Fig. 9. Locating the far point of a + 4.00-D eye in ophthalmoscopic retinoscopy when the retinoscope is 5 cm from the subject's eye. Start with the sleeve all the way down and move slowly toward the top. At or within 1 mm or so of the top, a bright, thin, focused image will emerge on the retina if the far point of the eye is 40 cm behind the cornea. Lowering the sleeve permits you to detect lesser amounts of hyperopia by moving the virtual focus of the retinoscope from about 25 cm behind the eye further toward the horizon, allowing the detection of lesser amounts of hyperopia until midsleeve, where the retinoscope detects plano. The distance that the sleeve is lowered is a measure of the refractive distance between + 4.00 D and plano. |