The refraction of the eye; including a complete treatise on opthalmometry; a clinical text-book for students and practitioners . entire satisfaction for almost three years. The Last four cases reported are somewhat out of the ordi-nary, because of the absence of lenticular astigmatism. Fur-thermore, they serve to show the necessity of testing for anyastigmatism thai the ophthalmometer indicates, for it maybe theonly form of astigmatism present. Cask IX, Hypermetropic astigmatism against the rale, 1 eye, .•> I>. left eye; Patient accepts .50 I), more than the in-strumt nt /•< a
The refraction of the eye; including a complete treatise on opthalmometry; a clinical text-book for students and practitioners . entire satisfaction for almost three years. The Last four cases reported are somewhat out of the ordi-nary, because of the absence of lenticular astigmatism. Fur-thermore, they serve to show the necessity of testing for anyastigmatism thai the ophthalmometer indicates, for it maybe theonly form of astigmatism present. Cask IX, Hypermetropic astigmatism against the rale, 1 eye, .•> I>. left eye; Patient accepts .50 I), more than the in-strumt nt /•< ads. — L. M.,1 aged thirty-nine, general health eyes have not given herany special trouble until thelasl year, when they beganto pain her and the vision toblur when she read or sewedfor any great length of night she had to give upwork ami reading. Ophthalmometer. — Ast ig-matism against tin- rule. 1 I).,axis 180° + or W° - right : .75 I)., axis lSU° + or90 Fig. 26. bigure zo is a diagram-matic section of such an eye showing where the rays of light 1 Reported from Drs. Lewis ami Van Fleets 54 THE REFRACTION OF THE EYE focus respectively in the vertical and horizontal meridians. The horizontal meridian is emmetropic and focusses rays on the retina; while the vertical meridian is Irvpermetropic, less curved than the horizontal, and allows the rays of light tofocus back of the retina. Test cards and trial lenses. — The vertical lines on theGreens* clock-dial are seen plainest. R. V. = ft: ft + W. + D. cyl., 180°. L- v. = U: U + W- + L25 D- cyL 180°- Ophthalmoscope. — Simple hypermetropic astigmatism againstthe rule. On a second test the same glasses were accepted by thepatient and were ordered. The above glasses have been wornfor three years with perfect satisfaction. Usually in cases ofastigmatism against the rule we add .50 D. to the reading ofthe instrument. However, it may be more or less, as illus-trated by some of the following c
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