A technique is described to determine the change in image contrast as a result of the spherical aberration induced by the radial keratotomy procedure. The hypothesis that the loss in contrast sensitivity of the RK eye is due to the change in spherical aberration postsurgically, is found to be acceptable for some patients. However, this is not a sufficient explanation in all cases. This conclusi...

PURPOSE To compare changes of anterior corneal aberration (Pentacam) and ocular aberration (aberrometer, LADARWave) after laser refractive surgery. METHODS Sixty-six eyes underwent laser refractive surgery and were retrospectively reviewed. Anterior corneal aberration and ocular aberration were measured by Pentacam and an aberrometer (LADARWave) respectively. Changes of root mean square (RMS)...

As semiconductor lithography is pushed to smaller dimensions, the process yields tend to suffer due to subwavelength imaging effects. In response, resolution enhancement technologies have been employed together with optimization techniques, specifically source mask optimization (SMO), which finely tunes the process by simultaneously optimizing the source shape and mask features. However, SMO ha...

PURPOSE To compare the validity and effectiveness of 2 methods for expanding depth of focus to correct for presbyopia; that is, induction of spherical aberration and small-pupil apertures. SETTING University of California, Berkeley, California, USA. DESIGN Comparative case series. METHODS A random 4-alternative forced-choice acuity task was performed on 13 subjects. Visual performance and...

PURPOSE To evaluate the theoretical influence of the change in corneal asphericity (ΔQ) on the change in fourth-order Zernike spherical aberration coefficient (ΔC(4)0) with customized aspheric refractive correction of myopia and hyperopia. METHODS The initial anterior corneal surface profile was modeled as a conic section of apical radius of curvature R0 and asphericity Q₀. The postoperative ...

This paper reviews the optics of higher-order and spherical aberrations and discusses aspheric intraocular lenses, attempting to address 2 questions that, despite an abundance of information, remain unanswered: what amount of ocular spherical aberration has been correlated with optimum visual performance, and for what final amount of spherical aberration should the cataract surgeon aim? Finally...

We enjoyed reading the article by Esteve-Taboada et al.,1 but were disappointed by their interpretation of their data. Their optical model has important limitations that make it inappropriate to make broad clinical generalizations from their findings. First, the “aberration-free” eye model is highly artificial. In particular, the absence of any spherical aberration is relevant to only a small p...

PURPOSE To evaluate the quality of vision and depth of focus induced by controlled amounts of negative spherical aberration in patients implanted bilaterally with light-adjustable intraocular lenses. DESIGN Prospective, nonrandomized clinical trial. METHODS Seventeen patients were implanted and treated with appropriate spatial irradiance light profiles. One eye was set for emmetropia, and t...