Yonsei Med J.  2018 Nov;59(9):1115-1122. 10.3349/ymj.2018.59.9.1115.

Biomechanical Properties of the Cornea Using a Dynamic Scheimpflug Analyzer in Healthy Eyes

• Lee H
• Kang DS
• Ha BJ
• Choi JY
• Kim EK
• Seo KY
• Kim TI

• KMID: 2422497
• DOI: http://doi.org/10.3349/ymj.2018.59.9.1115

Abstract

PURPOSE
To investigate biomechanical properties of the cornea using a dynamic Scheimpflug analyzer according to age.
MATERIALS AND METHODS
In this prospective, cross-sectional, observational study, participants underwent ophthalmic investigations including corneal biomechanical properties, keratometric values, intraocular pressure (IOP), and manifest refraction spherical equivalent (MRSE). We determined the relationship of biomechanical parameters and ocular/systemic variables (participant's age, MRSE, IOP, and mean keratometric values) by piecewise regression analysis, association of biomechanical parameters with variables by Spearman's correlation and stepwise multiple regression analyses, and reference intervals (RI) by the bootstrap method.
RESULTS
This study included 217 eyes of 118 participants (20-81 years of age). Piecewise regression analysis between Corvis-central corneal thickness (CCT) and participant's age revealed that the optimal cut-off value of age was 45 years. No clear breakpoints were detected between the corneal biomechanical parameters and MRSE, IOP, and mean keratometric values. Corneal velocity, deformation amplitude, radius, maximal concave power, Corvis-CCT, and Corvis-IOP exhibited correlations with IOP, regardless of age (all ages, 20-44 years, and over 44 years). With smaller deformation amplitude and corneal velocity as well as increased Corvis-IOP and Corvis-CCT, IOP became significantly increased. We provided the results of determination of confidence interval from RI data using bootstrap method in three separate age groups (all ages, 20-44 years, and over 44 years).
CONCLUSION
We demonstrated multiple corneal biomechanical parameters according to age, and reported that the corneal biomechanical parameters are influenced by IOP.

Keyword

Corneal biomechanical property; dynamic Scheimpflug analyzer; healthy adult population; age

MeSH Terms

Cornea*
Humans
Intraocular Pressure
Methods
Observational Study
Prospective Studies
Radius

Figure

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  Fig. 1 Flow diagram according to the Consolidated Standards of Reporting Trials statement, showing enrollment, randomization, and patient flow in this study.

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  Fig. 2 Piecewise linear regression of Corvis-central corneal thickness (CCT) with participant's age. (A) Locally weighted scatterplot smoothing fit between Corvis-CCT and age. Estimated breakpoint between Corvis-CCT and age is 45 years of age. (B) Fitting of the model. Colored range: 95% confidence limits.

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