In a recent evaluation of subclinical markers of strabismus in children, researchers at the Mayo Clinic found that inferior oblique muscle dysfunction, anisometropia and subnormal stereopsis were most prevalent.

The team used a combination of ophthalmic exam and family history to determine the prevalence of subclinical markers for pediatric strabismus. Markers included oblique muscle dysfunction, stereopsis <60 arcsec, monofixation, nasal-temporal pursuit asymmetry, dissociated strabismus and anisometropia.

The community-based study included 1,000 children (49.8% male) aged five to 18 (mean age 10.6), of which 5.7% had strabismus and 13% had some form of phoria. Of those without strabismus, 10.9% had one or more subclinical markers. These included inferior oblique dysfunction (4.5%), anisometropia (3.9%), subnormal stereopsis (3.6%), nasal-temporal pursuit asymmetry (6, 0.6%) and monofixation (3, 0.3%).

A subclinical marker of strabismus occurred in 12.7% of the 157 nontropic children with family history of either strabismus, amblyopia or both and in 10.6% of the 786 nontropic children without a family history.

Ultimately, the researchers concluded that subclinical disorders of binocular vision occur in about 10% to 13% of children without strabismus. “Identifying these disorders among strabismic families may be useful in elucidating the genetic puzzle of childhood strabismus,” they wrote.