Normal Values for Ocular Parameters in Spanish Caucasian Children

Abstract

<em><strong>Objective</strong><em> To quantify the ocular biometric parameters, the corneal biomechanical properties, the anatomical configuration of the optic nerve and the retinal nerve fiber layer (RNFL) in a group of children through non-invasive techniques. <em><strong>Material and methods</strong><em> A cross-sectional, descriptive and non-randomized study was conducted in 293 healthy Caucasian children between the ages of 6 and 17. The subjects were divided according to refractive error. <em><strong>Results</strong><em> A statistically significant correlation was found between axial length (AL) and corneal hysteresis (CH) (p < 0.001). CH decrease was also found with increasing myopia, and CH increase with increasing hypermetropia (p < 0.001). In the posterior segment, a positive correlation was found between the average thickness of the RNFL and the CH (p = 0.01). Likewise, a decrease in the average thickness of the RNFL was observed with the increased AL (p < 0.001) and myopia (p < 0.0001). <em><strong>Conclusions</strong><em> The mechanical strength of the anterior segment of the eye is affected in myopic subjects at early ages and in severe myopia, regardless of age. Lower CH values, in addition to a reduction in the corneal viscoelastic damping capacity, indicate the existence of a more easily deformable optic nerve, together with a thinning of the RNFL, especially in myopic children. This study provides normal values of these parameters and makes it possible to correlate them with refractive errors.