Intraocular lens power calculation by ray-tracing after myopic excimer laser surgery

Giacomo Savini, Andrea Bedei, Piero Barboni, Pietro Ducoli, Kenneth J. Hoffer

Research output: Contribution to journalArticlepeer-review


Purpose To investigate the refractive outcomes of intraocular lens (IOL) power calculation by ray-tracing after myopic excimer laser surgery. Design Prospective, interventional case series. Methods setting: Multicenter study. participants: Twenty-one eyes of 21 patients undergoing phacoemulsification and IOL implantation after myopic laser in situ keratomileusis or photorefractive keratectomy were enrolled. intervention: IOL power calculation was performed using internal software of a Scheimpflug camera combined with a Placido disc corneal topographer (Sirius; CSO). Exact ray-tracing was carried out after the axial length (measured either by immersion ultrasound biometry or partial coherence interferometry), target refraction, and pupil size had been entered. main outcome measures: Median absolute error, mean absolute error, and mean arithmetic error in refraction prediction, that is, the difference between the expected refraction (as calculated by the software) and the actual refraction 1 month after surgery. Results The mean postoperative refraction was -0.43 ± 1.08 diopters (D), with a range between -1.28 and 0.85 D. The mean arithmetic error was -0.13 ± 0.49 D. The median and mean absolute errors were +0.25 D and 0.36 D, respectively. Also, 71.4% of the eyes were within ± 0.50 D of the predicted refraction, 85.7% were within ± 1.00 D, and 100% within ± 1.50 D. Conclusions Ray-tracing can calculate IOL power accurately in eyes with prior myopic laser in situ keratomileusis and photorefractive keratectomy, with no need for preoperative data.

Original languageEnglish
JournalAmerican Journal of Ophthalmology
Issue number1
Publication statusPublished - Jan 2014

ASJC Scopus subject areas

  • Ophthalmology


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