Association between axial length elongation and spherical equivalent progression in Chinese children and adolescents

Abstract

Background It is generally believed that a 1‐mm axial length (AL) elongation of the eye corresponds to a −3.00 D spherical equivalent (SE) progression, but this is disputed. Purpose To investigate the association between AL elongation and SE progression among children and adolescents. Methods A prospective cohort study of 710 children and adolescents aged 6–16 years was included. Ophthalmic examinations, including cycloplegic SE, AL and corneal curvature, were performed at baseline and 1‐year follow‐up. The ratio of SE change (ΔSE) to AL change (ΔAL) (ΔSE/ΔAL) was calculated, and its association with age and refractive status was explored using a general linear model. Results Among all participants, 396 (55.77%) were male, with 265 (37.32%) myopes at baseline. The average 1‐year ΔSE and ΔAL were 0.61 ± 0.40 D and 0.33 ± 0.22 mm, respectively. Both ΔSE and ΔAL gradually decreased with age (p < 0.001). In the general linear model analyses, age and refractive status were independently associated with ΔSE/ΔAL after adjustment for covariates (age: trueβ̂$$ \hat{\beta} $$ = 0.04, p < 0.05; myopia vs nonmyopia: trueβ̂$$ \hat{\beta} $$ = 0.28, p < 0.05). Based on the developed formula ΔSE/ΔAL = 1.74 + 0.05*age (for myopes), mean ΔSE/ΔAL in myopes increased from 2.06 D/mm in the 6‐year‐olds to 2.59 D/mm in the 16‐year‐olds. In nonmyopes, ΔSE/ΔAL = 1.33 + 0.05*age, and the ratio increased from 1.65 D/mm in the 6‐year‐olds to 2.18 D/mm in the 16‐year‐olds. Conclusions The ratio of ΔSE/ΔAL varied with age and refractive status in children and adolescents. The age‐specific ΔSE/ΔAL could be used to estimate SE progression through the actual AL change.

Longitudinal analysis of refraction and ocular biometrics in preschool children with early-onset high myopia

“…The present study focused on preschoool children under the age of 6, so ∆SE/∆AL was relatively lower compared to the results of the study conducted on school children. This finding is consistent with a previous study on myopia, where a 1 mm increase in AL corresponded to more myopic progression in SE for older children 18 .…”

“…Our study showed gradually decreased myopic progression and axial elongation over 3-year study period, which was like previous studies 16 , 18 . The previous study reported that AL elongation decreased to the order of 0.14 mm/year from 3 to 6 years of age 14 .…”

Comparing the effects of highly aspherical lenslets versus defocus incorporated multiple segment spectacle lenses on myopia control

“…Some children did not have cycloplegic refraction in the follow-up tests, and the results might overestimate the progression of myopia. However, we found a corresponding axial elongation associated with SER progression in children 25 . In addition, the data were from Chinese children in only one region.…”

Normative data for axial elongation in Asian children

“…Axial shortening >0.25 mm/year (i.e., progression <−0.25 mm/year) was removed as outliers given that no anti‐myopia product was used. Additionally, the following filters were applied: age range of 6.0–16.9 years, spherical equivalent RE −6.00 to +6.00 D, outliers above the 99.5 percentile (1%), outside the 3 × standard deviation (SD) boundary limits applied to the linear relationship of spherical equivalent progression versus axial elongation 26 (2.4%) and missing progression data (5%). Finally, 91.6% of the sample was retained.…”