Dacryocystitis is characterized by localized pain, edema, and erythema over the lacrimal sac at the medial canthus of the eye. Dacryocystitis is usually unilateral. There is often purulent discharge from the puncta. Episcleritis Episcleritis must be differentiated from injection of the more superficial conjunctival vessels and from the deeper scleral vessels. Unlike conjunctivitis, the inflammation tends to be limited to an isolated patch, not involving the eye diffusely.
Foreign body Stain the patient's eye with fluorescein to detect evidence of corneal abrasion.
Exclude penetration of the globe by thorough slit lamp examination. Always evert the lid should to exclude retained material. The eye develops a perilimbal flush due to dilation of the radial vessels. Compare to conjunctivitis, in which the intensity of vascular engorgement decreases toward the limbus. Cells and flare are present in the anterior chamber as seen under high magnification under specific light conditions with the slit lamp.