Ptosis covering the optical axis may contribute to amblyopia, study finds

J Pediatr Ophthalmol Strabismus. 2010;47(2):101-104.

Patients with congenital ptosis may be at higher risk of amblyopia due to interference with the visual axis, a study found.

The records of 83 eyes of 72 patients with congenital ptosis who underwent surgery were evaluated to assess the incidence of amblyopia and determine the association between amblyopia and amblyogenic factors, the study said. All patients underwent a complete ophthalmic examination, including measurement of visual acuity, strabismus, refractive error and ptosis. Visual acuity could not be objectively measured in 10 eyes of nine patients who were younger than 4 years of age, so the study was conducted on the remaining 73 eyes.

According to the study, amblyopia was detected in 35 of 73 eyes, and strabismus was detected in 17 of the 35 amblyopic eyes. Of the 35 eyes with amblyopia, 19 eyes had only refractive errors, and six eyes had both strabismus and refractive errors. Eighty percent had severe ptosis.

“The rate of amblyogenic refractive errors, refractive errors with strabismus, and ptosis was markedly higher in eyes with severe ptosis (40%, 14% and 26%, respectively) than those with moderate ptosis (14%, 0% and 0%, respectively). No amblyopia was detected with mild ptosis,” the study authors said. “These results suggested a correlation between the severity of congenital ptosis and the presence of refractive errors and strabismus.”

According to the study, the authors recommend early examination that includes measurement of the degree of ptosis, levator muscle function, amount of deviation and cycloplegic refraction. Early surgery to treat ptosis should be performed in patients with stimulus deprivation amblyopia that results from severe ptosis occluding the visual axis, they said.