Inclusion criteria were healthy eyes with a corrected distance visual acuity of 20/20. The study adhered to the principles outlined in the Declaration of Helsinki. The volunteers were informed about the objective of the study. Because the devices undergo constant alteration and improvement, we advise potential users to verify all parameters for each model and device.Įighty eyes of 40 healthy young adults (mean age 26.5±4.5y) were examined with two clinical wavefront analyzers without the instillation of dilating eye drops. We note that our results only represent the devices as they were made available to us during the study period. We measured high order aberration (HOA) of corneal, internal and total ocular using a KR-1W (based on Hartmann-Shack) and iTrace (based on ray tracing) to compare the difference and agreement of KR-1W and iTrace for measurement of HOA. 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. The ray-tracing system is an ingoing aberrometry sensor. ![]() The Hartmann-Shack aberrometer is an outgoing wavefront aberrometer. Ingoing aberrometers operate by examining how wavefronts external to the eye are altered as they pass through the optics of the eye. Point source of light on the retina emits diverging spherical wavefronts that pass through the crystalline lens and the cornea to exit the eye. Outgoing aberrometers operate by placing a point source of light on the retina and determining the shape of the wavefront emerging from the eye. Wavefront sensors can be divided into 2 categories: outgoing and ingoing. 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. So the choice of the most appropriate machine depends mainly on the clinical practice. Aberrometry presents larger applications than just enhancing the quality of the ablation zone in an excimer laser treatment. ![]() ![]() Visual function analyzer could provide pupillomerty, keratometry, and autorefraction assessment, allowing to acquire wavefront data and topography data simultaneously. The broadening of clinical applications for these instruments favored the quick expansion into all visual health-related practices, particularly cataract surgery. A number of systems developed as clinical tools for the assessment of wavefront aberrations of the eye are currently available.
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