调节对近视性散光的影响

摘要

Objective To analyze the existence of astigmatism with accommodation and its possible effect on near vision work.Methods It was a cross-sectional study.The refraction of 166 astigmatic eyes of 87 patients were measured at distance (at 5 m) and near (at 40 cm).The distance corrected near visual acuity (DCNVA) and accommodative astigmatism corrected near visual acuity (ACNVA) were measured with distance-corrected glasses and neas-corrected glasses,respectively,using near vision chart.The astigmatism at near was measured under monocular condition with crosscylinder lenses.The degree of astigmatism at far and near,the axis of astigmatism at far and near,DCNVA and ACNVA were compared by paired t test respectively if the data were normal distribution,if not,compared by Wilcoxon matched-pairs signed-ranks test.Analyzed the association between the astigmatism changes and residual astigmatism.Results The degree of astigmatism with accommodation and the near visual acuity when accommodative astigmatism corrected were both increased significantly (Z=-5.32,P＜0.01 ; Z=-5.74,P＜0.01),similar resulta were obtained in subjects had with-the-rule and oblique astigmatism and astigmatism ≤-1.00 D.But the axis showed no statistical significance.The astigmatism changes showed no significant association with residual astigmatism.Conclusion A change in astigmatism with accommodation does indeed exist,and sometimes affects near vision,especially for tbose who had with-the-rule and oblique astigmatism and astigmatism ≤-1.00 D.So optometrists should pay attention to the examination of near astignatism,especially for those who have near vision problems.%目的 探讨调节对近视性散光的可能影响及散光的变化对近距离工作的可能影响.方法 横断面研究.序贯选取近视性散光者87例(166眼存在散光),检查其屈光不正度、远矫正下近视力(DCNVA)、视近(眼前40 cm)状态下的散光修正度及视近散光修正后的近视力(ACNVA).视近状态下散光的修正采用交义柱镜.对视远与视近状态下的散光度、视远与视近状态下散光轴位、DCNVA与ACNVA 三对数据的差值进行正态性检验,若服从正态分布则采用配对t检验进行分析,若不服从则采用配对秩和检验.对视近状态下和视远状态下散光的差异量与残余散光度之间进行相关性分析.结果 视近与视远状态下散光度的差异具有统计学意义(Z=-5.32,P＜0.01),且视近时散光度呈增加的趋势；二者轴位的差异无统计学意义；DCNVA与ACNVA的差异具有统计学意义,且散光修正后视力有提高的趋势(Z=-5.74,P＜0.01).顺规、斜轴及低度散光(≤-1.00 D)者与总体趋势相一致,而逆规散光及散光度＞-1.00 D者不具有该趋势.结论 人眼各子午线的调节不均衡使调节时散光发生改变,不同程度地影响着近视力,从而影响近距离工作,这于顺规、斜轴及低度散光患者更为明显.