Ocular refraction and the shadow test . the operator must be taken into consideration, asin the use of the ophthalmoscope, but merely that the best possiblevisual acuity is essential to the Refractionist so that he may be ableto recognize what he sees. In the practice of retinoscopy some operators advocate the use ofa cycloplegic, and contend that the test is useless without it. Theauthor disputes this claim, and contends that not only is a cycloplegicnot necessary, but that more satisfactory results are obtained withoutit. While a cycloplegic holds the accommodation in abeyance, it di-lates t
Ocular refraction and the shadow test . the operator must be taken into consideration, asin the use of the ophthalmoscope, but merely that the best possiblevisual acuity is essential to the Refractionist so that he may be ableto recognize what he sees. In the practice of retinoscopy some operators advocate the use ofa cycloplegic, and contend that the test is useless without it. Theauthor disputes this claim, and contends that not only is a cycloplegicnot necessary, but that more satisfactory results are obtained withoutit. While a cycloplegic holds the accommodation in abeyance, it di-lates the pupil, exposes the peripheral portions of the crystalline lens R E T I N O S C O P Y. i67 and discloses its aberrations that are concealed, or cut out by the iris,under normal conditions. The accommodation may be held in checkby other means. This is a fortunate circumstance tor the optician,who is not qualified nor permitted to use a cycloplegic. It also meetswith the approval of the majority of people who object to drops inthe Workinc toncl Plate 135 inoscope at one metre di: positions of 168 OCULAR REFRACTION. If the test be conducted in a darkened room, the pupil will dilatesufficiently to obtain a good reflex. The refracting room need not bein absolute darkness, particularly if using the self-luminous retino-scope. The authors refracting room is painted a dull-surface black,but the partition does not extend clear to the ceiling, so that a suf-fused light fills the room which is only comparatively dark. The only direct source of light in the room during the retinosco-pic test must be that used in connection with the instrument. PUtes 135 and 1 j6 are made from photographs taken in theauthors operating rooms; a photograph faithfully reproduces everydetail, and these plates will serve better than any diagram to illus-trate actual working conditions. The patient is seated in a revolving chair, which permits of theproper adjustment for height, so tliat the eyes of tliep
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