Lay summary
Vision screening is conducted in >90% of preschool children in New Zealand (NZ) as part of the B4 School Check, a national well-child programme. The current NZ protocol uses the a letter-matching test at 4 metres (Parr Vision Chart) to detect lazy eye, squint and focusing errors. A recent retrospective evaluation of referrals from the B4 School Check vision screening showed many children with normal vision were referred unnecessarily and factors which may to contribute to this include the use of a non-validated vision chart, the training of screening personnel or difficult testing environments. This study aims to explore two alternative methods of vision screening that have been recently identified as best practice: (1) a picture-based vision chart and (2) automated measures of eye focus to determine whether these tests would improve the diagnostic accuracy of preschool screening in NZ.