The results of ischaemia in chemical injuries.

Severe burns of the anterior eye segment which include cornea, limbus and adjacent conjunctiva necrosis were accompanied by ischaemia. While necrotic conjunctival and subconjunctival tissue should be removed to eliminate its toxic influence, the opaque cornea and ischaemic sclera could not be removed. The ciliary body and the iris also suffer from ischaemic damage and under such conditions nutrient metabolites are deficient in the anterior segment of the eye. In the surrounding healthy tissues an inflammatory reaction begins after several days which induces an infiltration of the damaged tissues by leucocytes and an increase of N-acetylglucosaminidase and Cathepsin-D as demonstrated in model experiments and in patients. These destructive enzymes are apparently involved in the corneal and corneo-scleral ulceration and their activities may therefore be used to assess the severity of the ocular burn.