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February 1995

One-Year Results of the Intrastromal Corneal Ring in Nonfunctional Human Eyes

Author Affiliations

From the Anheuser-Busch Eye Institute, St Louis (Mo) University. Dr. Schanzlin is a paid consultant for KeraVision Inc, Fremont, Calif. The other authors have no proprietary interest in any research or materials presented in this article.

Arch Ophthalmol. 1995;113(2):159-167. doi:10.1001/archopht.1995.01100020041026

Objective:  The intrastromal corneal ring (ICR), a new keratorefractive device designed to correct myopia, was evaluated for safety and efficacy as part of a phase I Food and Drug Administration clinical trial.

Patients and Methods:  Ten patients, each with one nonfunctional eye, underwent surgical implantation of the ICR, which is a split ring composed of polymethyl methacrylate. The eyes were followed up during a 1-year period and were evaluated for wound healing, implant-related inflammation, intraocular pressure, corneal thickness, endothelial cell count, and refractive effects.

Results:  Wound healing was uncomplicated in all of the patients. No patient experienced implant-associated inflammation or extrusion. Intraocular pressure, corneal thickness, and endothelial cell counts were unaffected by the ICR. Non—sight-threatening intraoperative events included ring decentration and inadequate attachment of a vacuum-centering guide. The ICR reduced keratometrically determined spherical equivalence by an average of −2.5±1.1 diopters (mean±SD). Spherical equivalence, as determined by retinoscopy, was reduced by an average of−2.4±1.0 D. Results of corneoscopy and computerized videokeratography further confirmed this reduction of myopia.

Conclusions:  The ICR may be a safe and efficacious device that offers predictable results with few side effects, and it may be a feasible alternative to current keratorefractive procedures.