The term panuveitis refers to an inflammation of the eye that can quickly become a serious, sight-threatening condition. Uveitis is the general name for inflammation affecting the uvea, the middle layer of the eye. Panuveitis represents the most extensive form, signifying that the entire uveal tract is involved. Because the uvea provides blood flow and nutrition to the retina, this widespread inflammation poses a significant risk to vision.
The Anatomy of Panuveitis
The uvea is the pigmented, vascular middle layer of the eye, situated beneath the sclera. It is structured into three distinct parts, and the prefix “pan” indicates that all three are simultaneously affected by inflammation. This extensive involvement distinguishes panuveitis from other forms of uveitis, which may be confined to the anterior, intermediate, or posterior segments of the eye.
The iris is the most anterior component, forming the colored part of the eye and controlling the amount of light entering the pupil. Directly behind the iris is the ciliary body, a ring of tissue that produces aqueous humor, the fluid that fills the anterior chamber. This structure also contains muscles that change the shape of the lens for focusing, known as accommodation.
The most posterior part is the choroid, a dense network of blood vessels that supplies oxygen and nourishment to the outer layers of the retina. When panuveitis occurs, inflammation spreads across all three structures. This widespread inflammatory response often affects surrounding tissues, including the vitreous humor and the retina, leading to diffuse damage across the front and back of the eye.
Signs and Patient Experience
A person experiencing panuveitis typically presents with symptoms indicating widespread inflammation. Severe, deep-seated eye pain is common, often accompanied by noticeable eye redness. This discomfort is frequently exacerbated by light, a condition known as photophobia, which makes it difficult to function in brightly lit environments.
Vision is often significantly affected, with patients reporting blurred or decreased sight. Inflammation in the vitreous humor, the gel-like substance that fills the eye, causes floaters—dark specks or strands that drift across the field of vision. These symptoms reflect inflammatory activity in both the anterior segment (causing pain and redness) and the posterior segment (leading to visual impairment).
The overall experience can be debilitating, as the combination of pain, light sensitivity, and reduced visual acuity interferes with daily activities. Since panuveitis involves the entire uveal tract, the resulting inflammation can lead to swelling of the central retina, or macular edema, a significant cause of central vision loss. Timely medical attention is required because the condition carries a high risk of permanent vision damage.
Triggers and Associated Conditions
Identifying the underlying cause of panuveitis is complex, as inflammation can be triggered by systemic conditions, injuries, or infections. These causes are broadly categorized as infectious, non-infectious, or idiopathic (meaning no specific trigger is found). For some patients, the cause remains undetermined despite extensive diagnostic testing.
Infectious agents are a significant category of triggers, often involving organisms that have traveled to the eye through the bloodstream. Bacterial infections, such as Mycobacterium tuberculosis (tuberculosis) or Treponema pallidum (syphilis), are known to induce panuveitis. Parasitic infections, most notably toxoplasmosis, are also common causes of infectious uveitis that can progress to panuveitis.
Viral infections, including those from the herpes family (Herpes simplex virus and Varicella-zoster virus), can also provoke this widespread inflammation. When an infectious cause is identified, the treatment strategy must be dual-focused: addressing the ocular inflammation while simultaneously targeting the specific pathogen.
Non-infectious causes frequently involve systemic autoimmune or autoinflammatory diseases where the immune system mistakenly attacks the body’s own tissues, including the uvea. Conditions like sarcoidosis, an inflammatory disease affecting multiple organs, and Behçet’s disease, a form of vasculitis, commonly manifest with panuveitis. Vogt-Koyanagi-Harada (VKH) syndrome is another cause, a rare autoimmune disorder that primarily affects pigmented tissues, leading to inflammation in both eyes.
A distinct form is sympathetic ophthalmia, an autoimmune response where a severe penetrating injury to one eye leads to inflammation in the uninjured, opposite eye, nearly always presenting as bilateral panuveitis. In non-infectious cases, the eye inflammation is a manifestation of a broader systemic disease, which guides long-term management beyond the eye itself.
How Panuveitis is Diagnosed and Treated
The diagnostic process begins with a comprehensive eye examination to confirm inflammation in all three parts of the uvea. A specialized slit lamp allows the ophthalmologist to view the anterior segment for signs like inflammatory cells and protein deposits. Ophthalmoscopy is used to evaluate the posterior structures, including the retina and choroid.
To assess the extent of damage, specialized imaging techniques are often employed. Optical Coherence Tomography (OCT) provides high-resolution cross-sectional images of the retina to detect swelling like macular edema. Fluorescein angiography is another common test, involving injecting a dye to visualize blood vessel leakage and inflammation in the retina and choroid.
Identifying the root cause requires a systematic approach involving laboratory work and collaboration with other specialists. Blood tests are routinely ordered to check for markers of systemic autoimmune diseases or evidence of specific infections like syphilis or tuberculosis. If the diagnosis is unclear, a diagnostic vitreous tap may be performed to collect a fluid sample from the eye for analysis, including polymerase chain reaction (PCR) to detect microbial DNA.
The immediate goal of treatment is to quickly reduce inflammation to preserve vision. Corticosteroids are the primary line of therapy, administered in various forms depending on the severity and location. This can include topical eye drops for anterior inflammation, injections directly into or around the eye for localized delivery, or oral tablets for systemic, widespread disease.
For panuveitis caused by an infection, corticosteroids are paired with specific antimicrobial drugs (antibiotics, antivirals, or antiparasitics) to eliminate the underlying pathogen. If inflammation is severe, chronic, or does not respond sufficiently to steroids, second-line treatments are introduced. These often include immunosuppressive medications, such as conventional agents or newer biologic drugs, which modulate the overactive immune system to control the long-term inflammatory process.