Tears are the natural way to keep eyes moist, and tears are important for good vision and healthy eyes. Eyes without enought tears get dry and sore.
The natural and normal way to stimulate secretion of tears is by turning on cold sensors that are located on the cornea of the eye. Tear are normally released across the eyeball in a finely balanced system that balances out that natural evaporation. But sometimes there is not enough tear secretion to balance out the evaporation of tears and eyes can get sore.
The aim here is to test whether menthol in its vapor form may possibly turn on those cold sensors and thus cause secretion of tears. Use of menthol vapors may be like having a switch to release more tears.
The aim of this clinical trial is to test the hypothesis that a menthol solution applied onto a cheek will release enough menthol vapor into the air flowing up over the eye's cornea to stimulate cold sensors enough to make a tear flow from the eye.
If the hypothesis that menthol safely stimulates tear secretion in healthy people proves to be correct, then this clinical trial may inspire more new research into the use of menthol as an alternative to the use of eye drops for some people.