. Refraction and motility of the eye, with chapters on color blindness and the field of vision . h eves he sees all four numbers. 2 and -Ibeing actually seen with the right eve. Through the stereo-scope however, •!. which is actually seen by the left eveappears to be almost directly under the 2, and both beingon the right of the combined picture seem to be seen withthe right eye. It i- easy enough i<» make op your own card- witbprint for which the rapid reading requires the use of both and the reverse cards which can be read easily writheitber eve alone but not with both together. In using
. Refraction and motility of the eye, with chapters on color blindness and the field of vision . h eves he sees all four numbers. 2 and -Ibeing actually seen with the right eve. Through the stereo-scope however, •!. which is actually seen by the left eveappears to be almost directly under the 2, and both beingon the right of the combined picture seem to be seen withthe right eye. It i- easy enough i<» make op your own card- witbprint for which the rapid reading requires the use of both and the reverse cards which can be read easily writheitber eve alone but not with both together. In using a ?cope jre;it care must be taken that the patient does 374 REFRACTION AND MOTILITY OF THE EYE. not close his pretended bad eye and so deceive you. It isbetter to cut away most of the hood of the instrument. The person who claims poor vision in one eye will gen-erally admit very good in the other. For this type the barreading test is a good one, having him read fine type withboth eyes open while you hold a pencil or fountain pen ver-tically four or five inches in front of him. If he reads. Fig. 124. without hesitation or twisting of his head he must be usingboth eyes. One of the simplest and best means of detecting themalingerer is the diploscope. (Fig. 124.) It consistsessentially of a diaphragm with a central opening throughwhich a row of letters is seen with both eyes open. Theimpression is that the letters are all seen with both eyeswhile as a matter of fact those on the left are seen with theright eye and vice versa. The fakir who does not under-stand the principle involved is very apt to insist that he isseeing the right letters with the right eye, which is impos- OCULAR MALINGERING. 375 sible. Unfortunately the device is not practicable for dis-tant vision. The amblyoscope (Fig. 100) can also be made veryuseful. In all possible positions of the tubes the card inthe right tube can only be seen with the right eye and vice
Size: 2087px × 1198px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1900, bookdecade1920, booksubjecteye, bookyear1920
