Assessing amblyogenic factors in 100 patients with congenital ptosis

AIM: To study the frequency of amblyogenic factors in patients with congenital ptosis. METHODS: In this cross-sectional study, 114 eyes of 100 patients with congenital ptosis more than 1 year old were included. Amblyopia was defined as best-corrected visual acuity (BCVA) less than 1 0/10 or a difference between the two eyes of at least 2/10. In patients too young to be measured by the linear Snellen E test, fixation behav ior was observed. Different types of amblyopia were assessed for each patient as: 1 ) anisom etropic amblyopia: Astigmatic anisom etropia =1 dpt, hyperopic spherical anisom etropia =1 dpt, myopic spherical anisom etropia =-3 dpt (with cycloplegia); 2 ) strabismic amblyopia, and 3) stimulus deprivation amblyopia (SDA). Then the total incidence of amblyopia and each type of it were obtained. Patients with uni- and bi-lateral ptosis were also compared. RESULTS: The incidence of amblyopia in ptotic eyes was 39/114 (34.2%), and for each specific cause was: refractive amblyopia in 29.8%, SDA in 10.5%, strabismic amblyopia in 4.3%. Amblyopia was more frequent in severe ptosis, 76% in patients with covered optical axes (OA), compared to non-cov ered OA (22.5%). In unilateral ptosis with covered OA, astigm atic anisom etropic amblyopia was more frequent, and in bilateral ptosis with at least one eye covered OA, spherical anisom etropic amblyopia was more frequent. In both unilateral and bilateral ptosis, SDA was more common if the OA was covered. CONCLUSION: As refractive anisom etropic am bly opia is m ore prev alent than SDA, pay ing attention to all causes of amblyopia may be important in preventing amblyopia in a child with aptotic eye.