Lens-based wavefront sensorless adaptive optics swept source OCT

Jian, Yifan; Lee, Sujin; Ju, Myeong Jin; Heisler, Morgan; Ding, Wei‐Guang; Zawadzki, Robert J.; Bonora, Stefano; Sarunic, Marinko V.

doi:10.1038/srep27620

Cited by 43 publications

(33 citation statements)

References 43 publications

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“…In order to eliminate this roll off, the spectrum needs to be recorded in the 1/λ domain as can be achieved with SS-OCT [107]. SS-OCT at 1060nm has been combined with AO in a multimodal instrument [105] and a wavefront sensor less approach [108]. Finally, many different combinations of the above mentioned AO-OCT systems with complimentary imaging modalities have been presented [33,34,40,84,92,105].…”

Section: Ao In Combination With Different Oct Techniquesmentioning

confidence: 99%

Review of adaptive optics OCT (AO-OCT): principles and applications for retinal imaging [Invited]

Pircher

Zawadzki

2017

Biomed. Opt. Express

149

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Abstract:In vivo imaging of the human retina with a resolution that allows visualization of cellular structures has proven to be essential to broaden our knowledge about the physiology of this precious and very complex neural tissue that enables the first steps in vision. Many pathologic changes originate from functional and structural alterations on a cellular scale, long before any degradation in vision can be noted. Therefore, it is important to investigate these tissues with a sufficient level of detail in order to better understand associated disease development or the effects of therapeutic intervention. Optical retinal imaging modalities rely on the optical elements of the eye itself (mainly the cornea and lens) to produce retinal images and are therefore affected by the specific arrangement of these elements and possible imperfections in curvature. Thus, aberrations are introduced to the imaging light and image quality is degraded. To compensate for these aberrations, adaptive optics (AO), a technology initially developed in astronomy, has been utilized. However, the axial sectioning provided by retinal AO-based fundus cameras and scanning laser ophthalmoscope instruments is limited to tens of micrometers because of the rather small available numerical aperture of the eye. To overcome this limitation and thus achieve much higher axial sectioning in the order of 2-5µm, AO has been combined with optical coherence tomography (OCT) into AO-OCT. This enabled for the first time in vivo volumetric retinal imaging with high isotropic resolution. This article summarizes the technical aspects of AO-OCT and provides an overview on its various implementations and some of its clinical applications. In addition, latest developments in the field, such as computational AO-OCT and wavefront sensor less AO-OCT, are covered. 1178-1181 (1991). 2. M. Wojtkowski, B. Kaluzny, and R. J. Zawadzki, "New directions in ophthalmic optical coherence tomography," Optom. Vis. Sci. 89(5), 524-542 (2012). 3. T. E. de Carlo, A. Romano, N. K. Waheed, and J. S. Duker, "A review of optical coherence tomography angiography (OCTA)," Int J Retina Vitreous 1(5), 5 (2015). 4. W. Drexler and J. G. Fujimoto, "State-of-the-art retinal optical coherence tomography," Prog. Retin. Eye Res.27(1), 45-88 (2008). 5. G. Walsh, W. N. Charman, and H. C. Howland, "Objective technique for the determination of monochromatic aberrations of the human eye," J. Opt. Soc. Am. A 1(9), 987-992 (1984). 6. J. Liang and D. R. Williams, "Aberrations and retinal image quality of the normal human eye," J. Opt. Soc. Am.A 14(11), 2873-2883 (1997). Office, 2014). 27. J. Liang, B. Grimm, S. Goelz, and J. F. Bille, "Objective measurement of wave aberrations of the human eye with the use of a Hartmann-Shack wave-front sensor," J. Opt. Soc. Am. A 11(7), 1949-1957 (1994). 28. M. Laslandes, M. Salas, C. K. Hitzenberger, and M. Pircher, "Influence of wave-front sampling in adaptive optics retinal imaging," Biomed. Opt. Express 8(2), 1083-1100 (2017). 29. S. Tuohy and A. G. Podoleanu,...

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Section: Ao In Combination With Different Oct Techniquesmentioning

confidence: 99%

Review of adaptive optics OCT (AO-OCT): principles and applications for retinal imaging [Invited]

Pircher

Zawadzki

2017

Biomed. Opt. Express

149

View full text Add to dashboard Cite

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“…We centered our approach on a sequential/coordinate search with a hill climbing algorithm. [17][18][19]21,22,[35][36][37] While this algorithm is not likely to perform as well and as efficiently as AO-dedicated algorithms such as the DONE algorithm, 25 the hill-climbing algorithm is easily implemented and can provide decent correction within a few iterations. 36 We combined the hill-climbing algorithm with a merit function that used the normalized variance (NV) of a B-scan as an image-quality-judgment metric.…”

