Vision Screening Intervention

Recording clinical suspicion before and after testing is intended to measure how much the tests change GP diagnostic accuracy. The intervention was co-designed with patients, relatives, ophthalmologists, GPs, GP nurses, and optometrists and was pilot-tested before launch. GP staff receive standardized ophthalmologist training, and a researcher observes the first recruitment day at each clinic for protocol adherence. GP staff administer three tests: the Colenbrander Mixed Contrast Card, Amsler Grid, and confrontational visual field test.