Precision of a Commercial Hartmann-Shack Aberrometer: Limits of Total Wavefront Laser Vision Correction

Total ocular aberrations, total HOAs, and second-order terms can be measured reliably by Zywave aberrometry without anatomic recognition. Third-order terms and Z40 are repeatable, but not as reproducible between visits. Fourth-order terms, except for Z40, and fifth-order terms are not sufficiently reliable for clinical decision making or treatment. Because the variability of Zywave can be a major limitation of a truly successful wavefront-guided excimer laser procedure, surgeons should consider treating HOA magnitudes that are more than the intrasession repeatability values (2.77 × Sw) as those presented in this study.