Fouda Sameh M, Al-Nashar Haitham Y, Ibrahim Basem M, Bor'i Ashraf
Department of Ophthalmology, Faculty of Medicine, Zagazig University, Zagazig, 44519, Egypt.
Int Ophthalmol. 2016 Feb;36(1):85-90. doi: 10.1007/s10792-015-0075-5. Epub 2015 May 19.
Determining an accurate central corneal power (K) measurement is crucial for calculating the intraocular lens power in patients who are undergoing cataract extraction. The ideal method for measuring K is to use a device that works independently of the refractive surgery information. The Scheimpflug camera system offers a promising means of measuring the true corneal power after keratorefractive surgery. In this study, we investigated the accuracy of this system in measuring central corneal power after photorefractive corneal surgery by comparing it to the theoretically derived central corneal power by history method. A total of 120 eyes of 65 (35 females and 30 males) patients were included in this study. The mean change of refraction at the spectacle plane was 3.75 D, whereas the mean change of refraction at the corneal plane was 3.37 D. Using the Sirius dual-scanning corneal tomography, the mean change in corneal power was 3.96 D. No significant differences were detected between the mean post-operative corneal power measured by the Sirius tomographer and the mean change in refraction at the corneal plane calculated clinically (P = 0.076) and the correlation was found to be high (0.913). This study suggests that Sirius dual-scanning corneal tomography offers high predictability when measuring the central 5 mm corneal power in patients who have had myopic corneal photorefractive surgery.
对于接受白内障摘除术的患者，确定准确的中央角膜屈光力（K值）测量结果对于计算人工晶状体屈光力至关重要。测量K值的理想方法是使用一种独立于屈光手术信息的设备。Scheimpflug相机系统为测量角膜屈光手术后的真实角膜屈光力提供了一种有前景的手段。在本研究中，我们通过将其与历史方法理论推导的中央角膜屈光力进行比较，研究了该系统在测量光折射角膜手术后中央角膜屈光力方面的准确性。本研究共纳入65例患者（35例女性和30例男性）的120只眼。眼镜平面的平均屈光变化为3.75 D，而角膜平面的平均屈光变化为3.37 D。使用Sirius双扫描角膜断层扫描，角膜屈光力的平均变化为3.96 D。Sirius断层扫描仪测量的术后平均角膜屈光力与临床计算的角膜平面屈光平均变化之间未检测到显著差异（P = 0.076），且相关性较高（0.913）。本研究表明，Sirius双扫描角膜断层扫描在测量近视性角膜光折射手术后患者中央5 mm角膜屈光力时具有较高的可预测性。
