Preferential looking acuity of pediatric patients with developmental disabilities.

The grating acuity of 181 patients from 6 weeks to 18 years of age who had neurological abnormalities and documented developmental delay was assessed using preferential looking (PL) procedures. PL acuities were estimated by a staircase procedure in 79% of all patients (143 of 181) on the first attempt. PL acuities were poorer than normal on the average in all patient groups, including those without ophthalmological disorders. However, PL acuities varied systematically with the severity of the eye disorder in each category, with two exceptions, high refractive error and nystagmus. Interocular acuity differences were sensitive to such asymmetric eye disorders as strabismic amblyopia and unilateral ocular abnormalities and enabled monitoring of occlusion therapy for these conditions. Many patients who were 'visually inattentive' despite the absence of major ophthalmological abnormalities were testable but had very poor acuity. This study evaluates the clinical applicability of PL procedures for routine assessment of visual acuity in pediatric patients with developmental disabilities.