Effects of axial length and corneal curvature on corneal biomechanics in elderly population / 国际眼科杂志(Guoji Yanke Zazhi)

ABSTRACT

@#AIM:To explore the corneal biomechanical properties of the elderly with different axial length(AL)and corneal curvature by Corneal Visualization Scheimpflug Technology(Corvis ST). <p>METHODS: A cross-sectional study. A total of 220 patients(426 eyes)undergoing phacoemulsification were collected in this study. One of them whose the AL was 22-24 mm and the corneal curvature was 42-44 D were divided into male and female groups(44 eyes and 49 eyes, respectively). One of them whose the corneal curvature was 42-44 D were divided into 22-24 mm, 24-26 mm, and more than 26 mm groups according to AL(99 eyes, 22 eyes and 12 eyes, respectively). One of them whose the AL was 22-24 mm were divided into 42-44 D, and more than 44 D according to corneal curvature(88 eyes, 102 eyes, respectively). Corvis ST was used to measure the biomechanical parameters of the cornea. The differences in the parameters between different groups were analyzed using the independent-samples <i>t</i>-test or one-way analysis of variance and correlation analyses were performed using Pearson correlation analysis.<p>RESULTS: When comparing the corneal biomechanical parameters, no statistically significant differences were found between male and female groups(<i>P</i>>0.05). The first applanation length and second applanation length among different corneal curvatures were statistically significant(<i>P</i><0.05). There was statistically significant only for the difference of the second applanation length and central cornea thickness between two groups of 22-24 mm and 24-26 mm(<i>P</i><0.05). There was statistically significant for the difference of the second applanation length, deformation amplitude, central cornea thickness, the first applanation time, intraocular pressure and corrected intraocular pressure between the two groups of 22-24 mm and more than 26 mm(<i>P</i><0.05). But there was no statistically significant differences of the parameters between groups of 24-26 mm and more than 26 mm(<i>P</i>>0.05). The patient's AL was positively correlated with deformation amplitude, intraocular pressure and corrected intraocular pressure(<i>r</i>=0.263, <i>P</i>=0.002; <i>r</i>=0.463, <i>P</i>=0.000; <i>r</i>=0.449, <i>P</i>=0.000), and there is negative correlation between the patient's AL and central cornea thickness, the second applanation length(<i>r</i>=-0.240, <i>P</i>=0.006; <i>r</i>=-0.344, <i>P</i>=0.000).<p>CONCLUSION: The corneal curvature and ocular AL may be the factor affecting the corneal biomechanical properties. The longer AL, the thinner corneal thickness, the more easily the corneal is deformed, and with the increase of the AL, intraocular pressure also increases. When discussing whether the preparation of the cataract incision is affected by the patient's own factors, the different corneal curvatures and AL shall be considered.