The sight of the white part of the eye appearing loose or blistered can be unsettling. This visual change often suggests that the thin, protective layers covering the eye’s surface have become swollen. This condition, which involves a buildup of fluid, is usually temporary and treatable once the underlying cause is identified.
The Anatomy of the Eye Surface
The surface of the eye is protected by two distinct layers: the sclera and the conjunctiva. The sclera is the dense, opaque, white layer that forms the globe’s outer wall, providing structural integrity. The sclera is firm and does not swell or become loose.
Draped over the sclera is the conjunctiva, a thin, transparent mucous membrane that also lines the inside of the eyelids. The bulbar conjunctiva covers the white of the eye and is normally very thin and clear. When this membrane swells, it lifts away from the underlying sclera, creating the loose, watery appearance observed.
Identifying Conjunctival Chemosis
The medical term for the fluid accumulation that causes the conjunctiva to swell and appear loose is Conjunctival Chemosis. This condition occurs when the small blood vessels within the conjunctiva become leaky due to irritation or inflammation. The increased permeability allows plasma and other fluid components to escape into the subconjunctival tissue, which is the space between the conjunctiva and the sclera.
Visually, chemosis often presents as a clear, gelatinous, or blister-like swelling on the white of the eye. The tissue may look watery or baggy and can sometimes become so large that it partially protrudes between the eyelids. Common sensations include a feeling of pressure, a gritty or foreign body sensation, and itchiness. Since the conjunctiva is highly flexible, the trapped fluid causes the tissue to balloon outward, creating the characteristic disruption to the normally smooth ocular surface.
Underlying Causes and Triggers
Conjunctival chemosis is a sign of irritation, and the fluid accumulation is the body’s inflammatory response to a trigger. Allergic reactions are among the most frequent causes, where exposure to environmental factors like pollen, dust, or animal dander prompts the release of histamines. Histamine increases the permeability of the conjunctival blood vessels, leading to a rapid and localized fluid buildup.
Physical irritation can also trigger this response, such as excessive or vigorous eye rubbing. Prolonged or improper contact lens wear can also cause constant friction that results in swelling. Infections, specifically viral or bacterial conjunctivitis (pink eye), are other common causes. Chemosis can also occur following trauma or as a complication after eye surgeries, such as blepharoplasty, due to localized inflammation.
When to Seek Medical Attention and Treatment Options
While many cases of mild chemosis, particularly those from allergies, can resolve on their own, certain signs indicate the need for prompt professional evaluation. You should seek immediate medical attention if you experience sudden changes in vision, severe eye pain, or an inability to close your eye completely due to the swelling. The presence of thick, colored discharge, which may suggest a bacterial infection, or symptoms like fever or difficulty breathing, possibly indicating a systemic allergic reaction, are also red flags.
The treatment for chemosis is always directed at resolving the underlying cause. For mild cases, applying a cool compress to the closed eye or using over-the-counter artificial tears may help reduce the swelling and discomfort. If allergies are the cause, topical or oral antihistamines are often prescribed to block the histamine response and decrease vascular permeability. In the event of a bacterial infection, an eye care professional will prescribe antibiotic eye drops. Viral infections are typically managed with supportive care, such as cold compresses and lubricating drops, while the body clears the virus.