Mafra C H, Dave A S, Pilai C T, Klyce S D, Wilson S E
Department of Opthalmology, University of Texas Southwestern Medical Center, Dallas, USA.
Cornea. 1996 Mar;15(2):196-203. doi: 10.1097/00003226-199603000-00014.
Cataract surgery is known to induce refractive and corneal astigmatism, but little is known regarding the specific corneal topographic alterations produced by this surgery. We evaluated the corneal topographic effects of extracapsular cataract extraction (ECCE) performed with an 8- to 11-mm posterior limbal incision closed with interrupted sutures and subsequent selective suture removal. Corneal topography was analyzed in 15 eyes with the TMS-1 videokeratoscope preoperatively, before selective suture removal 4-6 weeks after surgery, 2-5 weeks after selective removal of sutures, and at 5 1/2-8 months after surgery. The Surface Regularity Index was significantly increased before suture removal and after suture removal but returned to normal at the final examination. The Irregular Astigmatism Index remained significantly increased at all examinations after surgery. Corneal asymmetry (Surface Asymmetry Index) continued to be significantly increased compared with the preoperative examination after suture removal and at 6 months after surgery. The standard deviation of powers (SDP) was significantly elevated before and immediately after suture removal, but was not significantly different at 6 months. Mean corneal astigmatism remained significantly increased (0.80 +/- 0.11 preoperatively, 1.39 +/- 0.24 at maximum follow-up, p = 0.04). Significant changes in corneal topography occurred in each patient between suture removal and final examinations. A few patients developed against-the-rule astigmatism ranging from 0.6 to 2.2 diopters. ECCE significantly altered corneal tomography compared with the preoperative contour in all patients. In those patients in whom surgically induced nonspherical and noncylindrical distortions occur (radially asymmetrical power distribution, lack of central corneal smoothness), corneal topography may provide information that is useful for management.
已知白内障手术会诱发屈光不正和角膜散光，但对于该手术所产生的具体角膜地形图改变却知之甚少。我们评估了采用8至11毫米后缘角膜切口并间断缝合关闭，随后进行选择性缝线拆除的囊外白内障摘除术（ECCE）的角膜地形图效应。在15只眼中，于术前、术后4至6周选择性缝线拆除前、选择性拆除缝线后2至5周以及术后5个半月至8个月，使用TMS-1视频角膜镜分析角膜地形图。表面规则性指数在缝线拆除前和拆除后均显著升高，但在最终检查时恢复正常。不规则散光指数在术后所有检查中仍显著升高。与术前检查相比，角膜不对称性（表面不对称指数）在缝线拆除后及术后6个月仍持续显著升高。屈光力标准差在缝线拆除前及刚拆除后显著升高，但在6个月时无显著差异。平均角膜散光仍显著升高（术前为0.80±0.11，最大随访时为1.39±0.24，p = 0.04）。在缝线拆除和最终检查之间，每位患者的角膜地形图均发生了显著变化。少数患者出现了逆规散光，范围为0.6至2.2屈光度。与所有患者的术前轮廓相比，ECCE显著改变了角膜断层扫描。在那些发生手术诱发的非球面和非柱面变形的患者中（径向不对称屈光力分布，角膜中央缺乏平滑度），角膜地形图可能会提供有助于处理的信息。
