Examination of Low-Luminance Myopia with a Laser Optometer

Abstract

With a simple version of a laser optometer, Fig. 1, which enables testing of accommodation at photopic, mesopic and scotopic luminance levels (120 cd m⁻², 0.5 cd m⁻² and 0.001 cd m⁻², respectively), low-luminance myopia studies were performed on about 400 eyes. This method has numerous advantages over previously used techniques. The most important are these: since the speckles produced by constructive and destructive interference of reflected laser light, the sharpness of its retinal image is independent of the focus of the eye; the pattern per se does not serve as an accommodative stimulus [1, 2, 3]; and the subject, being asked to evaluate the direction of the movement of the speckles, cannot relate this movement to the direction or amplitude of accommodation and is thus unable to influence the result. Also, the superimposing of the speckle pattern onto the subject’s visual field causes only minimal interference with the ongoing task.