Visual field defect after pars plana vitrectomy.

OBJECTIVE: This study aimed to report the occurrence of visual field defects after pars plana vitrectomy (PPV) for the treatment of each of the following conditions: macular hole (MH), subretinal neovascular membrane (SRNVM), and epiretinal membrane proliferation (EMP). This study also aimed to speculate on the pathogenic mechanisms for the observed field defects. DESIGN: Noncomparative case series. PARTICIPANTS: The study included 48 subjects (50 eyes). Twenty-one of the 50 eyes had stage 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-fluid exchange had been performed in all patients found to have a postvitrectomy field defect. The difference in rate of visual field defects in eyes that had air-fluid exchange (EMP group) was statistically significant (P < 0.05, chi-square). No significant correlation was found between visual field defect and preoperative intraocular pressure, postoperative intraocular pressure, patient's age, and iatrogenic detachment of the vitreous cortex. The field defects identified were altitudinal (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 treatment of MHs or SRNVMs. Air-fluid exchange procedure was the common denominator 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.

Unrecognised and unregistered visual impairment.

Recent community based studies have shown that only a minority of visually impaired people who are eligible to be registered as partially sighted or blind are actually registered as such. To determine how many unregistered but eligible people are attending ophthalmic clinics a prospective study was undertaken of all patients (n = 1543) attending ophthalmic outpatient departments, at a single specialty eye hospital and two district general hospitals over a 1 week period. All patients with visual acuity < or = 6/18 or restricted visual field were interviewed. Registration status and factors affecting this were then determined. Although 95/174 patients interviewed were eligible for registration, 68 as partially sighted and 27 as blind, only 46 (48.4%) of these were registered. Asians and Afro-Caribbeans were under-represented in the group eligible for registration. Active treatment impeded registration. Patients having four or more hospital visits were on average 16 times more likely to be registered as those who had fewer attendances. Disabilities, in addition to visual impairment, were present in 40% (n = 38). This study shows that there is unregistered visual impairment in patients attending ophthalmic departments. As registration triggers multidisciplinary support, ophthalmologists need to be more alert to the benefits and criteria for partial sight and blind registration.