Anatomy and physiology of the eye, with hints for the preservation of the eyesight (1901)
Herbert, John Frederick, 1860- · Philadelphia, Pa., The author · leaf 43
tism, the rays com-ing through one of the principal meridians, which in thiscase is normal, focus exactly on the retina, while thosecoming through the meridian at right angles to the formerfocus beyond the retina. See figure 23. 37 2. Ill simple in3Opic astigmatism, the rays going throughone of the… … Figure 23.Vertical ineridian is normal. Horizontal meridian is hyi)ermetropic. 3. In compound hypermetropic astigmatism the ra3^s aretoo long and are projected beyond the retina through boththe principal meridians, the point of focus however in onedirection being behind that of the other. See…
Eye · Lenses
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