准分子激光术后双眼影像不等的立体视代偿能力探讨

Aniseikonic limit on condition of keeping normal stereoacuity in myopic patients

目的:了解近视者在保持正常立体视锐度时耐受突发性双眼影像不等的限度。方法:基本对称的近视患者两眼非同期施行准分子激光屈光性角膜手术(PRK或LASIK),利用单眼术后造成的明显屈光参差与影像不等作为研究模型,测定了46例(92眼)术前、单眼术后及双眼术后的双眼影像不等和立体视锐度。结果:术前立体视正常者单眼术后影像不等≤6%时均有正常立体视锐度(≤60″),影像不等在7～11%时55%有正常立体视锐度,影像不等>11%时立体视锐度均≥200″或无立体视。7例术前立体视轻度异常者单眼术后有3例无同时视。结论:近视者在保持正常立体视锐度时耐受突发性双眼影像不等的限度在7～11%,与正常人基本相同。原立体视锐度轻度异常者耐受影像不等的能力降低。

Purpose:To investigate the maximum limit ot suddenly occurred aniseikonia on condition of keeping normal stereoa-cuity(≤60")in myopic patients.Methods:Excimer laser photorefractive keratectomy(PRK)or excimer laser in situ keratorrrileusis(LASIK)was performed on 46 cases(92 eyes)of symmetry myopia with a period of 1~6 weeks between their right and left eye treatment.The anisometropia and aniseikonia were formed after unilateral operation.We measured their aniseikonia and Stereoacuity before operation,after unilateral operation and after bilateral operation.Re-Sults;(1)39 cases with normal Stereoacuity before operation:Stereoacuity was normal in every case whose aniseikonia was ≤6%.There are 55% patients whose aniseikonia was 7 ~ 11% when kept normal Stereoacuity.When aniseikonia was>11% every patient’s Stereoacuity was abnormal(≥200" or no stereoacuity).(2)Among 7 cases with slight abnormal stereoacuity before operation there are 3 cases who had no simultaneous perception after unilateral operation.Con-clusion:Aniseikonic maximum limit was 7-11% on condition of keeping normal stereoacuity in myopic patients.It was similar to emmetropia and lower than the limit of the patients whose stereoacuity was slightly abnormal before operation.