Ocular refraction and the shadow test . t iron cylinder makes a very satis-factory screen for the lamp, the top an bottom being closed. Anytinsmith will be able to make one at a small cost. This same light may also be used with the ophthalmoscope. To control the beam of light profected from the retinoscope requiresconsiderable practice. It may be supposed that it is a simple thing todirect the mirror so that the light will reach the eye of the student need not be surprised to find that it is quite difficult atfirst; in fact, that he cannot locate the eye with it. To avoid anysuch e
Ocular refraction and the shadow test . t iron cylinder makes a very satis-factory screen for the lamp, the top an bottom being closed. Anytinsmith will be able to make one at a small cost. This same light may also be used with the ophthalmoscope. To control the beam of light profected from the retinoscope requiresconsiderable practice. It may be supposed that it is a simple thing todirect the mirror so that the light will reach the eye of the student need not be surprised to find that it is quite difficult atfirst; in fact, that he cannot locate the eye with it. To avoid anysuch evidence of lack of skill, the studsnt should not attempt thehuman eye until he has had some practice on the model eyes. Agood scheme for practice will be to paste a small bit of paper, about an inch in diamer, on the wall at the level of the eye and try to locateit by projecting the light beam upon it. The expression — to rotate the mirror —that is so frequentlyused in describing the handling of the instrument is apt to be mislead-. The retinoscopic exa ing; while it is entirely correct, it may make the point clearer to statethat the mirror should be tilted or inclined. Plate 137 illustrates the correct method of holding the retino-scope. The handle is lightly but firmly grasped, close up to the mir- I70 OCULAR REFRACTION. ror ; the instrument is heldsquarely before the eye and touching theforehead. Either eye may be used as preferred by the operator. The mirror is inclined in various directions, or tilted, by amovement of the wrist alone, the head to be held motionless. Thisdirects the movement of the light beam; a very slight movement issufficient to cause the light to pass across the face of the patient.
Size: 1614px × 1548px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookidocularrefrac, bookyear1903
