Biomedical subjects
Publications and source records attributed to I Nose.
A new instrument, the membrane peeler cutter (MPC), has a solenoid-activated right-angled microscissors (diameter, 0.9 mm) that can be used as a hooked needle as well. It has been successfully used in more than 50 vitrectomy procedures that were complicated by intraocular membrane formation at the preretinal level. It has also been helpful in the cutting of pupillary membranes.
We developed an automated diaphragm control to achieve constant good exposure during televised microsurgery by using a commercially available diaphragm control for a movie camera and modifying slightly the television camera.
A new digital surgical keratometer (SK-1, Canon Inc) designed to fit existing operating microscopes and provide quantitative measurements at a nominal 2.0- and 3.6-mm diameter optical zone of the central cornea was modified for single foot-switch operation by the surgeon. The instrument was tested against three calibrated steel spheres, an astigmatic test-jig, and compared with a standard clinical keratometer (CLC, A.O. Co) in two studies involving six eye bank eyes and five healthy human corneas. Assessed with the steel spheres, the SK-1 calibration error was -0.042 diopters at the 3.6-mm diameter and +0.207 D at the 2.0-mm chord, while it was -0.120 D for the CLC. With cylindrical power greater than 0.50 D, the astigmatic angle was accurate to +/- 1 degree. After correction for calibration error, the CLC readings on eye bank eyes were 1.00 D higher in average (range +0.45 to +1.90) than those obtained with the SK-1 which gave lower keratometric values at the 2-mm chord diameter (-0.254 D, range: +0.05 to -0.7). The human subject corrected readings at the 3.6-mm chord were within 0.137 D (range -0.09 to +0.41) from the CLC values. A mean corrected difference of +0.068 D (range -0.27 to +0.30) was found between the two chords. The SK-1 instrument was easier to use than the CLC. A more accurate calibration and the addition of automated averaging and video display of readings as well as of a motorized Placido disc would further augment its clinical usefulness.