RELIABILITY OF THE OTAGO PHOTOSCREENER - A STUDY OF 1000 CASES

The Otago photoscreener is a 35 mm single lens reflex camera in which the flash light comes from a narrow ring around the outer margin of it s lens. The margin is also the limiting aperture of the optic system a nd in the centre of the lens is a flickering fixation light. In a colo ur photograph taken at a distance of 66 cm from the face of the subjec t who is accurately focusing on and fixing the camera fixation light w ith both eyes, the fundus reflex in each pupil is very dark red and th e corneal light reflexes are symmetrical. If either or both eyes are n ot appropriately focused or fixing, the fundus reflex is brighter and yellow or white. This article describes a prospective trial of the per formance of the Otago photoscreener in a series of 1 000 infants with actual or suspected amblyopia, refractive error or strabismus. In this study photoscreening showed a sensitivity of 94% and a specificity of 79%. Photoscreening also identified some cases of esotropia and of re fractive error which were missed on clinical examination. In this seri es photoscreening passed as normal three children with mild to moderat ely severe amblyopia. This represents les than 1% of the clinically ab normal children.