External Limiting Membrane and Inner Segment/Outer Segment Status at pre- and post-pars plana vitrectomy in DME

Abstract

Purpose: It has been reported that the preserved external limiting membrane (ELM) and inner segment/outer segment (IS/OS) are associated with maintaining visual acuity (VA) in diabetic macular edema (DME) patients and pars plana vitrectomy (PPV) may be effective for maintaining VA. Then we studied the ELM and IS/OS status of optical coherence tomography (OCT) images in DME at pre- and post- PPV.

Methods: We retrospectively reviewed the spectral-domain OCT images of 40 eyes from 31 cases with DME who were treated with PPV and evaluated various factors such as the status of ELM and IS/OS, foveal macular thickness (FMT) and VA at pre- and post-PPV up to 12 months (M). We used a percentage disruption to evaluate the status of ELM and IS/OS.

Results: logMAR VA was 0.481 at pre-PPV and improved to 0.396 at 12M after PPV. FMT was 534.0 μm at pre-PPV, decreased gradually to 343.3 μm at 6M and increased again 400.3 μm at 12M after PPV. The percentage disruption of ELM and IS/OS were 15.0 and 38.0 % at pre-PPV, then deteriorated to 21.6 and 46.9 % at 1M. The ELM status did not changed, while the disruption of IS/OS decreased gradually at 3M (44.7) or later (39.7 at 6M and 38.8 % at 12M) after PPV.

Conclusions: ELM and IS/OS status once deteriorated after PPV, then ELM did not recovered, while IS/OS status recovered and VA improved after that.

Keywords: 499 diabetic retinopathy • 505 edema • 762 vitreoretinal surgery