Dehydration and physicochemical changes in myopia control contact lenses: influence of material and maintenance...

To assess the dehydration rate in different myopia control contact lenses (CLs) and the physicochemical changes that occur after exposure to different maintenance solutions.

First, the dehydration rate of CLs and its impact on refractive index and diameter were evaluated in three myopia control CLs models (MiSight 1 Day, Bloom Day, and MYLO). Measurements were taken immediately after the CL was removed from the blister and at 5-min intervals over a 30-min period. Second, the effect of different maintenance solutions on the physicochemical properties of monthly replacement myopia control CLs (MYLO) with different diameters were assessed. Refractive index, water content, diameter, lens surface hydrophobicity, and dynamic mechanical properties were measured immediately after the CL was removed from the blister and again after 12 h of immersion in each of the three maintenance solutions studied (Hidro Health HA, OPTI-Free PureMoist and Biotrue).

The dehydration rate exhibited significant disparities among the CLs examined, with daily replacement CLs (MiSight 1 Day and Bloom Day) demonstrating the fastest dehydration and, consequently, the most significant change in refractive index. In contrast, MYLO CLs exhibited the greatest reduction in diameter. When assessing the impact of maintenance solutions on MYLO properties, changes were observed in all evaluated parameters, except for mechanical properties. These changes varied depending on the maintenance solution used and the diameter of CL.

Myopia control CLs can undergo dehydration and changes due to the solutions used for their care, which may significantly affect their physicochemical properties, lens performance, comfort, and stability. Therefore, careful consideration should be given to the properties of the CL material and the maintenance solutions properties to optimize the user experience and ensure consistent lens behavior over time.