The refraction of the eye; including a complete treatise on opthalmometry; a clinical text-book for students and practitioners . ch permits the manipulation of the mires fromthe back of the large dial; and by means of a circular scale withdouble automatic pointers corresponding to the graduations on thean-, the relative position of the mires on the arc can be read withgreat accuracy. Another new feature is the raising and lowering of the chin-restfrom the opposite end of the ophthalmometer, by means of a camoperated by a long rod and milled head at the end of same, so thatthe operator need not
The refraction of the eye; including a complete treatise on opthalmometry; a clinical text-book for students and practitioners . ch permits the manipulation of the mires fromthe back of the large dial; and by means of a circular scale withdouble automatic pointers corresponding to the graduations on thean-, the relative position of the mires on the arc can be read withgreat accuracy. Another new feature is the raising and lowering of the chin-restfrom the opposite end of the ophthalmometer, by means of a camoperated by a long rod and milled head at the end of same, so thatthe operator need not change his position. Below a good cut of theinstrument is given. Another new model of the ophthalmometer is that made byChambers and Inkeep, of Chicago. The special advantages that 1 New York Eye and Ear Infirmary Beports, 1894, If. l7. 392 THE REFRACTION OF THE EYE they claim are: (1) Stationary luminous mires; (2) Adjustableprisms. There are still other models of the instrument on the market,but, in my opinion, the 1889 model of Javal and Schiotz is as accu-rate as any of them. Not only that, but measurements outside of. the visual line can be made with the 1889 model, because it has thelarge dial of Placido attached, while all of the new model instru-ments have replaced it with a plane black disk or dial. Artificial Corner Some eight or nine years since, Javal made an artificial cornea,astigmatic in nature, which could be attached to the chin-rest of theinstrument, and used for testing the correctness of the ophthal- APPENDIX 393
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