic macular oedema in vitrectomised eyes

Abstract

Purpose : There is little data looking at the outcomes of anti-vascular endothelial growth factors (anti-VEGF) treatment in eyes that have been previously vitrectomised. We performed a retrospective study to review outcomes after intravitreal ranibizumab therapy for diabetic macular oedema (DMO).

Methods : Eyes that had undergone vitrectomy prior to the initiation of treatment for DMO were included. Parameters recorded include best-corrected visual acuity (BCVA) as measured on standardised Early Treatment Diabetic Retinopathy Study (ETDRS) visual chart, central subfield thickness (CST) and macular volume (MV) on optical coherence tomography (OCT) at recruitment and follow-up. The average number of injections per month were calculated for the follow-up period.

Results : Thirty-nine eyes of 35 patients who underwent one or more injections for DMO were included. Of these, one patient died from unrelated causes during the follow-up period.
The mean follow-up period was 18 months (range 11.5 - 23.5 months). There was a mean visual gain of 3.5 letters (standard deviation 14.0) over the follow-up period. The mean change in CST was -50.2 microns (standard devaition 135.2) and the mean change in MV was +0.199mm² (standard deviation 1.339). Subgroup analysis by diagnosis showed a mean decrease in CST in all groups except those eyes that underwent vitrectomy for rhegmatogenous retinal detachment (n=4) or for dropped nucleus during cataract surgery (n=1).
The subgroups with the largest gains in BCVA were vitrectomy only, vitrecomy with delamination, and vitrectomy with membrane peel plus intravitreal steroid injection with gains of 30, 9.3 and 8.0 letters respectively. The average number of injections given per month was 0.4 (range 0 - 0.8). Of the 38 eyes, three went on to have intravitreal triamcinolone and a further three underwent Iluvien implants.

Conclusions : Intravitreal anti-VEGF treatment can have favourable effects on visual acuity and central macular thickness in previously vitrectomised eyes. The indication for vitrectomy may be linked to the outcome as it may be a marker of severity of diabetic retinopathy or other retinal disease. Larger numbers are required to further define the effects of vitrectomy on outcomes of anti-VEGF therapy in diabetic macular oedema.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.