The Leland refractor, designed by George H. Leland, an electrical engineer, of Dayton, Ohio, is an instrument for use in refraction under binocular condition.
The visual targets are placed opposite the patient at a distance of 6 meters, or they are placed beside the patient and are viewed in a mirror at a distance of 3 meters. One of the targets (fig. 1, A) is a slit, 4.8 mm. (3/16 inches) in width and 8.5 cm. (3⅜ inches) in length, which can be rotated to any desired meridian and is evenly illuminated by diffused red light. The large dial (fig. 1, C) makes it possible to read easily single degrees of the axis of astigmatism. A second target (fig. 1, B) consists of two slits at right angles, having the same measurements and forming a cross. The same unit also provides a muscle light (fig. 1, D) and a visual
van WIEN S. THE LELAND REFRACTOR: A METHOD FOR REFRACTION UNDER BINOCULAR CONDITIONS. Arch Ophthalmol. 1940;23(1):104–111. doi:10.1001/archopht.1940.00860130116010
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