Validity of the laser refraction technique for determining spherical error in different refractive groups.

ABSTRACT The purpose of the study was to establish for a large sample the validity of the laser refraction technique. Using the method spherical errors were determined for the dominant eyes of 100 observers. Their task was to observe through a phoropter a defocused laser pattern and report when the speckle movement ceased. The data were analyzed for four refractive groups (low myopes, high myopes, low hyperopes, high hyperopes) in terms of the degree to which the laser findings correlated with the other objective and subjective techniques for determining spherical error. It was found for all groups that the laser determinations were highly valid. The laser findings were also analyzed for each group to determine the variability of the procedure, and the results confirmed our earlier findings that the technique is also very reliable. Taken as a whole, the findings indicate that laser refraction may have greater application than mere use in gross screening situations, as is often asserted.