青少年正视眼与近视眼调节微波动的差异及其与波前像差的关系

Association analysis of accommodative microfluctuations and wavefront aberration in emmetropia and myopia in teenagers

背景 人眼在观察外界的物体时,调节反应呈现出持续波动状态.青少年阶段是近视发生和发展的关键时期,通过研究这一人群的调节微波动的特点及眼球像差的分布情况,将有助于我们理解近视的发生和进展.目的 研究持续阅读情况下青少年正视眼与近视眼调节微波动的差异及其与眼球像差之间的关系,探讨产生微波动差异的原因及其对近视发生和发展的影响.方法 前瞻性对照研究.纳入2010-2011年在温州医科大学附属眼视光医院进行定期眼科常规检查的12～15岁青少年54人,包括正视者19人和近视者35例,受试者均进行扩瞳后客观和主觉验光,然后根据受试者近2年来近视屈光度的变化情况将近视眼分为初发性近视组18例和进展性近视组17例.受试者分别在25、33和50 cm距离处阅读计算机显示屏上的文字,使用WAM-5500红外验光仪测量受试者阅读过程中的调节反应和调节微波动,每个注视距离检测5 min.将测得的调节反应值经频谱傅里叶分析后将微波动能量按频率划分为低频段组分（LFC） （0 ～0.6 Hz）、中频段组分（MFC）（0.6～0.9 Hz）和高频段组分（HFC）（1.0～1.4 Hz）进行计算和分析.采用i-Trace波前像差仪测量受试者全眼像差,用Humphrey角膜地形图仪采集和计算角膜像差,比较正视眼组、初发性近视组和进展性近视组受试眼调节反应、调节微波动和波前像差的差异,对受试者调节指标与波前像差间的关系进行分析.结果 在25 cm和33 cm的阅读距离下,正视眼组调节反应值分别为（2.78±0.35）D和（2.19±0.27）D,明显高于进展性近视组的（2.44±0.33）D和（1.89±0.35）D,差异均有统计学意义（P=0.002、0.003）.受试者的LFC、MFC及HFC随阅读距离的缩短而增加,差异均有统计学意义（F阅读距离=8.480、14.270、21.400,均P＜0.01）,但仅LFC值在3个组间总体差异有统计学意义（F分组=4.115,P＜0.05）,其中进展性近视眼组LFC能量高于正视眼组,差异均有统计学意义（25 cm：P=0.044;33 cm：P=0.038;50 cm：P=0.032）,3个组间MFC以及HFC值的差异均无统计学意义（F分组=0.859、0.682,均P＞0.05）.在25 cm和33 cm阅读距离下,LFC值与角膜彗差、眼内彗差、全眼总高阶像差和眼内总高阶像差间均呈正相关（均P＜0.05）,而MFC和HFC与像差间均无明显相关性.结论 青少年正视眼的调节反应强于进展性近视眼,而正视眼和初发性近视眼调节微波动能量小于进展性近视眼.近距离阅读下,调节微波动中仅LFC能量与人眼的高阶像差相关.

Background When focusing on a target,the accommodative system exhibits small variations in power within a range,termed microfluctuations.Exploring the correlation between the characters of microfluctuations and the aberrations of the eyes through a critical period-teenager can deepen the understanding of the onset and development of myopia.Objective This study was to investigate the correlation between accommodative microfluctuations and wavefront aberrations of human eyes,and to explore the role of accommodative microfiuctuations in the development of myopia.Methods A cross-sectional study was designed and performed.Fifty-four teenagers aged from 12 to 15 years were enrolled in this study in Eye Hospital,Wenzhou Medical University from 2010 to 2011,including 19 emmetropic subjects,18 incipient myopic subjects and 17 progressive myopic subjects,who were chosen based on the refractive changes for the last two years.The accommodative response and microfluctuations were measured by WAM-5500 infrared autorefractor with RSVP at 25,33 and 50 cm respectively,each RSVP distance was tested for 5 minutes.The accommodative values were divided into low frequency component （LFC） （0-0.6 Hz）,middle frequency component（MFC） （0.6-0.9 Hz） and high frequency component （HFC） （1.0-1.4 Hz） after Fourier spectrum analysis.The wavefront aberrations of the whole eye and corneal were recorded by i-Trace aberrometer and Humphrey corneal topography.The differences of accommodative response,microfluctuations and aberrations were evaluated and compared among the emmetropic group,incipient myopic group and progressive myopic group.The correlations of accommodation and aberrations were analyzed.This study followed Declaration of Helsinki,and informed consent was obtained from each subject.Results Under the 25 cm and 33 cm reading distance,the accommodative response values were （2.78 ± 0.35） D and （2.19 ± 0.27） D in the emmetropic group,which were significantly higher than （2.44±0.33） D and （1.89±0.35）D in the progressive myopic group （P=0.002,0.003）.LFC,MFC and HFC were remarkably increased as the reading distance decreased （Fdistance =8.480,14.270,21.400;all at P 〈0.01）.A significant difference was seen in LFC among different reading distances （Fgroup =4.115,P〈0.05）,and the LFCs in the progressive myopic group were considerably higher than those in the emmetropic group in the 25,33 and 50 cm reading distances （P=0.044,0.038,0.032）.No significant differences were found in MFC and HFC among the three groups （Fgroup =0.859,0.682;both at P〉0.05）.Under the 25 cm and 33 cm reading distances,significant positive correlations were found between LFC and corneal coma,intraocular coma,whole ocular aberrations or intraocular higher order aberrations （all at P〈0.05）,however,no significant correlations were seen between MFC or HFC and wavefront aberrations （all at P〉0.05）.Conclusions In teenagers,the accommodative response of emmetropia is much stronger than that of progressive myopia,and the accommodative microfluctuation in emmetropia and incipient myopia is much less than that in progressive myopia.These shifts are possibly associated with the variability,and microfluctuations of accommodation is greater in progressive myopes than emmetropes.There are certain correlations between wavefront aberrations and accommodative microfluctuations.The refractive group differences in the accommodative microfluctuations may be related to differences in the wavefront between myopes and emmetropes.Under near reading distance,LFC is correlated with higher order aberrations.