Walsh & Hoyt: Neuro-Ophthalmologic Symptoms Associated with Optic Chiasmal Syndromes

The most common complaints of patients with lesions that damage the optic chiasm are progressive loss of central acuity and dimming of the visual field, particularly in its temporal portion. In addition, bitemporal field defects, whether complete or scotomatous, may produce two other types of visual symptoms. One type consists of a disturbance of depth perception, and patients with this symptom complain of difficulties with such tasks as threading needles, sewing, and using precision tools. In such patients, convergence results in crossing of the two blind temporal hemifields. This produces a completely blind triangular area of field with its apex at fixation. The image of an object posterior to fixation falls on blind nasal retinas and thus disappears. Testing for stereopsis can also be helpful in the clinical testing of patients with suspected chiasmal disorders.