The purpose of the present study was to evaluate the effectiveness of a new vision-screening programme in detecting ophthalmic disorders in children with developmental delay (DD; IQ< or =80) and in children with normal IQ. A group of 467 children with an IQ< or =80 (272 males, 195 females; age range 4-15y; mean age 10y 4mo [SD 2y 10mo]) and 123 children with an IQ>80 (85 males, 38 females; age range 3-16y; mean age 10y 5mo [SD 3y 2mo]) had an examination that included new vision-screening items: distance and near visual acuity and stereopsis for near objects (Lang stereo test II). A full ophthalmological examination was also conducted to determine the effectiveness of the new screening items. The previous screening programme consisted of only monocular visual acuity at distance. Sensitivity, specificity, the positive predictive value (PPV), and negative predictive value (NPV) of the tests were calculated with regard to the following ophthalmic disorders: hyperopia, myopia, astigmatism, anistometropia, amblyopia, low vision, and strabismus. Overall, the prevalence of ophthalmic disorders was 33.4% in children with DD and 11.4% in typically developing children. With the use of the new programme, the effectiveness of vision screening in both groups of children was improved. In children with DD, sensitivity increased from 49.4 to 80.1%, specificity decreased from 98.1 to 83.3%, PPV decreased from 92.8 to 70.6%, and NPV increased from 79.4 to 89.3%. In typically developing children, sensitivity improved from 50.0 to 85.7%, specificity declined from 98.2 to 87.2%, PPV decreased from 77.8 to 46.2%, and NPV increased from 93.9 to 97.9%. We conclude that the currently used vision-screening programme can be significantly improved. The speed and simplicity of the proposed screening programme makes it suitable for use by school nurses. The improvements were most prominent in children with DD.