Author/Authors :
Baradaran‑Rafii, Alireza Shahid Beheshti University of Medical Sciences, Tehran , Fekri, Sahba Shahid Beheshti University of Medical Sciences, Tehran , Rezaie, Mohammad Shahid Beheshti University of Medical Sciences, Tehran , Salehi‑Rad, Shahram Shahid Beheshti University of Medical Sciences, Tehran , Moradi, Ali Shahid Beheshti University of Medical Sciences, Tehran , Motevasseli, Tahmineh Shahid Beheshti University of Medical Sciences, Tehran , Kalantarion, Masumeh Department of Medical Education - School of Medical Education - Shahid Beheshti University of Medical Sciences, Tehran
Abstract :
Purpose: To compare the corneal power measurements obtained using different topographic instruments
after myopic photorefractive keratectomy (PRK).
Methods: Patients with myopia who were candidates for corneal refractive surgery were sequentially
included. Pre‑PRK and six months post‑PRK corneal powers were measured using Javal manual keratometer,
Orbscan II, Galilei, Tomey TMS4, and EyeSys 2000 topographers. Measured values were compared with
those obtained using the clinical history method (CHM).
Results: This study included 66 eyes of 33 patients. The lowest keratometric measurements were obtained
using the Galilei topographer (42.98 ± 1.69 diopters, D) and the highest measurements were obtained using
the Javal manual keratometer (43.96 ± 1.54 D) preoperatively. The same order was observed postoperatively.
Effective refractive power (EffRP) measured using EyeSys was most similar to the values obtained using
CHM (ICC, intraclass correlation coefficient = 0.951), followed by the total corneal power measured using
the Galilei system (ICC = 0.943). The values obtained using the adjusted EffRP formula (EffRP – 0.015*Δ
Refraction – 0.05) were more consistent with the values obtained using CHM (ICC = 0.954) compared
to those obtained with the adjusted average central corneal power formula measured using the Tomey
system (ICC = 0.919).
Keywords :
PRK , Keratectomy , Topographic , Calculating Corneal