Section: Optimization Algorithmmentioning

confidence: 99%

“…DMs or multiactuator lenses 21 typically need high voltages that are generated with expensive high-voltage amplifiers. This system can correct defocus with a power ranging from −4.3 D to þ4.3 D and vertical and oblique astigmatism with a power in a range from −2.5 D to þ2.5 D. If one wants to correct aberration with higher speed and a larger range, or correct a larger number of orders, for instance for a system with a larger beam size, a deformable-mirror, 19 a multiactuator adaptive lens, 21 or multiactuator adaptive lens and variable focal lengh 22 -based sensorless AO-OCT concept may be a better option. The used defocus correction module is a motorized Badal optometer, which is driven through USB, whereas a liquid lens for defocus correction requires a high voltage driver and a graphics processing unit for depth-tracking optimization.…”

Section: Human Eye Imagingmentioning

confidence: 99%

“…To further reduce the cost and complexity of DM-based sensorless AO-OCT systems, alternative correction modules have been studied. 21,22 Recently, Bonora et al 21 reported on a multiactuator lens for aberration correction up to the fourth Zernike order. The multiactuator lens requires a 16-channel high-voltage driver (AE125 V).…”

Section: Introductionmentioning

confidence: 99%

“…21 Due to the limited defocus correction ability of the multiactuator lens, a second correction module, a variable focal length, was used specifically for defocus correction. 22 The 4.8-mm-wide aperture of the system was corrected with five Zernike modes on human subjects. 22 In wavefront-sensors-less AO-OCT, a sequential/coordinate search with a hill climbing algorithm, [17][18][19]21,22 annealing algorithm, 23 NEWUOA algorithm, 24 and data-based online nonlinear extremum-seeker (DONE) algorithm 25 have been implemented.…”

Section: Introductionmentioning

confidence: 99%

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Optical coherence tomography with a 2.8-mm beam diameter and sensorless defocus and astigmatism correction

et al. 2017

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Cense, "Optical coherence tomography with a 2.8-mm beam diameter and sensorless defocus and astigmatism correction," J. Biomed. Opt. Abstract. An optical coherence tomography (OCT) system with a 2.8-mm beam diameter is presented. Sensorless defocus correction can be performed with a Badal optometer and astigmatism correction with a liquid crystal device. OCT B-scans were used in an image-based optimization algorithm for aberration correction. Defocus can be corrected from −4.3 D to þ4.3 D and vertical and oblique astigmatism from −2.5 D to þ2.5 D. A contrast gain of 6.9 times was measured after aberration correction. In comparison with a 1.3-mm beam diameter OCT system, this concept achieved a 3.7-dB gain in dynamic range on a model retina. Both systems were used to image the retina of a human subject. As the correction of the liquid crystal device can take more than 60 s, the subject's spectacle prescription was adopted instead. This resulted in a 2.5 times smaller speckle size compared with the standard OCT system. The liquid crystal device for astigmatism correction does not need a high-voltage amplifier and can be operated at 5 V. The correction device is small (9 mm × 30 mm × 38 mm) and can easily be implemented in existing designs for OCT. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Retinal imaging with optical coherence tomography and low‐loss adaptive optics using a 2.8‐mm beam size

Reddikumar

Cervantes

Otani

et al. 2019

Journal of Biophotonics

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As data acquisition for retinal imaging with optical coherence tomography (OCT) becomes faster, efficient collection of photons becomes more important to maintain image quality. One approach is to use a larger aperture at the eye's pupil to collect more photons that have been reflected from the retina. A 2.8‐mm beam diameter system with only seven reflecting surfaces was developed for low‐loss retinal imaging. The larger beam size requires defocus and astigmatism correction, which was done in a closed loop adaptive optics method using a Shack‐Hartmann wavefront sensor and a deformable mirror (DM) with 140 actuators and a ±2.75 μm stroke. This DM facilitates defocus correction ranging from approximately −3 D to +3 D. Comparing the new system with a standard 1.2‐mm system on a model eye, a signal‐to‐noise gain of 4.5 dB and a 2.3 times smaller speckle size were measured. Measurements on the retinas of five subjects showed even better results, with increases in dynamic range up to 13 dB. Note that the new sample arm only occupies 30 cm × 60 cm, which makes it highly suitable for imaging in a clinical environment. Figure: B‐scan images obtained over a width of 8 deg from the right eye of a 31‐year‐old Caucasian male. While the left side was imaged with a standard 1.2‐mm OCT system, the right side was imaged with the 2.8‐mm system. Both images were collected with the same integration time and incident power, after correction of aberrations. Using the dynamic range within the images, which is determined by comparing the highest pixel value to the noise floor, a difference in dynamic range of 10.8 dB was measured between the two systems.

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Lens-based wavefront sensorless adaptive optics swept source OCT

Cited by 43 publications

References 43 publications

Review of adaptive optics OCT (AO-OCT): principles and applications for retinal imaging [Invited]

Review of adaptive optics OCT (AO-OCT): principles and applications for retinal imaging [Invited]

Optical coherence tomography with a 2.8-mm beam diameter and sensorless defocus and astigmatism correction

Retinal imaging with optical coherence tomography and low‐loss adaptive optics using a 2.8‐mm beam size

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