Uveitis and Ocular Inflammation: Causes, Signs, Treatment

Uveitis is inflammation of the uvea, the middle layer of the eye containing the iris, ciliary body and choroid. It is classified by location: anterior uveitis (iritis) affects the front, intermediate the vitreous, posterior the retina and choroid, and panuveitis the whole eye.

Uveitis matters because it is a painful, sight-threatening red eye often mistaken for simple conjunctivitis. Untreated inflammation causes cataract, secondary glaucoma and retinal damage. It is also a window into the body — many cases are the first clue to ankylosing spondylitis, sarcoidosis or tuberculosis.

Key Concepts

• Cells and flare: white cells floating in the anterior chamber ("cells") and leaking protein ("flare"), seen with a slit lamp. The SUN scale grades cells in a 1 × 1 mm beam: 0.5+ is 1–5 cells, 1+ is 6–15, 2+ is 16–25, 3+ is 26–50, 4+ is over 50.
• Keratic precipitates: inflammatory deposits on the cornea's back surface; large "mutton-fat" ones suggest granulomatous causes like sarcoidosis or TB.
• Posterior synechiae: adhesions where the inflamed iris sticks to the lens, distorting the pupil and sometimes raising eye pressure.
• Uveitis vs conjunctivitis: uveitis causes deep pain, marked photophobia and blurred vision with redness around the cornea (ciliary flush); conjunctivitis itches or discharges but rarely hurts in bright light.
• Causes: often idiopathic, but key associations are HLA-B27 diseases, sarcoidosis, tuberculosis, toxoplasmosis, herpes viruses, Behçet disease and juvenile idiopathic arthritis.
• Treatment: anterior disease gets topical steroids plus a cycloplegic (atropine) that relieves pain and prevents synechiae; posterior disease needs systemic steroids or immunosuppressants with slow tapering.

How It Works

1. History: pain, photophobia and blurred vision point to uveitis; ask about joint pain, mouth ulcers and TB contact hinting at systemic disease.
2. Slit-lamp exam: count cells in the 1 × 1 mm beam, assign the SUN grade, and note flare, keratic precipitates and synechiae.
3. Dilated fundus exam: look for vitreous cells, retinal lesions or vasculitis marking posterior involvement.
4. Systemic workup: HLA-B27 testing, chest X-ray, TB tests or syphilis serology as clues dictate, then treat eye and underlying disease together.

Worked Example

1. A 30-year-old man presents with a painful red left eye, severe photophobia and blurred vision for three days, plus chronic low back stiffness.
2. Slit-lamp shows 20 cells in the 1 × 1 mm beam with mild flare. On the SUN scale, 20 cells falls in the 16–25 band → grade 2+ anterior uveitis, moderate inflammation. Fine keratic precipitates and early synechiae are also present.
3. He starts prednisolone acetate 1% drops hourly plus atropine 1% twice daily to keep the pupil mobile and ease pain. HLA-B27 is ordered for the back symptoms, and steroids are tapered over weeks once cells reach zero.

Common Misconceptions

• Myth: Every red eye just needs antibiotic drops. Fact: pain plus photophobia signals uveitis, which needs steroids — misdiagnosis lets inflammation scar the eye.
• Myth: Stop steroid drops once the eye feels better. Fact: sudden stopping causes rebound inflammation; steroids must be tapered slowly.
• Myth: Uveitis affects only the front of the eye. Fact: posterior uveitis attacks the retina painlessly and is missed without a dilated exam.

Real-World Applications

• Ophthalmology clinics: slit-lamp grading standardizes diagnosis and tracks response visit to visit.
• Rheumatology: uveitis workups uncover ankylosing spondylitis, sarcoidosis and Behçet disease.
• Pediatric screening: children with juvenile arthritis get regular slit-lamp checks since their uveitis is painless but blinding.

Uveitis inflames the eye's middle layer and is graded 0 to 4+ by counting cells in a slit-lamp beam; pain and photophobia separate it from conjunctivitis. Anterior cases respond to steroid and atropine drops, while posterior cases need systemic treatment and a hunt for underlying diseases like HLA-B27 arthritis, sarcoidosis or TB.