Purchase this article with an account.
Shinichiro Nakano, Masaharu Iida, Takahiro Hiraoka, Tetsuro Oshika; Measurements of corneal astigmatism axis with anterior segment swept source optical coherent tomography versus auto refractokearatometer. Invest. Ophthalmol. Vis. Sci. 2016;57(12):1904.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Precise preoperative measurement of corneal astigmatism is of crucial importance to achieve good surgical results with toric intraocular lens (T-IOL) implantation. In this study, the axis of corneal astigmatism was assessed by two methods; anterior segment swept source optical coherent tomography (AS-OCT) and auto refractokearatometer before cataract surgery. The results of these two methods were compared and the factors which influence the difference were examined.
Two hundred twenty-six eyes of 155 patients (69 male 86 female, 74.8 ± 5.8 [mean ± SD] years) undergoing cataract surgery and IOL implantation were included. Preoperatively, corneal astigmatism axis was measured by two methods; auto refractokeratometry (KR8100A, TOPCON) and AS-OCT (CASIA, TOMEY). The difference between two methods was analyzed in relation to various parameters including preoperative factors (age, corrected distance visual acuity (CDVA), objective astigmatism) and postoperative factors (3-month postoperative uncorrected visual acuity (UCVA) and 3-month postoperative objective astigmatism). In addition, the influence of corneal astigmatism type (against-the-rule; ATR, with-the-rule; WTR, and oblique) was also examined.
Difference in corneal astigmatism axis measured with the two methods was within 10 degrees in 107 cases (47%), from 10 to 19 degrees in 25 cases (11%), from 20 to 29 degrees in 31 cases (14%), and 30 degrees or more in 34 cases (15%). The difference showed no correlation with age, preoperative CDVA, 3-month postoperative UCVA, and 3-month postoperative objective astigmatism, but exhibited a significant correlation with preoperative corneal astigmatism power (r = 0.341, p＜0.001: Pearson’s correlation coefficient). When compared among preoperative corneal astigmatism types, eyes with ATR astigmatism showed significantly lower disparity in corneal astigmatism axis between the two methods than eyes with WTR and oblique astigmatism (p＜0.001, p＜0.001: Mann-Whitney U test).
There was considerable difference in the measurement results of corneal astigmatism axis between AS-OCT and refractokeratometer, and the difference was larger in eyes with greater preoperative astigmatism as well as WTR/oblique astigmatism.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
This PDF is available to Subscribers Only