METHODS: A dynamic Purkinje-meter with a movable fixation target was assembled. A coaxial circular pattern formed by infrared LEDs was projected onto the eye and evoked Purkinje images (1st, 3rd, 4th = P1, P3, P4). The measurement was performed on 29 eyes with an implanted toric IOL (intraocular lens), under mydriatic conditions, with reference to the visual axis. The IOL tilt was calculated from the position of a fixation target at the moment of P3 and P4 superposition. The IOL decentration was determined based on the relative position of P1 during on-axis fixation and of P3 and P4 superposition during off-axis fixation. A custom-developed software was used for distance measurements. Using CASIA2, the IOL position was fully calculated by the device.
RESULTS: The mean absolute difference between CASIA2 and Purkinje-meter values was 0.6° ± 0.4° for the tilt magnitude and 10° ± 10° for the tilt direction, and 0.11 mm ± 0.08 mm for the decentration magnitude and 16° ± 14° for the decentration direction. There was no statistically significant difference between the values determined by the two methods for the tilt and decentration direction. The differences were statistically significant for the tilt and decentration magnitude.
CONCLUSIONS: The values of IOL tilt and decentration direction are similar for both devices. The values of IOL tilt and decentration magnitude measured by Purkinje-meter are higher than those from CASIA2, but overall, they correspond to the values presented in other published studies.
方法:组装了具有可移动固定目标的动态Purkinje-meter。由红外LED形成的同轴圆形图案被投射到眼睛上,并引起浦肯野图像(第1,3rd,第四=P1、P3、P4)。对29只眼植入复曲面IOL(人工晶状体)进行测量,在散瞳条件下,参考视觉轴。根据P3和P4叠加时刻的固定目标的位置计算IOL倾斜。IOL偏心是根据轴上固定期间P1的相对位置以及离轴固定期间P3和P4叠加的相对位置确定的。使用定制开发的软件进行距离测量。使用CASIA2,通过设备完全计算IOL位置。
结果:CASIA2和Purkinje-meter值之间的平均绝对差对于倾斜幅度为0.6°±0.4°,对于倾斜方向为10°±10°,偏心幅度为0.11mm±0.08mm,偏心方向为16°±14°。对于倾斜和偏心方向,通过两种方法确定的值之间没有统计学上的显着差异。倾斜和偏心幅度的差异具有统计学意义。
结论:两种设备的IOL倾斜和偏心方向的值相似。Purkinje仪测量的IOL倾斜和偏心幅度值高于CASIA2,但总体而言,它们对应于其他已发表研究中提出的值。