BACKGROUND The excellent co-operation with the pediatric public health service of the local health authorities enables us to present the collected results of a vision screening survey of all children starting primary school in 1998 in the Federal State of Saarland. The aim is to analyze the prevalence of amblyopia, strabismus, reduced visual acuity, refractive errors and severe visual impairment in one complete grade of pre-schoolers. METHODS The examination parameters had been determined in co-operation with the Department of Pediatric Ophthalmology at the University of Saarland and had been fitted to the needs and abilities of lay persons (health workers) doing a vision screening as part of a general health check-up. Parameters were: visual acuity (Rodenstock R21), color vision (Ishihara), stereopsis (Lang), and test for latent hyperopia. Referral to an ophthalmologist if: visual acuity < 0.7; difference in visual acuity in both eyes of more than one line, or any other pathological test result. A total of 12,192 children were screened. RESULTS The preventive pediatric examinations were complete in 5756 children (56.4%), incomplete in 4449 children (43. 6%) and in 1987 children (16.3%) the degree of completion could not be determined. Eyes: pathological findings in 41.7%. Reduced visual acuity in 30.8%, color vision defects in 1.3%, severe visual impairment in 0.3%. Pathological findings in other organ systems: skeleton 33.5%, teeth 32.6%. For the urban confederacy of Saarbrücken: referrals to ophthalmologists: n=1108. No feedback information: 380; refractive correction: 226; recommendation for regular checks: 346; no pathological findings: 156. CONCLUSION. The high percentage of pathological findings in the vision screening of 12,192 pre-schoolers is an important confirmation that there is a need for a preventive ophthalmologic examination before the age of six. Only an area-wide ophthalmologic vision screening around the second or third year of life can effectively reduce the high prevalence of pathological findings at the time of starting primary school. To improve the present screening situation, networks between ophthalmologists and pediatricians would be beneficial.