Purpose: To investigate the incidence and causes of amblyopia in congenital ptosis.
Methods: The frequency and causes of amblyopia were evaluated in 83 eyes of 72 patients with congenital ptosis. Patient ages ranged between 10 months and 70 years. Amblyopia was defined as best-corrected visual acuity of 0.7 or less. After a complete ophthalmologic examination, the amount of ptosis and levator function was determined and the following amblyogenic factors were identified: ametropia, anisometropia, and strabismus. In cases with no other reason for amblyopia, stimulus deprivation amblyopia due to ptosis was assumed.
Results: The amount of ptosis was mild in 5 (6%), moderate in 26 (31%), and severe in 52 (63%) of 83 eyes with congenital ptosis. Strabismus was present in 17 (20%) eyes. Visual acuity could not be determined in 10 of 83 eyes with ptosis in children younger than 4 years. The overall incidence of amblyopia in the remaining 73 eyes was 48%. Of those patients with amblyopia, 54% had refractive errors such as anisometropia or ametropia, 20% had strabismus with or without refractive errors, and 26% had amblyopia solely attributed to ptosis. When all eyes with ptosis were included, the rate of stimulus deprivation amblyopia was 12% and all of these eyes had severe ptosis.
Conclusion: Early detection and treatment of amblyogenic factors such as refractive errors and strabismus is recommended and, when the pupillary axis is occluded with severe ptotic eyelids, surgery should be performed as soon as possible to prevent stimulus deprivation amblyopia.
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