Association Between Pupil Dynamics and Peripheral Defocus Spectacle Lens Effectiveness in Slowing Myopia Progression in European Caucasian Pediatric Patients. Preliminary Study

Background: To evaluate whether pupil dynamics affect the effectiveness of peripheral defocus spectacle lenses in slowing myopia progression in European Caucasian pediatric patients. Methods: This non-randomized retrospective observational study included 53 children (mean age 10±3 years) with documented progressive myopia and no ocular disease. We retrospectively reviewed the records of patients who had worn Defocus Incorporated Multiple Segments (DIMS; Hoya MiyoSmart, group A) or Highly Aspherical Lenslet Target (HALT; Stellest; EssilorLuxottica, group B) spectacle lens for at least 24 months. Cycloplegic spherical equivalent (SE) and axial length (AL), were measured at baseline and at 24 month follow- up, and myopia progression was calculated as the difference between mean SE and AL during the follow-up time. Dynamic pupillometry was measured once during the follow-up and the pupil diameter change (PDC) was calculated as the millimeters difference between scotopic and photopic diameter. Results: After 24 months, group A and B did not differ significantly in SE, AL and PDC change (p > 0.05). In group A and B the SE change was positively correlated with PDC (p < 0.05), while AL change and PDC did not show significant correlation in both groups (p > 0.05). For group A and B the PDC median was respectively 4.5 and 4.7mm.Conclusion: These findings suggest that AL change could be considered not dependent by pupil dynamics for evaluating myopia progression, and that a PDC lower than 4.5mm seems to improve the effectiveness of peripheral defocus spectacle lenses in slowing SE increase in European Caucasian pediatric patients, without significant differences between DIMS and HALT design.