Abstract
Purpose :
There is limited data available on the effect of vitrectomy on treatment outcomes of intravitreal anti-VEGF therapy for diabetic macular oedema (DMO). We performed a retrospective study to determine whether treatment outcomes of intravitreal ranibizumab for DMO differed in eyes that had undergone vitrectomy prior to initiation of treatment from those in non-vitrectomised eyes. We also looked at whether there was a difference in the number of injections needed over the first 12 months of treatment.
Methods :
235 eyes that underwent at least 3 intravitreal ranibizumab treatments for centre-involving DMO at a tertiary centre over a 2-year time frame were included. Eyes that had undergone vitrectomy prior to the intitiation of ranibizumab were identified. Visual acuity (VA), central subfield thickness (CST) on optical coherence tomography (OCT) macular volume (MV) on OCT for each were recorded at the start of treatment and at 12 months. The number of injections required (based on a treatment regimen of 3 initial monthly loading doses then PRN injections) were determined for each patient. The outcomes were compared between the two groups.
Results :
199 eyes had no previous history of vitrectomy and 36 had undergone vitrectomy prior to the initiation of ranibizumab treatment. There was a mean gain of 6.1 ETDRS letters in the vitrectomy group and 7.0 letters in the no-vitrectomy group (p=0.1274). The mean change in CST was -55.5 microns (SD=134.2) vs -118.3 microns (SD=174.7) (p=0.0450) and the mean change in MV was -0.202 mm2 (SD=1.368) vs -1.496mm2 (SD=2.096)(p=0.00006) in the vitrectomy and no-vitrectomy groups respectively. The vitrectomy group underwent a mean of 6.1 injections over the first 12 months compared with 7.1 injections in the no-vitrectomy group (p=0.0131).
Conclusions :
The 2 groups had a similar gain in ETDRS letters over the first 12 months of treatment with intravitreal ranibizumab. The mean decrease in CST and in MV was slightly higher in the no-vitrectomy group compared with the vitrectomy group. Our data suggest that whilst the reduction in macular thickness and volume was slightly greater in non-vitrectomised eyes, the visual outcome was not affected by previous vitrectomy. Larger studies are required to further examine the influence of vitrectomy on treatment outcomes. Continued follow-up of these and similar patients may provide data on longer-term outcomes.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.