Measuring Ocular Aberrations Sequentially Using a Digital Micromirror Device

Abstract

The Hartmann–Shack wavefront sensor is widely used to measure aberrations in both astronomy and ophthalmology. Yet, the dynamic range of the sensor is limited by cross-talk between adjacent lenslets. In this study, we explore ocular aberration measurements with a recently-proposed variant of the sensor that makes use of a digital micromirror device for sequential aperture scanning of the pupil, thereby avoiding the use of a lenslet array. We report on results with the sensor using two different detectors, a lateral position sensor and a charge-coupled device (CCD) scientific camera, and explore the pros and cons of both. Wavefront measurements of a highly aberrated artificial eye and of five real eyes, including a highly myopic subject, are demonstrated, and the role of pupil sampling density, CCD pixel binning, and scanning speed are explored. We find that the lateral position sensor is mostly suited for high-power applications, whereas the CCD camera with pixel binning performs consistently well both with the artificial eye and for real-eye measurements, and can outperform a commonly-used wavefront sensor with highly aberrated wavefronts.

Wavefront Aberration Sensor Based on a Multichannel Diffractive Optical Element

“…The direct measurement of aberration coefficients is possible only for some types of aberrations. The calculation of the Zernike aberration coefficients [18][19][20][21] on the basis of a two-dimensional array of measured values of the wavefront deviations in each of the subapertures is provided in the data processing programs supplied with Shack-Hartmann sensors, as well as with ophthalmic aberrometers. However, it should be noted that due to the rather rough discretization of wavefront data, the calculation of high-order aberrations is difficult.…”

Effects of Machining Errors on Optical Performance of Optical Aspheric Components in Ultra-Precision Diamond Turning

“…The main evaluation parameters of optical performance for optical surfaces include wavefront aberration [19,20], modulation transfer function (MTF) [21], point spread function (PSF) [22] and power spectral density (PSD) [23,24], etc. As a comprehensive index, wavefront aberration can transform with other evaluation parameters [18], so the evaluation parameter based on wavefront aberration was applied in this paper to study the influence of machining errors.…”

Editorial for the Special Issue on Optical MEMS

“…This special issue contains twelve research papers covering MEMS mirrors [1,2,3,4,5,6,7,8,9,10], MEMS variable optical attenuators (VOAs) [11], and tunable spectral filters [12]. These MEMS devices are based on three of the commonly used actuation mechanisms: electrothermal [1], electrostatic [2,3,4,5,6,7,11], and electromagnetic actuation [8,9,10]. MEMS optical scanners involving single mirrors are demonstrated or used in [1,2,3,8,9,10], while all other optical microsystems employ MEMS mirror arrays that are all based on DMDs [4,5,6,7].…”

“…These MEMS devices are based on three of the commonly used actuation mechanisms: electrothermal [1], electrostatic [2,3,4,5,6,7,11], and electromagnetic actuation [8,9,10]. MEMS optical scanners involving single mirrors are demonstrated or used in [1,2,3,8,9,10], while all other optical microsystems employ MEMS mirror arrays that are all based on DMDs [4,5,6,7]. This special issue also includes one review paper on metalens-based miniaturized optical systems [13].…”

“…Among the papers on single MEMS mirrors, two are focused on MEMS device fabrication [1,10], one on optimization of the driving signals [3], one on applying MEMS mirrors for confocal microscopy [2], and two on using MEMS mirrors to generate structural light patterns for 3D measurement [8,9]. Interestingly, there are several papers reporting various applications of DMDs, including spectral filtering [4], Hadamard spectroscopy [5], wavefront/aberration correction [6], and a tunable fiber laser [7].…”