Soft daily disposable contact lenses are often cited as the healthiest lens choice because of their lower risk of infection, but a new study reports they also don’t appear to change corneal epithelial thickness. A team of Turkish researchers found that anterior corneal topographic readings rose and fluctuated naturally at times during the day, and the daily disposable lenses appeared to mask the steepening.

The study enrolled 32 healthy volunteers. At the first visit, researchers recorded keratometric measurements and corneal and epithelial thickness maps both in the morning and again eight hours later. The researchers then randomly fit each participant with one of four different brands of daily disposable lenses and on different days. All fitted lenses had a power of -3.00D. The investigators repeated the measurements prior to the fitting and again after eight hours of lens wear.

When patients weren’t wearing lenses, anterior topographic readings showed significant steepening. Corneal thickness also decreased substantially in the central and temporal portion of the cornea in the afternoon, the researchers noted. No significant changes were found in the posterior topographical readings or corneal epithelial thickness.

When patients were wearing the daily disposable lenses, no significant change was seen in corneal and epithelial thickness or in the anterior and posterior curvatures during the day.

Additionally, the study found no major difference in epithelial thickness among the groups wearing the different contact lens types.