What Causes Glassy Eyes?

A glassy eye is a non-medical term used to describe eyes that look shiny, glazed over, or out of focus. Symptoms of glazed or glassy eyes can be caused by several health conditions, ranging from seasonal allergies to more severe conditions such as infection or disease.

Are Glassy Eyes Dangerous?

Glassy eyes are common and often go away on their own. They're typically harmless and are more of a nuisance.

However, glassy eyes can indicate a more serious concern. Glassy eyes may be a symptom of an underlying health condition.

9 Possible Causes of Glassy Eyes

There are several possible causes of glassy eyes. Each cause has its own signs, symptoms, and treatment methods.

These include:

1. Allergies

Seasonal allergies are a common cause of glassy and itchy eyes. Many environmental factors trigger allergies, including: 

• Pollen
• Dust
• Grass
• Trees
• Mold
• Perfume
• Cigarette smoke

In addition to itchiness and glassy eyes, other symptoms of allergies include:

• Redness
• Burning
• Tearing
• Clear watery discharge 

Treatment

Eliminating the allergen is the best way to treat allergies. You can also purchase over-the-counter (OTC) allergy medication (antihistamine such as Benadryl) and apply eye drops to minimize symptoms. 

2. Substance Intoxication

People who are intoxicated can have glassy, unfocused eyes. Drugs (illegal and prescription) and alcohol abuse slow down the central nervous system (CNS), contributing to decreased blinking and dehydration, which causes dry, glassy eyes. 

Other symptoms of intoxication include:

• Slurred speech
• Bloodshot eyes
• Dazed look
• Droopy eyelids
• Change in behavior

Treatment

Symptoms of intoxication will typically subside over time after the body detoxes from the effects of alcohol and drugs.

3. Dry Eyes 

Eyes can appear glassy when they are dry or not producing enough tears. 

Several factors can cause dry eyes, including:

• Age
• Medications
• Blepharitis (inflammation of the eye surface)
• Exposure to wind, smoke, or dry conditions
• Long-term contact lens use
• Eye surgery
• Extensive time in front of a computer screen

Other symptoms of dry eyes include:

• Redness
• Stinging or burning sensation
• Mucus discharge
• Blurry vision
• Watery eyes

Treatment

Medicated or OTC eye drops are commonly used to treat dry eyes. Surgery to block tear ducts may be necessary to conserve tears in severe cases that are not relieved by medication. You should contact your surgeon if you're experiencing dry eyes after eye surgery.

4. Dehydration 

Dehydration is a common cause of glassy eyes, especially in children, because of decreased tear production. Severe dehydration can lead to serious health consequences, including:

• Seizures
• Heatstroke
• Shock
• Disorientation

In addition to glassy eyes, common symptoms of dehydration include:

• Dry mouth and tongue
• Dry eyes
• No tears
• Decrease in urination 
• Sunken eyes
• Fatigue 
• Dizziness and confusion
• Extreme thirst

Treatment

Mild dehydration is treated with drinking water and getting out of extreme heat. A hospital visit for intravenous (IV) fluids is needed for more severe cases of dehydration. 

5. Eye Infections 

Glassy eyes are a common symptom of certain eye infections, including conjunctivitis (pink eye) and eye herpes. Oftentimes, conjunctivitis is caused by a bacterial infection, a viral infection, or allergies.

Common symptoms of conjunctivitis include:

• Pink or red eyes
• Eyelid swelling
• Itchiness
• Watery eyes
• Pus or mucus discharge
• Crusting of the eyelids

Eye herpes is caused by the herpes simplex virus (HSV) infecting the cornea (keratitis). 

Symptoms of eye herpes include:

• Pain
• Redness
• Watery discharge
• Light sensitivity
• Blurred vision 

Treatment

Most eye infections are treated with eye drops. Bacterial conjunctivitis is treated with antibiotic eye drops. Viral conjunctivitis clears on its own over a couple of days or weeks.

