Physiological Changes in the Cornea When Wearing Rigid Gas Permeable Contact Lenses

Rigid gas permeable (RGP) contact lenses are made of materials with excellent oxygen permeability and wettability, so they not only improve oxygen permeability compared to existing lenses, but also provide correction of refractive errors and improved vision in irregular corneas such as keratoconus. However, the hard material of the lens along with hypoxia and hypercapnia of the cornea caused by wearing RGP contact lenses cause various physiological changes in the cornea. Physiological changes in the cornea that may occur when wearing RGP contact lenses include mucin balls, decreased corneal epithelial thickness and increased size, decreased epithelial barrier function, corneal erosion and staining, decreased keratocyte density, decreased corneal sensitivity, and stromal opacities, contact lens‐induced peripheral ulcers, endothelial blebs, increased endothelial polymegethism, and changes in corneal shape. It is necessary to know the performance of the RGP contact lenses being prescribed, be aware of the physiological changes in the cornea caused by wearing RGP contact lenses, and provide the correct lens prescription along with appropriate education to the patient.