Subclinical markers of strabismus in children 5-18 years of age

To report the prevalence of subclinical markers of strabismus from a community-based screening of children. A family history and ophthalmic examination (including six markers of strabismus: oblique muscle dysfunction, stereopsis <60 arcsec, monofixation, nasal-temporal pursuit asymmetry, dissociated strabismus, and anisometropia) were obtained from consecutive children, aged 5-18 years, in the local school system and the pediatric outpatient clinic of Mayo Clinic, Rochester, Minnesota. A total of 1,000 children (498 males [49.8%]) were examined at a mean age of 10.6 years (range, 5-18.98). Of the 1,000, 57 (5.7%) had strabismus, and 130 (13%) had some form of phoria. Of the 943 children without strabismus, 103 (10.9%) had one or more of the six subclinical markers, including 43 (4.5%) with inferior oblique dysfunction, 37 (3.9%) with anisometropia, 34 (3.6%) with subnormal stereopsis, 6 (0.6%) with nasal-temporal pursuit asymmetry, 3 (0.3%) with monofixation, and none with dissociated strabismus. A subclinical marker of strabismus occurred in 20 (12.7%) of the 157 nontropic subjects who had a family history of either strabismus, amblyopia, or both and in 83 (10.6%) of the 786 nontropic children without a family history. In this community-based screening of children, subclinical disorders of binocular vision occurred in 10%-13% of children without strabismus, of which inferior oblique muscle dysfunction, anisometropia, and subnormal stereopsis were most prevalent. Identifying these disorders among strabismic families may be useful in elucidating the genetic puzzle of childhood strabismus.