Iritis is inflammation of the iris—the colored ring around the pupil—and it’s also called anterior uveitis because it affects the front part of the eye’s uvea (the eye’s middle layer).
This condition matters because it can be painful, can blur vision, and—when not treated appropriately—may lead to complications like glaucoma or vision loss.
The good news is that eye care professionals can usually diagnose it with an exam and guide treatment to calm inflammation and protect vision.
What is iritis (anterior uveitis)?
Iritis is swelling and irritation (inflammation) of the iris, and it’s another name for anterior uveitis.
More broadly, “uveitis” means inflammation of the uvea, which includes the iris, the ciliary body, and the choroid (and sometimes nearby structures can be involved too).
Because the eye is a small, enclosed space, inflammation can quickly disrupt comfort and vision—even if the trigger is outside the eye.
Quick definition (featured-snippet friendly): Iritis (anterior uveitis) is inflammation of the iris at the front of the uveal tract that can cause a painful red eye, light sensitivity, and blurred vision.
Causes and Risk Factors
In many people, no clear trigger is found, and clinicians may describe the case as idiopathic (unknown cause).
When a cause is identified, it may relate to immune or inflammatory diseases (including conditions associated with the HLA-B27 gene change), infections, or injury to the eye.
Commonly discussed categories include:
- Autoimmune/inflammatory conditions: Iritis can be linked with conditions such as ankylosing spondylitis, reactive arthritis, inflammatory bowel disease, psoriatic arthritis, Behçet disease, and sarcoidosis.
- Infections: Certain viral infections (including herpes viruses) and other infectious diseases have been associated with iritis/uveitis, which is one reason proper evaluation matters before starting steroid drops.
- Eye injury or surgery: Blunt trauma, penetrating injury, burns, and sometimes surgery can be associated with anterior uveitis.
- Medications (less common): Some medicines are linked to uveitis/iritis in rare cases, and clinicians consider this in the right context.
Risk can be higher in people with certain immune-system conditions or gene markers (HLA-B27), and some sources note smoking as a risk factor.
Common Signs and Symptoms
Iritis often comes on relatively suddenly (over hours to days) and may affect one eye, especially in acute anterior uveitis.
Typical symptoms include:
- Eye redness.
- Eye pain or aching/discomfort.
- Sensitivity to light (photophobia).
- Blurred or decreased vision.
- A small, irregular, or sluggish pupil can occur, sometimes because inflammation or scarring affects how the iris moves.
Because several eye problems can look similar early on, a “red eye” isn’t enough to tell what’s happening without an exam.
How the Condition is Diagnosed
Diagnosis is based on an eye examination, usually including a slit-lamp exam (a high-magnification microscope used to examine the front of the eye).
An eye care professional may also check vision, evaluate eye pressure (tonometry), and look for signs that inflammation involves other parts of the eye.
If iritis/uveitis is recurrent, severe, affects both eyes, or you have symptoms suggesting a systemic condition, clinicians may suggest additional testing (for example, blood tests or imaging) to look for an underlying cause.
Treatment Options Explained (non-prescriptive, informational)
Treatment depends on the severity, the part of the eye involved, and whether an infection or systemic condition is suspected.
In anterior uveitis/iritis, treatment commonly involves prescription eye drops aimed at reducing inflammation and improving comfort.
Common treatment approaches you may hear about include:
- Anti-inflammatory eye drops (often steroid drops): Steroid eye drops are widely described as a main treatment used to reduce inflammation, typically prescribed and monitored by an eye specialist.
- Dilating/cycloplegic drops: Drops that dilate the pupil can reduce pain by relaxing the inflamed iris/ciliary body and may help prevent the iris from sticking to the lens (synechiae).
- Treating the underlying cause when possible: If uveitis is linked to an infection or systemic inflammatory disease, treatment may also focus on that condition.
- Escalation for more severe cases: In more severe situations, steroids may be given by injection around/into the eye or by mouth, and longer-term control may involve other immune-modulating medicines under specialist care.
Follow-up visits matter because clinicians may need to adjust treatment and watch for pressure changes in the eye or other complications.
Possible Complications if Left Untreated
Without appropriate treatment, iritis/uveitis can lead to serious eye problems, including vision loss.
Complications described in major patient resources include:
- Glaucoma / elevated eye pressure.
- Cataract (clouding of the lens), especially with prolonged inflammation (and sometimes as a risk with long-term steroid use).
- Irregular pupil or iris adhesions (synechiae), where scar tissue causes the iris to stick to nearby structures.
- Retinal swelling / macular edema, which can affect central vision.
Not everyone will develop complications, but the possibility is why prompt evaluation and monitoring are emphasized.
Prevention and Risk Reduction (if applicable)
Iritis/anterior uveitis often can’t be fully prevented because the cause may be unknown.
If iritis is associated with an autoimmune condition, staying on top of that condition’s care may support overall health, including eye health.
Protecting the eyes from injury (for example, using appropriate eye protection during higher-risk activities) is a practical way to reduce trauma-related risk.
When to See an Eye Doctor
Seek prompt care from an eye specialist if you develop symptoms suggestive of iritis, such as eye pain, light sensitivity, redness, and decreased vision.
Some situations may need urgent evaluation—especially eye pain with vision changes—because timely treatment helps prevent complications.
If you’ve had iritis before and symptoms return, it’s still important to be assessed rather than restarting old drops on your own, since infections and other conditions can mimic uveitis and may change what treatment is safest.
Frequently Asked Questions (FAQ)
Iritis is a form of uveitis—specifically anterior uveitis—because it involves inflammation in the front part of the uveal tract (including the iris).
Some episodes may improve, but patient resources emphasize that uveitis/iritis should be evaluated and treated to reduce the risk of complications and vision loss.
Mayo Clinic notes iritis often develops suddenly and can last up to three months, and resources also describe acute disease as lasting under three months (with chronic disease persisting longer).
Common symptoms include eye redness, pain/ache, sensitivity to light (photophobia), and blurred or decreased vision.
Causes may be unknown, or linked to autoimmune/inflammatory diseases (including HLA-B27–associated conditions), infections, trauma, and—in some cases—medications.
Major medical resources advise seeing an eye specialist as soon as possible if you have symptoms of iritis, and note that eye pain with vision problems may require urgent care.
Key Takeaways
Iritis (anterior uveitis) is inflammation of the iris that can cause a painful red eye, light sensitivity, and blurred vision.
Because it can lead to complications like glaucoma, cataract, retinal swelling, or vision loss, it’s important not to ignore symptoms.
Diagnosis and treatment require an eye exam and follow-up, and care may include anti-inflammatory drops and dilating drops, with escalation in more complex cases.
