. Refraction and how to refract : including sections on optics, retinoscopy, the fitting of spectacles and eye-glasses, I METER Fig. 141.—Light over Patients Head, and the Observer with Mirror at OneMeter Distance. patients eye, it is always necessary to have the light andmirror widely separated. Usually, the light with the 3 in the screen is placed to one side or over the pa-tients head, and the surgeon with the mirror is seated aboutone meter from the patient. This will place the focus of the25 cm. mirror at about 33 cm. in front of the of Surgeon from Patien
. Refraction and how to refract : including sections on optics, retinoscopy, the fitting of spectacles and eye-glasses, I METER Fig. 141.—Light over Patients Head, and the Observer with Mirror at OneMeter Distance. patients eye, it is always necessary to have the light andmirror widely separated. Usually, the light with the 3 in the screen is placed to one side or over the pa-tients head, and the surgeon with the mirror is seated aboutone meter from the patient. This will place the focus of the25 cm. mirror at about 33 cm. in front of the of Surgeon from Patient.—With the plane mirror he may approach w ilhin a few inches of the patientseye to fintl the point of reversal, hut with the concaxe minor RETINOSCOPY. 159 he must remain at a sufficient distance to have the focus ofthe mirror in front of the patients eye. How to Use the Mirror.—It should be held firmly in. Fig. 142.—Illustrating High Myopia with a Concave of light from the lamp (L) are reflected by the mirror (w), and fonn aconjugate focus at L, and the rays from this focal point illuminate theretina at L^. Con-esponding effects result when reflection takes placefrom the mirror at m. The eye (E) behind the mirror recognizes pointsof reversal between the eye and mirror, moving in the same direction tothat in which the mirror is tilted.
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Keywords: ., bookcentury1900, bookdecade1900, bookidref, booksubjecteyeglasses
