Transactions . E. G. Loeing, of New-York, seems to be thebest mechanical contrivance for using the ophthalmoscope asan optometer. Lorings three discs, however, cause considera-ble loss of time by changing from one to the other, and Cohnsmodification, which puts all the glasses of Lorings three discsinto one large disc of 3 inches in diameter, appears clumsyand unmanageable. Apart from these inconveniences,, thediscs in Lorings ophthalmoscope have not a sufficient numberof glasses for the requirements of a careful ophthalmic practi-tioner. Some years before Dr. Loring constructed his in-strumen
Transactions . E. G. Loeing, of New-York, seems to be thebest mechanical contrivance for using the ophthalmoscope asan optometer. Lorings three discs, however, cause considera-ble loss of time by changing from one to the other, and Cohnsmodification, which puts all the glasses of Lorings three discsinto one large disc of 3 inches in diameter, appears clumsyand unmanageable. Apart from these inconveniences,, thediscs in Lorings ophthalmoscope have not a sufficient numberof glasses for the requirements of a careful ophthalmic practi-tioner. Some years before Dr. Loring constructed his in-strument, I had a complete collection of small trial-glassesmade which I could insert into an ordinary small (Liebreich)ophthalmoscope, and Dr. H, D. ISfoyes had his ophthalmoscopeso changed that he could place behind the mirror all the num-bers of his trial case of spectacles. All this, however, requirestoo much time for constant use. The ophthalmoscope which Ihave the honor to show you aifords the greatest possible. Fig. 1. number of trial-glasses behind the eye, permits them to berapidly changed, while the instrument is nearly as small as 110 Lorings. It consists of the ordinary mirror, beliind which two discs can be rotated like the diaphragm in some—for instance, Kellners—microscopes. In each disc are thirteen little aper- A Btransactionsoph02ameruoft
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectophthalmology, bookye
