The layer of tear film on your eyes is constantly thinning out and evaporating. Normally, this process, known as tear film break-up, isn’t a problem: new tears are continually being produced, then washed out through tiny holes on the edges of your eyelids, keeping your tear film fresh. When you blink, that’s just your body’s automatic reflex to spread new tear film across your eyeballs.
Problems arise, however, when the quantity or quality of your tear film changes. If you’re producing an insufficient amount of tears – or tears that break up too quickly, before your impulse to blink – you may begin to develop dry spots on the surface of your eye. These dry spots may make your eyes feel uncomfortable.
Even if all the components of your tears are normal, dry spots can still appear on your eyes in certain situations. The corneal cells on the eye’s surface have very delicate structures that allow the tears to “stick” to the eye. If these structures are damaged, tear film can break up too quickly.
You might not be able to tell that you have damaged corneal cells, but if your eyes feel dry, or you have a burning sensation often described as “gritty eyes,” you may want to see your eye care professional. Using a corneal staining method (a diagnostic fluorescent stain) and a slit lamp (a special lamp used to see these stains up close), they’ll be able to determine if you have surface damage.
If you do have surface damage, your corneal cells can heal more quickly if they are coated with a lubricant that protects them and keeps them moist