| 摘要 |
An improved conical keratometer (10) wherein the parent image of the pattern to be reflected upon a target positioned adjacent to the illuminated bore is recorded on a film slide (40) retained within the keratometer bore (12). Opposite edges (51, 52) of the slide (40) are chamfered at equal but opposite angles so that, when the spindeled slide is released, the chamfered edges (51, 52) will meet along a line of contact rather than butting squarely together. The film slide (40) is rolled so that the emulsion side (53) is toward the periphery of the cone bore (12) and the chamfering allows that side to lie smoothly against the cone bore (12) without any gaps so that an undistorted image may reliably be reflected upon a standard target.
|
