Uveitis is an inflammation of the uvea, the middle layer of the eye that includes the iris (the colored part), the ciliary body (which helps the eye focus), and the choroid (which supplies blood to the retina). The inflammation can also spread to nearby parts of the eye such as the retina, the clear gel-like fluid called the vitreous, or the optic nerve.
Common symptoms include eye pain, redness, sensitivity to light, blurry vision, and seeing small moving spots called floaters. Uveitis can appear suddenly and severely or develop slowly and come back over time, depending on its cause and which part of the eye is affected.
The condition can be triggered by a range of factors, including infections caused by bacteria, viruses, fungi, or parasites; autoimmune or inflammatory diseases that affect the whole body; or injuries to the eye. In some cases, no specific cause is found, and it is described as idiopathic. Because it may be linked to conditions elsewhere in the body, diagnosis often involves both an eye examination and additional medical tests.
Without treatment, uveitis can cause serious eye problems such as glaucoma (increased pressure in the eye), cataracts (clouding of the lens), swelling of the retina, or permanent vision loss. Treatment aims to reduce inflammation and treat the underlying cause, and may include steroid eye drops, anti-inflammatory or immune-suppressing medications, or antibiotics or antiviral drugs if an infection is present. Preventive measures depend on the cause and may involve controlling underlying diseases, treating eye infections early, and protecting the eyes from injury.
Anatomy of the Uvea
The uvea is the middle layer of the eye located between the retina (the light-sensitive tissue at the back of the eye) and the sclera (the tough, white outer covering of the eye). It is highly vascular, meaning it contains many blood vessels, which play a crucial role in nourishing the inner structures of the eye. However, this rich blood supply also makes the uvea more prone to inflammatory conditions such as uveitis, because circulating immune cells and infectious agents can easily reach it.
The uvea is composed of three parts:
- Iris: This is the colored part of the eye that surrounds the pupil. It regulates the size of the pupil and controls how much light enters the eye. By adjusting the pupil size, the iris helps protect the retina from excessive light.
- Ciliary body: Located behind the iris, the ciliary body performs two key functions: it produces aqueous humor (the clear fluid that nourishes the eye and maintains pressure inside the eye) and contains the ciliary muscle, which adjusts the shape of the lens to help the eye focus on near or distant objects.
- Choroid: This is the largest portion of the uvea and lies between the retina and the sclera. It contains a dense network of blood vessels that supply oxygen and nutrients to the retina. The choroid is essential for maintaining the health and function of retinal tissue, which is responsible for vision.
Together, these structures support vision by supplying nutrients, regulating light, and allowing the eye to focus properly. Because the uvea is deeply involved in the eye’s circulation and immune response, any inflammation in this layer can quickly interfere with normal visual function.
Types of Uveitis
Uveitis can be classified based on the location of inflammation within the eye:
| Type | Location | Characteristics |
| Anterior Uveitis | Iris and ciliary body | This is the most common type. It usually causes eye redness, pain, light sensitivity, and sometimes blurred vision. It may appear suddenly and is often linked to autoimmune conditions. |
| Intermediate Uveitis | Vitreous and peripheral retina | Involves the clear gel-like fluid inside the eye. Symptoms often include floaters (small moving spots in vision) and mild visual disturbances. Pain or redness may be minimal or absent. |
| Posterior Uveitis | Retina or choroid | Affects the back of the eye and often interferes with central vision. It is frequently associated with infections or systemic inflammatory diseases. Because it affects the retina, vision loss may be more pronounced. |
| Panuveitis | All parts of uvea | A severe form involving inflammation throughout the eye. It can damage multiple eye structures at once and has a high risk of complications if not promptly treated. |
Causes of Uveitis
Uveitis arises from various factors including infections, immune system disorders, unknown origins, and physical injury.
Infectious Causes
Infectious uveitis occurs when microorganisms such as bacteria, viruses, fungi, or parasites infect the uveal tissue. These organisms can reach the eye through the bloodstream or from nearby tissues. Bacterial infections such as tuberculosis (caused by Mycobacterium tuberculosis) and syphilis (caused by Treponema pallidum) are well-known triggers and may affect both the eye and other organs. Viral infections frequently responsible for uveitis include herpes simplex virus (HSV) and cytomegalovirus (CMV), both of which can remain dormant in the body and reactivate during periods of weakened immunity.
