Determining total corneal power after small‐incision lenticule extraction in myopic eyes. Issue 11 (November 2017)

• Record Type: Journal Article
• Authors: Wei, Pinghui; Wang, Yan; Chan, Tommy C.Y.; Ng, Alex L.K.; Cheng, George P.M.; Jhanji, Vishal
• Is Part Of: Journal of cataract and refractive surgery. Volume 43:Issue 11(2017)
• Publication Date: 2017-11
• Subjects: 617.7
• DOI: 10.1016/j.jcrs.2017.08.015
• Languages: English
• ISSNs: 0886-3350

Abstract

Abstract : Purpose : To evaluate the methods to correct corneal power after myopic small‐incision lenticule extraction (SMILE) and to estimate the preoperative corneal power based on postoperative values. Setting : Tianjin Eye Hospital, Tianjin, China. Design : Retrospective case series. Methods : Equivalent keratometry (K) and mean K readings were obtained with the Pentacam HR. The clinical history method was used to calculate the theoretical postoperative K, which was then compared with equivalent K readings. In addition, the anterior–posterior (A–P) method was used to estimate the preoperative mean K. The agreement between computed and actual values was estimated using the Bland‐Altman method. Results : A significant correlation was observed between the theoretical postoperative K (38.52 diopters [D] ± 1.57 [SD]) and mean K after surgery (39.44 ± 1.43 D) ( R 2 = 0.9317, P < .001). The mean equivalent K readings at 4.0 mm, 4.5 mm, and 5.0 mm were not significantly different from the theoretical postoperative K values ( P = .620, P = .514, and P = .622, respectively). Bland‐Altman plots showed a high level of agreement when comparing the theoretical postoperative K with the clinical history K (−0.94 to +0.9 D, −0.83 to +0.88 D, and −0.84 to +0.88 D, respectively). In addition, the estimated preoperative mean K (43.28 ± 1.31 D) derived by the A–P method was comparable to the measured mean K ( P = .111). Conclusions : Equivalent K readings provided a relatively good estimation of corneal power in eyes after small‐incision lenticule extraction. The A–P method might be an option to predict preoperative corneal power.