ABSTRACT
Purpose: To evaluate the genetic aspects of strabismus. Methods: Ophthalmic and orthoptic evaluations were performed prospectively on 110 strabismic probands and 478 relatives. We used 3 different criteria in the diagnosis of strabismus: primary diagnósis (dxl) defined as any manifest horizontal or vertical deviation, a secondary diagnosis (dx2) including esophoria (>7 prism diopters) or exophoria (>9 prism diopters), and a tertiary diagnosis (dx3) including abnormal fusional amplitudes, accommodative convergence/accommodation (AC/A) ratio, andor stereopsis; monofixation syndrome; 4 prism diopters base out; and/or abnormal Maddox test responses. Analyses were carried out within mating types. Results: Hypotheses of autosomal dominant or recessive inheritance with no sporadics were rejected. Based on the dx 1, 25 percent of the families had more than one individual affected and there was vertical transmission in 13 percent; adding dx2 there were 36 percent of the families with more than one affected and 21 percent had vertical transmission; and adding dx3, there were 73 percent with more than one affected and 51 percent with vertical transmission. Conclusions: There is evidence for a pattern consistent with an autosomal dominant form of strabismus in most families.