Tear film break-up time in contact lens wearers.

The increasing number of people who wear contact lenses for longer times comfortably while achieving good vision has been attributed to advances in plastics technology. Contact lenses are now worn by any adventurous ametropic patient whose vision is capable of optical improvement. This study was planned to observe the effect of gas-permeable and hard contact lenses with the following objectives: (1) to see whether there is any effect on the tear film break-up time with the different lenses; (2) to study the effect of the blink rate, if any; and (3) to examine the change in the width of the palpebral fissure. We found that only the type of lens affected the tear film break-up time and recommend that gas-permeable lenses be preferred. Any change in the blink rate should be taken as an indication of a poor fit.