Schmid G F, Petrig B L, Riva C E, Logean E, Wälti R
Institut des Recherches en Ophtalmologie, Sion, Switzerland.
Int Ophthalmol. 2001;23(4-6):317-20. doi: 10.1023/a:1014486126869.
The precise and rapid measurement of eye length and eye shape is essential for investigating eye growth regulation and myopia. For this purpose, we developed an optical low coherence reflectometer (OLCR) and present preliminary measurements.
The OLCR includes a super luminescent diode (wavelength: 845 nm, coherence length: approximately 30 microm) and rotating glass cube to produce longitudinal scans at a velocity of 0.42 m/s and a repetition rate of approximately 13 scans/s. Heterodyne detection of light reflected from the anterior cornea and the posterior retina permits to measure axial eye length and eye shape (off-axis eye length). Each measurement consists of five consecutive scans. Reproducibility and precision were determined in one volunteer by measuring axial eye length five consecutive times, each time repositioning the eye. Eye shapes were determined in right eyes of four volunteers by measuring eye length every 3.3 degrees from 10 degrees nasally to 10 degrees temporally.
Axial eye length measured repeatedly in one volunteer did not differ between or within the measurements (one-factor ANOVA). The average standard deviation was 11 microm. Eye shapes (a) varied substantially among subjects and (b) differed considerably from the corresponding shapes of spherical model eyes with identical axial eye lengths.
The newly developed OLCR permits the precise and rapid measurement of eye length and eye shape. Such measurements, especially in children, may provide important information about mechanisms of eye growth regulation and the development of myopia.
精确快速地测量眼轴长度和眼睛形状对于研究眼球生长调节和近视至关重要。为此，我们开发了一种光学低相干反射仪（OLCR）并展示了初步测量结果。
OLCR包括一个超发光二极管（波长：845纳米，相干长度：约30微米）和旋转玻璃立方体，以0.42米/秒的速度和大约13次扫描/秒的重复率进行纵向扫描。对来自角膜前表面和视网膜后表面反射光的外差检测可测量眼轴长度和眼睛形状（离轴眼轴长度）。每次测量由五次连续扫描组成。通过对一名志愿者连续五次测量眼轴长度，每次重新定位眼睛，来确定可重复性和精度。通过对四名志愿者右眼从鼻侧10度到颞侧10度每隔3.3度测量眼轴长度来确定眼睛形状。
在一名志愿者中重复测量的眼轴长度在各次测量之间或测量内部均无差异（单因素方差分析）。平均标准差为11微米。眼睛形状（a）在受试者之间差异很大，并且（b）与具有相同眼轴长度的球形模型眼的相应形状有很大差异。
新开发的OLCR能够精确快速地测量眼轴长度和眼睛形状。这样的测量，尤其是在儿童中，可能会为眼球生长调节机制和近视发展提供重要信息。
