Ocular refraction and the shadow test . ropia of two dioptres themovement will be with. From this the following rule may beestablished. With a plane retinoscope, at a working distance of one metre, I7S OCULAR R E F R A C T I O N. myopia of over one dioptre shows movement against that of the lightarea Ilypermetropia, einmetropia or myopia of less than one di-optre shows movement with that of the light area. Myopia of onedioptre shows no movement of the reflex. Bear in mind that these experiments with the model eyes justoutlined are the practical operations involved m the theory illustrated by f
Ocular refraction and the shadow test . ropia of two dioptres themovement will be with. From this the following rule may beestablished. With a plane retinoscope, at a working distance of one metre, I7S OCULAR R E F R A C T I O N. myopia of over one dioptre shows movement against that of the lightarea Ilypermetropia, einmetropia or myopia of less than one di-optre shows movement with that of the light area. Myopia of onedioptre shows no movement of the reflex. Bear in mind that these experiments with the model eyes justoutlined are the practical operations involved m the theory illustrated by figures 129, 130, 131 and 132. In first operating the retinoscope let the transit of the light beslow, rapidity is acquired with practice. If the untrained eye andmind are called upon to see and interpret the movement of the reflex,it will be found difficult because the eye will see more quickly thanthe mind can interpret. Mental perception is slower than ocularperception. Havmg observed that the movement of the refl:;x in the first eye. Hyper ned by p ate I 42. no cope,he rig The 1 ght a rea ami 00 D S and the reflex reflex bolh passing to with, interpose a -f i 00 U, S. and the reflex will be found tobe choked because the emergent parallel rays of the emmetropiceye will be brought to a focus at the working distance of one the third eye, the movement of the reflex against will be choked by interposing a— D. S , the emergent rays whichconverged to a focus at ten inches being brought to a focus at the R E T I N O S C O P Y. 179 working distance of forty inches. The fourth eye in which themovement of the reflex is with will be choked by interposinga + 3 00 D S., the emergent rays which diverged being brought toa focus at the working distance of one metre.
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