Purpose: To compare the relation between vertical eyelid fissure height and downgaze in healthy subjects and in patients with Graves upper eyelid retraction and congenital blepharoptosis.
Methods: With a caliper rule, the authors measured the vertical eyelid fissure height of 25 patients with no previous history of eye disease, 34 patients with Graves disease, and 16 patients with congenital blepharoptosis. All measurements were done at the primary position and at four levels of downgaze (10 degrees, 20 degrees, 30 degrees, and 40 degrees). In 13 patients with Graves disease, vertical phoria was quantified with a Maddox rod and prism.
Results: The relation between vertical eyelid fissure height and downgaze is linear. The slope was identical for the control subjects and for the patients with Graves disease (b = -1.36) but it was almost zero for the patients with congenital blepharoptosis (b = -0.037). When vertical eyelid fissure height was corrected to arc values, the slope of the relation between vertical eyelid fissure height and downgaze was significantly greater for the patients with Graves disease. Vertical phoria was not related to the amount of Graves upper eyelid retraction.
Conclusions: The data support the hypotheses that upper eyelid retraction secondary to Graves eye disease results from hyperactivity of the levator palpebrae superioris muscle.