The effect of off-the-viual-axi retinocopy on objective refractive meaurement

Purpoe To determine the effect of off-axi retinocopy on objective refractive meaurement. Deign Propective experimental tudy. Method Eight volunteer underwent cycloplegic retinocopy of their right eye on-the-viual-axi, and 5, 10, 15, and 20 degree off-the-viual-axi in adduction. A ingle maked examiner performed all retinocopy with random order of the patient and axi refracted. Reult The average pherical retinocopic value at 0, 5,10,15, and 20 degree of off-axi alignment wa −0.40, −0.90, −1.00, −1.38, and −1.80 diopter, repectively. The average pherical equivalent retinocopic value obtained for each of the above poition of eye alignment wa −0.02, −0.59, −0.45, −0.64, and −0.98 diopter, repectively. The induced cylinder power increaed by an average of 3% for each degree of off-axi retinocopy, though the axi of the cylinder wa not predictable. Concluion Objective refractive meaurement by retinocopy i ignificantly altered by off-the viual-axi retinocopy. The induced error may be clinically important even with mall degree of eccentricity.