Dry eye is a very common condition with many different causes and associated symptoms. These subsets of dry eye can be divided into how they affect different components of the tear film. Many dry eye patients have a combination of more than one type of dry eye. The tear film is composed of an aqueous component (liquid), a lipid component (oil), and a mucin component (protein).
Aqueous tear deficiency
- The aqueous portion of the tear film is the watery component of the tears produced primarily by the lacrimal gland.
- A lack of aqueous tears may result in a sensation of gritty, burning, or sticky eyes.
- Conditions that cause chronic inflammation, such as Sjogren’s syndrome, rheumatoid arthritis, and lupus may cause chronic inflammation in the lacrimal gland and result in decreased aqueous tear production.
- Treatments for aqueous tear deficiency include artificial tears, prescription drugs such as Restasis or Xiidra, and permanent or temporary punctal plugs, which block the tear drains and keep the natural tears on the ocular surface longer.
Lipid tear deficiency / Tear film instability
- The lipid portion of the tear film is produced by the Meibomian glands in the upper and lower eyelids, as well as other accessory glands on the ocular surface. The lipid portion of the tears helps prevent rapid evaporation of the tear film.
- Insufficient lipid layer results in rapid tear breakup, which means that with each blink, the time to tear film breakdown and evaporation is quicker than normal. This results in chronic irritating symptoms including redness, burning, and pain.
- Blepharitis, which means inflammation of the eyelids, is the most common condition associated with lipid tear deficiency. Blepharitis may cause chronic inflammatory buildup on the base of the eyelashes (anterior blepharitis) and/or chronic inflammation and blockage of the Meibomian glands (posterior blepharitis).
- Treatment for this condition may include warm compresses and lid scrubs to open the Meibomian glands and remove inflammatory debris at the base of the lashes, artificial tears that contain supplemental oils, and prescription medications such as doxycycline or azithromycin pills to reduce eyelid inflammation.