Parasitic infections are another important cause, especially in regions where such diseases are more common. Toxoplasmosis, for example, is a parasitic infection that often leads to inflammation in the retina and choroid, which can severely affect vision if not treated promptly. Fungal infections are less common but tend to occur in individuals with weakened immune systems or those who have undergone eye surgery or trauma.
Autoimmune and Inflammatory Disorders
Autoimmune uveitis develops when the body’s immune system mistakenly attacks its own eye tissues, leading to inflammation. This form of uveitis is frequently linked to systemic inflammatory diseases, conditions that affect multiple organs. Examples include ankylosing spondylitis, a type of arthritis that affects the spine; sarcoidosis, an inflammatory disease that can involve the lungs, lymph nodes, and eyes; and Behçet’s disease, a rare disorder that causes inflammation of blood vessels throughout the body.
In these cases, the uveitis is often chronic or recurrent because the underlying autoimmune response does not resolve on its own. The inflammation is partly driven by a breakdown of the “blood-ocular barrier,” a natural protective mechanism that keeps immune cells and inflammatory proteins from entering the inner parts of the eye. Once this barrier is disrupted, ongoing immune activation can damage the delicate structures responsible for vision.
Idiopathic Uveitis
When no specific cause can be identified despite thorough medical evaluation, the condition is classified as idiopathic uveitis. This category accounts for a large proportion of uveitis cases worldwide. Idiopathic uveitis may represent early or undiagnosed autoimmune disease, low-grade infection that is difficult to detect, or immune activation triggered by unknown environmental or genetic factors.
Because the cause is unclear, management often focuses on controlling inflammation and monitoring for changes over time. Some patients experience only a single episode, while others develop recurring flare-ups that require long-term follow-up care.
Trauma-Related Uveitis
Trauma-related uveitis occurs when physical injury to the eye triggers inflammation. This may result from blunt trauma (such as a sports injury), penetrating injury (involving a sharp object), or postoperative complications following eye surgery. Inflammation can also occur if foreign material enters the eye or if the normal protective layers are disrupted during injury.
In such cases, treatment usually focuses on reducing inflammation and preventing secondary complications such as infection or scarring.
Symptoms and Clinical Presentation
Uveitis presents with a distinct set of signs and symptoms that vary depending on the inflammation’s intensity and location within the eye. Identification requires attention to specific visual and physical cues. Complications can arise if the condition remains untreated, affecting overall eye health.
Common Symptoms
The most typical symptoms of uveitis include eye redness, usually concentrated around the iris or deeper within the eye, and eye pain, which may worsen with light exposure or movement of the eye. Photophobia, or sensitivity to light, is common because inflammation irritates the tissues that help regulate light entering the eye.
Visual disturbances are also frequent. Many patients report blurred or hazy vision, which may worsen as inflammation spreads to nearby structures such as the retina or vitreous. The appearance of floaters, small dark specks, threads, or cobweb-like shapes drifting across the visual field, often indicates inflammation in the vitreous gel. In more severe cases, patients may notice reduced visual acuity, difficulty focusing, or a general dimming of vision.
While some individuals experience pronounced discomfort, others may have relatively mild symptoms early on, delaying recognition and treatment. The specific presentation often depends on whether the inflammation is located in the front of the eye (anterior uveitis), deeper inside (intermediate or posterior uveitis), or throughout the entire eye (panuveitis).
Acute vs. Chronic Uveitis
Acute uveitis develops rapidly and is marked by sudden onset of pain, redness, and sensitivity to light. Vision changes may appear abruptly, sometimes within hours or days. Because of its fast progression, acute uveitis is often alarming to patients and typically prompts urgent medical attention. Without timely treatment, inflammation can quickly damage ocular tissues.
Chronic uveitis persists for longer than three months or recurs repeatedly over time. Symptoms may be milder or gradual, making the condition harder to detect without professional examination. Instead of intense pain, patients may experience slow, progressive visual decline or intermittent flare-ups. Long-term inflammation poses a higher risk of structural complications because of continuous or repeated tissue damage.
Complications Arising From Uveitis
If left untreated, uveitis can interfere with the normal function of multiple parts of the eye, leading to serious and sometimes irreversible complications. These may include:
- Glaucoma: Inflammation can block the normal outflow of fluid from the eye, increasing intraocular pressure and potentially damaging the optic nerve.
- Cataracts: Chronic inflammation or long-term use of steroid treatment can cause clouding of the lens, resulting in impaired vision.
