DEVICE FOR CARRYING OUT OPHTALMOLOGICAL OPERATIONS.

摘要

Instrument has a holder with cornea stop and uses a locatable cutting tool on a sprung rod within the holder which is adjusted via a micrometer screw from the far end with a nut. A thrust sleeve (14) on he holder is carried via the micrometer thread (15) and is located by means of a sprung lever (19) whose axis (20) is hinged to the sleeve exterior and whose arm works with grooves (22,23) on the holder and sleeve which register to locate the sleeve. The sleeve groove (23) is continuous. The other lever arm (25) works with the nut (13) via nut flutings. The tool rod (7) thread and sleeve thread should differ in pitch. With the tool (9) in its locator (10) the lever (19) is depressed to register the grooves (22,23), homing the lever arm and thus zeroing coarse and fine scales. The nut is twisted to adjust the tool flush with the cornea stop (5), then the lever is released by a spring (21) to disengage it from the grooves and engage its flutings with those on the nut. The sleeve then rotates to set the tool to the required depth setting on the fine scale.