Eye herpes typically improves over time but can also be treated with antiviral eye drops or oral medication. Antiviral medicine with steroid eye drops can help reduce the swelling.

However, unlike conjunctivitis and eye herpes, pink eye is caused by allergies. This is treated by removing the triggering allergen. 

6. Hypoglycemia

Hypoglycemia (low blood glucose) predominantly affects people with diabetes and can cause glassy eyes when their sugar gets too low.

Symptoms of mild to moderate hypoglycemia include:

• Shakiness
• Dizziness
• Sweating
• Hunger
• Fatigue
• Irritability
• Confusion

Treatment

Low blood sugar is reversed by consuming carbohydrates. If left untreated, severe hypoglycemia can cause seizures and loss of consciousness.

7. Graves’ Eye Disease 

Graves’ eye disease, also called Graves’ ophthalmopathy, is an autoimmune disease caused by the overproduction of thyroid hormones (hyperthyroidism). It results in eyelid retraction and bulging, glassy eyes.

Symptoms of Graves’ disease include:

• Weight loss
• Nervousness
• Muscle weakness
• Irregular heartbeat
• Pain in the eyes
• Puffy eyes
• Enlarged thyroid gland (goiter)

Treatment

Mild cases of Graves’ ophthalmopathy involve medicated eye drops. Severe cases of Graves’ disease are treated with medication, radiation therapy, and surgery. 

8. Cholera 

Cholera is a bacterial intestinal infection typically spread through the water in countries with inadequate water treatment, such as:

• Africa
• Mexico
• Asia
• India
• South and Central America

In addition to a glassy appearance, symptoms of cholera include:

• Diarrhea 
• Vomiting
• Excessive thirst
• Leg cramps
• Restlessness and irritability 

Treatment

The primary treatment for cholera is hydration. Antibiotics are also used in conjunction with hydration, especially for people who are severely sick.

During rehydration treatment, people with severe dehydration are recommended to pass a large volume of stool. If left untreated, cholera can be deadly.

9. Computer Vision Syndrome (CVS)

Computer vision syndrome (CVS) is an eye strain from prolonged screen time that can cause the appearance of glassy eyes.

Uncorrected eye problems can make CVS worse. CVS is exacerbated by: 

• Poor lighting
• Screen glare
• Poor posture
• Viewing the screen from a distance or too close

Symptoms of CVS include:

• Eyestrain
• Headaches
• Dry eyes
• Blurred vision
• Neck and shoulder pain

Treatment

Adjusting seating, posture, and lighting are good ways to reduce symptoms of CVS. Computer glasses can also help with glare. 

Ways to Prevent Glassy Eyes

Preventing glassy eyes first starts with treating the underlying cause of glossy eyes. Tips on keeping your eyes healthy and clear include:

• Limit screen time
• Keep your hands clean to avoid infection
• Drink plenty of water to stay hydrated
• Control your blood sugar if you have diabetes
• Don’t drink alcohol excessively
• Avoid sharing cosmetics, eyeglasses, or other objects that can spread infection
• Keep your eyes moist by blinking often
• Visit the eye doctor regularly to identify conditions early 

What is the Outlook for Glassy Eyes? 

The appearance of glassy eyes is usually temporary and typically goes away after the underlying cause is treated or eliminated. Seek medical care if symptoms are persistent and don’t resolve on their own or with standard treatments. 

Summary

Glassy eyes are the side effect of many health conditions, including intoxication, allergies, eye infection, and dehydration. Mild symptoms of glossy eyes typically go away on their own or by treating the underlying issue.

There are ways to prevent the appearance of glassy eyes. These include includes limiting screen time, proper hand hygiene, limiting alcohol and drug intake, and drinking plenty of water to avoid dehydration. 

Glassy eyes are usually temporary and harmless. However, if symptoms persist, contact an eye doctor; glassy eyes may be a symptom of a more serious health issue.