Wavefront analysis and Zernike polynomial decomposition for evaluation of corneal optical quality

Wavefront-guided excimer laser refractive surgery and new customized intraocular lens and contact lens designs are major clinical applications of corneal wavefront analysis. Other therapeutic applications include corneal disorders, conventional excimer laser refractive surgery, incisional techniques and cataract surgery, corneal transplantation, intrastromal corneal ring segment implantation, and crosslinking therapy. Basic data regarding corneal wavefront aberrations, such as distribution in the population and changes with aging, are essential for understanding the nature of each aberration and correcting it. Corneal aberrometry also improved our comprehension of the optical effects of the aforementioned topics while helping us assess the success of the procedures. Zernike polynomials are representations of the higher- and lower-order aberrations of the cornea, allowing a mathematical approach to their determination. Polynomials are used to model individual components of the wavefront in familiar terms. This article reviews the current knowledge of the wavefront aberrations of the human cornea and analyzes studies in the fields of anterior segment surgery and/or therapy, diseases, and optical quality in the context of this knowledge.Supported by the Fundação para Ciência e a Tecnologia (grant PTDC/SAU-BEB/72220/2006) and grant Uminho/BI/141/2008 from Fundação para a Ciência (Oliveira)