Once measurements are taken, they are plugged into mathematical formulas to predict the necessary lens power. These formulas have evolved through "generations" based on how they estimate the —the final resting place of the IOL in the eye.
Patients who have had LASIK or PRK have altered corneal shapes that traditional formulas often miscalculate. Biometry & IOL Power Calculations - PDF
The total length of the eye from the cornea to the retina. Once measurements are taken, they are plugged into
Used both AL and K to predict ELP. These remain widely used today. Once measurements are taken