The immune ring is a feature of

A typical fungal corneal ulcer has following salient features: The corneal ulcer is dry-looking, greyish white, with elevated rolled out margins. Delicate feathery finger-like extensions are present into the surrounding stroma under the intact epithelium. A sterile immune ring (yellow line of demarcation) may be present where fungal antigen and host antibodies meet. Multiple, small satellite lesions may be present around the ulcer. Usually, a big hypopyon is present even if the ulcer is very small. Perforation of mycotic ulcer is rare but can occur. Corneal vascularization is conspicuously absent. The term fungal keratitis refers to a corneal infection caused by fungi. One type of fungus that can infect the cornea is Fusarium.This increased occurrence of fungal keratitis is a result of the frequent use of topical coicosteroids along with antibacterial agents in treating patients with keratitis Ref: Khurana; 4th edition; Pg no.100