Shoji Takuhei, Takahashi Hirokazu, Park Masami, Okazaki Kazusiro, Tanito Masaki, Chihara Etsuo
Sensho-kai Eye Institute, Kyoto, Japan.
J Glaucoma. 2007 Jan;16(1):137-45. doi: 10.1097/01.ijg.0000212286.55174.2e.
To identify factors that affect corneal birefringence, such as the corneal polarization axis (CPA) and corneal polarization magnitude (CPM), after laser in situ keratomileusis (LASIK) using scanning laser polarimetry with a variable corneal polarization compensator.
The CPA and CPM from 42 patients (42 eyes) who underwent LASIK and 24 normal untreated subjects (24 eyes) were measured 1 week before and 1 week after LASIK. Changes in the CPA and CPM after LASIK were studied using Student t test and Pearson correlation coefficient.
In the LASIK group, the post-LASIK CPA and CPM significantly changed, whereas both values did not change in normal subjects. Among 5 candidate factors [preoperative CPA (pre-CPA), preoperative CPM (pre-CPM), age, change in corneal curvature, and ablation depth], the change in CPA was significantly correlated with the pre-CPA (r=-0.793) and pre-CPM (r=0.339). The change in CPM was correlated with the pre-CPA (r=-0.455) and pre-CPM (r=-0.411). Over 83% case of postoperative corneal birefringence can be explained by only 2 parameters with regression analysis.
The pre-CPA and pre-CPM are strongly associated with LASIK-induced changes in CPA and CPM. Variations in age, changes in corneal curvature, and ablation depth do not contribute to changes in either parameter.
使用带可变角膜偏振补偿器的扫描激光偏振仪，确定准分子原位角膜磨镶术（LASIK）后影响角膜双折射的因素，如角膜偏振轴（CPA）和角膜偏振量（CPM）。
对42例行LASIK手术的患者（42只眼）和24名未经治疗的正常受试者（24只眼），在LASIK术前1周和术后1周测量其CPA和CPM。采用Student t检验和Pearson相关系数研究LASIK术后CPA和CPM的变化。
在LASIK组中，LASIK术后CPA和CPM显著改变，而在正常受试者中这两个值均未改变。在5个候选因素[术前CPA（pre-CPA）、术前CPM（pre-CPM）、年龄、角膜曲率变化和消融深度]中，CPA的变化与pre-CPA（r=-0.793）和pre-CPM（r=0.339）显著相关。CPM的变化与pre-CPA（r=-0.455）和pre-CPM（r=-0.411）相关。通过回归分析，仅2个参数就能解释超过83%的术后角膜双折射情况。
pre-CPA和pre-CPM与LASIK引起的CPA和CPM变化密切相关。年龄变化、角膜曲率变化和消融深度对这两个参数的变化均无影响。
