Uploaded: 12/10/2023

To calculate the predicted refractive error after rotating a toric phakic or pseudophakic IOL, when the toric power and/or axis are unknown due to lost records, small nondilating pupil, or presumed mislabled lens.

Assumptions: keratometric astigmatism is considered to be the main source of the ocular astigmatism and non-keratometric astigmatism amount is negligible, and the IOL is in its normal position without any significant tilt.

You should enter the keratometry values (a total refractive cornea cylinder is preferred incorporating the back corneal astigmatism), and the total refraction (subjective refraction) to calclate the IOL induced astigmatism; then you may enter the amount of desired rotation (plus sign for counterclockwise, and minus sign for clockwise), the calculator will predict the succeeding  refraction (what will be the new refraction if you rotate the toric IOL for a given amount).