[Therapy of advanced amoeba keratitis with keratoplasty à chaud and adjuvant cryotherapy]

Since the mid-1980s acanthamoeba keratitis has been diagnosed with increasing frequency, especially in contact lens wearers. The assignment to specialized centers is often delayed many months and there is hardly any chance of controlling the disease by conservative treatment alone. In these cases, penetrating keratoplasty offers the only chance for rehabilitation. The therapeutic role of penetrating keratoplasty and supportive intraoperative cryotherapy is demonstrated by the courses of six patients with unilateral acanthamoeba keratitis.

The data of six patients aged 41.2 (22-63) years with medically uncontrollable acanthamoeba keratitis were evaluated retrospectively. The diagnosis was confirmed histologically in all cases. All patients were contact lens wearers. They underwent a total of ten keratoplasties between November 1986 and January 1995. The donors were 44.8 (23-58) years of age. The transplant diameters varied between 7.7 and 9.5 mm. The margins of the host cornea were intraoperatively frozen by a cryoprobe in three patients with a far advanced stage of corneolimbal parasitic infiltration.

During a follow-up period of +/-10.2 (1-22) months, five of six eyes were rehabilitated with visual acuities between 0.4 and 1.0. One eye went blind after the fourth keratoplasty because of uncontrollable secondary glaucoma. After three keratoplasties with simultaneous application of cryocoagulation because of an especially high risk of persisting acanthamoeba infection, all corneae remained clear and free of recurrences.

In advanced acanthamoeba keratitis which has not responded to conservative treatment, penetrating keratoplasty not only provides elimination of the pathogen, but also good functional results. In far advanced stages, the intraoperative application of cryocoagulation for parasite elimination in the host cornea seems to be a very effective measure against local recurrences of the infection.