<prompt> Immune ring is a feature of -Interstitial keratitisFungal corneal ulcerBacterial corneal ulcerHerpes simplex keratitis  <response>: A sterile immune ring yellow line of demarcationmay be present where fungal antigen and host antibodies meet.Its a sign in fungal corneal ulcer Reference:Comprehensive ophthalmology,AK Khurana,6th edition,page no.106 