- Macular edema: Swelling in the macula, the part of the retina responsible for central vision, can distort and reduce fine-detail vision.
- Retinal detachment or scarring: Persistent inflammation may lead to structural changes or disruption of the retina, severely affecting vision.
- Permanent structural damage: Without control of inflammation, the delicate tissues within the eye may suffer long-term scarring or atrophy, resulting in irreversible vision loss.
Diagnosis of Uveitis
The examination begins with a thorough medical history focusing on symptom onset, duration, and severity. It includes specific questioning about eye pain, redness, vision changes, and associated systemic symptoms such as joint pain or skin rashes.
Physical examination uses slit-lamp biomicroscopy to identify inflammation inside the eye, such as cells and flare in the anterior chamber. Intraocular pressure measurement helps exclude secondary glaucoma. The fundoscopic exam assesses for posterior segment involvement like vitritis or chorioretinitis.
A detailed systemic examination may reveal signs of autoimmune or infectious diseases linked to uveitis. Documentation of laterality (unilateral or bilateral) assists in narrowing differential diagnoses.
Laboratory Tests
Laboratory investigations are tailored based on clinical suspicion. Common tests include complete blood count (CBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) to detect systemic inflammation.
Specific serologic tests depend on potential causes: antinuclear antibodies (ANA) and rheumatoid factor (RF) for autoimmune conditions; syphilis serology (RPR, VDRL); tuberculosis screening via interferon-gamma release assays or tuberculin skin testing.
Additional testing may include HLA-B27 typing for spondyloarthropathies and chest X-ray or CT to investigate sarcoidosis. Laboratory results assist in confirming infection or autoimmune etiology, guiding management.
Imaging Techniques
Ocular imaging is essential to evaluate the extent and anatomical location of uveitis. Fundus photography documents retinal and choroidal changes.
Optical coherence tomography (OCT) provides high-resolution cross-sectional images of the retina, identifying macular edema or structural damage. Fluorescein angiography highlights retinal vascular leakage and inflammation patterns.
Ultrasound B-scan is useful when media opacities hinder direct visualization. Imaging data supports clinical findings and helps monitor treatment response.
Treatment Options
Corticosteroids remain the first-line therapy for most cases of non-infectious uveitis due to their rapid anti-inflammatory effect. They act by suppressing multiple inflammatory pathways, reducing immune cell recruitment, and stabilizing the blood–ocular barrier.
Routes of Administration
- Topical (Eye Drops): Used primarily for anterior uveitis, where inflammation involves the iris and ciliary body. They are rapidly effective but require frequent dosing in the acute phase.
- Periocular or Intraocular Injections: Provide sustained drug delivery for intermediate or posterior disease when topical therapy is inadequate. Common agents include triamcinolone acetonide.
- Systemic (Oral or Intravenous): Indicated for severe, bilateral, or posterior segment involvement where broader immune suppression is required. Intravenous methylprednisolone may be used in aggressive disease or sudden vision-threatening flares.
- Steroid Implants: Long-acting intravitreal implants (e.g., fluocinolone acetonide or dexamethasone implants) provide controlled drug delivery for chronic or recurrent inflammation, reducing the need for repeated injections.
Monitoring and Side Effects
Long-term corticosteroid therapy carries risk. The most common ocular complications include:
- increased intraocular pressure leading to steroid-induced glaucoma,
- posterior subcapsular cataracts, particularly with prolonged therapy,
- delayed wound healing and increased susceptibility to ocular infection.
For systemic steroids, clinicians also monitor for weight gain, hypertension, osteoporosis, hyperglycemia, and mood changes. An essential principle of steroid therapy is gradual tapering, as abrupt withdrawal may trigger rebound inflammation or adrenal suppression.
Immunosuppressive Therapies
Immunosuppressive drugs are indicated for steroid-sparing purposes when corticosteroids alone are inadequate or unsafe for long-term use. They are particularly useful for chronic, recurrent, or systemic autoimmune-associated uveitis such as in sarcoidosis, Behçet disease, juvenile idiopathic arthritis, and ankylosing spondylitis.
Common Drug Classes
1. Antimetabolites:
- Methotrexate
- Azathioprine
- Mycophenolate mofetil
These agents reduce lymphocyte proliferation and are widely used due to favorable tolerance profiles.
