A bichromatic laser optometer

A laser refractive technique involving the simultaneous viewing of red (633 nm) and green (514 nm) speckle patterns has been investigated. The speckle patterns are displayed on adjacent, contra-rotating drums with a common axis, the refractive status being determined by matching the apparent speckle speeds for the two wavelengths. The refractive corrections found are compared with those determined by making either red or green speckles appear stationary, and with the independently determined results of conventional subjective refractive procedures. It is concluded that, although the bichrome technique is feasible, most subjects found the conventional laser method, involving red speckles alone, easier to use and that the associated results were slightly more reproducible.