Wavefront Aberrations In Eyes Research Articles

Analyzing the Dynamic Wavefront Aberrations in the Human Eye

The optics of the human eye are not static in steady viewing conditions and exhibit microfluctuations. Previous methods used for analyzing dynamic changes in the eye's optics include simple Fourier-transform-based methods, which have been used in studies of the eye's accommodation response. However, dedicated tools for the analysis of dynamic wavefront aberrations have not been reported. We propose a set of signal processing tools, the combination of which uncovers aspects of the dynamics of eye's optical aberrations which were hidden from conventional analysis techniques. The methodology includes extraction of artifacts from potentially significant eye movements, filtering, optimal parametric signal modeling, and frequency and time-frequency representations. The exposition of the techniques and their advantages over traditional techniques is illustrated for real dynamic eye wavefront aberration measurements.

Whole Eye Wavefront Aberrations in Mexican Male Subjects

To analyze the characteristics, incidence, and appearance of wavefront aberrations in undilated, normal, unoperated eyes. Eighty-eight eyes of 44 healthy male Mexican subjects (mean age 25.32 years, range 18 to 36 yr) were divided into three groups based on uncorrected visual acuity of greater than or equal to 20/20, 20/30, or 20/40. UCVA measurements were obtained using an Acuity Max computer screen chart. Wavefront aberrations were measured with the Nidek OPD-Scan ARK 10000, Ver. 1.11b. All measurements were carried out at the same center by the same technician during a single session, following manufacturer instructions. Background illumination was 3 Lux. Wavefront aberration measurements for each group were statistically analyzed using StatView; an average eye was characterized and the resulting aberrations were simulated using MATLAB. We obtained wavefront aberration maps for the 20/20 undilated normal unoperated eyes for total, low, and high order aberration coefficients. Wavefront maps for right eyes were practically the same as those for left eyes. Higher aberrations did not contribute substantially to total wavefront analysis. Average aberrations of this "normal eye" will be used as criteria to decide the necessity of wavefront-guided ablation in our facilities. We will focus on the nearly zero average of high order aberrations in this normal whole eye as a reference to be matched.

Wavefront aberrations in eyes of emmetropic and moderately myopic school children and young adults

Wavefront aberrations were measured using a psychophysical ray-tracing technique in both eyes of 316 emmetropic and moderately myopic school children and young adults. Myopic subjects were found to have greater mean root mean square (RMS) value of wavefront aberrations than emmetropic subjects. Emmetropic adults had the smallest mean RMS, which remained smaller than the values for myopic adults and children and for emmetropic children both when second order Zernike aberrations (astigmatism) and third order Zernike aberrations were removed. Twenty percent of myopic adults had RMS values greater than values for all of the emmetropic adults, with significantly greater values for Zernike aberrations from second to seventh orders. High amounts of wavefront aberrations, which degrade the retinal image, may play a role in the development of myopia.