Reduced myopia progression with low-dose atropine in DIMS non-responders and evidence of altered pupillary light reflex kinetics.

This study evaluated the efficacy of adding nightly 0.025% atropine to Defocus Incorporated Multiple Segments (DIMS) spectacle treatment in children with ongoing myopia progression and explored whether dynamic pupillometry could help identify such progression. In a mixed-method design, a longitudinal arm included 20 DIMS non-responders, defined by annual progression of ≥ 0.5 D spherical equivalent refraction or ≥ 0.2 mm axial elongation, who received adjunctive atropine and were followed for 12 months. In a separate cross-sectional arm, dynamic pupillometry was performed in 60 DIMS-treated children classified as fast or slow progressors based on prior-year progression. Combination therapy significantly reduced myopia progression, with mean axial elongation decreasing from 0.39 ± 0.18 to 0.20 ± 0.18 mm/year and mean refractive progression improving from - 0.82 ± 0.67 to - 0.28 ± 0.45 D/year. Transient axial shortening was observed in 20% of patients, while 25% remained unresponsive, predominantly those with high maternal myopia. Dynamic pupillometry revealed that fast progressors exhibited slower and prolonged pupil constriction compared with slow progressors, whereas dilation parameters and static pupil size did not differ. In conclusion, adjunctive low-dose atropine effectively reduced progression in most DIMS non-responders, and altered pupil constriction dynamics may reflect underlying physiological differences associated with treatment resistance.