VISUAL-FIELD DEFECT AFTER PARS-PLANA VITRECTOMY

Objective: This study aimed to report the occurrence of visual field d efects after pars plana vitrectomy (PPV) for the treatment of each of the following conditions: macular hole (MH), subretinal neovascular me mbrane (SRNVM), and epiretinal membrane proliferation (EMP). This stud y also aimed to speculate on the pathogenic mechanisms for the observe d field defects. Design: Noncomparative case series. Participants: The study included 48 subjects (50 eyes). Twenty-one of the 50 eyes had s tage III MH, 13 eyes had SRNVM, and 16 eyes had EMP. Testing: Goldmann kinetic perimetry was performed postoperatively. Main Outcome Measure : Visual field defects. Results: Nine (18%) of the 50 eyes had visual field defects. Four (19%) of the 21 eyes with MH and 5 (38%) of the 13 eyes with SRNVM had visual field defects. Of the 16 patients who had epiretinal membrane peeling, none had a visual field defect. An air-fl uid exchange had been performed in all patients found to have a postvi trectomy field defect. The difference in rate of visual field defects in eyes that had air-fluid exchange (EMP group) was statistically sign ificant (P < 0.05, chi-square), No significant correlation was found b etween visual field defect and preoperative intraocular pressure, post operative intraocular pressure, patient's age, and iatrogenic detachme nt of the vitreous cortex. The field defects identified were altitudin al (2 eyes), baring of the blind spot (1 eye), inferotemporal (3 eyes) , inferonasal (2 eyes), and superonasal (1 eye). Conclusions: Central and peripheral visual field defects may occur after PPV for the treatm ent of MHs or SRNVMs. Air-fluid exchange procedure was the common deno minator in all of the patients found to have visual field deficit. The etiology is likely to be trauma to the optic nerve region during the air-fluid exchange procedure.