| 摘要 |
The mounts (20, 21) for the lenses and for the bridge (22) are each attached to holding elements (11, 12, 13) on a threaded rod which acts as a support (10). These holding elements have angular gears and can be displaced axially on the support (10) by means of a knob (35). All knobs (16, 26, 35) lie in a common plane. The optician is therefore not obliged to grip the knobs from the front for adjustment in relation to the test subject's eyes, but can perform the adjusting operations outside the field of vision. To carry out the sight test, the images in both beam paths are altered separately or concurrently by means of an LCD unit situated in the beam path between a projection surface for polarized signs and the test subject's eyes. The use of LCD units for control purposes allows very rapid switching, which is virtually imperceptible to the test subject and consequently does not affect the evaluation. |
