Corneal Edema: Symptoms, Causes & Treatment

Corneal edema is a condition that involves swelling of the cornea. 

The cornea is the clear outer dome of the eye that enables light entry into the eye. Edema refers to the buildup of fluid. 

When fluid builds up in the cornea, vision becomes blurry. This makes things look blurry or cloudy.

Several corneal conditions create cloudy vision. In some cases of acute corneal edema, vision can be compromised. 

An ophthalmologist will need to assess the condition to determine the underlying cause. This will dictate the course of treatment.

Causes of Corneal Edema

The cornea is made up of layers of tissue that help the eye to work effectively and see clearly. The inner layer of cells called endothelium pumps out excess fluid from inside the eye. If this layer is damaged, fluid may build up and create blurry or cloudy vision. 

Corneal edema may be caused by acute or chronic conditions that affect the endothelium layer. Common causes include the following:

Inflammation

Endotheliitis occurs when the endothelium cell layer is inflamed. This can happen as part of the body’s immune response to herpes. Edema may also be caused by inflammation from other conditions, such as arthritis.

Injury

Swelling of the cornea can sometimes be caused by injury to the eye.

Fuchs’ Corneal Dystrophy

Fuchs’ corneal dystrophy is a medical condition that affects this cell layer. This is a hereditary condition that is typically noticed as people age, usually in their 50s. This condition is more common in women than men. 

Surgery

Eye surgery, such as phacoemulsification for cataract surgery, may cause corneal swelling. 

According to the Columbia Department of Ophthalmology, this edema typically resolves over several weeks. 

Contact Lenses

Irritations from contact lenses is a common cause of corneal edema. 

Medication

Some drugs increase the risk of developing edema in the cornea. These typically include chlorhexidine and benzalkonium chloride. 

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Symptoms

Signs of corneal edema may be most apparent in the morning when vision can be blurry and cloudy upon waking. During the day, the cornea often dries out, and these sensations diminish.

Additional symptoms include the following:

• Painful sensations in the eye
• Tenderness to touch 
• Feeling as if something is stuck in the eye
• Rings around light sources
• Seeing halos around lights
• Blisters on the eye in severe cases

Diagnosis of Corneal Edema

An ophthalmologist will conduct a complete eye exam and diagnostic tests to understand what is causing your symptoms.

As part of the exam, your doctor may use a slit lamp or ophthalmoscope to determine what is occurring in the cornea. An ultrasound may be part of the diagnostic testing. 

To determine the thickness of your cornea, your doctor may conduct a process called optical pachymetry. This is an outpatient procedure to take detailed measurements of the endothelium. 

Treatment for Corneal Edema

The specific treatment approach will depend on the severity of the condition and the underlying cause. Here are some different approaches:

Observation

If the condition is mild, treatment may not be needed. Your doctor may simply recommend that you monitor the condition and contact their office if it worsens or doesn’t resolve.

Eye Drops

If the swelling increases, saline eye drops may be recommended. Eye drops with hypertonic solutions may be prescribed to reduce swelling.

Using a Hair Dryer

If corneal edema is worse in the morning, talk with your doctor about using a hair dryer. This is a home remedy to help tears evaporate more quickly, dry the eye, and reduce corneal swelling.

Contact Lens Assessment

If contact lenses are contributing to corneal swelling, consider the use and timing of wearing the lenses. 

According to the Centers for Disease Control and Prevention (CDC), an estimated 45 million Americans wear contacts, and 1 in 3 users sleep with them. Sleeping and/or napping in contact lenses can increase the risk of eye infections substantially, and this can contribute to swelling.

If you wear contact lenses, talk to your eye doctor about their effect on your corneal edema. 

Medications

In assessing the severity of the condition, your doctor may prescribe medications such as antibiotics or corticosteroids. Beta-adrenergic blockers may be prescribed to prevent complications after surgery.

Bandage Contact Lenses

If the condition is severe, there may be blisters on the eyes. Very thin lenses with high water content may ease the discomfort and offer soothing relief from blisters.

Treating Underlying Medical Conditions

As corneal swelling may be caused by underlying medical conditions, treating these issues may reduce swelling and restore normal corneal function.

Surgery

For extreme cases where swelling interferes with vision, surgery may be recommended. Surgical procedures include DSEK surgery to replace the endothelial layer and corneal transplant surgery to replace the cornea.

Over 47,000 corneal transplants are performed every year across the United States. This number is expected to rise as the aging population grows.

Postoperative Management

According to the Columbia Department of Ophthalmology, it is important to evaluate the health of the cornea after surgery. This helps to rule out any potential problems that could result in corneal edema. 

Topical corticosteroids may also be prescribed to reduce the risk of inflammation.

Corneal Edema FAQs

What is the cause of corneal edema?

Corneal edema is typically caused by issues within the epithelium layer of the cornea. This vital layer is responsible for pumping fluid that collects in the eye. If the epithelium layer is affected by a medical condition or reacting to certain drugs, these cells may not be working effectively.

Will corneal edema go away?

In mild cases, corneal edema may resolve without treatment. In some cases, saline eye drops can reduce swelling, and the condition goes away.

Is corneal edema serious?

Corneal edema can be serious. It may indicate serious medical conditions. If left untreated, it may cause blurring and cloudy vision.

References

1. Corneal Conditions. National Eye Institute.

2. Cornea Edema. (2008). Retina.

3. Acute Corneal Edema Without Epithelium Compromise. A Case Report and Literature Review. (August 2016). Revista de la Facultad de Medicina.

4. Corneal Oedema and Its Medical Treatment. (November 2012). Clinical and Experimental Optometry.

5. Fuchs’ Corneal Dystrophy. University of Michigan Kellogg Eye Center.

6. Corneal Edema After Phacoemulsification. (December 2017). Indian Journal of Ophthalmology.

7. Corneal Edema. Columbia University Department of Ophthalmology.

8. Optical, Ultrasound Pachymetry Interchangeable in Glaucoma. (March 2018). Review of Optometry.

9. Postoperative Corneal Edema Treatment & Management. (October 2018). Medscape.

10. How often and for how long should I use a hair dryer to treat my Fuchs’ dystrophy? (May 2017). American Academy of Ophthalmology (AAO).

11. Corneal Infections Associated With Sleeping in Contact Lenses — Six Cases, United States, 2016 – 2018. (August 2018). Centers for Disease Control and Prevention.

12. Postoperative Corneal Edema Medication. (October 2018). Medscape.

13. Cornea Transplant. Cleveland Clinic.