Toric IOL rotation calculator
Work out whether rotating a misaligned toric intraocular lens will reduce residual astigmatism, and what the ideal axis would be.
Why toric alignment matters
A toric IOL delivers its full cylindrical correction only when it sits on the intended meridian. Off-axis rotation reduces the effective correction and induces astigmatism at a new axis, so both the magnitude and the axis of the residual error change.
Frequently asked questions
How much correction is lost when a toric IOL rotates?
Effective cylindrical correction falls as the lens rotates away from the intended meridian, and the correction is substantially lost by about 30 degrees of misalignment.
When should a rotated toric IOL be repositioned?
Repositioning is considered when the calculated ideal axis differs meaningfully from the current axis and the predicted residual astigmatism after rotation is materially lower than the current residual astigmatism.
See also the cylinder transposition calculator and browse toric IOL model numbers.