Huynh Son C, Mai Tung Q, Kifley Annette, Wang Jie Jin, Rose Kathryn A, Mitchell Paul
Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, University of Sydney, Sydney, Australia.
Cornea. 2006 May;25(4):383-7. doi: 10.1097/01.ico.0000214203.84081.ec.
To evaluate the repeatability and comparability of keratometry measured by both the IOLMaster and RK-F1 AutoRef-Keratometer in children.
Keratometry results from a sample (n = 447) of 6-year-old children who were examined in the Sydney Myopia Study were analyzed. Corneal power was analyzed along the flattest and steepest meridians to determine if there were any systematic differences between repeat measurements or between the two instruments. The 95% limits of repeatability (LR) and 95% limits of agreement (LA) (mean difference +/- 1.96 x standard deviation of differences) were calculated.
There were no systematic differences in repeat measurements for each instrument. For the IOLMaster, mean difference of the flattest corneal meridian was -0.01 (D) (P = 0.3, 95% LR, -0.22, 0.21 D) and of the steepest corneal meridian, 0.01 D (P = 0.3, 95% LR, -0.35, 0.38 D). For the RK-F1, mean difference of the flattest corneal meridian was -0.02 D (P = 0.3, 95% LR, -0.25, 0.21 D); and of the steepest corneal meridian, 0.00 D (P = 0.9, 95% LR, -0.39, 0.39 D). Systematic differences, however, were found between the two instruments. The IOLMaster gave significantly (P < 0.0001) steeper readings than the RK-F1 for both the flattest corneal meridian, 0.29 D (95% LA, -0.08, 0.66 D), and the steepest corneal meridian, 0.18 D (95% LA, -0.29, 0.65 D).
Keratometry was highly repeatable for both the IOLMaster and RK-F1 instruments when used in young children. These instruments would be suitable for use in monitoring changes of corneal curvature over time. Small significant systematic differences in keratometry between the two instruments were also found.
评估IOLMaster和RK-F1自动验光角膜曲率计在儿童中测量角膜曲率的可重复性和可比性。
分析悉尼近视研究中6岁儿童样本（n = 447）的角膜曲率测量结果。沿着最平及最陡子午线分析角膜屈光力，以确定重复测量之间或两种仪器之间是否存在任何系统差异。计算95%可重复性极限（LR）和95%一致性极限（LA）（平均差异±1.96×差异标准差）。
每种仪器的重复测量均无系统差异。对于IOLMaster，最平角膜子午线的平均差异为-0.01（D）（P = 0.3，95% LR，-0.22，0.21 D），最陡角膜子午线的平均差异为0.01 D（P = 0.3，95% LR，-0.35，0.38 D）。对于RK-F1，最平角膜子午线的平均差异为-0.02 D（P = 0.3，95% LR，-0.25，0.21 D）；最陡角膜子午线的平均差异为0.00 D（P = 0.9，95% LR，-0.39，0.39 D）。然而，发现两种仪器之间存在系统差异。对于最平角膜子午线，IOLMaster的读数比RK-F1显著更陡（P < 0.0001），为0.29 D（95% LA，-0.08，0.66 D）；对于最陡角膜子午线，为0.18 D（95% LA，-0.29，0.65 D）。
IOLMaster和RK-F1仪器用于幼儿时角膜曲率测量具有高度可重复性。这些仪器适用于监测角膜曲率随时间的变化。还发现两种仪器在角膜曲率测量上存在小的显著系统差异。
