THE SCOTOMETER OF ANTONELLI, French, c. 1900, in its original 4-3/4″ x 3-1/2″ x1-1/4″ wood case covered in black fabric. The blackened brass instrument, with wood handle, measures 8-1/4″ (21 cm) overall. It features a sighting hole with leaf diaphragm adjustable against a 1(1)15 mm scale, a large rotating wheel of eight colored glass filters (for use by daylight), and a superimposed wheel of eight opaque colored targets (for use by artificial light). In very fine functional condition throughout, the “scotometer” measures the perception of colors in the central vision field, enabling early diagnosis of certain optic nerve diseases. The inventor of the present instrument was Dr. Alberto Antonelli, well-published ophthalmologist in Paris. We are aware of one other example, in a private collection, and we find the device listed in a 1909 catalogue of Maison Luer, 104 blvd. St. Germain, Paris. A less elegant instrument, termed “Snellen’s scotometer,” is held in the Utrecht University Museum (see Eye and Instruments, p. 195). Most rare.
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David and Yola Coffeen both have enjoyed academic careers, as planetary astronomer and as linguist/educator. But since 1982 (yes, 1982!) they have been full-time dealers in early scientific and medical instruments, under the name Tesseract. Selling primarily by catalogue (over 100 issued so far) they also have a web presence at www.etesseract.com, and can be contacted at email@example.com.