Background: To determine the prevalence and clinical features of strabismus in patients with pathologic myopia.
Methods: Medical records of a total of 636 highly myopic patients were retrospectively reviewed. Pathologic myopia was defined as spherical equivalent (SE) of at least -8D, or axial length >26.5 mm in patients older than 9 years, <-4D in those younger than 5 years, <-6D in those aged from 6 to 8 years. Myopic refractive degree, axial length measurements, best-corrected visual acuity and eye position were then analyzed.
Results: Among 636 patients with pathologic myopia, 520 (81.8%) had orthophoria, 85 (13.4%) had exotropia and 31 (4.9%) had esotropia at near distance. At long distance, 499 (86.5%) had orthophoria, 51 (8.8%) had exotropia and 27 (4.7%) had esotropia. Vertical heterotropia was seen in 103 patients (16.2%). The mean axial length was significantly longer and the mean age was higher in esotropia than orthophoria and in patients with vertical heterotropia than without vertical heterotropia. There were 16 patients with myopic strabismus fixus or acquired progressive esotropia.
Conclusions: This study confirmed the relatively high prevalence of horizontal and vertical strabismus in patients with pathologic myopia.