In a patient with unilateral ocular pain, photophobia, blurred vision, a small irregular pupil, and circumcorneal (ciliary) injection, which diagnosis is most likely: acute angle-closure glaucoma, anterior uveitis, viral conjunctivitis, or subconjunctival hemorrhage?

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Anterior Uveitis (B)

The correct diagnosis is B. Anterior uveitis. The clinical presentation of unilateral pain, photophobia, blurred vision, a small irregular pupil, and ciliary (circumcorneal) injection is pathognomonic for anterior uveitis 1, 2, 3.

Key Distinguishing Features

Why Anterior Uveitis:

  • Small, irregular pupil is the critical distinguishing feature, resulting from posterior synechiae (iris adhesions to the lens) 1, 3
  • Ciliary injection (circumcorneal flush) indicates inflammation of deeper ocular structures, not superficial conjunctival disease 2
  • The triad of pain, photophobia, and blurred vision reflects intraocular inflammation 1, 2, 3
  • Patients typically complain of eye pain and headaches with potential progression to vision loss if untreated 2

Why Not the Other Options:

A. Acute Angle-Closure Glaucoma:

  • Would present with a mid-dilated, fixed pupil (not small and irregular) 4
  • IOP would be markedly elevated (often >40 mmHg) with corneal edema 4
  • Patients experience severe pain, nausea/vomiting, and see halos around lights 4
  • The pupil characteristics alone exclude this diagnosis

C. Viral Conjunctivitis:

  • Presents with watery discharge and follicular reaction, not ciliary injection 5
  • Pupil remains normal and reactive 5
  • Pain is minimal; patients report more irritation than true pain 5
  • No photophobia or significant vision changes 5

D. Subconjunctival Hemorrhage:

  • Completely painless with normal vision 5
  • Bright red blood under conjunctiva without ciliary injection
  • Pupil remains normal
  • No photophobia

Clinical Implications

Urgent ophthalmology referral is mandatory 2. Slit-lamp examination will confirm anterior chamber cells and flare, definitively diagnosing anterior uveitis 2. Initial treatment consists of topical corticosteroids (prednisolone acetate 1%) with cycloplegic agents 1, 3. The small irregular pupil indicates established posterior synechiae, suggesting this is not a first presentation and requires aggressive treatment to prevent vision-threatening complications including glaucoma, cataracts, and permanent vision loss 1, 3.

Critical pitfall: Do not mistake ciliary injection for simple conjunctival injection—ciliary injection indicates serious intraocular pathology requiring immediate specialist evaluation 2.

References

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