Acute membranous conjunctivitis: It is an acute inflammation of the conjunctiva, characterized by formation of a true membrane on the conjunctiva. The disease is typically caused by Corynebacterium diphtheriae. This organism produces a violent inflammation of the conjunctiva, associated with deposition of fibrinous exudate on the surface as well as in the substance of the conjunctiva resulting in formation of a thick, grey-yellow membrane. The membrane is tough and firmly adherent to the conjunctiva, which on removing bleeds and leaves behind a raw area. Ref: Ophthalmology By A. K. Khurana, 3rd edition, Page 86.