Comparison of Seasonal Variation in Myopia Progression: Defocus Incorporated Multiple Segment Spectacle Lenses in...

To investigate and compare seasonal variations in axial length (AL) in myopic children with defocus incorporated multiple segments (DIMS) spectacle lenses combined with 0.01% atropine (DIMSA) and orthokeratology (OK) lenses.

The present retrospective study involved 428 subjects, mean age 9.70 ± 1.94 years, categorized into two groups: DIMSA (203 cases), and OK lenses (225 cases). Data were classified as "summer" or "winter" based on the midpoint of the 6 months between visits. Initial clinical visit (baseline) and one-year follow-up data were collected, and only data from the right eye was retrieved for analysis. Axial elongation over time and between groups was analyzed.

The mean change in AL at 1 year was 0.18 ± 0.19 mm in the DIMSA group and 0.19 ± 0.15 mm in the OK group, with no significance between the two groups (p>0.05). In both groups, the change of AL in winter was significantly higher than that in summer (P<0.01). A similar seasonal pattern was found among children 7-8 years of age in the DIMSA group and 7-12 years of age in the OK group, as well as for those with an initial AL < 26 mm.

DIMSA and OK lenses show similar reductions in myopia progression at different times of the year. Axial elongation decreased in summer, and this phenomenon disappears with increasing age and AL.