Transactions . ich was fastenedin a spectacle frame. The distance at which the lens is placedbefore the eye does not change anything in the matter of en-largement as long as the condition is fulfilled that the object re-mains in the focus of the lens. Now the type can be held at a dis-tance of ten centimeters (4 inches) from the eye, but the enlarge-ment is proportionate to the shortening of the distance at whichthe paper is held from the lens. The other eye is excluded bya hard rubber plate fitted into the spectacle frame to preventdouble images at this short distance. The field of vision ofs
Transactions . ich was fastenedin a spectacle frame. The distance at which the lens is placedbefore the eye does not change anything in the matter of en-largement as long as the condition is fulfilled that the object re-mains in the focus of the lens. Now the type can be held at a dis-tance of ten centimeters (4 inches) from the eye, but the enlarge-ment is proportionate to the shortening of the distance at whichthe paper is held from the lens. The other eye is excluded bya hard rubber plate fitted into the spectacle frame to preventdouble images at this short distance. The field of vision ofsuch an arrangement is considerable, and sufficient to coverseveral words at a time. As the glass is held in an immov-able position, the] paper only has to be moved past the eye, or KoLLER: Reading with Defective Vision. 705 rather the head along the lines, which latter is more a short time the patient had learned to use this arrangementand read with comparative ease her daily paper for five She died last year, and always felt grateful for the service ren-dered to her. In the space of six years I had such reading glasses made*for several more patients, altogether five. The class of patientswho can be benefitted by it is naturally very limited. Station-ary defects of vision arising from incurable opacities of the cor-nea, or vitreous body, or lesions resulting from affections of theretina, choroid, and the optic nerve may furnish suitable defects of vision or such acquired in early youthmay also be benefitted, although as a general rule such pa-tients have already accommodated themselves to their condi-tions and are frequently able to read without the help ofglasses. They avail themselves of the very same principle ofenlargement by approach, entirely renouncing distinctness ofthe retinal images in favor of their size — a proceeding whichis well known to all ophthalmologists, and which goes by thename of seeing in circles of diffusion. * I
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