Closed-loop optical stabilization and digital image registration in adaptive optics scanning light ophthalmoscopy

Yang, Qiang; Zhang, Jie; Nozato, Koji; Saitô, Kenichi; Williams, David R.; Roorda, Austin; Rossi, Ethan A.

doi:10.1364/boe.5.003174

Cited by 65 publications

(75 citation statements)

References 40 publications

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“…Human images of RGC layer neurons did not match the quality of those from the monkey for several reasons, chief among them being the much lower light levels used for safety concerns. Nonetheless, refinements using existing technologies, particularly those recently developed for autofluorescence imaging (32,33), have the potential to improve image quality (SI Materials and Methods).…”

Section: Discussionmentioning

confidence: 99%

Imaging individual neurons in the retinal ganglion cell layer of the living eye

Rossi

Granger

Sharma

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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175

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Although imaging of the living retina with adaptive optics scanning light ophthalmoscopy (AOSLO) provides microscopic access to individual cells, such as photoreceptors, retinal pigment epithelial cells, and blood cells in the retinal vasculature, other important cell classes, such as retinal ganglion cells, have proven much more challenging to image. The near transparency of inner retinal cells is advantageous for vision, as light must pass through them to reach the photoreceptors, but it has prevented them from being directly imaged in vivo. Here we show that the individual somas of neurons within the retinal ganglion cell (RGC) layer can be imaged with a modification of confocal AOSLO, in both monkeys and humans. Human images of RGC layer neurons did not match the quality of monkey images for several reasons, including safety concerns that limited the light levels permissible for human imaging. We also show that the same technique applied to the photoreceptor layer can resolve ambiguity about cone survival in age-related macular degeneration. The capability to noninvasively image RGC layer neurons in the living eye may one day allow for a better understanding of diseases, such as glaucoma, and accelerate the development of therapeutic strategies that aim to protect these cells. This method may also prove useful for imaging other structures, such as neurons in the brain.

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Section: Discussionmentioning

confidence: 99%

Imaging individual neurons in the retinal ganglion cell layer of the living eye

Rossi

Granger

Sharma

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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175

151

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“…To a certain extent, we might be content to the current AO speed, but the proved existence of high frequency wave aberration rationalizes the needs of high speed AO. Furthermore, many applications, such as measuring the speed of the retinal blood or studying individual photoreceptor function, require that the retinal imaging maintaining consistent quality with well-corrected aberrations over time [46][47][48][49][50]. In clinical imaging, retinal images are often recorded continuously over time, demanding rapid correction after the fixation moved.…”

Section: Discussionmentioning

confidence: 99%

High-speed adaptive optics for imaging of the living human eye

Zhang

Meadway

et al. 2015

Opt. Express

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Abstract:The discovery of high frequency temporal fluctuation of human ocular wave aberration dictates the necessity of high speed adaptive optics (AO) correction for high resolution retinal imaging. We present a high speed AO system for an experimental adaptive optics scanning laser ophthalmoscope (AOSLO). We developed a custom high speed ShackHartmann wavefront sensor and maximized the wavefront detection speed based upon a trade-off among the wavefront spatial sampling density, the dynamic range, and the measurement sensitivity. We examined the temporal dynamic property of the ocular wavefront under the AOSLO imaging condition and improved the dual-thread AO control strategy. The high speed AO can be operated with a closed-loop frequency up to 110 Hz. Experiment results demonstrated that the high speed AO system can provide improved compensation for the wave aberration up to 30 Hz in the living human eye.

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“…Recent advances in real-time eye tracking can perform now with sub-cellular precision and adaptive optics imaging can be achieved routinely in patients with normal and to a certain extent compromised fixation capabilities [68,69].…”

Section: Future Prospect Of In Vivo Two-photon Imaging Of the Human Rmentioning

confidence: 99%

Safety assessment in macaques of light exposures for functional two-photon ophthalmoscopy in humans

Schwarz¹,

Sharma²,

Fischer³

et al. 2016

Biomed. Opt. Express

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Two-photon ophthalmoscopy has potential for in vivo assessment of function of normal and diseased retina. However, light safety of the sub-100 fs laser typically used is a major concern and safety standards are not well established. To test the feasibility of safe in vivo two-photon excitation fluorescence (TPEF) imaging of photoreceptors in humans, we examined the effects of ultrashort pulsed light and the required light levels with a variety of clinical and high resolution imaging methods in macaques. The only measure that revealed a significant effect due to exposure to pulsed light within existing safety standards was infrared autofluorescence (IRAF) intensity. No other structural or functional alterations were detected by other imaging techniques for any of the exposures. Photoreceptors and retinal pigment epithelium appeared normal in adaptive optics images. No effect of repeated exposures on TPEF time course was detected, suggesting that visual cycle function was maintained. If IRAF reduction is hazardous, it is the only hurdle to applying two-photon retinal imaging in humans. To date, no harmful effects of IRAF reduction have been detected.

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Closed-loop optical stabilization and digital image registration in adaptive optics scanning light ophthalmoscopy

Cited by 65 publications

References 40 publications

Imaging individual neurons in the retinal ganglion cell layer of the living eye

Imaging individual neurons in the retinal ganglion cell layer of the living eye

High-speed adaptive optics for imaging of the living human eye

Safety assessment in macaques of light exposures for functional two-photon ophthalmoscopy in humans

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