The effect of rigid gas permeable lenses on corneal sensitivity.

Long term wear of hard (PMMA) contact lenses decreases corneal sensitivity. Clinicians have noted that in some patients who are refitted with rigid gas permeable (RGP) lenses, there is often an increase in lens awareness. To document this symptom, we monitored changes in corneal sensitivity of long term PMMA wearers who were refitted with RGP lenses. Corneal sensitivity measurements were conducted over a 6-month period. During this time, corneal touch threshold decreased to normal levels within a few weeks after refitting with RGP lenses. These results suggest an oxygen dependency factor in the control of corneal sensitivity accompanying contact lens wear.