通过傅里叶域光学相干断层扫描获得的角膜曲率指数。
Keratometric index obtained by Fourier-domain optical coherence tomography.
作者信息
Hua Yanjun, Stojanovic Aleksander, Utheim Tor Paaske, Chen Xiangjun, Ræder Sten, Huang Jinhai, Wang Qinmei
机构信息
Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China.
Department of Ophthalmology, University Hospital of North Norway, Tromsø, Norway; SynsLaser Kirurgi AS, Tromsø/Oslo, Norway.
出版信息
PLoS One. 2015 Apr 17;10(4):e0122441. doi: 10.1371/journal.pone.0122441. eCollection 2015.
PURPOSE
To determine the keratometric indices calculated based on parameters obtained by Fourier-domain optical coherence tomography (FD-OCT).
METHODS
The ratio of anterior corneal curvature to posterior corneal curvature (Ratio) and keratometric index (N) were calculated within central 3 mm zone with the RTVue FD-OCT (RTVue, Optovue, Inc.) in 186 untreated eyes, 60 post-LASIK/PRK eyes, and 39 keratoconus eyes. The total corneal powers were calculated using different keratometric indices: Kcal based on the mean calculated keratometric index, K1.3315 calculated by the keratometric index of 1.3315, and K1.3375 calculated by the keratometric index of 1.3375. In addition, the total corneal powers based on Gaussian optics formula (Kactual) were calculated.
RESULTS
The means for Ratio in untreated controls, post-LASIK/PRK group and keratoconus group were 1.176 ± 0.022 (95% confidence interval (CI), 1.172-1.179), 1.314 ± 0.042 (95%CI, 1.303-1.325) and 1.229 ± 0.118 (95%CI, 1.191-1.267), respectively. And the mean calculated keratometric index in untreated controls, post-LASIK/PRK group and keratoconus group were 1.3299 ± 0.00085 (95%CI, 1.3272-1.3308), 1.3242 ± 0.00171 (95%CI, 1.3238-1.3246) and 1.3277 ± 0.0046 (95%CI, 1.3263-1.3292), respectively. All the parameters were normally distributed. The differences between Kcal and Kactual, K1.3315 and Kactual, and K1.3375 and Kactual were 0.00 ± 0.11 D, 0.21 ± 0.11 D and 0.99 ± 0.12 D, respectively, in untreated controls; -0.01 ± 0.20 D, 0.85 ± 0.18 D and 1.56 ± 0.16 D, respectively, in post-LASIK/PRK group; and 0.03 ± 0.67 D, 0.56 ± 0.70 D and 1.40 ± 0.76 D, respectively, in keratoconus group.
CONCLUSION
The calculated keratometric index is negatively related to the ratio of anterior corneal curvature to posterior corneal curvature in untreated, post-LASIK/PRK, and keratoconus eyes, respectively. Using the calculated keratometric index may improve the prediction accuracies of total corneal powers in untreated controls, but not in post-LASIK/PRK and keratoconus eyes.
目的
确定基于傅里叶域光学相干断层扫描（FD - OCT）获得的参数计算出的角膜曲率指数。
方法
使用RTVue FD - OCT（RTVue，Optovue公司）在186只未治疗的眼睛、60只准分子激光原位角膜磨镶术/准分子激光角膜切削术（LASIK/PRK）术后眼睛和39只圆锥角膜眼睛的中央3mm区域内计算前角膜曲率与后角膜曲率之比（Ratio）和角膜曲率指数（N）。使用不同的角膜曲率指数计算总角膜屈光力：基于平均计算出的角膜曲率指数的Kcal、由角膜曲率指数1.3315计算出的K1.3315以及由角膜曲率指数1.3375计算出的K1.3375。此外，基于高斯光学公式计算总角膜屈光力（Kactual）。
结果
未治疗对照组、LASIK/PRK术后组和圆锥角膜组的Ratio平均值分别为1.176±0.022（95%置信区间（CI），1.172 - 1.179）、1.314±0.
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