Shrinkage of the conjunctiva leads to obliteration of the conjunctival sac. Other ocular problems may also occur, including conjunctival and corneal oedema, and aqueous flare. Other ocular findings can include conjunctival and retinal vascular abnormalities and anterior/posterior spoke-like cataract. Additional cells present in the conjunctival epithelium include melanocytes, T and B cell lymphocytes. Intracytoplasmic inclusions may be seen in the epidermis and in conjunctival epithelium. The nerves enter the cornea via three levels; "scleral, episcleral and conjunctival". Treatment of conjunctival SCC is usually surgical excision followed by cryotherapy. Amniotic membrane transplantation offers practical alternative to conjunctival auto graft transplantation for extensive pterygium removal. Histamine also binds to H1 and H2 receptors of the conjunctival vasculature and causes vasodilatation. Like CS gas, this compound irritates the mucous membranes (oral, nasal, conjunctival and tracheobronchial). It results either from disease (conjunctival sequelae of trachoma) or trauma. Bilateral conjunctival inflammation has been reported to be the most common symptom after fever. Under local anesthesia, a conjunctival incision is created at the peg insertion site. The yellowing of the "white of the eye" is thus more properly termed "conjunctival icterus". Congenital conjunctival concretion condition is also more common.