Abstract: An optic for a head mounted display having a first concave surface, a convex surface, and a second concave surface. The first concave surface receives light incident to its surface and transmits the light. The convex surface reflects light. The second concave surface reflects the light transmitted by the first concave surface and transmits the light reflected by the convex surface so that the light reflected by the convex surface travels through the second concave surface and is emitted outwardly.

Abstract: Arthroscopic cervical discectomy instruments include a push knob for a guide wire, a pair of telescopically mounted dilator tubes, one of which includes a water port so that the tube provides the additional function of an irrigation tube, a ligament cutter, a continuous suction punch, a cervical osteotone, a cervical cureet, a nucleus extractor and a cureet nucleus extractor. The dilator tubes, the ligament cutter, and the continuous suction punch are all centrally bored to receive the guide wire. All of the instruments are of arthroscopic proportions and each instrument, exclusive of its handle, is slideably insertable through the bore of the largest in diameter dilator tube. The largest in diameter dilator tube serves as a dilator, an irrigation tube, and as the main sheath through which the other tools are inserted. In a second embodiment, the pair of dilator tubes are replaced with a plurality of telescoping dilator tubes of progressively larger diameters and shorter lengths.