Abstract
Purpose :
Percentile curves are used to classify eye length as a function of age and do not provide information about the classification of myopia. Therefore, a retrospective multicenter data analysis was performed to collect normative data of axial length (AXL), spherical equivalent (SE) and keratometric power (KP).
Methods :
High quality data sets of 8189 right eyes of Caucasian subjects between one and 70 years of age (mean 27.1 ± 17.5 years; 4892 female, 2810 male, 487 unknown) measured without cycloplegia with the Myopia Master (Oculus Optikgeräte GmbH, Germany) between 2020 and 2023 in 63 sites were collected. Gullstrand Refraction Analysis System (GRAS) data were used to analyze the main reasons for myopia.
Results :
Mean AXL was 24.17 ± 1.51 mm, mean SE was -2.17 ± 3.37 D and mean KP was 43.41 ± 1.54 D. Myopia and high myopia occurred in 68.2 %. Considering myopic eyes only (SE ≤ -0.5 D, N=5585) ametropia was mostly influenced by AXL in young age groups (1-5 years: -4.25 ± 2.82 D; 6-10 years: -3.39 ± 2.79 D; 11-15 years: -3.30 ± 2.87 D). From the age of 13 years the portion of the refractive power of the crystalline lens was increasing to a maximum of -0.99 ± 1.65 D in the age group of 41 to 45 years (Figure 1). In highly myopic eyes (SE ≤ -6.0 D) AXL was the main refractive influence in all age groups, while crystalline lens and cornea played minor roles. In moderate myopes (-6.0 dpt < SE ≤ -0.5 D) the refractive influence of crystalline lens was increasing in age groups between 16 to 20 years (-0.67 ± 1.40 D) and 46 to 50 years (-0.89 ± 1.60 D) (Figure 2).
Conclusions :
From the age of approximately 13 years the refractive influence of the crystalline lens was increasing in Caucasian subjects as a main component for myopic refractive error. All three components refraction, KP and AXL have to be taken into consideration to classify myopia. Neither AXL measurement, nor refraction are meaningful enough on its own for proper decisions in myopia management.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.