Effect of hard contact lenses on corneal sensitivity and thickness.

Corneal sensitivity and central corneal thickness were measured on 11 subjects before and after 8 hours of hard contact lens wear. Both factors were monitored for 30 min after removal. It was found that hard contact lenses affect both corneal sensitivity and thickness, significantly. After 8 hours the reduction of sensitivity was found to be, on average, 94% in the centre and 116% in the periphery, and the average increase increase in thickness was 6.9%. Thirty minutes after removal corneal sensitivity had recovered 82% and 100% in the centre and periphery, respectively, and corneal thickness had decreased by 6.3%. A high correlation was found between central and peripheral corneal sensitivity. This investigation shows that corneal sensitivity measurements offer an alternative method of assessing corneal integrity which is simple and precise.