Error sources and correction of intraocular lens power calculation after corneal refractive surgery

As the increasing popularity of corneal refractive surgery and the aging of the society population,it presents a major challenge in accurate calculation of intraocular lens (IOL) power in cataract patients with prior refractive surgery.To cope with this situation,great efforts have been made to reveal the sources of calculation error and available corrective process.Essentially,the instrument error,the keratometer index error and the IOL formula error are considered to be the main three sources,whereas other biometric measurements (e.g.axial length) contribute slightly.Numerous established algorithms aim to reduce I0L prediction error mainly through postoperative corneal power correction or direct adjustment of calculated IOL power.However,it presents a confusing of the variety of procedures and formulas for the controversy of optimal choice still going on,so it is important to make comprehensive consideration of reliable historic material,physician's experience,and patient' s expectation when faced with this issues clinically. Key words: intraocular lens;  corneal refractive surgery