Corneal sensation is lost in which of the following infection?
Disciform keratitisPathogenesis: It is due to the delayed hypersensitivity reaction to the HSV antigen. There occurs low-grade stromal inflammation and damage to the underlying endothelium. Endothelial damage results in corneal edema due to imbibation of aqueous humor. Signs:Focal disc-shaped patch of stromal edema without necrosis,Folds in Descemet's membrane,Keratic precipitates, Ring of stromal infiltrate (Wessley immune ring) may be present surrounding stromal edema. It signifies the junction between viral antigen and host antibody,Corneal sensations are diminished,Intraocular pressure (IOP) may be raised despite only mild anterior uveitis. In severe cases, anterior uveitis may be markedImpoant note: During active stage, diminished corneal sensations and keratic precipitates are the differentiating points from other causes of stromaledema. Herpes simplex infection is a common cause of corneal sensory loss, 8 although less severe than in keratitis caused by reactivation of varicella-zoster virus. The decrease in corneal sensitivity to mechanical stimulation in HSV keratitis patients is propoional to the number of recurrent episodes Ref: Khurana; Comprehensive Ophthalmology; 4th edition; Page no: 103
Trachoma
Fungal
Conjunctivitis
Herpes simplex
Cornea and sclera