Olsen H, Ehlers N, Hjortdal J O
Department of Ophthalmology, Arhus University Hospital, Denmark.
Acta Ophthalmol Scand. 1997 Aug;75(4):398-400. doi: 10.1111/j.1600-0420.1997.tb00397.x.
To investigate whether the immediate change in corneal power during radial keratotomy correlates with the long-term postoperative change in subjective refraction, and thereby being predictive for refractive outcome.
Manual keratometry was performed on 45 consecutively operated eyes of 45 young persons with myopia of 5 dioptres and less and immediately after radial keratotomy. Automated keratometry and subjective spherical equivalent refraction were investigated during a follow-up period of 6 months and correlated to the intraoperative keratometric measurements.
On average, the majority of the change in corneal curvature after radial keratotomy took place within 1 min. There was no correlation between the intraoperative curvature change and the changes in curvature measured up to 6 months after surgery. There was a weak significant positive correlation between intraoperative curvature change and the change in subjective refraction at 6 months after surgery (R = 0.48, p < 0.01). The prediction error in estimating subjective refractive changes from intraoperative keratometry changes was, however, similar in patients who had bilateral radial keratotomy. Inclusion of such fellow-eye information together with the age of the patient in a multiple linear regression analysis increased the correlation coefficient from 0.48 to 0.75.
The change in central corneal curvature takes place within minutes after corneal incision. As a single parameter, intraoperative keratometry cannot be used for titrating surgery. Information from the results of first eye radial keratotomy surgery with intraoperative keratometry is, however, predictive for radial keratotomy in the second eye. These findings suggest that a large source to refractive variability after radial keratotomy is related to individual patient factors, such as corneal biomechanics and wound healing.
研究放射状角膜切开术中角膜屈光度的即时变化与术后主观验光的长期变化是否相关，从而预测屈光结果。
对45例近视度数为5屈光度及以下的年轻人的45只连续手术眼进行手动角膜曲率计测量，在放射状角膜切开术后立即测量。在6个月的随访期内进行自动角膜曲率计测量和主观等效球镜验光，并与术中角膜曲率测量结果相关联。
平均而言，放射状角膜切开术后角膜曲率的大部分变化在1分钟内发生。术中曲率变化与术后6个月内测量的曲率变化之间无相关性。术中曲率变化与术后6个月主观验光变化之间存在微弱的显著正相关（R = 0.48，p < 0.01）。然而，在进行双侧放射状角膜切开术的患者中，根据术中角膜曲率测量变化估计主观屈光变化的预测误差相似。在多元线性回归分析中纳入同眼信息以及患者年龄后，相关系数从0.48提高到0.75。
角膜切开术后几分钟内中央角膜曲率就会发生变化。作为单一参数，术中角膜曲率计测量不能用于调整手术。然而，第一只眼放射状角膜切开术术中角膜曲率计测量结果的信息对第二只眼的放射状角膜切开术具有预测性。这些发现表明，放射状角膜切开术后屈光变异性的一个重要来源与个体患者因素有关，如角膜生物力学和伤口愈合。
