Keratoconic eyes are widely known to be different from those of healthy subjects, but a new study in Contact Lens & Anterior Eye found that kerotoconus patients have uniquely shaped corneal peripheries and scleras that may be altered by specialty lens wear.

Researchers conducted a cross-sectional study that compared three groups of keratoconus eyes: 24 lens-naïve eyes (17 patients, group one), seven eyes that wore corneal lenses (seven patients, group two) and another seven eyes that wore scleral lenses (seven patients, group three). For comparison, 25 eyes of 25 emmetropic participants and 11 eyes of 11 astigmatic individuals were included as controls. The investigators took corneoscleral topography measurements to evaluate the limbal radius and calculate the sagittal height and corneoscleral asymmetry.

In non–lens wearing keratoconus patients, sagittal height was significantly larger compared with the control eyes in both the corneal periphery and sclera. The level of peripheral corneal and scleral asymmetry was also significantly higher in non–lens wearing keratoconus eyes compared with the controls.

Of note, both corneal and scleral lens wear resulted in significant changes to the shape of the corneal periphery and sclera. In all three groups of keratoconus eyes, asymmetry of the peripheral cornea showed a very strong correlation with scleral asymmetry.

“Specialty lens wear induces significant regional changes to the shape of the anterior eye in keratoconus eyes,” the researchers wrote in their paper.