Correction of Irregular Astigmatism with the Excimer Laser

Background: Correction of irregular astigmatism has not been possible using available keratorefractive technology. Methods: The authors used a topographic map as a guide and created a custom excimer ablation program, designed to create a more regular surface. The program consisted of a combination of phototherapeutic and photorefractive ablation patterns. The amount of tissue to be removed was calculated on the basis of the diameter and steepness of the irregular areas of the corneal surface. Results: A more regular surface, as evidenced by topographic analysis, reduced astigmatism, and improved uncorrected visual acuity, was produced. Conclusion: Using the corneal topographical map as a guide, excimer laser ablation can be used to create a more regular optical surface with improved visual function.