![]() ![]() Such a comparison is needed to accurately analyze where in the eye light rays are most distorted. Internal aberration refers to light rays that are mainly disturbed in the anterior segment. The total optical aberration of an eye is the sum of all rays entering and exiting the eye. The purpose of this study is to provide a number of technical and practical parameters that may be useful in choosing an aberrometer for daily clinical practice. ![]() Making a practical comparison between the available devices is not an easy task because of the variety of principles used, such as ray tracing, Hartmann-Shack, Tscherning, and automatic retinoscopy. 4Īberrometry presents larger applications than just enhancing the quality of the ablation zone in an excimer laser treatment, so the choice of the most appropriate machine depends mainly on the clinical practice. 3Īberrometers are currently the most important tools for estimating optical conditions so that a more complete understanding of optical error can be quantified and corrected. 2 As skills developed for measuring wavefront, it was discovered that HOAs increased following excimer laser ablation of the cornea during refractive surgery. ![]() The twentieth century introduced the Zernike polynomials, which could quantitatively analyze optical HOAs in the human eye. 1 These came to be known as high order aberrations (HOAs). In the nineteenth century, Helmholtz found optical errors that could not be corrected using existing optical theory. ![]()
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