*Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea; and †Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY.
Cornea. 2014 Mar;33(3):261-5. doi: 10.1097/ICO.0000000000000034.
The study evaluated the ray tracing method [total corneal refractive power (TCRP)] in a Pentacam apparatus (Oculus, Wetzlar, Germany) for postoperative keratometry measurement after myopic photorefractive keratectomy (PRK).
Manifest refraction (MR) and Pentacam analyses were performed preoperatively and at 6 months postoperatively after the PRK (STAR S4 IR CustomVue; Abbott Medical Optics/Visx) in 49 right eyes from 49 patients (age, 25.42 ± 3.51 years). Postoperative corneal power was calculated using the clinical history method (CHM) and compared with postoperatively measured simulated keratometry (simK), true net power (TNP) at 3 mm, and pupil-centered TCRP at the center, 1, 3, and 4 mm (TCRP0, TCRP1, TCRP3, and TCRP4). Vertex-distance-adjusted refractive change (delta-MR) at the corneal plane was also compared with various keratometric changes (delta-K).
Postoperative TCRP0, TCRP1, TCRP3, and TCRP4 showed no significant difference compared with that of the CHM. Postoperative simK was significantly higher than that of the CHM, whereas the TNP was significantly lower compared with that of the CHM. The delta-Ks measured by simK, TNP, and TCRPs were significantly smaller than delta-MR, and delta-TCRP4 showed the least difference [mean ± SD, 0.28 ± 0.55 diopters (D)] with delta-MR. The 95% limit of agreement between delta-MR and delta-TCRP4 was -0.85 to 1.31 D. The difference between delta-TCRP4 and delta-MR was <0.5 D in 55.1% and <1.0 D in 87.8% of the eyes studied.
Although postoperative TCRPs showed no significant difference with CHM, delta-MR was still underestimated after myopic PRK.
本研究评估了 Pentacam 仪器（德国 Oculus 公司）中的光线追踪法（总角膜屈光力[TCRP]）在近视性光折射性角膜切削术（PRK）后角膜曲率计测量中的应用。
49 例（49 只眼）患者在接受 PRK（STAR S4 IR CustomVue；Abbott Medical Optics/Visx）治疗后 6 个月，进行术前和术后的主觉验光（MR）和 Pentacam 分析。术后角膜力采用临床病史法（CHM）计算，并与术后测量的模拟角膜曲率（simK）、3mm 处真实净力（TNP）以及中心、1、3 和 4mm 处瞳孔中心 TCRP（TCRP0、TCRP1、TCRP3 和 TCRP4）进行比较。还比较了角膜平面的顶点距离调整后屈光变化（delta-MR）与各种角膜曲率变化（delta-K）的差异。
与 CHM 相比，术后 TCRP0、TCRP1、TCRP3 和 TCRP4 无显著差异。术后 simK 明显高于 CHM，而 TNP 明显低于 CHM。simK、TNP 和 TCRPs 测量的 delta-Ks 明显小于 delta-MR，而 delta-TCRP4 与 delta-MR 的差异最小[平均±标准差，0.28±0.55 屈光度（D）]。delta-MR 和 delta-TCRP4 之间 95%一致性界限为-0.85 至 1.31 D。研究中 55.1%的眼 delta-TCRP4 与 delta-MR 的差值<0.5 D，87.8%的眼差值<1.0 D。
尽管术后 TCRP 与 CHM 无显著差异，但近视性 PRK 后 delta-MR 仍被低估。
