Stroke

Patients who complain of visual symptoms after a stroke quite often have an associated homony-mous hemianopia and the association between hemiplegia and homonymous hemianopia should always be borne in mind. A simple confrontation field test might be all that is required to confirm this in a patient with poor vision and normal fundi following a hemiplegic episode. The vertical line of demarcation between blind and seeing areas is well defined and can cut through the point of fixation. Fortunately, the central 2° or 3° of the visual field are often spared. When there is so-called macular sparing, the visual acuity as measured by the Snellen chart can be normal. Patients tend to complain of difficulty in reading if the right homonymous field is affected rather than the left, and although they might be able to read individual words, they have great difficulty in following the line of print. Thus, a patient with a right hemiplegia and a right homonymous hemi-anopia might have normal fundi and visual acuity of 6/6 and yet be unable to read the newspaper. The picture can be further complicated by true dyslexia and the patient might admit to being able to see the paper and yet be unable to make any sense of it. Dyslexia might be suspected if other higher functions, such as speech, have been affected by the stroke. One of the features of a homonymous hemianopic defect in the visual field is the patient's complete lack of insight into the problem, so that even a doctor might fail to notice it in himself. It is unusual for a homonymous hemianopia to show any signs of recovery, but once the patients understand the nature of the handicap they can learn to adapt to it to a surprising degree.

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