Stimulus deprivation myopia in human congenital ptosis: a study of 95 patients.

PURPOSE: To establish differences between the frequency of suspected deprivation myopia in unilateral and bilateral congenital ptosis with and without covered optical axis.

METHODS

Ametropia was evaluated in both eyes of 95 patients with congenital ptosis. The amount of refraction was documented as spherical equivalent (100% cycloplegia). Statistical analysis was performed using the chi-square and sign tests.

RESULTS

In unilateral ptosis, the frequency of myopia was lower (10/68: 15%) than that of hyperopia (58/68: 85%) in the ptotic eye (P <0.001). However, myopia occurred more often in the ptotic eye (10/68: 15%) than in the fellow eye (3/68: 4.4%). Myopic anisometropia was found only in the ptotic eye (5/68 vs 0/68), but was less frequent than hyperopic anisometropia (6/68 vs 8/68). In bilateral ptosis 7/54 myopia as compared with 47/54 hyperopia were observed and 1/27 myopic anisometropia vs 6/27 hyperopic anisometropia. Covered center of the pupil, in children < or = 8 years of age, was associated with myopia more frequently in bilateral than in unilateral ptosis (6/30 vs 1/27). We found a significantly higher rate of myopia <-1 diopter and hyperopia >2 diopter in comparison of children 5 to 7 years old with first-grade school children.

CONCLUSIONS

Two expected results were (1) compared with the normal population, an overall higher frequency of myopia in human congenital ptosis; (2) in unilateral ptosis, a higher frequency of myopia in the ptotic, than in the fellow eye.