Limbo-sclerotomy--a refractive procedure outside the cornea. Preliminary report

Abstract

Complications of refractive corneal procedures are a consequence of inevitable corneal deformation or thinning. We aim to reduce corneal refractive power but omit laceration on the cornea itself. 1. Rabbits: The procedure war first studied in 16 chinchilla rabbits (32 eyes). Seven eyes were enucleated in different intervals for microscopic evaluation. In rabbits the corneal diameter increased and refractive power of the cornea was diminished by 3.0 to 6.0 diopters. Refraction was controlled after 1, 2, 6 and 12 months. 2. Incision of the conjunctiva 4 mm peripheral to the limbus in all 4 quadrants and mobilisation to the corneal insertion. In each quadrant 4 to 5 radial incisions are placed from the exposed limbus in the adjacent sclera. The incisions have a depth of 500 micrometers and extend until 4 to 5 mm. The conjunctiva was restored by running sutures. So far, we observed no complications. Thereafter the procedure was carried out in eleven patients (16 eyes) aged between 18 and 55 years. Preoperative errors varied between -5.0 and -19.0 diopters. In patients the power of the procedure was in the same range as in animals. Visual acuity improved in all cases. Preoperatively, 10 eyes had uncorrected visual acuity of 0.01 to 0.1 and 6 eyes 0.1 to 0.3. Postoperatively, uncorrected visual acuity improved to 0.02/0.06 and 0.5 in 5 eyes. In eleven eyes visual acuity improved to 0.2/0.7 and 0.8 eyes. Refraction was stable during a follow-up of 3 years. Limbosclerotomy is an effective and safe approach to correct myopic refractive errors. Its effect may be explained by weakening of circular collagen fibers in the pericorneal area.