What Is Conjunctival Chemosis and How Does It Affect The Eyes?

Conjunctival chemosis is a condition that acts as a sign of eye irritation. We'll explain why it occurs and how it's treated here.

Reviewed and approved by the doctor Diego Pereira.

Written by Carmen Martín

Last update: 22 June, 2023

Conjunctival chemosis is a sign of ocular irritation. It’s a benign inflammatory process that affects the conjunctiva, an almost transparent membrane that is the outermost surface of the eyeball. It covers both the sclera (white part of the eye) and the inside of the eyelids.

In most cases, this condition is related to allergic reactions or eye infections. However, there are other possible causes. The drawback is that if it’s not treated properly, it can worsen and alter vision or the ability to close the eye. How can you recognize it? What is its treatment? Let’s take a closer look.

What is conjunctival chemosis?

Conjunctival chemosis is the inflammation of the mucous membrane that covers the eyeball. According to a Mount Sinai Health System publication Mount Sinai Health System, its occurrence is linked to allergies, infections, injuries, or a complication from an ocular surgery.

Because of this, it’s not a disease as such, but rather a symptom. It can occur unilaterally or bilaterally. Furthermore, it isn’t contagious and can occur in people of all ages and either sex.

The conjunctiva is the membrane that lines the sclera and the inner surface of the eyelids. When chemosis occurs, irritation causes it to swell and edema. Thus, the eye resembles a large fluid-filled blister.

Chemosis is usually confined to the crease of the eye. The problem is that, in many cases, the inflammatory process reaches the cornea. The cornea is one of the lenses that allows light rays to focus properly in the eye.

When affected, vision is impaired. On the other hand, this condition can become recurrent and chronic, especially when it’s linked to allergic processes. Hence the importance of proper treatment.

What are its symptoms?

A publication through the Vision Center explains that chemosis causes the accumulation of liquid in the eyelids and in the membrane that covers the eyes. As a result, other symptoms such as pain and itching are experienced, which usually increase when opening and closing the eyes. Other clinical manifestations include the following:

• Watery eyes
• Excessive tearing
• Redness and irritation of the eyes
• Diplopia (double vision)
• Blurred vision
• The sensation of a foreign body in the eye

If the inflammation becomes severe, so much fluid may accumulate that the eye resembles a blister. Some people feel unable to close the eyelid completely and, once it advances to the cornea, visual acuity decreases.

Causes of conjunctival chemosis

Conjunctival chemosis is not a disease as such. It’s an inflammatory reaction that can appear for numerous reasons. Its most frequent causes are the following:

• Ocular injuries. These are usually caused by contact with aggressive agents, such as chemical products, and dust particles, among other substances. Also due to aggressive rubbing of the eyes.
• Infectious processes. For example, there’s conjunctivitis, which is caused by viruses or bacteria.
• Allergic reactions.
• Angioedema. This is swelling (edema formation) under the skin, mucous membranes, and submucosal tissue.
• Graves’ disease.
• Thyroid problems, such as hyperthyroidism.

Other possible causes

Sometimes conjunctival chemosis is a symptom associated with fluid retention. When a person suffers from severe edema (the main cause is certain medications), symptoms may spread to the eye.

Although rare, a tumor in the periorbital part of the eye can cause conjunctival chemosis. The same occurs if there’s an alteration in the flow of ocular fluids. This condition can even be caused by being in a very dry climate.

How is it diagnosed?

In order to diagnose conjunctival chemosis, it’s essential that the physician performs a proper physical examination. In addition, he/she must know when the symptoms started, what other symptoms have appeared, if there has been a triggering factor, etc.

Ideally, the examination should be performed by an ophthalmologist. With the naked eye, redness of the sclera or the inner part of the eyelids can be seen. In addition, tearing and swelling of the conjunctival sac are very characteristic signs.

Treatments for conjunctival chemosis

The treatment of conjunctival chemosis will depend on the cause. Therefore, it’s essential to make a correct diagnosis. Otherwise, the condition may worsen and affect vision, or it may recur and become chronic.

In most cases, adequate medical treatment is sufficient. When the cause is a bacterial infection, such as bacterial conjunctivitis, antibiotic eye drops are usually prescribed. If it’s of viral origin, other types of eye drops are used.

In all cases, it’s recommended to apply cold compresses to the eye. When it’s due to an allergic reaction, it’s possible to use antihistamine drugs. These are drugs that in many cases are available without a prescription and reduce the body’s reaction to the allergen in question.

Can it be prevented?

Although it’s not always possible, conjunctival chemosis can be prevented in many cases. For example, by preventing the eyes from coming into contact with aggressive or infectious agents.

To do this, it’s important to use eye protection whenever you are in a ‘dangerous’ environment, such as in places where it’s very windy and particles can enter the eye.

To avoid infections, it’s essential not to touch your eyes with dirty hands. Sharing cosmetic products or neglecting contact lenses is also discouraged.

Allergy sufferers should try to stay away from the substance causing the reaction. If not, it’s useful for them to carry antihistamines to slow down the reaction when it appears.

What to remember

Conjunctival chemosis is a condition that often causes pain, eye swelling, inability to close the eye, and even a distortion of vision. In most cases, it’s associated with allergic reactions or infections.

Although it’s usually benign, it’s important to always consult a specialist when symptoms appear. Appropriate treatment can then be established depending on the cause.