Effect of the posterior corneal surface on total corneal astigmatism in patients with age-related cataract
Effect of the posterior corneal surface on total corneal astigmatism in patients with age-related cataract作者机构:Tianjin Medical University Tianjin 300070 China Clinical College of Ophthalmology Tianjin Medical University Tianjin Eye Hospital Tianjin 300020 China Tianjin Key Laboratory of Ophthalmology and Visual Science Tianjin 300020 China Tianjin Eye Institute Tianjin 300020 China
出 版 物:《International Journal of Ophthalmology(English edition)》 (国际眼科杂志(英文版))
年 卷 期:2018年第11卷第6期
页 面:958-965页
核心收录:
学科分类:1002[医学-临床医学] 100212[医学-眼科学] 10[医学]
基 金:Supported by the National Natural Science Foundation of China(No.81670837) the Scientific and Technological Project of Tianjin Health Bureau(No.2015KY38)
主 题:posterior comeal astigmatism total comealastigmatism multi-colored spot reflection topographer cataract
摘 要:AIM: To explore the effect of the posterior astigmatism on total corneal astigmatism and evaluate the error caused by substituting the corneal astigmatism of the simulated keratometriy (simulated K) for the total corneal astigmatism in age-related cataract patients. METHODS: A total of 211 eyes with age-related cataract from 164 patients (mean age: 66.8±9.0y, range: 45-83y) were examined using a multi-colored spot reflection topographer, and the total corneal astigmatism was measured. The power vector components J0 and J45 were analyzed. Correlations between the magnitude difference of the simulated K and total cornea astigmatism (magnitude differenceSimK-Tca), anterior J0, and absolute meridian difference (AMD) between the anterior and posterior astigmatisms were calculated. To compare the astigmatism of the simulated K and total cornea both in magnitude and axial orientation, we drew double-angle plots and calculated the vector difference between the two measures using vector analysis. A corrective regression formula was used to adjust the magnitude of the simulated K astigmatism to approach that of the total cornea. RESULTS: The magnitude differenceSimK-Tca was positively correlated with the anterior corneal J0 (Spearman’s rho= 0.539; P〈0.001) and negatively correlated with the AMDR (Spearman’s rho=-0.875, P〈0.001). When the anterior J0 value was larger than 1.3 D or smaller than -0.8 D, the errors caused by determining the total corneal astigmatism with the karatometric calculation tended to be greater than 0.25 D. An underestimation by 16% was observed for against the rule (ATR) astigmatism and an overestimation by 9% was observed for with the rule (WTR) astigmatism when ignoring the posterior measurements. CONCLUSION: Posterior corneal astigmatism should be valued for more precise corneal astigmatism management, especially for higher ATR astigmatism of the anterior corneal surface. We suggest a 9% reduction in the magnitude of the simulated K in eyes with WT