Vector summation of anterior and posterior corneal topographical astigmatism
Vector summation of anterior and posterior corneal topographical astigmatism
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DOI：
10.1016/s0886-3350(01)01258-5
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发表时间：
2002-09-01
影响因子：
2.8
通讯作者：
Azar, DT
中科院分区：
文献类型：
--
作者：
Prisant, O;Thanh, HX;Azar, DT
目的：探讨角膜后向散光是否能改善地形性散光与屈光度散光的相关性。单位：马萨诸塞州眼耳医院和美国波士顿哈佛医学院。方法：对31例(40只眼)散光度数为1.0~6.0的OrbScan地形图进行分析。测量角膜前、后表面地形性散光。结果：屈光散光在0.25~5.00D之间，整体地形图散光(1.06 D+/-0.92[SD])明显小于前地形图散光(1.37+/-1.04 D)(P<；0001)。整体地形法散光与屈光散光的轴向平均误差(10.4±13度)小于前地形法(15.5±30.6度)和SimK法(13.3±15.1度)，但差异无统计学意义。结论：考虑OrbScan测量角膜后表面屈光度可提高屈光散光大小的预测。
Purpose: To determine whether vector addition of posterior corneal astigmatism improves the correlation between topographical and refractive astigmatism.Setting: Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts, USA.Methods: Orbscan topographical maps of 40 eyes (31 patients) showing 1.0 to 6.0 diopters (D) of astigmatism were analyzed. Topographical anterior and posterior corneal surface astigmatism was determined. Refractive astigmatism was compared to topographical astigmatism using 3 methods: anterior topographical astigmatism, overall topographical astigmatism obtained by vector summation of anterior and posterior topographical astigmatism, and simulated keratometry (SimK).Results: Refractive astigmatism ranged from 0.25 to 5.00 D. The mean error in magnitude between topographical and refractive astigmatism was significantly smaller with the overall topographical method (1.06 D +/- 0.92 [SD]) than the anterior topographical method (1.37 +/- 1.04 D) (P < .0001). The mean error in axis between topographical and refractive astigmatism was smaller with the overall topographical method (10.4 ± 13 degrees) than with the anterior topographical method (15.5 ± 30.6 degrees) and with SimK (13.3 ± 15.1 degrees), but these differences were not statistically significant.Conclusion: Consideration of the Orbscan measurement of posterior corneal surface toricity may improve the prediction of the magnitude of refractive astigmatism.