Wavefront Aberration and Its Relationship to the Accommodative Stimulus-Response Function in Myopic Subjects

Abstract

The relationship between the accommodation accuracy as measured with the autorefractor and the total wavefront aberration as measured with a Hartmann-Shack wavefront sensor is largely influenced by the higher-order (fourth and above) aberration levels. For the emmetropic subjects, the errors measured by the two methods agree when adjusted to measure at similar pupil sizes. For the myopic subjects with similar pupil sizes, however, the Hartmann-Shack wavefront sensor underestimates the accommodation error at higher accommodation levels (2 to 4 D) compared with the autorefractor.

Wavefront aberration changes caused by a gradient of increasing accommodation stimuli

“…A similar trend was reported by Hazel et al in their study with 30 healthy participants (10 emmetropes and 20 myopes) between 18 and 27 years of age. 22 Cheng et al found that spherical aberration was the most affected of the Zernike terms evaluated, with the negative change in spherical aberration being proportional to the accommodative response. 10 Others have reported that decreases in the spherical aberration increased the accommodation stimuli.…”

“…Several studies have indicated that high levels of individual variation exist in terms of the effects of accommodation on wavefront aberrations. 7,9,22,27 Owing to the large number of the types of aberrations evaluated in the present study, only mean results are reported herein. A large-scale study, of similar design, including participants of different ages and ethnicities would provide additional data to more fully characterize the wavefront aberrations that take place during accommodation.…”

Wavefront-guided laser in situ keratomileusis using the WaveScan system for correction of low to moderate myopia with astigmatism: 6-month results in 277 eyes

“…3 Customized correction of refractive errors using wavefront technology is of interest to refractive surgeons as it has the potential of improving conventional refraction-only based excimer laser surgical vision correction systems. 4 The WaveScan software creates a treatment table describing the number, size (ranging from 0.65 mm to 6.5 mm), distribution, and placement of laser pulses to best fit the WaveScan defined ablation pattern desired.…”

Effect of cataract surgery incision location and intraocular lens type on ocular aberrations

“…13 The instrumentation and procedures have been described in detail. 14 The only modifications were the use of a 632.8 nm light wavelength and the capture and averaging of wavefront aberration results from 5 Hartmann-Shack wavefront sensing images per eye. Wavefront aberrations were described in terms of the orthonormal Zernike polynomials up to the 6th order and RMS values for each higher order (3rd to 6th) and total higher order (3rd to 6th) over a 6.0 or 3.5 mm pupil diameter.…”