Question

Immune ring is a feature of?

• A. Interstitial keratitis
• B. Fungal corneal ulcer
• C. Bacterial corneal ulcer
• D. Herpes simplex keratitis

Hint:

Think of the sterile ring of Wesseley with feathery margins and satellite lesions.

Answer 1

The Correct Option is B

Step 1: A fungal (mycotic) corneal ulcer has very prominent signs that are typically out of proportion to the symptoms. One of its hallmark features is a sterile immune ring.

Step 2: The sterile immune ring, also called the yellow ring of Wesseley, forms around the ulcer due to an antigen-antibody reaction to fungal antigens. Along with it one sees a greyish-white dry ulcer with rolled out feathery hyphate margins and multiple satellite lesions.

Step 3: These features (feathery margins, satellite lesions, immune ring, dry slough) point specifically to a fungal cause rather than a bacterial one, where the ulcer is wet with mucopurulent discharge.

Step 4: Therefore the immune ring is a feature of fungal corneal ulcer. It is not characteristic of interstitial keratitis, bacterial ulcer or herpes simplex keratitis.