Correlation of age, corneal curvature and spherical equivalent with central corneal thickness

Abstract

Objective: To describe the distribution of the central corneal thickness (CCT) measurements on a healthy Hispanic sample population and its correlation with age, mean simulated keratometry (SimK), and mean refractive spherical equivalent (MRSE). Methods: Retrospective analysis on the records of healthy patients from the Ophthalmology and Visual Sciences Institute, Tecnologico de Monterrey, January 2015 to August 2015. CCT data, age, gender, corneal curvature, and spherical equivalent was obtained. A descriptive analysis and correlation by the Spearman method was performed. The sample was divided by age subgroups: than 40 years old and correlation analysis with CCT values was determined. Results: A total of 93 (186 eyes) patients were included. Mean age: 32.54 ± 12.04 years. 43% were women. Mean CCT: 545.69 ± 36.88 μm, mean SimK: 43.56 ± 1.90 D and MRSE: −2.54 ± 3.15 D. No correlation was registered between CCT and the variables when analyzed with the Anderson–Darling (p = 0.006), Shapiro–Wilk (p = 0.043), and Kolmogorov–Smirnov (p = 0.01). CCT showed a bimodal distribution with higher density at 540 μm. Age groups 40 years showed significant difference in CCT (p = 0.016), a positive correlation with CCT was observed in the group <20 (ρ = 0.596, p = 0.001). Conclusions: The findings regarding the lack of normality, the bimodal distribution (540 μm), and the correlation between age and CCT in younger patients, may lead us to redefine the “normal” CCT value in our population in order to be used properly for clinical purposes.

Keywords

• Central corneal thickness
• Bimodal distribution
• Age
• Keratometry
• Spherical equivalent