Dry eyes, a common condition, occur when there are insufficient tears or when the tears produced are of poor quality. This imbalance in the tear film, the protective layer over the eye, often leads to uncomfortable symptoms. Dry eyes can indeed cause inflammation of the ocular surface. This inflammation can worsen the condition, creating a persistent cycle of discomfort and potential damage.
Understanding Dry Eye Disease
The tear film plays an important role in maintaining eye health, providing lubrication, protecting against infection, and ensuring clear vision. It is composed of three main layers: an oily outer layer, a watery middle layer, and an inner mucus layer. The outermost lipid layer, produced by meibomian glands in the eyelids, helps prevent tear evaporation and maintains a smooth optical surface. The aqueous layer, primarily from the lacrimal glands, provides moisture, nutrients, and antimicrobial properties. The innermost mucin layer, secreted by goblet cells, helps spread tears evenly across the eye’s surface.
Dry eye disease arises when any of these tear film components are compromised, either through inadequate tear production or excessive tear evaporation. One type is aqueous deficient dry eye, where the lacrimal glands do not produce enough watery tears. The other main type is evaporative dry eye, which occurs when tears evaporate too quickly, frequently due to dysfunction of the meibomian glands. Common symptoms include a gritty, scratchy, or burning sensation, along with blurred or fluctuating vision.
The Inflammatory Cycle
When the tear film becomes unstable or deficient, the ocular surface is exposed to stress, initiating an inflammatory response. This chronic dryness stresses the cells on the eye’s surface, leading to cellular damage. In response, these stressed cells release inflammatory mediators, such as cytokines and chemokines, into the tear film. These molecules act as signals, triggering an immune response and attracting inflammatory cells, like T cells and neutrophils, to the ocular surface.
A significant factor contributing to this inflammation is increased tear film osmolarity, meaning the tears become too salty. This hyperosmolarity directly damages corneal and conjunctival epithelial cells, further activating inflammatory cascades. This damage leads to a self-perpetuating cycle where dryness causes inflammation, and the inflammation, in turn, further damages the tear glands and ocular surface, exacerbating the dryness.
Recognizing Inflammatory Dry Eye
Certain signs indicate that inflammation is a component of dry eye. Persistent redness of the eyes, known as conjunctival hyperemia, often points to ongoing inflammation. Individuals may also experience increased light sensitivity (photophobia) and eye pain that extends beyond a simple feeling of dryness or grittiness. A foreign body sensation, as if something is constantly in the eye, can also be more pronounced when inflammation is present.
Blurred vision that does not clear easily with blinking can also be a symptom of inflammatory dry eye. Inflammation can also manifest as eyelid swelling or affect the glands within them. Conditions like blepharitis (inflammation of the eyelid margins) and meibomian gland dysfunction (MGD), which involves inflammation of the oil-producing glands, are frequently linked to inflammatory dry eye. If these symptoms persist or worsen, consult an eye care professional for diagnosis and treatment.
Managing and Treating Inflammatory Dry Eye
Managing inflammatory dry eye involves a multi-faceted approach aimed at alleviating dryness and addressing inflammation. Initial strategies include artificial tears, with preservative-free options preferred for frequent use to avoid irritation. For evaporative dry eye, warm compresses applied to the eyelids can help soften thickened oils in the meibomian glands, improving their function and stabilizing the tear film. Lid hygiene, involving gentle cleaning of the eyelids, is also recommended, especially if blepharitis is present.
When basic measures are insufficient, prescription eye drops targeting inflammation become necessary. Cyclosporine and lifitegrast are two common immunomodulatory drops that work by reducing inflammation on the eye’s surface, thereby helping to increase natural tear production over time. For severe flare-ups, corticosteroid eye drops may be prescribed for short-term use to quickly reduce inflammation, though long-term use is generally avoided due to potential side effects. Other interventions can include punctal plugs, small devices inserted into tear drainage canals to keep tears on the eye longer, and dietary changes, such as supplementing with omega-3 fatty acids, for potential anti-inflammatory benefits.