. The principles and practice of surgery. Veins and Arteries of the Optic Ophthalmoscopy. Indirect Method. observer is himself myopic or hypermetropic. If myopic, the concave 37 578 TEST-TYPES. EXOPHTHALMOS. lens will be interposed between the observers eye and the mirror;if hypermetropic, the convex lens will be employed in the samemanner. One may easily improvise a very useful ophthalmoscope by punchinga hole in the centre of a circular piece of polished tin. A commonpocket lens will complete the apparatus. Test-Types. Test-types are now generally employed by ophthalmologists to d
. The principles and practice of surgery. Veins and Arteries of the Optic Ophthalmoscopy. Indirect Method. observer is himself myopic or hypermetropic. If myopic, the concave 37 578 TEST-TYPES. EXOPHTHALMOS. lens will be interposed between the observers eye and the mirror;if hypermetropic, the convex lens will be employed in the samemanner. One may easily improvise a very useful ophthalmoscope by punchinga hole in the centre of a circular piece of polished tin. A commonpocket lens will complete the apparatus. Test-Types. Test-types are now generally employed by ophthalmologists to de-termine various qualities of vision. Those of Jaeger are ordinaryprinters type of various sizes, ranging from No. 1, Diamond, to , 8-line Roman; the numbers 1 or 20 representing the distance atwhich the corresponding type may be read at a distance of 1 or 20feet, by a normal eye. Snellens test-types, which are the best for de-termining acuteness of vision, are selected letters, arranged withoutorder, in a gradually enlarging series, with numerals attached to eachseries for
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