Visual function after pars plana vitrectomy in macular edema with branch retinal vein occlusion.

The objective of this study is to evaluate functional and morphological changes of the macula after pars plana vitrectomy (PPV) for macular edema with branch retinal vein occlusion (BRVO). Eighteen patients with BRVO (mean age: 71.3 ± 5.9 years; six women and 12 men) received PPV. Macular function was documented by microperimetry and best-corrected visual acuity (BCVA) was determined. Retinal thickness and retinal volume were measured by optical coherence tomography (OCT), and mean retinal sensitivity was calculated for each of nine macular subfields. Ischemia and serous retinal detachment (SRD) were evaluated by fluorescein angiography and OCT, respectively. Mean BCVA was significantly improved at 3 and 6 months after PPV. Mean retinal sensitivity, retinal thickness, and retinal volume were significantly improved after 3 and 6 months in five, eight, and eight subfields, respectively. Improvement of visual acuity and the percent change in retinal thickness or retinal volume were not correlated in any of the nine subfields, while improvement of retinal sensitivity was correlated with the percent change in both retinal thickness and retinal volume in the temporal outer subfield. There were significant differences with respect to the percent changes in retinal thickness and volume in the temporal outer field between the non-ischemic and ischemic groups, as well as between the patients with and without SRD. There was also a significant difference between the non-ischemic and ischemic groups with respect to the improvement of retinal sensitivity in three out of nine fields. These findings suggest that PPV can improve both functional and morphological changes due to macular edema in BRVO patients, and that morphological improvement in the temporal outer subfield after PPV might influence the functional prognosis of these patients.