Intelligence Quotient in Patients with Congenital Strabismus

The purpose of this study was to evaluate intelligence quotient (IQ) in patients with congenital strabismus scheduled for surgery at Labbafinejad Medical Center in Tehran. All patients with congenital strabismus scheduled for surgery were enrolled consecutively over a one year period in a cross-sectional study. Patients were evaluated for verbal, performance, and total IQ and compared with the normal population whose mean IQ was 100±15. During the study period, 109 patients with a mean age of 18.4±10.5 years (range: 4 – 63 years) were included. Educational status of the majority of patients (80%) was less than a high-school diploma. Most patients (79.8%) lived in urban areas, and 46 patients (42.2%) had some degree of unilateral or bilateral amblyopia. Mean verbal IQ was 87.2±19.6 (range 45 – 127), performance IQ was 81±15.5 (range 44 – 111) and total IQ was 83.5±18.3 (range 40 – 120). Total IQ was lower in comparison with the normal population (P<0.0l) and was significantly higher in urban residents as compared to rural residents (85.1±19.5 vs. 77.3±10.8, P=0.016). Patients with coexisting amblyopia whose parents were not educated had lower IQ levels. Total IQ was higher in myopes than emmetropes, of which both exhibited higher IQ levels than hyperopes. IQ levels were better with vertical deviations and higher in ETs than XTs, however these comparisons were not statistically significant (P> 0.05). Patients with congenital strabismus assessed in this study had lower mean IQ levels than the normal population. The reasons may be genetically related or resulting from acquired causes secondary to strabismus.