Comperation Of Accommodation And Vergence In Myopias Before And After Laser In Situ Keratomileusis

Objective To compare the changes of accommodation and vergence in myopia before and after excimer laser in situ keratomileusis,to evaluate its effect on visul quality,to provide a theoretical basis for the improvement of postoperative visual quality.Method 45 myopic patients(90 eyes), including 13 men and 32 women,aged from 18 to 30 years old. The mean age is (23.13±2.42) years. Their preoperative best-corrected visual acuity≥1.0, j=1. According to the degree of myopia, attendants were divided into two groups: low to moderate myopia group, 28 cases(≤-6.00 D); high myopia group, 17 cases (≥-6.25D). According to the near points of accommodation and convergence, attendants were divided into dominant eye group and nondominant eye group. Their postoperative visual acuity>1.0. For the patients above-mentioned, manifest refraction, distent and near level phoria, distent and near level fused image gather and scatter movement, near point of accommodationation, near point of convergence and gradient AC/A were measured with Synthetic Optometry Uni. before surgery,1-3 months after surgery. And they were also measured at near point and symptoms of asthenopia assessed by questionnaire.Results 1. The changes of spherical refractive diopters before surgery, and after surgery 1-3 months both in low to moderate myopia group and high myopia group have statistically significance(P<0.05). 2.The changes of distent level phoria and near level phoria before surgery and after surgery 1-3 months both in low to moderate myopia group and high myopia group all have no statistically significance (P>0.05).The differences of near level phoria between high myopia group and low to moderate myopia group are significantly different(P<0.05).3.The changes of gradient AC/A ratio before surgery and after surgery 1-3 months both in low to moderate myopia group and high myopia group have no statistically significance (P>0.05).4.The positive relative accommodation increases after surgery (P<0.05),but there are no significant changes of negative relative accommodation(P>0.05).5.After surgery the positive vergence decreases and the negative vergence increases(P<0.05).6. The near points of accommodation and convergence after surgery are all close to the normal level,but gradually leave far away from the eye(P<0.05).7.The changes of near points of accommodation and convergence before surgery and after surgery 1-3 months have no statistically significance(P>0.05).8.The asthenopia symptoms slightly increase 1 month after surgery with no statistically significance (P>0.05), but decrease 3 month after surgery in both low to moderate myopia group and high myopia group (P<0.05). Conclusion LASIK can improve the accommodation and vergence of myopia and reduce their asthenopia.