Dehydration can dry the eyes, causing symptoms such as sunken eyes. Drinking enough fluids and using artificial tears may help resolve dry eyes and prevent this issue in the future.

Dehydration occurs when a person’s body loses more water than they replace. It can cause dryness of the skin, lips, and certain parts of the eyes.

Dry eyes due to severe dehydration may lead to further symptoms, including irritation, redness, and blurred vision. However, people may be able to treat these symptoms by rehydrating.

This article looks at dehydration and the eyes, symptoms and treatment for dry eyes, and how to prevent dehydration.

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Dehydration can cause dryness of the mucous membranes. This includes the conjunctiva of the eye that lines the eyelid and surface of the eye.

A 2021 article also suggests that dehydration may have links to high salt levels in tears, a condition called tear hyperosmolarity. High levels of salt in tears may be a useful indicator in diagnosing dry eye or dehydration.

According to the American Optometric Association (AOA), preventing dehydration by drinking 8–10 glasses of water throughout the day may help prevent dry eyes and reduce the associated symptoms.

Dehydration can cause sunken eyes. Severe dehydration may cause dryness in the eyes, but other factors can also cause this problem, including certain medications, diabetes, thyroid problems, and Sjögren disease.

Symptoms of dry eyes may include:

If a person uses contact lenses, they may also feel painful to wear.

Replacing lost fluids can help to treat dry eyes. The AOA recommends drinking 8–10 glasses of water each day to treat and prevent dry eyes from dehydration.

The American Academy of Ophthalmology (AAO) recommends the following treatments for dry eyes:

  • Artificial tears: Artificial tears are eye drops that lubricate the eyes similarly to natural tears. People can buy them over the counter but may need to try several brands to find what works best for them.
  • Warm compress: Applying a warm compress to the eye may help ease eye irritation.
  • Prescription medication: Prescription eye drops can help the eyes produce more tears.
  • Punctal plugs: Punctal plugs are small gel or silicone plugs that go into the corner of the eye to block the tear ducts. This helps tears stay in the eye longer to lubricate the eye and prevent dry eye.
  • Eyelid care: Massaging the eyelids or using an eyelid cleaner may help ease any irritation.

Drinking plenty of water throughout the day is important in preventing dehydration. The Centers for Disease Control and Prevention (CDC) recommend the following tips for drinking more water each day:

  • Keep a water bottle on hand and keep refilling it throughout the day.
  • Use ice cubes or use a freezer-safe water bottle if a person prefers drinking cold water.
  • Serve water with meals or ask for water when eating out.
  • Add lemon, lime, cucumber, berries, or mint to water to add flavor.
  • Drink alternatives, such as plain tea or coffee, sports drinks, and fruit juices.

People can also consume water through fruits and vegetables with a high water content.

Preventing dry eyes

Certain environments may cause or worsen the symptoms of dry eyes. The AAO recommends the following steps to help a person prevent dehydrated eyes:

  • avoiding or limiting the use of hair dryers or fan heaters
  • avoiding warm environments
  • using a humidifier to add extra moisture into the air or placing a pot of water by a radiator
  • wearing sunglasses or wrap-around glasses when outside in windy weather
  • adding omega-3 fatty acids to the diet through foods such as fatty fish and flaxseed or as a supplement
  • using artificial tears before bed to prevent waking up with dry eyes

Dry eyes are a symptom that can occur in several health conditions. If people think they have dry eyes, they can speak with a healthcare professional, particularly if symptoms persist and do not ease with increasing hydration or home remedies.

To check if someone has dry eye, a doctor may carry out an eye exam. A doctor may use eye drops to dilate the pupil and examine the eye for any issues.

During a dry eye exam, a doctor will check the amount of tears the eye is producing, the eyelid structure, and how long tears take to evaporate.

Dehydration can dry out the mucous membranes in the body, which includes the lining of the eyes. People may have dry eyes if they experience a burning, stinging sensation, blurred vision, or redness of the eyes.

Treating dehydration by increasing fluid intake may help replace fluids and improve dry eyes. Other treatments for dry eyes may include artificial tears or tear duct plugs.

If dry eyes persist, people may need to contact a doctor. A doctor can carry out an eye exam to check for any underlying issues causing these symptoms.