Photorefractive Keratectomy to Create Toric Ablations for Correction of Astigmatism

Peter J. McDonnell, Hamilton Moreira, Jenny Garbus, Terrance N. Clapham, John D'arcy, Charles R. Munnerlyn

Research output: Contribution to journalArticlepeer-review

68 Scopus citations


Excimer laser photorefractive keratectomy, developed to perform radially symmetric ablations to correct myopic or hyperopic refractive errors, was used to create toric ablations designed to correct cylindrical errors. An expanding slit was created, with no refractive change intended parallel to the slit opening, and central flattening was induced in the meridian in which the slit was expanded. In polymethyl methacrylate blocks, the induced cylinder (as measured with a lensometer) agreed closely (r2=.99) with the intended change, and in plastic corneas, induction of the cylinder could be demonstrated with computer-assisted topographic analysis. Adult pigmented rabbits underwent induction of toric ablations in two-diopter increments; measured keratometric change correlated with desired change (r2=.87 at 3 weeks; r2=.89 at 12 weeks). Toric ablations with the excimer laser appear to represent a promising strategy for the correction of cylindrical errors that do not rely on creation of deep corneal incisions, excisions, or compression sutures.

Original languageEnglish (US)
Pages (from-to)710-713
Number of pages4
JournalArchives of ophthalmology
Issue number5
StatePublished - May 1991
Externally publishedYes

ASJC Scopus subject areas

  • Ophthalmology


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