Ladarvision excimer laser

Abstract

We read with great interest the recent article by Salz et al regarding the LASIK correction of spherical hyperopia, hyperopic astigmatism, and mixed astigmatism with the LADARVision laser system (Alcon Surgical, Orlando, FL).1 The authors used a nomogram adjustment of adding +1.00 diopters (D) to the preoperative cycloplegic sphere for all eyes, including those with spherical hyperopia, hyperopic astigmatism, and mixed astigmatism. However, the postoperative refractive results differed for these groups. As shown in their Figure 2, in the eyes with spherical hyperopia, the mean spherical equivalent (SE) fell from +2.40±1.12 D preoperatively to −0.13±0.72 D at 3 months and +0.05±0.71 D at 1 year, and in the hyperopic astigmatism group, the SE changed from +2.38±1.21 D preoperatively to −0.13±0.65 D at 3 months and +0.06±0.78 D at 1 year. Conversely, for the eyes with mixed astigmatism, the SE was overcorrected, with values of +0.04±0.80 D preoperatively to −0.67±0.76 D at 3 months and −0.45±0.64 D at 1 year. Thus, adding +1.00 D to the sphere in the eyes with spherical hyperopia and hyperopic astigmatism could be appropriate. But adding the same amount in mixed astigmatism patients will cause overcorrection. The authors did not say whether they adjusted the nomogram for astigmatism treatment. As displayed in their Table 4, the results of vector analysis of astigmatism correction showed that there was an overcorrection of the cylinder in the hyperopic astigmatism group and undercorrection in the mixed astigmatism group. Therefore, it would be suggested that the nomogram should be developed individually for different treatment groups and should involve the spherical and astigmatism components separately, especially for the correction of mixed astigmatism.