Abstract
A corneal aberrometer based on Shack–Hartmann wave-front sensing was developed and validated by using calibrated aspheric surfaces. The aberrometer was found to accurately measure corneal reflective aberrations, from which corneal topography and corneal refractive aberrations were derived. Measurements of reflective aberrations correlated well with theory to 0.994). The sag error root mean square (RMS) was small, ranging from 0.1 to 0.17 μm for four of the five calibrated surfaces with the fifth at 0.36 μm as a result of residual defocus. Measured refractive aberrations matched with theory and whole-eye aberrometry to within a small fraction of a wavelength. Measurements on three human corneas revealed very large refractive astigmatism (0.65–1.2 μm) and appreciable levels of trefoil (0.08–0.47 μm), coma (0.14–0.19 μm), and spherical aberration (0.18–0.25 μm). The mean values of these aberrations were significantly larger than the RMS in repeated measurements.
© 2004 Optical Society of America
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