Editor,—Ligneous conjunctivitis is a rare chronic membranous conjunctivitis with typical woody induration of the conjunctival tissue.1 2 It occurs most often bilaterally in female children and is of unknown aetiology.1-3 The disease process may involve other mucous membranes, such as the cervix and the trachea, occasionally leading to death by tracheal obstruction.4 Few patients with adult onset ligneous conjunctivitis have been seen.3 5 They generally experience a milder course and systemic involvement is less common. Autoimmune dysfunction, infection with an unidentified virus, and an inherited predisposition possibly combined with trauma have all been proposed as possible causes for the disease.3 5 6 Recent studies have found an inherited defect in the plasminogen system of affected children.7 Treatment of …