BACKGROUND: Limited data are available on the causes of visual impairment in preschool children in New Zealand. We aimed to review demographic and visual parameters in children referred to the Ophthalmology Department, Manukau Super Clinic from vision screening programs in South Auckland. METHODS: Retrospective medical record review of 131 children, aged three to five years, referred from community-based vision screening programs to the Ophthalmology Department for further assessment. Medical records were reviewed to determine: the reason for referral; findings from ophthalmic assessments; treatment received; and visual acuity at the final visit. The main outcome measures were the cause of visual impairment in children referred from preschool vision screening and the visual acuity at the final follow-up visit. RESULTS: Thirty-eight (29.0 per cent) children were discharged after their initial assessment as false positive referrals. Almost half (45.5 per cent) of the children were prescribed glasses for the correction of refractive error, amblyopia or strabismus. Twenty-nine (22.1 per cent) children were diagnosed with amblyopia with an average follow-up period of 17.5 ± 2.7 months. In general, compliance with therapy for amblyopia was poor with 48.3 per cent non-compliant with their prescribed treatment regimen. Despite this, visual outcomes were good with an average final visual acuity in the amblyopic eye of 0.294 ± 0.231 logMAR (Snellen 6/12). CONCLUSIONS: The 'positive predictive value' for the Counties-Manukau preschool vision screening program was 47.4 per cent, suggesting that the visual acuity measurements alone produce a significant number of false positive results. In children diagnosed with amblyopia, early detection and intervention showed significant improvement in vision in the amblyopic eye, with many children also showing improved binocular function.