SECTION 1 EVOLUTION OF INTRAOCULAR LENS POWER CALCULATION 1. Evolution of Intraocular Lens Power Calculation SECTION 2 BIOMETRY 2. Axial Length 3. Keratometry 4. Optical Biometry 5. Posterior Corneal Curvature SECTION 3 INTRAOCULAR LENS POWER CALCULATION FORMULAE 6. Regression Formulae 7. Vergence Formulae 8. Aberrometrybased Formulae 9. Artificial Intelligence in Intraocular Lens Power Calculation SECTION 4 INTRAOCULAR LENS POWER CALCULATION IN CHALLENGING SITUATIONS 10. Postrefractive Surgery Intraocular Lens Power Calculation 11. Intraocular Lens Power Calculation in Children 12. Intraocular Lens Power Calculation in Corneal Pathologies 13. Intraocular Lens Power Calculation in Posterior Segment Pathology 14. Intraocular Lens Power Calculation in Extremes of Axial Length 15. Intraocular Lens Power of Piggyback IOLs and Secondary IOLs