Dry eye is a common and often chronic condition that occurs when the eyes are unable to maintain a healthy tear film—either due to insufficient tear production or excessive tear evaporation. A stable tear film is essential not only for keeping the eyes lubricated, but also for maintaining clear vision and protecting the surface of the eye from irritation and infection.
There are two main types of dry eye. The first is aqueous-deficient dry eye, where the lacrimal glands do not produce enough tears. The second is evaporative dry eye, which is more common and often linked to dysfunction of the meibomian glands in the eyelids. These glands are responsible for producing the oily layer of the tear film, which prevents tears from evaporating too quickly. When this layer is compromised—often due to eyelid inflammation (blepharitis)—the tears become unstable and evaporate faster, leading to dryness.
All of these can lead to reduced vision.
