What Is Evaporative Dry Eye? Causes, Symptoms, Diagnosis, and Treatment

There are two main types of dry eye disease: evaporative and aqueous tear deficiency.

Evaporative dry eye occurs when there's an imbalance or instability in the tear film, the thin layer of fluid covering the surface of the eye. This imbalance can result from various factors, leading to increased evaporation of tears and inadequate lubrication of the eyes.

With evaporative dry eye, the quantity of tears produced is normal, but the low quality of the tears leads to excessive tear evaporation.

Aqueous deficient dry eye occurs when your eyes don’t produce enough tears. More specifically, the lacrimal glands of your eyelids fail to produce enough of the tear film’s watery (middle) layer, which makes up most of what we see in tears and serves to wash away particles from the eyes.

Evaporative dry eye can be caused by a variety of factors that disrupt the delicate balance of the tear film and contribute to increased tear evaporation.

• Eye inflammation
• Blinking too slowly or not completely, such as when looking at digital screens for long periods of time
• Environmental factors such as dry or windy climates, air-conditioning, heating systems, and low humidity levels
• Vitamin A deficiency
• Prolonged contact lens use
• Changes in the anatomy or structure of the eyes and eyelids, such as from surgery, aging, and thyroid disease

• A persistent sensation of dryness in one or both eyes, especially in environments with low humidity or increased air circulation
• Eyes that appear red or bloodshot (from inflammation and irritation), which may be more pronounced in the lower eyelids and accompanied by a burning or stinging sensation
• A feeling of grittiness as if a piece of sand is stuck in your eyelids
• A stringy, waxy discharge from the eyelids (meibum from dysfunctional meibomian glands)
• Blurring or fluctuation in vision, particularly during activities that require sustained visual focus, such as reading, using digital screens, or driving
• Light sensitivity
• Excessive tearing or watery eyes, a reflexive response to eye irritation and dryness that tries to flush out irritants

Diagnosing dry eye typically begins with a comprehensive examination by an eye care professional. Your provider will review your symptoms and medical history to understand both what you’re experiencing and any potential underlying conditions or factors contributing to your issues, such as systemic diseases, allergies, medications, and previous surgeries.

• Ocular surface staining, a test to evaluate the tear film and ocular surface after temporarily staining the surface of the eyes with nontoxic fluorescein or lissamine green eye drops
• Tear film breakup time, a measurement of the time it takes for the tear film to break up after a blink
• Schirmer's test, which measures the quantity of tears produced by the eyes over a specified period
• Tear osmolarity, a test to measure the salt content in tears (higher amounts are associated with dry eye)
• Slit lamp exams, which involve examining your eyes under a microscope and direct light
• Meibography, the imaging and assessment of the meibomian glands
• Meibomian glands expression, applying pressure along the eyelids to release or express meibum (thick or cloudy meibum indicates gland dysfunction)

There are many possible treatments for evaporative dry eye that vary depending on the severity of the disease. The ultimate goal of treatment is ensuring the meibomian glands can let their oils out.

• Lifestyle and environmental changes such as using humidifiers, practicing blinking exercises to encourage regular blinking, avoiding direct high airflow or fans, reducing screen time, and wearing wrap-around sunglasses or protective eyewear
• Reduction or elimination of medications and topical agents that may worsen evaporative dry eye
• Artificial tear eye drops
• Warm compresses to alleviate meibomian gland blockage
• Eyelid hygiene practices, such using a non-irritating cleanser or scrub solutions for the eyelids
• Omega-3 fatty acids supplements
• Prescription medications, such as corticosteroids eye drops, lipid-based eye drops, antibiotic ointments or solutions to treat any bacterial infections or blepharitis (inflammation of the eyelids), inflammation-suppressing eye drops such as cyclosporine (Restasis) and lifitegrast (Xiidra), and the nasal spray varenicline (Tyrvaya)
• Intense pulsed light therapy and thermal pulsation therapy to improve meibomian gland function
• Punctal plugs, which are inserted into the tear drainage ducts (puncta) to block tear outflow and increase tear film volume on the ocular surface

Work with your eye-care professional to find the combination of treatments and lifestyle changes that help you the most. If you feel you’ve “tried everything” and still have uncomfortably dry eyes, you may benefit from seeing a dry eye specialist.