Abstract
Abstract: :
Purpose: To evaluate the effects of Visual Restitution Training (VRT) in patients with homonymous visual field defects (VFDs) using the NovaVision High Resolution Campimetry with repeated testing. Methods: 17 patients (age: 23 - 73 yrs) with homonymous VFDs caused by cerebral lesions (age ≷1 yr ) were evaluated before and after VRT with the campimetry program "NovaVision status" (250 test locations, excentricity 27° horizontal and 22° vertical). This procedure measures areas of residual vision by 5 repeated measurements binocularly and also reaction time. Patients carried out the VRT on their computer at home daily for one hour for 6 months (see Kasten et al., Nature med. 4, 1998, p. 1083). The number of correct responses were counted in the central 5° and in the total visual field (about 27°) after VRT which represents detection performance in the absolute and the relative defect. Training parameters were regularly adjusted to the individual pattern of residual vision for each patient. Results: VRT produced variable improvements in detection performance as some patients did not profit from VRT while others did. Specifically, in the 5° area 14 patients improved (+ 8 % on average) and in the 27° area 15 patients improved (average: 6 %). After VRT, reaction time was significantly reduced due to VRT from 435 ms to 409 ms (t=2.6, p <0.02), but the improvement did not correlate with target detection. Patients had ≷ 90% fixation ability, as measured by the number of correct reactions to a minor color change of the fixation point. Fixation ability either improved (n=13), remained constant (n= 2) or declined (n= 2). Interestingly, fixation ability did not correlate with campimetric improvements (r=-0.172, ns) nor was it correlated with reaction time gains (r=0.086, ns). Conclusion: As shown with computerized, binocular campimetry, improvements of detection performance occured in 15 patients after VRT with considerable between-patient variability. To what extend these improvements are due to visual field enlargements and/or due to increased functioning of the relative defect is currently under study. Because reaction time improvements correlated with subjective improvements (see Sabel, B.A. et al., this volume), plasticity of neuronal processing in space (visual field enlargements) and in time (reaction time) are independent parameters, both of which contribute to restoration of vision. TABLE CAP
Keywords: 485 neuro-ophthalmology: cortical function/rehabilitation • 624 visual fields • 511 perimetry