Dry eye, also known as ocular surface disease, is a condition that affects the eyes and can cause discomfort and vision problems. It occurs when there is an imbalance in the tear film that normally keeps our eyes moist and lubricated.
The tear film consists of three layers: the mucin layer, the aqueous (watery) layer, and the lipid (oily) layer. Each layer has an important role in maintaining a healthy ocular surface. When there is an issue with any of these layers, dry eye can occur.
There are two main types of dry eye: aqueous deficient and evaporative dry eye. Aqueous deficient dry eye happens when the lacrimal glands, which produce the watery component of tears, don't produce enough tears or produce poor-quality tears. This can result in an insufficient amount of moisture on the ocular surface, leading to dryness and discomfort.
On the other hand, evaporative dry eye occurs when the meibomian glands, located in the eyelids, don't function properly. These glands secrete the oily layer of the tear film, which helps prevent the evaporation of tears. When the meibomian glands become blocked or dysfunctional, the tears evaporate too quickly, causing dryness and irritation.
Both types of dry eye can have similar symptoms, such as a sandy or gritty sensation in the eyes, stinging or burning, redness, and blurry vision. People with dry eye may also experience excessive tearing, as the eyes try to compensate for the lack of moisture.
Several factors can contribute to the development of dry eye, including age, gender (women are more prone to it), certain medical conditions (such as rheumatoid arthritis and Sjögren's syndrome), environmental factors (like dry or windy climates), prolonged screen time, and the use of contact lenses.
It's important to understand that dry eye is a chronic condition that requires proper management and care. If you suspect you have dry eye, it's recommended to consult with an eye care professional who can evaluate your symptoms, perform diagnostic tests, and provide appropriate guidance for managing the condition.