Rehabilitation of Lesions in the Visual Pathway
This review considers diseases of the visual pathways at different levels, their consequences for relevant everyday functions and their rehabilitation. Infrachiasmatic lesions are mostly associated with central or ring scotomas causing reading problems. The use of an eccentric fixation locus in combination with text magnification often allows the patient to maintain reading ability. Chiasmatic lesions can cause orientation disability by bitemporal hemianopia and reading problems by slide phenomena along the vertical midline. Suprachiasmatic lesions lead to homonymous visual field defects. Regarding the hemianopic orientation disorder, there are two different training approaches, which have been discussed controversially: restitution of the visual field by visual stimulation versus compensation by explorative eye movements towards the hemianopic side. Previously described positive effects of exploration training were not entirely convincing due to the lack of control groups. A new randomised and controlled study has proved the effectiveness of exploration training and showed that the patients apply the improved exploration strategy to everyday life. In the control group, which received a visual field stimulation training - a potential restitution training - neither exploration nor visual fields changed. The hemianopic reading disorder depends on the distance of the field defect from the centre, i. e., the size of the reading visual field, the side of the field defect in regard to the reading direction and the presence of spontaneous adaptive strategies, such as eccentric fixation or predictive saccades. Specific reading training can be helpful. Cerebral visual impairments with visual field defects are often associated with disorders of information processing in higher cortical areas. These complex disorders usually require an interdisciplinary rehabilitation. Specific examination methods to assess functions of everyday relevance and their use as a basis for rehabilitation measures are discussed. Visual rehabilitation can be very successful in many cases and improves the patients' quality of life. One should expect that the demand for neuro-ophthalmological rehabilitation will increase, because the survival rate after severe cerebral lesions and the general lifespan are rising.