Busse B J, Mittelman D
Int Ophthalmol Clin. 1976 Summer;16(2):63-74.
High quality photographs of the peripheral retina are made possible by the proper positioning of the astigmatism correction device on the Zeiss fundus camera. Using a plus cylinder, axis perpendicular or a minus cylinder, axis parallel to that around which the eye is rotated will eliminate the astigmatism induced by viewing the retina obliquely through the optical surfaces of the eye, resulting in a sharply focused image at the film plane. Proper use of this instrument can be helpful in evaluating and diagnosing retinal lesions that occur in the peripheral fundus.