Fig. 16. A method of estimating the magnification of image “of the retina” as compared with image “on the retina.” Eye has 10.00 D of myopia. Magnification = Image of/Image on = 10/2 = 5. (Safir A: Retinoscopy. In Tasman W, Jaeger EA [eds]: Duane's Clinical Ophthalmology. Philadelphia: JB Lippincott, 1982.)