نتایج جستجو برای: corneal wavefront aberration
تعداد نتایج: 38950 فیلتر نتایج به سال:
A new adaptive optics system for the eye using a pyramid wavefront sensor interfaced in closed-loop with a piezoelectric deformable mirror is presented. Sensing parameters such as CCD integration time, pupil sampling and beam steering amplitude are tested on the bench and in vivo on several volunteers to optimize real-time optical correction. The system allows closed-loop operation at a frame r...
We compare the image quality between asymmetric wavefront codings and the simpleto-manufacture spherical aberration over an extended focal range. We verify and explain the superior performance of the spherical aberration via simulation results. c © 2009 Optical Society of America OCIS codes: (060.2320) Fiber optics amplifiers and oscillators; (060.4510) Optical communications
PURPOSE To evaluate the clinical outcomes of aspheric ocular wavefront ablation profiles in LASIK treatments. METHODS Thirty eyes treated by ocular wavefront were retrospectively analyzed at 6-month follow-up. Custom Ablation Manager (CAM) software was used to plan wavefront-customized aspheric treatments, and the ESIRIS system was used to perform ablations (SCHWIND eye-tech-solutions). Outco...
Optical aberration due to the nonflatness of spatial light modulators used in holographic optical tweezers significantly deteriorates the quality of the trap and may easily prevent stable trapping of particles. We use a Shack-Hartmann sensor to measure the distorted wavefront at the modulator plane; the conjugate of this wavefront is then added to the holograms written into the display to count...
In some adaptive optics systems the aberration is determined not by using a wavefront sensor but by sequential optimization of the adaptive correction element. Efficient schemes for the control of such systems are essential if they are to be effective. A scheme is introduced that permits the efficient measurement of large amplitude wavefront aberrations that are represented by an appropriate se...
Numerous types of wavefront correctors have been employed in adaptive optics (AO) systems for correcting the ocular wavefront aberration. While all have improved image quality, none have yielded diffraction-limited imaging for large pupils (>/=6 mm), where the aberrations are most severe and the benefit of AO the greatest. To this end, we modeled the performance of discrete actuator, segmented ...
We demonstrate a fast, direct wavefront-sensing method for dynamic in vivo adaptive optical two-photon microscopy. By using a Shack-Hartmann wavefront sensor and open-loop control, the system provides high-speed wavefront measurement and correction. To measure the wavefront in the middle of a Drosophila embryo at early stages, autofluorescence from endogenous fluorophores in the yolk were used ...
Wavefront sensing technology can directly test the phase distribution of wavefront distortion and has the advantages of simple operation, real-time and large dynamic range. It is widely used in adaptive optics, laser beam quality diagnosis, laser atmospheric communication, optical element and optics system detection, quantitative phase microscope, human eye aberration measurement and other fiel...
OBJECTIVE To evaluate the effects of photorefractive keratectomy on corneal optical aberrations using a 5.5-mm optical zone and a 7.0-mm transition zone. METHODS Videokeratographs of 72 eyes from 47 patients treated for low to moderate (1-9 diopters) myopia were obtained at the preoperative and 1-, 3-, 6-, 12-, and 18-month postoperative examinations. The videokeratoscopy data files were used...
PURPOSE To develop a prototype instrument that uses adaptive optics to introduce virtually any desired aberration profile in a subject's eye. At the same time, the instrument could be used to evaluate the subject's spatial vision for each controlled aberration profile. This "aberration testing station" or "visual simulator" allows us to study the relationship between specific aberrations and vi...
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