The refraction of the eye; including a complete treatise on opthalmometry; a clinical text-book for students and practitioners . he retina (— .25 to + D. = + D.), that is, the myopia of .25 that amount (.25 D.) of the presbyopia. From thisit is quite evident, for reading purposes, the eye has been con-verted into, a compound hypermetropic astigmatism, the merid-ian at 100° being D. presbyopic, and that at 10°. order to correct this, a 4- D. sphere, combined with+ .75 D. cyl., 10°, is necessary. This, in fact, was changes took pla
The refraction of the eye; including a complete treatise on opthalmometry; a clinical text-book for students and practitioners . he retina (— .25 to + D. = + D.), that is, the myopia of .25 that amount (.25 D.) of the presbyopia. From thisit is quite evident, for reading purposes, the eye has been con-verted into, a compound hypermetropic astigmatism, the merid-ian at 100° being D. presbyopic, and that at 10°. order to correct this, a 4- D. sphere, combined with+ .75 D. cyl., 10°, is necessary. This, in fact, was changes took place in the left eye, as will be seen by look-ing at Figs. 89 and 90. STRATIVE CASES 207 T have presented tl of mixed astigmatism in fcheir various forms at some Length, for the purpose of showing thateven these difficult cases may be fitted, in most Instances, with-out the aid of a mydriatic. The cases here presented are notBelected ones. The indications for the use of a mydriatic ina - are exactly the same as in others of refractive error,to wit, lack of uniformity in tests, Bpasm of accommodation,and so R. E. L. E. Fig. 90. — Showing the effect of a presbyopia of D. on the near-point in the casejust reported. Set- Fig. 89 for the distance locus. The amblyopia present in most cases of mixed astigmatismis the one great stumbling-block for many observers, and servesto induce them to use a mydriatic whether there are any otherindications for its use or not. In regard to amblyopia, a certainamount f it is to be looked for in must cases of astigmatism,especially if the astigmatism is large in amount; consequently,we should not expect to bring vision up to normal, -,,,. or nearlyso, in all cases. If the patient accepts the same !i two or three sue --s. and they correspond with the objective . we may give the glasses without hesitation. In order to make myself doubly sure that I am not giving 208 THE REFRACTION OF THE EYE too weak plus, and too strong m in u
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