Ciliary injection: a differential diagnosis for the patient with acute red eye.

This case presents the challenge of how to accurately assess the unilateral painful red eye with ciliary injection. The diagnosis can be clarified with careful clinical observation and a few basic clinical tests. Physical examination should focus on visual acuity; presence of pain; location of redness; shape, size, and reaction of the pupil; and the IOP, if it can be obtained safely. If a slit lamp is available, the diagnosis can be made more definitively. Because the diagnosis in a situation like this is usually made by an eye specialist, a clinical presentation of unilateral painful red eye will normally be referred after an initial examination and early management commences. A crucial role for the physician assistant or other primary care provider is to carefully observe the physical findings, accurately describe the signs and symptoms, and initiate appropriate management. These steps will facilitate the referral to an eye specialist and optimize resolution of these potentially sight-threatening conditions.