Unilateral congenital ptosis with ipsilateral superior rectus muscle overaction

Congenital ptosis may be accompanied by weakness of the ipsilateral superior rectus muscle. We report the finding of a hypertropia of the ipsilateral eye in patients with isolated unilateral congenital ptosis that became manifest only in upgaze.

Seventy consecutive patients with congenital ptosis were recalled and 58 reexamined. Examination included assessment of visual acuities, palpebral apertures, levator muscle function, and an orthoptic examination. Particular attention was paid to the assessment of upgaze.

Thirty-eight patients had an isolated unilateral congenital ptosis. Four patients had bilateral ptosis, six had upgaze deficits, and ten others had a variety of other syndromes associated with ptosis. Seventeen of the 38 patients with isolated unilateral congenital ptosis were found to have an ipsilateral hypertropia on upgaze. The size of the vertical deviation varied from 5 to 30 prism diopters and, in the more severe cases, produced a cosmetic problem that became more noticeable after successful ptosis surgery. In one of these patients, a superior rectus muscle posterior fixation suture was effective in reducing the hypertropia.

Of a number of possible causes for the ipsilateral hypertropia in upgaze in patients with unilateral congenital ptosis that we observed either a misdirection syndrome within the superior division of the oculomotor nerve or an exaggerated Bell's reflex is the most likely.