近视及散光眼LASIK后非接触眼压计测量值的影响因素及其预测

目的 比较近视和(或)散光患者在LASIK手术前后非接触眼压计测量结果的差异及其影响因素,并得到预计眼压的计算公式.方法 对2005年12月至2006年11月在北京协和医院准分子激光手术中心行初次准分子激光原位角膜磨镶术(LASIK)矫正近视和(或)散光的患者进行回顾性研究,共93例(183只眼),采用非接触眼压计(NCT)测量术前和术后2周、1个月、3个月的眼压值,计算眼压变化值并分析其与各种变量之间的相关性,应用多元线性回归从相关变量得到术后预计的测量眼压值及眼压变化值.结果 患者术后3个月眼压较术前平均下降(5.74±2.03)mmHg,其变化与性别、年龄均不相关,但与术前屈光度有明显的关系.多元线性回归分析得到术后实际测量的眼压与术前眼压呈正性相关,而与手术切削量呈负相关(R2=0.442,P<0.001),术后预计测量眼压=5.175+0.411×术前眼压-0.0205×切削量,手术后眼压测量下降值0.589×术前眼压+0.0205×切削量-5.175.结论 通过术后实际测量眼压值与预测值比较,可以及时发现高眼压的患者,避免低估眼压以致漏诊青光眼而造成患者视功能损失.虽然可以通过预测公式来判断实际测量眼压值是否在正常范围.但更有效的方法是使用不受角膜变化影响的眼压计测定眼压.

Influence Factors and Prediction of Noncontact Tonometry Measurements after Myopic and Astigmatism LASIK Surgery

Objective To evaluate the changes and influence factors of intraocular pressure (IOP) measurements by noncontact tonometry(NCT)after laser in situ keratomileusis(LASIK)for myopia and astig- matism,and to find a correction formula for predictive measured IOP. Methods Retrospective case series was performed on 93 patients (183 eyes)receiving primary LASIK for myopia and astigmatism in Peking Union Medical Collage Hospital from December 2005 to November 2006. IOP was measured by NCT before and after operation including 2 week, 1 month, and 3 months after LASIK. The amount of IOP change was computed and its relation to different variables was analyzed. Correction formula for predictive IOP and IOP change were e- valuated by multiple linear regression analysis. Results IOP of NCT was reduced by a mean of (5.74±2.03 ) mmHg at 3 months after LASIK. The change in IOP was not related to gender or age of the patient,but related to preoperative diopter significantly. Multiple linear regression analysis of the IOP before and after LASIK showed a significant correlation between the measured IOP and preoperative lOP and ablation depth(R2=0.442, P <0.001). Predictive measured IOP after LASIK=5.175+0.411× preoperative IOP -0.0205× ablation depth, Change of measured IOP after LASIK=0.589× preoperative IOP+0.0205× ablation depth -5.175. Conclusions Through comparing actual and predictive measured IOP and detecting hypertension in time, we can avoid un- derestimation of IOP after LASIK and detect potential glaucoma patients. Although correction formula can be used to estimate predictive measured IOP after LASIK, alternative methods should be investigated to assess IOP independent of corneal change after LASIK.