Merriam J C, Zheng L, Urbanowicz J, Zaider M
Edward S. Harkness Eye Institute, College of Physicians and Surgeons, Columbia University, New York, New York, USA.
Trans Am Ophthalmol Soc. 2001;99:187-95; discussion 195-7.
To compare the course and magnitude of change on the horizontal and vertical meridians of the cornea after 5 different incisions for cataract: extracapsular cataract extraction (ECCE), 6 mm superior scleral tunnel (6Sup), 3 mm superior scleral tunnel (3Sup), 3 mm temporal scleral tunnel (3Temp), and 3 mm temporal corneal incision (3Cor).
Retrospective chart review of 665 cases of preoperative regular astigmatism. The preoperative keratometry (K) reading was subtracted from the postoperative K reading to determine mean net change on each meridian at 1 day, 1 week, 2 weeks, 1 month, 1.5 months, 2 months, 4 months, 6 months and 12 months and at 6 month intervals thereafter. After the superior incisions, the temporal changes on each meridian are well described by an analytic model with an initial and final plateau. The changes after the temporal incisions are described by a linear equation.
After each superior incision, the steepness and length of the transition from the initial to final plateau for each meridian depend on incision length. Considering the uncertainty of measuring K, the corneal meridians stabilized 4.5 months after ECCE, 1.2 months after 6Sup, and 0.3 months after 3Sup. No significant change was detected on the horizontal and vertical meridians after 3Temp and 3Cor.
The magnitude and the duration of changes on the horizontal and vertical meridians of the cornea after cataract surgery depend on both incision length and location. Small temporal incisions induce less change than superior incisions.
比较白内障手术5种不同切口（囊外白内障摘除术（ECCE）、6mm上方巩膜隧道切口（6Sup）、3mm上方巩膜隧道切口（3Sup）、3mm颞侧巩膜隧道切口（3Temp）和3mm颞侧角膜切口（3Cor））后角膜水平和垂直子午线方向变化的过程及幅度。
对665例术前规则散光患者的病历进行回顾性分析。用术后角膜曲率计（K）读数减去术前K读数，以确定术后1天、1周、2周、1个月、1.5个月、2个月、4个月、6个月、12个月以及此后每6个月各子午线方向的平均净变化。上方切口后，各子午线方向的颞侧变化可用具有初始和最终平台期的分析模型很好地描述。颞侧切口后的变化用线性方程描述。
每种上方切口后，各子午线方向从初始平台期到最终平台期的陡峭程度和转变长度取决于切口长度。考虑到测量K的不确定性，ECCE术后4.5个月、6Sup术后1.2个月、3Sup术后0.3个月角膜子午线方向趋于稳定。3Temp和3Cor术后水平和垂直子午线方向未检测到显著变化。
白内障手术后角膜水平和垂直子午线方向变化的幅度和持续时间取决于切口长度和位置。颞侧小切口引起的变化比上方切口小。
