Can lack of sugar cause dry eyes? Unpacking the link between blood glucose and ocular health

November 18, 2025 •

4 min read

According to the American Diabetes Association, over 54% of people with diabetes have dry eye syndrome. So, can lack of sugar cause dry eyes? While it may seem like a logical conclusion, the answer is more complex, as high blood sugar and other nutritional factors are more directly implicated in this uncomfortable condition.

Quick Summary

The link between a lack of sugar and dry eyes is a common misconception. Dry eyes are primarily associated with chronically high blood sugar levels, though other nutritional factors also play a role.

Key Points

High Blood Sugar is the Culprit, Not Lack of Sugar: Chronic dry eye syndrome is primarily linked to hyperglycemia, a condition associated with diabetes, which damages ocular nerves and glands.
Low Blood Sugar Causes Different Visual Issues: Hypoglycemia causes temporary problems like blurred or double vision, but it is not a direct cause of chronic dry eye.
Dehydration Is a Major Factor: Insufficient fluid intake directly reduces tear production and can cause or worsen dry eye symptoms, independent of blood sugar.
Vitamins A and D Are Crucial for Eye Health: Deficiencies in these vitamins are associated with poor tear quality and quantity, contributing to dry eye disease.
Managing Blood Sugar and Hydration is Key: For people with diabetes, controlling blood glucose is the primary way to manage and prevent dry eye; for everyone, staying hydrated is vital.
Dietary Choices Affect Inflammation: High-sugar diets can increase inflammation, while balanced nutrition with Omega-3s and antioxidants can support eye health and reduce inflammation.

Understanding the Real Connection: High Blood Sugar and Dry Eyes

While the search query asks if a lack of sugar can cause dry eyes, clinical evidence points to the opposite: high blood sugar (hyperglycemia), often linked to diabetes, is a significant risk factor for chronic dry eye syndrome (DES). Prolonged periods of elevated blood glucose damage the delicate nerves and blood vessels in the eyes, which are essential for tear production and function. This damage impacts the lacrimal glands (which produce the watery part of tears) and meibomian glands (which produce the oily layer), leading to both decreased tear quantity and poor tear quality.

The Mechanisms Behind Diabetes-Related Dry Eyes

Several interconnected mechanisms explain why poorly controlled blood sugar leads to dry eye symptoms:

Nerve Damage: High blood sugar can cause diabetic neuropathy, affecting the sensory nerves on the eye's cornea. This reduces corneal sensitivity, leading to a weaker blinking reflex and less effective tear production.
Gland Dysfunction: The high blood glucose environment impairs the function of the meibomian glands, causing a less stable, low-quality lipid layer in the tear film. This results in tears evaporating too quickly from the eye's surface.
Increased Inflammation: High blood glucose triggers a cascade of inflammatory responses throughout the body, including the ocular surface. This inflammation further impairs the function of the tear-producing glands.
Tear Osmolarity: Hyperglycemia can lead to tear film hyperosmolarity, an imbalance in the salt content of tears, which also contributes to the dry eye vicious cycle.

The Effect of Low Blood Sugar (Hypoglycemia) on Vision

While low blood sugar isn't directly linked to chronic dry eye syndrome, it can cause temporary vision problems. Unlike the chronic damage caused by high blood sugar, these symptoms typically resolve once glucose levels stabilize. Common visual effects during a hypoglycemic episode include:

Blurred or double vision
Dimness of vision
Central scotomas (blind spots)
Reduced contrast sensitivity
Fatigue and headaches that can indirectly affect visual comfort

These symptoms are not caused by a lack of tears but rather by the brain's diminished energy supply during a period of low glucose. The temporary change in the eye's lens shape can also cause blurriness as blood sugar fluctuates rapidly.

The Role of Diet, Dehydration, and Nutritional Deficiencies

Beyond blood sugar levels, overall diet and hydration are critical for tear production and eye moisture.

