title: Scheimpflug camera combined with placido-disk corneal topography and optical biometry for intraocular lens power calculation.
abstract: The purpose of this study was to compare the keratometry (K) values obtained by the Scheimpflug camera combined with placido-disk corneal topography (Sirius) and optical biometry (Lenstar) for intraocular lens (IOL) power calculation before the cataract surgery, and to evaluate the accuracy of postoperative refraction. 50 eyes of 40 patients were scheduled to have phacoemulsification with the implantation of a posterior chamber intraocular lens. The IOL power was calculated using the SRK/T formula with Lenstar K and K readings from Sirius. Simulated K (SimK), K at 3-, 5-, and 7-mm zones from Sirius were compared with Lenstar K readings. The accuracy of these parameters was determined by calculating the mean absolute error (MAE). The mean Lenstar K value was 44.05 diopters (D) ±1.93 (SD) and SimK, K at 3-, 5-, and 7-mm zones were 43.85 ± 1.91, 43.88 ± 1.9, 43.84 ± 1.9, 43.66 ± 1.85 D, respectively. There was no statistically significant difference between the K readings (P = 0.901). When Lenstar was used for the corneal power measurements, MAE was 0.42 ± 0.33 D, but when simK of Sirius was used, it was 0.37 ± 0.32 D (the lowest MAE (0.36 ± 0.32 D) was achieved as a result of 5 mm K measurement), but it was not statistically significant (P = 0.892). Of all the K readings of Sirius and Lenstar, Sirius 5-mm zone K readings were the best in predicting a more precise IOL power. The corneal power measurements with the Scheimpflug camera combined with placido-disk corneal topography can be safely used for IOL power calculation.
authors: Eye Clinic, Bagcilar Training and Research Hospital, Istanbul, Turkey. ahmetk1@yahoo.com.
authors: Ahmet
authors: http://orcid.org/0000-0001-7498-3693
authors: A
authors: Kirgiz
authors: Eye Clinic, Bagcilar Training and Research Hospital, Istanbul, Turkey.
authors: Kurşat
authors: K
authors: Atalay
authors: Eye Clinic, Bagcilar Training and Research Hospital, Istanbul, Turkey.
authors: Havva
authors: H
authors: Kaldirim
authors: Eye Clinic, Bagcilar Training and Research Hospital, Istanbul, Turkey.
authors: Kubra Serefoglu
authors: KS
authors: Cabuk
authors: Department of Ophthalmology, Bulent Ecevit University School of Medicine, Zonguldak, Turkey.
authors: Mehmet Orcun
authors: MO
authors: Akdemir
authors: Beyoglu Eye Training and Research Hospital, Istanbul, Turkey.
authors: Muhittin
authors: M
authors: Taskapili
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001699:Biometry / Q000379:methods*; D003315:Cornea / Q000000981:diagnostic imaging*; D019781:Corneal Topography / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D007910:Lenses, Intraocular; D008875:Middle Aged; D055095:Optics and Photonics; D018918:Phacoemulsification; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology*; D015203:Reproducibility of Results
keywords: Intraocular lens power calculation; Optical biometry; Placido-disk corneal topography; Scheimpflug camera