Restoration of Photoreceptor Outer Segments up to 24 Months after Pars Plana Vitrectomy in Patients with Diabetic Macular Edema

Abstract

To evaluate the ellipsoid zone (EZ) and external limiting membrane (ELM) status on optical coherence tomography images in patients with diabetic macular edema (DME) before and after pars plana vitrectomy (PPV). Retrospective observational analysis. Sixty-one eyes of 49 patients with DME. We retrospectively reviewed the spectral-domain optical coherence tomography images of 61 eyes of 49 patients with DME who were treated with PPV and evaluated the percentage disruption of the EZ and ELM before and up to 24 months after PPV. Longitudinal changes in visual acuity (VA), central retinal thickness (CRT), and EZ and ELM spectral-domain optical coherence tomography findings in patients with DME. The logarithm of the minimum angle of resolution VA was 0.477 before PPV and then improved to 0.372 and 0.344 at 12 and 24 months after PPV, respectively (P < 0.005 and P < 0.001, respectively). The CRT was 505.5 μm before PPV and then decreased gradually to 345.0 and 301.4 μm at 12 and 24 months, respectively (P < 0.001 for both). The percentage disruption of the EZ was 29.3% and ELM was 9.6% before PPV and then deteriorated to 41.6% (P < 0.001) and 15.1% (P < 0.05), respectively, 1 month after PPV. The disruption of the EZ and ELM decreased gradually. The percentage disruption of the ELM recovered but did not improve by 24 months, compared with baseline (11.6%; P= 0.875), whereas the percentage disruption of the EZ recovered to baseline by 6 months (29.4%; P= 1.000) and then decreased significantly at 24 months (21.3%; P < 0.05). Both the EZ and ELM deteriorated after PPV. Whereas the ELM recovered but did not improve by 24 months when compared with baseline, the EZ and VA improved up to 24 months.