To the Editor.
—I read with interest the excellent article1 on the Visiscreen 100 (Medical Sciences Corp, Wedowee, Ala) in the November 1987 issue of the Archives. I began using a similar technique in 1976 for the purpose of evaluating ocular alignment in infants. With color transparencies, I use a 500-mm catadioptric telephoto lens attached to a 35-mm camera by extension tubes at a distance of 2.4 m, with the flash as close as possible to the top of the lens. I measure the lateral position of the corneal light reflex for each eye, relative to the pupil center, assigning nasal displacement positive numbers and temporal displacement negative numbers. I use a projection distance so that the magnification is approximately ×4. By measuring the position of the projected corneal reflex to the nearest 0.5 mm, I measure the position of the reflex to the nearest 0.12 mm (0.5 mm