A hypopyon is the accumulation of white blood cells in the anterior chamber of the eye, the fluid-filled space between the cornea and iris. This collection of cells appears as a white or yellowish layer and is not a disease itself, but a visible sign of significant internal eye inflammation. Its presence indicates a serious underlying medical issue that requires immediate evaluation by a specialist to determine the cause and prevent complications like vision loss.
Underlying Causes of Hypopyon
A hypopyon results from severe inflammation, which can have infectious or non-infectious origins. Infectious causes are a frequent source of this response. Endophthalmitis, a serious infection of the eye’s internal fluids and tissues, is a primary infectious cause and can arise following eye surgery or a penetrating injury.
Keratitis, an infection of the cornea, is another cause. When a corneal ulcer becomes severely infected by bacteria or fungi, the body’s immune system sends white blood cells to fight the infection, and these cells accumulate in the anterior chamber.
Non-infectious, or sterile, inflammation can also cause a hypopyon and is often linked to autoimmune disorders. Uveitis, the inflammation of the eye’s middle layer (uvea), is a common example. Systemic diseases like Behçet’s disease, a rare disorder causing blood vessel inflammation throughout the body, are also associated with hypopyon where the immune system attacks eye tissues. Direct trauma to the eye can also induce a sterile inflammatory response.
Associated Symptoms and Presentation
The most distinct sign of a hypopyon is a visible layer of whitish or yellowish fluid that settles in the lower portion of the anterior chamber, in front of the iris. Gravity causes this collection of cells to form a horizontal line, and its size can vary with the severity of the inflammation.
A hypopyon is also accompanied by other symptoms. Patients often experience severe eye pain and significant redness of the white part of the eye (conjunctival injection).
Vision is frequently affected, with many individuals reporting blurred or decreased sight. Another symptom is photophobia, an extreme sensitivity to light that can make normal lighting conditions painful. People may also notice excessive tearing or swelling of the eyelids.
The Diagnostic Process
A comprehensive examination by an ophthalmologist is required to identify the underlying cause of a hypopyon. The diagnostic process may include several steps.
- Slit-lamp examination: This specialized microscope provides a magnified, three-dimensional view of the eye. It allows the doctor to visualize the hypopyon, assess inflammation, and inspect the eye for signs of infection or damage.
- Intraocular pressure measurement: The fluid pressure inside the eye is measured. Elevated pressure can be a sign of complications like glaucoma, which may be caused by inflammatory debris clogging the eye’s drainage system.
- Visual acuity test: This standard test is performed to quantify the extent of any vision loss.
- B-scan ultrasound: If inflammation obscures the view to the back of the eye, this test uses sound waves to create an image of the internal structures and detect issues like endophthalmitis.
- Aqueous or vitreous tap: If an infection is suspected, a small fluid sample may be taken from the eye with a thin needle. This sample is sent for laboratory analysis to identify the specific bacteria or fungus responsible.
Medical Treatment Approaches
Treatment is directed at the underlying cause, not the hypopyon itself. The therapeutic strategy depends on whether the source is infectious or inflammatory, and the hypopyon resolves as the primary condition is controlled.
For infectious causes like endophthalmitis or keratitis, treatment involves intensive antibiotic therapy. This often begins with fortified antibiotic eye drops, which are much stronger than standard drops. In severe cases, medication may be injected directly into the eye (intravitreal injection) to deliver a high concentration of antibiotics or antifungal agents.
If the cause is non-infectious, such as uveitis, treatment focuses on controlling inflammation. High-potency corticosteroid eye drops are frequently prescribed to suppress the inflammatory response. For systemic diseases like Behçet’s disease, oral corticosteroids or other immunosuppressive medications may be necessary.
In severe cases of infectious endophthalmitis where the infection has filled the eye’s vitreous cavity, a surgical procedure called a vitrectomy may be required. This surgery removes the infected vitreous gel from the eye to clear the infection and prevent further damage. The prognosis for vision and eye health depends on the underlying cause and how quickly treatment is initiated.