超长深度扫描OCT测量人工晶状体眼调节下眼轴变化的重复性评价

摘要

背景 调节是指人眼为看清近物改变屈光力的能力,调节过程中眼轴长度(AL)的变化一直是研究难点. 目的 本研究中利用超长深度扫描OCT(UL-OCT)对人工晶状体(IOL)眼调节下AL变化的重复性进行评价,为研究眼轴变化与眼调节的关系提供参考. 方法 采用前瞻性研究设计.纳入2014年10月至2015年1月在温州医科大学附属眼视光医院行白内障摘出联合单焦点IOL植入术的年龄相关性白内障患者12例20眼,年龄56 ～ 84岁,平均(69.9±7.6)岁,用自主研发的UL-OCT经瞳孔对放松状态或调节状态下的全眼图像进行拍摄.UL-OCT光源中心波长为840 nm,轴向分辨率为7μm,扫描深度为37.71 mm(空气中),采用自主开发设计软件对所得图像进行分析计算,获得中央角膜厚度(CCT)、前房深度(ACD)、IOL厚度、玻璃体深度(VL)及AL,放松状态下和调节状态下均测量2次,计算2次测量的重复性系数(COR)百分比;采用Bland-Altman一致性检验分析重复测量结果的一致性. 结果 调节放松状态下2次重复测量的AL平均值为(23.241±0.882) mm,重复测量的差值为(-0.008±0.026)mm,2次重复测量比较差异无统计学意义(P=0.283);调节状态下2次重复测量的AL平均值为(23.274±0.889) mm,重复测量的差值为(0.002±0.028) mm,2次重复测量比较差异无统计学意义(P=0.724).调节过程中,AL较放松状态下增加约(32±35) μm.COR数值在放松状态和调节状态分别为0.222和0.240,COR％分别为1.03％和0.96％.一致性检验显示,各参数2次重复测量95％ LoA范围较窄,一致性良好. 结论 UL-OCT重复测量CCT、ACD、IOL厚度、VL及AL的可重复性良好,是观察IOL眼AL随调节变化的有用工具.%Background Accommodation is the ability of human eye to change refractive power to see near target clearly.Objective This study was to investigate the repeatability of imaging axial length (AL) under the pilocarpine-induced accommodation in pseudophakic patients using ultra-long scan depth OCT (UL-OCT).Methods A prospective study was carried out.Twenty eyes of 12 subjects who received monofocal intraocular lens (IOL)implantation were incuded in the Eye Hospital of Wenzhou Medical University from October 2014 to January 2015.The patients aged from 56 to 84 years (mean:[69.9±7.6] years).A self-built UL-OCT,with center wave length 840 nm and the axial resolution 7 μm and scan depth 37.71 mm (in the air), was employed to image the whole eye picture through the pupil in relax and accommodative states.The images were analyzed by a self-developed software to acquire the central corneal thickness (CCT), anterior chamber depth (ACD), IOL thickness, vitreous length (VL)and AL.The parameters were repeatly measured for two times, and the percentage of coefficient of repeatability (COR) was calculated.The consistency between the two measurements was evaluated by Bland-Altman agreement test.Results The average AL value was (23.241 ±0.882) mm,and the difference of repeated measurement values was (-0.008 ± 0.026)mm under the relax state, without statistical difference between two measurements (P=0.283).The average AL value was (23.274±0.889)mm, and the difference of repeated measurement values was (0.002±0.028)mm under the accommodation state, without statistical difference between two measurement values (P =0.724).AL increased by (32±35) μm after the accommodation.The CORs were 0.222 and 0.240, and the COR percentages were 1.03％ and 0.96％ under the relax condition and accommodation condition,respectively.The Bland-Altman plots showed that the mean differences between the two repeated measurement values were close to zero in the relax condition and accommodation condition.Conclusions UL-OCT is a potential tool of obtaining AL of whole eye in pseudophakic eyes.