WaveLight® Contoura topography-guided planning: contribution of anterior corneal higher-order aberrations and posterior corneal astigmatism to manifest refractive astigmatism

Abstract

Avi Wallerstein,1,2 Mathieu Gauvin,1,2 Mark Cohen2,3 1Department of Ophthalmology, Faculty of Medicine, McGill University, Montreal, QC, Canada; 2LASIK MD, Montreal, QC, Canada; 3Department of Surgery, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC, CanadaClinical refractive astigmatism (RA) and topography-measured anterior corneal astigmatism (ACA) are rarely identical in magnitude and axis.1 This difference, when expressed vectorially, is termed ocular residual astigmatism (ORA).1 What accounts for this difference remains a topic that needs further research, and has implications as to what refraction to treat with topography-guided excimer laser ablations in order to maximize outcomes.1 This research letter investigates aspects of two contributing factors: posterior corneal astigmatism (PCA) and anterior corneal higher-order aberrations (CHOAs).

Keywords

• Contoura
• Corneal higher-order aberrations
• Anterior Corneal Astigmatism
• Posterior Corneal Astigmatism
• Refractive Astigmatism