Purpose: To report the distribution of stereoacuity thresholds and ocular characteristics associated with reduced stereoacuity in a representative sample of 12-year-old Australian children.
Methods: Stereoacuity thresholds were determined using the three quantitative plates of the TNO test in 2343 children, either unaided or with spectacles, if worn. Logarithm of minimum angle of resolution (logMAR) visual acuity was measured. Cycloplegic autorefraction (using cyclopentolate), cover testing, and dilated fundus examination were performed. Reduced stereoacuity was defined as > 120 arcsec. Myopia was defined as spherical equivalent refraction (SER) < or = -0.50 D hyperopia as spherical equivalent refraction > or = +2.0 D, anisometropia as spherical equivalent refraction difference between eyes > or =1.00 D, and astigmatism as cylinder > or = 1.0 D.
Results: Stereoacuity was based on unaided visual acuity in 1975 children (84.3%) and on spectacle-corrected visual acuity in 368 children (15.7%); 87 children (3.7%) had reduced stereoacuity. Amblyopia was the most common identifiable cause, accounting for 32%, followed by strabismus (15%) and anisometropia (14%). Presence of anisometropia was significantly associated with reduced stereoacuity; 78.6% of anisometropic children achieved normal stereoacuity versus 98.9% without anisometropia (p < 0.0001).
Conclusions: Reduced stereoacuity was relatively uncommon in a population of 12-year-old Australian children. Its functional and psychosocial impact on individuals and on the whole population remains uncertain.