Dehydration: Simply not drinking enough water can reduce overall fluid levels in the body, including tear production. Dehydration can cause dry, irritated eyes and blurred vision. Staying properly hydrated is a cornerstone of managing dry eyes.
Nutritional Deficiencies: A diet lacking key vitamins can negatively impact eye health. For example, Vitamin A is crucial for maintaining the cornea, and a deficiency can lead to severe dry eyes. Omega-3 fatty acids are also important for their anti-inflammatory properties and for improving the quality of the tear film's oily layer.

Blood Sugar's Impact on Vision: High vs. Low


Feature	High Blood Sugar (Hyperglycemia)	Low Blood Sugar (Hypoglycemia)
Mechanism	Causes inflammation, nerve damage, and gland dysfunction, leading to chronic issues.	Temporarily affects the brain's visual processing and can alter the eye's lens shape.
Common Visual Symptoms	Chronic dry eye, blurred vision, diabetic retinopathy.	Transient blurred or double vision, dimness, blind spots.
Symptom Duration	Persistent or chronic, worsens over time without proper management.	Temporary, resolves within minutes after blood sugar levels return to normal.
Underlying Condition	Often a complication of unmanaged Type 1 or Type 2 diabetes.	An acute episode that can occur in individuals with diabetes and others.

A Comprehensive Approach to Preventing Dry Eyes

Controlling blood sugar, maintaining good hydration, and ensuring a nutrient-rich diet are fundamental for preserving eye health. For people with diabetes, tight glycemic control is the most effective preventative measure against dry eye syndrome. For everyone, these habits form the foundation for healthy eyes. For more information on managing eye conditions related to diabetes, refer to the resources provided by reputable organizations like the American Diabetes Association.

In addition to addressing the systemic causes, lifestyle modifications can also help. Taking frequent breaks from computer screens, using a humidifier in dry environments, and being mindful of contact lens wear can all reduce dryness. For persistent or severe symptoms, consulting an optometrist or ophthalmologist is essential to determine the root cause and receive a targeted treatment plan.

Conclusion

The idea that a lack of sugar causes dry eyes is inaccurate. The most significant connection between sugar and dry eye syndrome is rooted in high blood sugar levels associated with uncontrolled diabetes. Chronically elevated glucose leads to nerve damage, inflammation, and gland dysfunction that impairs the tear film. While low blood sugar can cause temporary visual disturbances, it is not a cause of chronic dry eyes. A healthy, balanced diet rich in specific vitamins, alongside adequate hydration, is the best nutritional strategy to support optimal eye moisture and overall ocular health.

American Diabetes Association: Dry Eye in Diabetes

Frequently Asked Questions

No, a lack of sugar (low blood sugar or hypoglycemia) does not directly cause chronic dry eyes. It can cause temporary visual issues like blurred vision, but long-term dry eye syndrome is more often associated with high blood sugar.

Chronically high blood sugar can damage the delicate nerves and glands in the eyes responsible for tear production. This leads to decreased tear production and poor tear quality, a condition known as diabetic dry eye.

No, dehydration is a lack of water in the body, while a lack of sugar refers to low blood glucose. While high blood sugar can lead to dehydration, they are not the same condition.

Symptoms of hypoglycemia can include blurred vision, double vision, and reduced contrast sensitivity. These are usually temporary and resolve once blood sugar levels are stabilized.

Deficiencies in certain vitamins, particularly Vitamin A and Vitamin D, can be linked to dry eye syndrome. These nutrients play crucial roles in maintaining the health of the eye's surface and reducing inflammation.

Yes. A balanced diet rich in Omega-3 fatty acids, antioxidants, and adequate hydration is beneficial. Incorporating foods like fatty fish, leafy greens, and staying well-hydrated supports tear film stability and reduces inflammation.

If dry eye symptoms are persistent, severe, or accompanied by other vision problems, it is important to consult an eye care professional. This is especially true for individuals with diabetes.