What Causes Dry Eyes? 4 Reasons

Dry eyes are a frustrating condition that can significantly affect your quality of life, as eye dryness can impact your ability to see clearly, concentrate, and complete day-to-day tasks.

While occasional dryness may be linked to weather or allergies, persistent symptoms often point to deeper underlying factors–many of which can relate to nutritional imbalances.

Discover four common causes of dry eyes and learn how to promote natural moisture balance in the eyes.

What are dry eyes?

Dry eyes occur when the tear film, the watery layer that helps keep the eyes lubricated, becomes imbalanced or unstable. 

A healthy tear film comprises three layers:

• The mucin layer forms the innermost layer lining the inside of the eyelids and covering the white part of the eye. It comprises gel-like proteins that help tears spread evenly across the cornea and adhere to the eye’s surface. 
• The aqueous layer, produced by the lacrimal glands, forms a watery middle layer that delivers hydration, oxygen, and nutrients to the eye.
• The lipid layer contains a fatty substance called meibum, which is secreted by the meibomian glands on the inner eyelids. This oily layer forms a protective topcoat over the eye’s surface that helps prevent evaporation and supports tear stability.

When any part of the tear film is disrupted, it can impact eye functions and comfort, resulting in dry eye symptoms, which can lead to other complications if left unaddressed.

Aqueous-deficient dry eye syndrome occurs when the lacrimal glands don’t produce enough fluid to keep the eye properly lubricated.

Evaporative dry eye develops when the tear film’s oily layer is impaired, causing tears to evaporate too quickly.

Common symptoms of dry eyes include:

• Dryness or a sandy, gritty feeling
• Itching, burning, or stinging
• Redness or inflammation
• Eye fatigue
• Sensitivity to light
• Blurred or fluctuating vision
• A feeling of a foreign object in the eye
• Watery eyes

According to data published by the National Eye Institute (NEI), left untreated, chronic dry eye can damage the tear duct and cornea, increasing the risk of pain, inflammation, corneal ulcers or scarring, and even a degree of vision loss.

Watch the video below to learn what causes dry eyes and natural ways to promote eye comfort.

What causes dry eyes?

Dry eyes are often linked to dietary and environmental factors that can affect tear quality and stability.

Here are four common causes of dry eyes and what you can do about them.

1. High-carb diets

One of the most overlooked contributors to dry eye symptoms is a diet high in refined carbohydrates and sugars.

“High-carb eating causes repeated blood sugar and insulin spikes that, over time, can contribute to insulin resistance,” explains Dr. Berg. “This imbalance can significantly stress the vascular system and disrupt nutrient delivery to tissues–including the nerves that help maintain a stable tear film.”

Research supports this connection, and a study published in Diabetes, Metabolic Syndrome and Obesity found that individuals with higher fasting blood glucose levels had more severe dry eye disease symptoms than those with normal glucose levels.

High-carb diets may also reduce the uptake or deplete essential nutrients for eye health, such as vitamins A, B1, B12, D, E, and K.

Since diet influences both insulin function and nutrient availability, shifting toward a low-carb, nutrient-dense meal plan, such as Healthy Keto®, can provide long-term support for eye comfort.

2. Imbalanced fatty acid intake 

Your eyes rely on healthy fats to function properly, particularly for maintaining the retina, lens, and tear film. 

Without adequate amounts of saturated fats, cholesterol, and omega-3 fatty acids, your body may struggle to produce the lipids needed to keep the eyes lubricated.

Moreover, diets high in unhealthy fats, such as refined seed oils like canola oil, soybean oil, and corn oil, contain excessive amounts of omega-6 fatty acids, which can contribute to unstable ocular fluid production.

Research published in Investigative Ophthalmology & Visual Science highlights that consuming more omega-6 fatty acids than omega-3 fatty acids was linked with tear film dysfunction and ocular surface stress, two key factors in the development of dry eyes.

To provide the eyes with the building blocks needed to maintain moisture, it’s recommended to replace omega-6-rich seed oils with nutrient-dense fats such as grass-fed butter, beef tallow, ghee, and egg yolks.

