Longitudinal Study on Myopia Progression Considering Axial Length and Refraction in Caucasian Students

Abstract

Purpose: Students are a risk group for myopia progression because of their intensive levels of near work. This study aimed to evaluate the progression of myopia in Caucasian students over a period of two years. Material and Methods: In a prospective multivariate longitudinal design over a period of two years, data from both eyes of 84 subjects (mean age = 23.7 ± 3.7 years; mean spherical equivalent = −2.01 ± 2.52 D) were randomized for statistical analysis. Axial length, non-cycloplegic refraction and corneal refractive power were measured using the Myopia Master (Oculus Optikgeräte GmbH, Germany). Additionally, data on near phoria, accommodation, outdoor activity, daily time with near work, and refractive influences were collected. Results: The subjects showed a statistically significant increase in axial length from baseline mean 23.98 ± 1.19 mm by 0.067 ± 0.025 mm ( = 0.010). The objective spherical equivalent (baseline mean = −2.01 ± 2.52 D) showed no statistically significant shift towards myopia (p = 0.113). In the moderate myopic subgroup, 40.0 %, 50.0 %, and 10.0 % showed axial myopia and refractive myopia of the crystalline lens or cornea, respectively. The main reasons for myopia progression were an increase in axial length (51.3 %), a change in refractive power of the lens (41.0 %), and a change in refractive power of the cornea (7.7 %). Near phoria and progression of myopia were correlated (p = 0.033). All other parameters were within the normal range and did not show a correlation with the progression of myopia. Conclusion: The risk group of Caucasian students showed neither a clinically relevant increase in axial length of the eye nor a change in objective spherical equivalent towards myopia over a period of two years. Nevertheless, the change in the refractive power of the crystalline lens is supposed to be an important factor for myopia progression, in addition to the change in axial length.