Abstract:Objective: To explore the linear relationship among total astigmatism, corneal astigmatism and intraocular astigmatism. Methods: This was a retrospective study. A total of 76 cases (126 eyes) from Lianyungang Maternal and Child Health Hospital from June 2018 to December 2018 were selected according to the inclusion criteria: Children with astigmatism ≥1.00 D aged 3 to 6. Data for corneal astigmatism and axes, total astigmatism and axis after cycloplegia were collected. The parallelogram rule of the vector and the trigonometric function formula were used to analyze and calculate the astigmatism and axis of the eyes, and multiple linear regression analysis was performed to calculate total astigmatism, corneal astigmatism and intraocular astigmatism. Results: Total astigmatism, corneal astigmatism, and intraocular astigmatism were calculated by the formula Ctotal=0.004+0.988×Ccorneal+0.928×Cintraocular (R2 =0.998, P< 0.001). The total astigmatism axis, corneal astigmatism axis and intraocular astigmatism axis were calculated by the formula Atotal=48.391+0.708×Acorneal-0.185×Aintraocular (R2 =0.531, P<0.001). For the intraocular astigmatism from 126 astigmatic eyes, 92 eyes (73.0%) had hyperopic astigmatism. The minimum was +0.25 D, maximum was +2.00 D, and average was +0.58±0.29 D. Thirty-four eyes (27.0%) had myopia astigmatism. The minimum was -0.03 D, maximum was -1.03 D, and average was -0.26±0.24 D. Conclusions: Total astigmatism has a high linear correlation with corneal astigmatism and intraocular astigmatism. Intraocular astigmatism can be calculated by the formula Ctotal=0.004+0.988×Ccorneal+0.928×Cintraocular, and the accuracy is high. Most intraocular astigmatism compensates for corneal astigmatism. Intraocular astigmatism has little effect on the corneal axis and is mainly against-the-rule astigmatism.
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Jian Lin. Multiple Linear Regression Analysis of Total Astigmatism, Corneal Astigmatism and Intraocular Astigmatism in Children. Chinese Journal of Optometry Ophthalmology and Visual science, 2020, 22(6): 459-463. DOI: 10.3760/cma.j.cn115909-20190626-00185
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