Additionally, wild-caught fatty fish, such as cod liver, mackerel, and sardines, and grass-fed beef are excellent sources of healthy fats and fat-soluble vitamins A, D, E, and K, which further support tear film integrity and ocular surface health.

3. Lack of vitamin A 

Vitamin A plays a central role in keeping the eyes comfortable and well-lubricated. Without enough vitamin A, eyes can become rougher and less efficient at maintaining moisture.

Research published in Cureus summarizes: “Vitamin A is crucial for mucin-producing conjunctival goblet cells. Their dysfunction can lead to the development of severe dry eye disease and associated complications.”

Vitamin A deficiency can also thicken epithelial cells that line the glands of the eye and ocular surface. Over time, this may lead to blockages of ducts, preventing the excretion of protective tear films and further contributing to eye dryness.

Animal products are the best dietary sources of vitamin A, as they offer its active form, retinol. Unlike beta-carotene found in plant foods, which must be activated in the liver, retinol can be utilized immediately.

Some of the top whole food sources of bioavailable vitamin A include grass-fed beef liver, wild-caught cod liver, pasture-raised egg yolks, and grass-fed butter.

Absorption of vitamin A also depends on overall fat metabolism. Since it’s a fat-soluble vitamin, it requires healthy bile flow, optimal liver function, and adequate sources of dietary fat to be utilized and stored efficiently.

This highlights the importance of adopting a nutrient-dense diet such as Healthy Keto, which supports fat adaptation, fat-soluble vitamin absorption, and overall metabolic function.

4. Environmental factors

External conditions can also impact the tear film, as individuals who wear contact lenses are at increased risk of dry eyes. 

In addition, air conditioning, central heating, and dry climates can speed up tear film evaporation, especially when the lipid layer is compromised. Windy weather and seasonal shifts may also dry out the eyes or increase exposure to airborne irritants.

Exposure to cigarette smoke or secondhand smoke, as well as allergens such as pollen, pet dander, or dust, can trigger ocular inflammation and discomfort on the eye’s surface.

Looking at a computer screen for long periods can reduce blink rate, preventing tears from spreading evenly and causing the eyes to dry.

To help keep the eyes healthy, take regular breaks from screens. Additionally, staying hydrated, using a humidifier, avoiding irritant exposure, and wearing wraparound sunglasses in harsh environments can also help reduce tear evaporation and protect the eyes.

Other risk factors for dry eyes may include laser eye surgery or refractive surgery, age-related decline, and certain prescription medications.

When to talk to your doctor

While occasional dryness can potentially be managed with lifestyle changes and nutritional adjustments, it’s important to consult an eye doctor if you notice painful eyes, blurry vision, a gritty or itchy sensation, or sudden sensitivity to light. 

In some cases, dry eyes can signal underlying medical conditions, including meibomian gland dysfunction, Sjogren’s syndrome, liver disease, thyroid eye disease, blepharitis, high blood pressure, or rheumatoid arthritis. 

In addition to lifestyle modifications, a healthcare practitioner may suggest various treatments, such as therapeutic contact lenses, eye drops, nasal spray, or surgery, depending on the exact underlying cause of dry eyes. 

Early diagnoses and timely medical intervention can help relieve eye discomfort, protect vision, and support long-term ocular health.

Key takeaways

While dry eyes can be caused by medications, genetic factors, or underlying medical conditions, many cases are linked to nutritional deficiencies, environmental stressors, and metabolic imbalances.

Imbalanced fatty acid intake and a high-carb diet can deplete nutrients, impair circulation, and disrupt tear film stability. 

Following a nutrient-dense Healthy Keto diet can help support eye comfort by providing vitamin A, B1, B12, and omega-3 fatty acids, while minimizing the intake of refined carbs and processed foods.

FAQ

Sources

1. https://www.nei.nih.gov/sites/default/files/health-pdfs/factsaboutdryeye.pdf 
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC11806745/ 
3. https://iovs.arvojournals.org/article.aspx?articleid=2520646& 
4. https://assets.cureus.com/uploads/case_report/pdf/78527/20220405-13380-yw7dly.pdf