Which type of ocular examination finding may indicate a severe allergic reaction to a preservative?

Follicular conjunctivitis is characterized by the presence of small raised bumps (follicles) on the conjunctiva, often indicative of an allergic reaction, including those triggered by preservatives found in eye drops. In the context of a severe allergic reaction, these follicles result from a hypersensitivity response that can cause inflammation and irritation in the conjunctival tissue.

The presence of follicles, especially in conjunction with symptoms like redness, itching, or discharge, suggests that the immune system is reacting to the allergen, which in this case is likely a preservative in an ocular medication. In contrast, diffuse superficial punctate keratitis (SPK) refers to burn-like spots on the cornea, which may arise from a variety of causes, but is not specific to a severe allergic reaction. Corneal ulceration can occur from infections or severe dryness but does not specifically indicate an allergic response. Lastly, a normal conjunctiva would indicate no reaction or inflammation, which does not align with the scenario of a severe allergic reaction. Therefore, the presence of follicular conjunctivitis serves as a clear indication of an allergic response, particularly to topical agents containing preservatives.