激光周边虹膜切除术对角膜像差及生物力学的影响

Effect of Laser Peripheral Iridotomy on corneal aberrations and biomechanics

目的评估激光周边虹膜切除术(LPI)对角膜像差及生物力学的影响及应用价值。方法选择因可疑原发性房角关闭眼行LPI术的连续病例23例41眼,测量LPI术前1 h及术后1 h、10 d、1月的角膜像差变化及角膜生物力学特性变化。结果术前1 h、术后1 h、术后10 d、术后1月角膜Pentacam像差指标总均方根值(t RMS)、低阶均方根值(LRMS)、高阶均方根值(HRMS)比较,差异均无统计学意义(χ2分别=1.83、1.71、5.11,P均>0.05)。术前1 h、术后1 h、术后10 d、术后1月角膜生物力学指标Goldmann相关性眼内压(IOPg)、角膜补偿性眼内压(IOPcc)、角膜阻力因子(CRF)、角膜滞后量(CH)比较,差异均有统计学意义(F分别=27.03、27.42、3.94、8.68,P均<0.05)。IOPg术后1 h高于术前1 h,术后10 d和术后1月(t分别=-5.04、6.81、6.84,P均<0.05),IOPcc术后1 h高于术前1 h,术后10 d和术后1月低于术前1 h(t分别=-4.38、2.98、3.49,P均<0.05),CRF术后1 h高于术前1 h(t=-2.88,P<0.05),CH术后1 h低于术前1 h(t=2.78,P<0.05),CH术后10 d和术后1月高于术后1 h,差异均有统计学意义(t分别=-4.40、-4.43,P均<0.05)。结论 LPI术后角膜的波前像差无变化。排除角膜厚度影响,LPI术降眼压效果良好。排除术后1 h应激效应,LPI术不改变角膜总体抵抗外力的能力。LPI术可能造成一过性的角膜吸收和分散能量能力的下降,然而,这种下降是可恢复的。

Objective To evaluate the effect of laser peripheral iridectomy（LPI）on corneal aberration and biomechanics. Methods Twenty-three consecutive patients（41 eyes）with suspected primary angle closure underwent LPI. The corneal aberrations and corneal biomechanical characteristics were measured at 1 hour before LPI and 1 hour,10 days and 1 month after LPI. Results There was no significant difference in the total mean square root（t RMS）,low order root mean square（LRMS）and high order root mean square（HRMS）of Pentacam aberration among 1 h before operation,1 h after operation,10 d after operation and 1 month after operation（χ2=1.83,1.71,5.11,P〉0.05）. The corneal biomechanical parameters including Goldmann-related intraocular pressure（IOPg）,compensatory intraocular pressure（IOPcc）,corneal resistance factor（CRF）,corneal hysteresis（CH）were significantly different among 1 hour before operation,1 hour after operation,10 days after operation and 1 month after operation（F= 27.03,27.42,3.94,8.68,P〈0.05）. IOPg was higher at 1 hour after operation than 1 hour before operation,10 days after operation and 1 month after operation（t=-5.04,6.81,6.84,P〈0.05）. 1 hour after operation,the IOPcc was higher than 1 hour before operation,while the IOPcc at 10 days after operation and 1 month after operation were lower than 1 hour before operation（t=-4.38,2.98,3.49,P〈0.05）. The CRF at 1 hour after operation was higher than 1 hour before operation（t=-2.88,P〈0.05）. CH at 1 hour after operation was lower than 1 hour before operation（t=2.78,P〈0.05）,but the 10 days after operation and 1 month after operation,the CH were significantly higher than 1 hour after operation（t=-4.40,-4.43,P〈0.05）. Conclusion There is no change in corneal wavefront aberration after LPI. The effect of LPI on reducing intraocular pressure is good when excluding corneal thickness. LPI does not change the ability of the cornea to resist external force for not considering the stress effect of 1 hour after operation. LPI surgery may result in a transient decrease in the ability of the cornea to absorb and distribute energy which is recoverable.