Magnetic resonance imaging of optic tract involvement in multiple sclerosis.

We studied two cases of optic tract involvement in multiple sclerosis with documentation by magnetic resonance imaging. In one, incongruous homonymous hemianopsia was accompanied by a decrease in visual acuity in one eye from chiasmal involvement. In the other, the involvement was restricted to the optic tract and the homonymous hemianoptic visual field defect was nearly congruous.

Inherited levator-medial rectus synkinesis.

We examined two sisters with lid retraction on adduction, the classic sign of levator-oculomotor synkinesis. In both women, the left eye was involved. No history of trauma or ocular surgery or complaints of diplopia were elicited, and both had good visual acuity and full ocular motility. Each exhibited 2 mm of left upper lid elevation on adduction and 4 to 6 mm of lid elevation on adduction with depression. In one of the sisters, 1 mm of ptosis was present in straight ahead gaze in the involved eye, which increased to almost 2 mm on abduction, but full levator function was observed. Four other family members in three consecutive generations were similarly affected, suggesting an autosomal-dominant mode of inheritance. To our knowledge, this type of isolated levator-oculomotor synkinesis has not been reported previously on a congenital and inherited basis.

Studies of hyperthermia in optic neuropathy. Consideration of a humoral factor.

Three patients with multiple sclerosis and prominent Uhthoff's symptom were studied. Visual loss was found to be related not only to increase in body temperature but to the rate of increase. Blood removed at the time of maximal visual loss and readministered in the normothermic state did not reproduce the symptom. The study supports the prevailing concept that Uhthoff's symptom is a direct effect of hyperthermia on conduction in damaged axons.