Type of soft contact lens affects myopia change, study finds

Changes in myopia during use of extended-wear soft contact lenses seem to differ based on the material of the lens, a recent study found. Patients wearing high-oxygen-permeability silicone hydrogel lenses had a mean positive change, while those wearing lower-permeability hydrogel lenses had a mean negative change, the study found.

Isabelle Jalbert, OD, FAAO, and colleagues who performed the study said the changes in the patients wearing high-Dk silicone hydrogel lenses may be driven by pressure-related redistribution of corneal tissue, while the changes in the low-Dk hydrogel wearers may be induced by hypoxia-associated corneal thinning.

To measure the changes in myopia associated with extended-wear contact lens wear, the researchers randomly assigned 92 adults to either high-Dk or low-Dk hydrogel lenses. Subjective refraction and autokeratometry were performed at baseline and at 6 and 12 months.

After 6 months of extended wear, myopia regressed by a mean of 0.18 D in the high-Dk group and progressed by 0.23 D in the low-Dk group. No further changes were noted at the 12-month follow-up. Only 35% of the variation could be accounted for by changes in corneal curvature and lens type.

The authors recommended that further studies confirm whether the effects of high-Dk silicone lens wear on myopia are permanent.

The study is published in the August issue of Optometry and Vision Science.