What causes swelling on the white part of your eye?

Chemosis (conjunctival edema) is a blister-like swelling of the clear tissue that covers the white part of your eye. Explore the common causes, symptoms, and potential treatments your doctor may recommend.

Published on August 25, 2025

Get to know chemosis

You may hear it referred to as chemosis, conjunctival edema, or simply “eye swelling”. They all refer to the swelling of the conjunctiva, the membrane that covers the whites of your eyes and the inner surfaces of your eyelids. When this tissue swells, it can visibly bulge, often making it difficult to close the eye completely. This swelling could have any number of causes, and it is often a symptom rather than a standalone disease. If you’re experiencing swelling on the white of your eye, see your eye care professional for a diagnosis and treatment plan.

What types of things cause swelling on the white part of the eye?

Allergies

Allergic reactions are a leading cause of conjunctival edema. When exposed to allergens like pollen, dust, animal dander, or certain foods, the body can release histamines. These histamines can cause itchy, watery eyes, and can sometimes lead to swelling on the white part of your eye. If you know you're prone to allergies, take proactive steps, like avoiding known triggers and keeping your environment clean.

Infections

Infections like viral conjunctivitis, or "pink eye," can cause the white of your eyes to become inflamed. Depending on the cause, treatment may include steps to minimize discomfort. If the infection is bacterial, an antibiotic eye drop may be prescribed. Keeping your hands clean is crucial for helping prevent infections that may lead to swelling. Washing your hands before touching your face or eyes helps lower the risk of transferring harmful bacteria or viruses to your eyes.

Eye injuries

A chemical splash, a foreign body (like sand or rust), or other forms of trauma can cause swelling of the conjunctiva. It’s crucial to seek immediate medical attention if you experience eye trauma. Prevention may include protective eyewear like safety glasses or goggles, and avoiding rubbing your eyes.

Pre-existing medical conditions

Certain underlying issues, like thyroid disease or heart failure, can also lead to chemosis. In thyroid eye disease, the tissue around the eyes can swell due to inflammation caused by autoimmune activity. In heart failure, fluid can build up in the body, including around the eyes, leading to swelling of the conjunctiva. Recognizing these underlying conditions is important for helping your doctor recommend the right treatments.

Other symptoms of chemosis

The most obvious symptom of the swelling of the white of your eyes is exactly that—swelling. For many, this looks like a blister or blisters on the white part of your eye. On top of this, there may be other symptoms you’ll notice.

Redness and irritation

This redness is typically a response to irritation or infection, indicating that the tissues are reacting to an underlying problem. Talk to your eye doctor immediately if the redness continues, worsens, or does not respond to your doctor’s recommended treatment.

Watery eyes

As the eye tries to protect itself from irritants, it produces more tears. While intended to be helpful, this may also lead to blurred vision.

Sensitivity to light

Light sensitivity often means that the inflammation is not limited to the conjunctiva, but extends to other parts of the eye like the cornea or iris. If you’re experiencing swelling that causes light sensitivity, contact your eye doctor immediately.

Diagnosing swelling of the whites of your eyes

Diagnosing conjunctival edema requires a visit to a health care professional. They typically start by asking about your symptoms and any recent activities that may have caused irritation. Next, a thorough examination may follow, using tools like a biomicroscope to get a detailed view of the conjunctiva and surrounding tissues. In some cases, your provider may perform other assessments to identify the underlying cause.

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Common treatments your eye doctor may recommend for eye swelling

The way your eye care professional treats the swelling on the white part of your eye depends on the cause of the swelling. Once they determine the cause, they can provide a comprehensive treatment plan, which may include:

Over-the-counter antihistamines

If the swelling is due to allergies, your healthcare provider may recommend taking antihistamines to reduce the body's allergic response. Antihistamines may help alleviate symptoms like redness and itchiness while relieving swelling.

Cold compresses

Applying a cold compress to the closed eyes can help reduce swelling and discomfort. This home remedy is simple, just wrap ice or a cold pack in a clean cloth and hold it over your eyes for about 10 to 15 minutes. Cold compresses may soothe inflammation and provide immediate relief for irritation.

Prescription medications

For bacterial infections, your healthcare provider may prescribe antibiotic eye drops to manage the symptoms and help address the infection.
If inflammation is significant, topical steroids might be recommended to reduce swelling.
For help relieving discomfort, your eye care professional may prescribe an NSAID eye drop.

Avoiding irritants

It’s crucial to identify and minimize contact with potential irritants that could worsen the swelling. This might include avoiding allergens, wearing protective eyewear during hazardous activities, and getting proper rest to allow your eyes to recover from irritation.

For eye swelling or other concerns, see a professional

The key to diagnosing and treating chemosis is understanding the underlying cause, and the only person that can do that is an eye care professional. If you don’t have one, browse our list of eye care professionals available near you.

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FAQs

Frequently asked questions

What is conjunctival edema?

Conjunctival edema, or chemosis, is the swelling of the conjunctiva, the membrane covering the whites of your eyes and the inner surfaces of your eyelids. It can be caused by things like irritation, allergens, or infections.

What causes swelling on the white part of the eye?

Swelling can result from various factors, including allergies, eye infections, injuries, or even some systemic medical conditions. Identifying the cause is important for effective treatment, so see an eye care professional if you’re experiencing concerning eye swelling.

How is conjunctival edema treated?

The treatment of conjunctival edema, or chemosis, depends on the diagnosis that your eye care professional provides. Possible treatments could include over-the-counter antihistamines for allergies, cold compresses to reduce swelling, and prescription medications for infections.

Can conjunctival edema be prevented?

You can reduce the risk of conjunctival edema (chemosis) by practicing good hygiene, wearing protective eyewear, managing allergies effectively, and avoiding any irritating substances.

When should I see an eye doctor for conjunctival edema?

You should seek medical attention if symptoms persist or worsen. Also, if you experience pain, changes in vision, or if swelling is accompanied by discharge, consult your eye care professional.