Dynamics of the eye's wave aberration

Citation
H. Hofer et al., Dynamics of the eye's wave aberration, J OPT SOC A, 18(3), 2001, pp. 497-506
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Optics & Acoustics
Journal title
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION
ISSN journal
1084-7529 → ACNP
Volume
18
Issue
3
Year of publication
2001
Pages
497 - 506
Database
ISI
SICI code
1084-7529(200103)18:3<497:DOTEWA>2.0.ZU;2-U
Abstract
It is well known that the eye's optics exhibit temporal instability in the form of microfluctuations in focus; however, almost nothing is known of the temporal properties of the eye's other aberrations. We constructed a real- time Hartmann-Shack (HS) wave-front sensor to measure these dynamics at fre quencies as high as 60 Hz. To reduce spatial inhomogeneities in the short-e xposure HS images, we used a low-coherence source and a scanning system. HS images were collected on three normal subjects with natural and paralyzed accommodation. Average temporal power spectra were computed for the wave-fr ont rms, the Seidel aberrations, and each of 32 Zernike coefficients. The r esults indicate the presence of fluctuations in all of the eye's aberration , not just defocus. Fluctuations in higher-order aberrations share similar spectra and bandwidths both within and between subjects, dropping. at a rat e of approximately 4 dB per octave in temporal frequency. The spectrum shap e for higher-order aberrations is generally different from that for microfl uctuations of accommodation. The origin of these measured fluctuations is n ot known, and both corneal/lenticular and retinal causes are considered. Un der the assumption that they are purely corneal or lenticular, calculations suggest that a perfect adaptive optics system with a closed-loop bandwidth of 1-2 Hz could correct these aberrations well enough to achieve diffracti on-limited imaging over a dilated pupil. (C) 2001 Optical Society of Americ a.