In a standard square plastic or glass prism, averaging about 38 mm. square, two small holes were drilled, each about 5 mm. in length and 2 mm. wide, one into the base and the other in one side of the prism. The hole in the base of the prism was drilled perpendicularly at a point midway of this rectangular surface. The hole in the side of the prism was drilled perpendicularly at a point midway between the apex and the basal edge. The holes were then tapped to permit the ready insertion of a rod about 6 inches (15 cm.) long, with one end threaded to screw readily into either of these spiraled openings. The result was a simple prism holder which could be changed readily to a base-down, base-in or base-out position. In a more recent model the holes were not threaded. One end of the rod holder was
KRIMSKY E. A COMBINATION SQUARE PRISM AND LOLLIPOP HOLDER. AMA Arch Ophthalmol. 1951;46(3):337–338. doi:10.1001/archopht.1951.01700020346010
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