The extent to which compensation for the prismatic effects of spectacle lenses is maintained.

PURPOSE

The ability of subjects to compensate for the visual displacement caused by the prismatic effects of spectacle lenses was studied over 4 days.

METHODS

Subjects were made myopic using contact lenses and then corrected with spectacles. Pointing behavior was used to assess directional localization. Compensation for the refractive lenses was induced by showing subjects their pointing errors.

RESULTS

Compensation was maintained for 4 days in 3 of 4 subjects despite 24 h of normal viewing between testing sessions. One subject demonstrated a negative directional aftereffect which has not been previously reported in studies of spectacle lens adaptation.

CONCLUSIONS

Compensation for the prismatic effects of spectacle lenses can be maintained for several days in some subjects. This compensation may be functionally useful for some patients who switch between spectacles and contact lenses.