Corneal Parameters in Healthy Subjects Assessed by Corvis ST

Ramin Salouti, Mansoureh Bagheri, Anis Shamsi, Mohammad Zamani, Ramin Salouti, Mansoureh Bagheri, Anis Shamsi, Mohammad Zamani

Abstract

Purpose: To evaluate corneal biomechanics using Corvis ST in healthy eyes from Iranian keratorefractive surgery candidates.

Methods: In this prospective consecutive observational case series, the intraocular pressure (IOP), central corneal thickness (CCT), and biomechanical properties of 1,304 eyes from 652 patients were evaluated using Corvis ST. Keratometric readings and manifest refraction were also recorded.

Results: The mean ( ± SD) age of participants was 28 ± 5 years, and 31.7% were male. The mean spherical equivalent refraction was -3.50 ± 1.57 diopters (D), the mean IOP was 16.8 ± 2.9 mmHg, and the mean CCT was 531 ± 31 μ m for the right eye. The respective means ( ± SD) corneal biomechanical parameters of the right eye were as follows: first applanation time: 7.36 ± 0.39 milliseconds (ms); first applanation length: 1.82 ± 0.22 mm; velocity in: 0.12 ± 0.04 m/s; second applanation time: 20.13 ± 0.48 ms; second applanation length: 1.34 ± 0.55 mm; velocity out: -0.67 ± 0.17 m/s; total time: 16.84 ± 0.64 ms; deformation amplitude: 1.05 ± 0.10 mm; peak distance: 4.60 ± 1.01 mm; and concave radius of curvature: 7.35 ± 1.39 mm. In the linear regression analysis, IOP exhibited a statistically significant association with the first and second applanation times, total time, velocity in, peak distance, deformation amplitude, and concave radius of curvature.

Conclusion: Our study results can be used as a reference for the interpretation of Corvis ST parameters in healthy refractive surgery candidates in the Iranian population. Our results confirmed that IOP is a major determinant of Corvis parameters.

Keywords: Corneal Biomechanics; Corvis ST; Intraocular Pressure; Central Corneal Thickness.

Conflict of interest statement

There are no conflicts of interest.

Copyright © 2020 Salouti et al.

Figures

Figure 1
Figure 1
Significant determinants of the selected Corvis ST parameters at the first applanation moment. CCT, central corneal thickness; IOP, intraocular pressure.
Figure 2
Figure 2
Significant determinants of the selected Corvis ST parameters at the second applanation moment. CCT, central corneal thickness; IOP, intraocular pressure; Km, mean keratometry; Ka, astigmatic keratometry.
Figure 3
Figure 3
Significant determinants of the selected Corvis ST parameters at the highest concavity moment. CCT, central corneal thickness; IOP, intraocular pressure; SE, spherical equivalent refraction.

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