Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Room D513, O Block, Victoria Park Road, Kelvin Grove 4059, Brisbane, Queensland, Australia.
Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Room D513, O Block, Victoria Park Road, Kelvin Grove 4059, Brisbane, Queensland, Australia.
Cont Lens Anterior Eye. 2018 Apr;41(2):162-168. doi: 10.1016/j.clae.2017.07.002. Epub 2017 Jul 14.
To examine the time course of the reduction in central corneal clearance and horizontal and vertical lens translation (decentration) during miniscleral contact lens wear and the theoretical influence upon the optics of the post-lens tear layer.
Repeated high-resolution OCT images were captured over an 8h period of miniscleral contact lens wear (using a rotationally symmetric 16.5mm diameter lens) in 15 young, healthy participants with normal corneae. Central corneal clearance and lens decentration were derived from OCT images using semi-automated image processing techniques.
Central corneal clearance decreased exponentially over time, reducing by 76±8μm over 8h. Fifty percent of this reduction occurred within 45min of lens wear and seventy-five percent within 2h, with thinning of the post-lens tear layer plateauing 4h after lens insertion. Lens translation exhibited a similar pattern of change (0.18±0.04mm temporal and 0.20±0.09mm inferior decentration) stabilising 1.5-2h after insertion. The change in the lens fit over time resulted in a small reduction in the power of the post-lens tear layer (-0.12±0.01 D) and induced a prismatic effect of 0.01±0.16 Δ base out and 0.50±0.19 Δ base down relative to the pupil centre.
For the miniscleral contact lens studied, horizontal and vertical lens decentration followed an exponential decay over 8h that plateaued approximately 2h after lens insertion, while central post-lens tear layer thinning plateaued after 4h of lens wear.
研究巩膜迷你接触镜佩戴过程中中央角膜间隙和水平及垂直方向的晶状体平移（离焦）减少的时间过程，以及对透镜后泪液层光学性质的理论影响。
在 15 名健康年轻的正常角膜受试者中，使用旋转对称的 16.5mm 直径镜片，在 8 小时的巩膜迷你接触镜佩戴过程中，重复拍摄高分辨率 OCT 图像。使用半自动图像处理技术，从 OCT 图像中得出中央角膜间隙和晶状体离焦。
中央角膜间隙随时间呈指数减少，8 小时内减少 76±8μm。50%的减少发生在佩戴镜片后的 45min 内，75%发生在 2h 内，透镜后泪液层的变薄在插入透镜 4h 后趋于稳定。晶状体平移也呈现出类似的变化模式（颞侧 0.18±0.04mm，下侧 0.20±0.09mm），在插入后 1.5-2h 稳定下来。随着时间的推移，透镜的适配变化导致透镜后泪液层的屈光力略有降低（-0.12±0.01 D），并产生 0.01±0.16 Δ基底向外和 0.50±0.19 Δ基底向下的棱镜效应，相对于瞳孔中心。
对于研究中的巩膜迷你接触镜，水平和垂直方向的晶状体离焦在 8 小时内呈指数衰减，在佩戴镜片后约 2 小时达到稳定，而中央透镜后泪液层的变薄在佩戴 4 小时后达到稳定。
