间歇性外斜视患者的屈光状态对立体视功能影响的研究

The effects of refractive errors on stereoacuity in patients with intermittent exotropia

目的 分析合并不同屈光状态的间歇性外斜视患者立体视功能的差异。设计 回顾性病例系列。研究对象 北京同仁医院2014年7月至2015年8月间歇性外斜视需要进行手术治疗的238例患者。方法 将患者按照屈光状态分为远视组（双眼等效球镜均≥＋1.00 D）、正视组（-1.00 D＜双眼等效球镜＜＋1.00 D）、近视组（双眼等效球镜均≤-1.00 D）和屈光参差组（双眼等效球镜相差≥1.00 D），用同视机检查患者的远立体视，颜少明《立体视觉检查图》检查近立体视，比较分析四组患者的远近立体视功能状况。主要指标 远立体视功能和近立体视功能。结果 （1）238例间歇性外斜视患者平均看近斜视度（45.71±18.81）△，平均看远斜视度（43.98±19.55）△，远视组、正视组、近视组和屈光参差组保留远立体功能的比率分别为23.3%、15.5%、19.7%、 18.8%，各组之间远立体视功能比较差异无统计学意义；保留近立体视功能的比率分别为66.7%、79.8%、81.6%、64.6%，屈光参差组的近立体视功能丢失最多，近视组的近立体视功能丢失最少，屈光参差组与近视组的近立体视功能有统计学差异（P=0.033）。（2）间歇性外斜视合并屈光参差的检出率为20.1%，其中近视性屈光参差所占比例（12.6%）最高，远视性屈光参差所占比例（1.3%）最低。（3）间歇性外斜视合并屈光参差的患者中，有、无远立体视的患者双眼等效球镜差值分别为（2.35±0.75）D和（2.34±1.75）D，两组间差值比较无统计学意义（P=0.21）；无近立体视患者双眼等效球镜的差值（3.11 D±2.29 D）明显大于有近立体视患者的双眼等效球镜差值（1.93 D±0.83 D），两组的差值间比较有统计学意义（P=0.002）。结论 对于斜视角度较大的间歇性外斜视患者，不同的屈光状态对远立体视功能影响不大，屈光参差加重对近立体视功能的损伤，屈光参差度越大，近立体视功能损伤越重。

Objective To evaluate and compare stereoacuity with respect to refractive error in intermittent exotropia （IXT）. Design Retrospective case series. Participants 238 patients with IXT undergoing strabismus surgeries in Beijing Tongren Hospital from Jul 2014 to Aug 2015 were involved. Methods All patients were divided into four groups according to preoperative refractive error： IXT with hyperopia （binocular spherical equivalent （SE）≥＋1.00 D ）, IXT with emmetropia （-1.00 D〈binocular SE〈＋1.00 D）, IXT with myopia （binocular SE≤-1.00 D）, and IXT with anisometropia （binocular SE difference≥1.00 D）. The stereoacuity at distance and near were compared among the four groups. Main Outcome Measures Stereoacuity at distance and near. Results （1） The mean near deviation of 238 IXT patients was （45.71±18.81）△ and mean distant deviation was （43.98±19.55）△. The ratio of having distant stereoacuity in IXT with hyperopia, IXT with emmetropia, IXT with myopia and IXT with anisometropia were 23.3%, 15.5%, 19.7% and 18.8%. There was no significant different in distance stereoacuity among the four groups. The ratio of having near stereoacuity in IXT with hyperopia, IXT with emmetropia, IXT with myopia and IXT with anisometropia were 66.7%, 79.8%, 81.6%, 64.6%. The near stereoacuity was most serious damaged in IXT with anisometropia while slightest in IXT with myopia. There was significant difference in near stereoacuity between IXT with anisometropia and IXT with myopia （P=0.033）. （2） The prevalence of IXT with anisometropia was 20.1%, and myopia anisometropia had highest prevalence while hyperopia anisometropia had lowest prevalence （12.6% vs 1.3%）. （3） The mean difference in SE between each eye in IXT with anisometropia with and without distant stereoacuity were 2.35±0.75 D and 2.34±1.75 D（P=0.21）. The mean difference SE in between each eye in anisometropia without near stereoacuity was significantly bigger than in that with near stereoacuity （3.11±2.29 D vs. 1.93±0.83 D, P=0.002）. Conclusion For the IXT patients with large deviation, refractive errors have little effect on distant stereoacuity, but anisometropia damages the near stereoacuity. The greater degree of anisometropia, the more serious damage of near stereoacuity occurred.