Abstract
Purpose:
To evaluate the expansion of visual fields in hemianopia after binocular application of low-power prisms
Methods:
Retrospective study of 26 patients with different types of hemianopic defects secondary to cerebral lesions: 10 with right homonymous hemianopia, 11 with left homonymous hemianopia, 2 with upper-right homonymous quadrantopsia, 1 with lower-right homonymous quadrantopsia, 1 with bitemporal heteronymous hemianopia, 1 with a complex type of hemianopic defect combined with hemianopic macular scotoma. Evaluation included ETDRS BCVA at 4m, Greene Test, Humphrey visual field test 30-2, and Esterman binocular visual field test before and after application of binocular correction with low-power half lens prisms (≤10 prismatic diopters) with the base placed towards the blind site. Main outcome measures were tolerance to prisms and expansion of Esterman binocular grid. To measure personal satisfaction, a custom questionnaire for visual adaptation to prism lenses and the Environmental Social State test (ESS) were used
Results:
Age median (range) was 54 (19-83) years, and BCVA was 0 (0-2) logMAR. Prismatic correction ranged from 8 to 2 prismatic diopters (median 6 D). Esterman binocular visual field on the meridian of greater involvement measured 80° median (range 40-100°) before treatment, and 100° (50-120°) after the application of prismatic lenses. The median of visual field expansion was 10° (range 5-35°). Tolerance as reported by patients about the use of prisms during the activities of daily living was high in all but 2 patients: so, 24 patients (92.3%) wore prisms all day. Among these, only one patient complained about image displacement. Orientation and mobility improvement was the most frequent achievement, and 7 patients regained their driving license. Patients also reported reading with more ease
Conclusions:
Low-power half lens prisms for the rehabilitation of hemianopia resulted in an expansion of binocular visual fields and were well tolerated by a great majority of patients, so that prisms were worn all day in 92.3%. The highest satisfaction was reported about the increase in orientation and mobility (7 patients had their driving license back!), and in reading endurance
Keywords: 759 visual impairment: neuro-ophthalmological disease •
758 visual fields •
584 low vision