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Editor,—Ligneous conjunctivitis is a rare chronic pseudomembranous conjunctivitis that in some cases is associated with membrane formation in other mucous tissues. Involvement of the palpebral conjunctiva is the most common site of the disease although formation of bulbar membrane and even corneal membrane have been reported.1 Induction of membrane formation may occur after minor trauma (for example, conjunctivitis, surgery, toxic agents).
The disorder has an AR inheritance and is caused by an impaired fibrinolysis related to deficient plasminogen type I. Recently causative mutations in the plasminogen gene have been identified in affected patients.2
Pathological findings disclose fibrin as the major component within amorphous hyalin-like eosinophilic material, fibroblastic proliferation, inflammatory cellular infiltration, and acid mucopolysaccharides.3
The treatment of the disorder has generally been unsuccessful, although spontaneous resolution may occur. Excision of the membrane (with cryocoagulation and/or autologous conjunctival graft or scleral graft) often worsens the conjunctivitis within a few days after surgery.
Treatment strategies that act on the different constituents found in the ligneous membrane have been proposed; topical proteolytic enzymes (hyaluronidase and chymotrypsin),4 fibrinolysin drops that cause fibrinolysis,5 and topical anti-inflammatory agents (corticosteroids and cyclosporin).6
In 1995 De Cock et al 7suggested the administration of topical heparin (antifibrin action) in combination with the above agents. The authors reported efficacy of their treatment although it was not consistent in all patients.
In an earlier report we discussed a boy who underwent eight consecutive unsuccessful excisions of a ligneous conjunctival membrane between August 1997 and February 1999.8 Surgery was combined with topical medications—chymotrypsin, hyaluronidase, dexamethasone, and heparin.
Research on type I plasminogen deficiency conducted by Schusteret al disclosed in our patient a decreased plasminogen activity (36% of normal activity) and a causative mutation in the plasminogen gene.9
On 12 March 1999 we performed another excision of the recurrent membrane and we applied mitomycin C for 3 minutes followed by an amniotic membrane graft. Adjuvant medical treatment consisted of the administration of systemic prednisone 1 mg/kg/day and topical heparin for 14 days. This treatment was successful (Fig 1) and since then the membrane has not recurred.
On ocular follow up examination we observed the formation of complicated SCP cataract.
On 27 January 2000 we performed a lensectomy with insertion of a PC-IOL and peroperatively we injected 25 μg tissue plasminogen activator (r-tPA) intracamerally, to prevent fibrinous effusion. During the first postsurgical week, slit lamp examinations showed the absence of reaction in the anterior chamber. The child was discharged from hospital on day 7. On control examination (day 9) slit lamp examination revealed multiple fibrin strands emerging from the pupil towards the cornea over 360° (Fig 2). The child was again admitted and received a protective shell to prevent eye robbing. This measure was followed by the disappearance of fibrin after 1 day. The PC-IOL restored the visual acuity.
Up to now strategies that have been proposed for the treatment of conjunctivitis lignosa act on different aspects in the cascade of wound healing. We added two agents, mitomycin C and r-tPA, that had not yet been applied for this indication.
Mitomycin C is an antiproliferative drug that prevents the development of scar tissue and is widely used in ocular surgery. We propose to use mitomycin C in combination with heparin and corticosteroids in the treatment of ligneous conjunctivitis.
If intraocular surgery is needed in affected patients, we suggest using intracameral recombinant tissue plasminogen activator in order to stimulate fibrinolysis. The intracameral injection of 25 μg r-tPA has proved to be efficient and safe in the treatment of severe postoperative fibrinous reactions.10
Until causative treatment with pharmacological plasminogen is possible we believe that mitomycin C and r-tPA may be useful adjuvant agents respectively in conjunctival and intraocular surgery in patients with ligneous conjunctivitis.