Abstract: A retinoscope utilizing a plurality of infrared light sources each positioned at a difference distance, or eccentricity, from the optical axis of a camera is disclosed. The plural light sources are scanned while the fundus reflex is observed. Whether or not a reflex can be detected depends on the defocus of the eye relative to the camera, the pupil size, the eccentricity of the light source from the optical axis, and the camera-to-subject distance. The light sources are preferably light emitting diodes which are flashed repeatedly and sequentially. One-half of the camera aperture is occluded to permit determination of the amount and the direction of defocus. By noting which LED just creates a crescent of light in the pupil, and by measuring the pupil diameter, the relative defocus of the eye is determined.

Abstract: A simple pointspread retinoscope and method of retinoscopy is described. The retinoscope consists of a variable radius shield mounted on a light source, to provide variable eccentricity between the axis of the light source and the edge of the shield. The observer points the retinoscope light source at the eye of a subject, and observes the retinal reflex over the edge of the shield. If a crescent is observed, the shield is rotated to a larger radius location and the procedure repeated. The highest numbered radial step at which a crescent of light appears in the pupil provides the eccentricity of the light source, and from this value, the value of the radius of the pupil, and the value of the distance between the shield and the pupil the defocus of the subject eye can be determined.