2. Calcineurin Inhibitors:
- Cyclosporine
- Tacrolimus
Effective in T-cell mediated disease but require monitoring for nephrotoxicity and hypertension.
3. Alkylating Agents (reserved for severe refractory cases):
- Cyclophosphamide
- Chlorambucil
These are powerful agents but carry risks such as bone marrow suppression and secondary malignancies, so they are used sparingly.
Because these medications suppress the immune system more broadly, routine laboratory monitoring is essential. Physicians regularly check liver enzymes, kidney function, and complete blood counts to prevent toxicity. Unlike corticosteroids, which act quickly, immunosuppressants may require weeks to months to reach full therapeutic effect. Therefore, they are often started alongside steroids initially and maintained long-term to sustain remission.
In modern practice, biologic agents such as tumor necrosis factor (TNF) inhibitors (e.g., adalimumab, infliximab) are also used in refractory or systemic autoimmune-associated uveitis. They target specific inflammatory cytokines, offering a more directed mechanism of control with promising outcomes in preventing relapses.
Antimicrobial Treatments
For infectious uveitis, the therapeutic approach shifts entirely toward eliminating the underlying pathogen, as corticosteroids alone can worsen infection if not carefully paired with appropriate antimicrobials.
Pathogen-Specific Therapy
- Viral Uveitis: Commonly associated with herpes simplex virus (HSV) or varicella-zoster virus (VZV). Antivirals such as acyclovir, valacyclovir, or ganciclovir are used.
- Bacterial Uveitis: May result from intraocular infections (endophthalmitis) or systemic diseases like tuberculosis or syphilis. Therapy may involve broad-spectrum or pathogen-specific antibiotics, sometimes combined with intravitreal injections.
- Fungal Uveitis: Seen in immunocompromised patients or following trauma; treated with systemic or intravitreal antifungals (e.g., amphotericin B, voriconazole).
- Parasitic Causes: More common in tropical regions; therapy includes antiparasitic agents tailored to organisms such as Toxoplasma gondii (treated with pyrimethamine, sulfadiazine, and leucovorin).
Management and Prognosis
Effective management of uveitis requires regular assessment and appropriate treatment adjustments. Monitoring disease activity and recognizing potential complications are crucial. Prognosis depends on the cause, severity, and timely intervention.
Monitoring and Follow-Up
Patients with uveitis require frequent eye examinations to evaluate inflammation, intraocular pressure, and response to therapy. Initial follow-ups may occur weekly or biweekly, then extend as inflammation stabilizes.
Imaging techniques like optical coherence tomography (OCT) and fluorescein angiography assist in detecting subtle changes. Lab tests and systemic evaluations help monitor underlying systemic diseases.
The risk of recurrence necessitates ongoing surveillance even after remission. Adjustments to corticosteroids or immunosuppressants depend on clinical progress.
Prognosis and Outcomes
Visual prognosis varies depending on uveitis type, etiology, and treatment timeliness. Infectious causes generally require prompt antimicrobial therapy for better outcomes.
Non-infectious uveitis responds well to immunosuppressive agents if diagnosed early. Delays in treatment increase the chance of irreversible damage.
Regular management and adherence to therapy improve long-term vision. However, some patients may experience recurrent episodes or chronic inflammation despite treatment.
Prevention and Risk Reduction
Preventing uveitis involves managing underlying health conditions that may trigger inflammation. Regular medical checkups help identify systemic diseases such as autoimmune disorders or infections that increase risk.
Patients should avoid eye injuries by using protective eyewear during activities with a high risk of trauma. Maintaining good hygiene reduces the chance of eye infections, a known cause of uveitis.
Immunizations against infectious agents like herpes and tuberculosis can lower the risk of infection-related uveitis. Early treatment of infections prevents the spread of pathogens to the eye.
Medication adherence for chronic illnesses is critical. Immunosuppressive drugs and corticosteroids prescribed for autoimmune diseases should be taken as directed to reduce inflammation risk.
A healthy lifestyle supports the immune system. Balanced nutrition, regular exercise, and avoiding smoking improve overall health and may decrease susceptibility to uveitis.
| Risk Factor | Prevention Method |
| Autoimmune disorders | Regular medical monitoring |
| Eye injuries | Use of protective eyewear |
| Infectious agents | Vaccinations and hygiene practices |
| Chronic illnesses | Adherence to prescribed treatments |
| Smoking and poor lifestyle | Healthy habits and avoidance of smoking |