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Moon B, Linebach G, Yang A, Jenks SK, Rucci M, Poletti M, Rolland JP. High refresh rate display for natural monocular viewing in AOSLO psychophysics experiments. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.26.595808. [PMID: 38854135 PMCID: PMC11160679 DOI: 10.1101/2024.05.26.595808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
By combining an external display operating at 360 frames per second with an Adaptive Optics Scanning Laser Ophthalmoscope (AOSLO) for human foveal imaging, we demonstrate color stimulus delivery at high spatial and temporal resolution in AOSLO psychophysics experiments. A custom pupil relay enables viewing of the stimulus through a 3-mm effective pupil diameter and provides refractive error correction from -8 to +4 diopters. Performance of the assembled and aligned pupil relay was validated by measuring the wavefront error across the field of view and correction range, and the as-built Strehl ratio was 0.64 or better. High-acuity stimuli were rendered on the external display and imaged through the pupil relay to demonstrate that spatial frequencies up to 54 cycles per degree, corresponding to 20/11 visual acuity, are resolved. The completed external display was then used to render fixation markers across the field of view of the monitor, and a continuous retinal montage spanning 9.4 by 5.4 degrees of visual angle was acquired with the AOSLO. We conducted eye-tracking experiments during free-viewing and high-acuity tasks with polychromatic images presented on the external display. Sub-arcminute eye position uncertainty was achieved, enabling precise localization of the line of sight on the monitor while simultaneously imaging the fine structure of the human central fovea. This high refresh rate display overcomes the temporal, spectral, and field of view limitations of AOSLO-based stimulus presentation, enabling natural monocular viewing of stimuli in psychophysics experiments conducted with AOSLO.
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Johnston R, Smith MA. Brain-wide arousal signals are segregated from movement planning in the superior colliculus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.26.591284. [PMID: 38746466 PMCID: PMC11092505 DOI: 10.1101/2024.04.26.591284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The superior colliculus (SC) is traditionally considered a brain region that functions as an interface between processing visual inputs and generating eye movement outputs. Although its role as a primary reflex center is thought to be conserved across vertebrate species, evidence suggests that the SC has evolved to support higher-order cognitive functions including spatial attention. When it comes to oculomotor areas such as the SC, it is critical that high precision fixation and eye movements are maintained even in the presence of signals related to ongoing changes in cognition and brain state, both of which have the potential to interfere with eye position encoding and movement generation. In this study, we recorded spiking responses of neuronal populations in the SC while monkeys performed a memory-guided saccade task and found that the activity of some of the neurons fluctuated over tens of minutes. By leveraging the statistical power afforded by high-dimensional neuronal recordings, we were able to identify a low-dimensional pattern of activity that was correlated with the subjects' arousal levels. Importantly, we found that the spiking responses of deep-layer SC neurons were less correlated with this brain-wide arousal signal, and that neural activity associated with changes in pupil size and saccade tuning did not overlap in population activity space with movement initiation signals. Taken together, these findings provide a framework for understanding how signals related to cognition and arousal can be embedded in the population activity of oculomotor structures without compromising the fidelity of the motor output.
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Affiliation(s)
- Richard Johnston
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, USA
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, USA
- Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, USA
| | - Matthew A. Smith
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, USA
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, USA
- Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, USA
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Liu R, Wang X, Hoshi S, Zhang Y. Substrip-based registration and automatic montaging of adaptive optics retinal images. BIOMEDICAL OPTICS EXPRESS 2024; 15:1311-1330. [PMID: 38404341 PMCID: PMC10890855 DOI: 10.1364/boe.514447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/22/2024] [Accepted: 01/24/2024] [Indexed: 02/27/2024]
Abstract
Precise registration and montage are critical for high-resolution adaptive optics retinal image analysis but are challenged by rapid eye movement. We present a substrip-based method to improve image registration and facilitate the automatic montaging of adaptive optics scanning laser ophthalmoscopy (AOSLO). The program first batches the consecutive images into groups based on a translation threshold and selects an image with minimal distortion within each group as the reference. Within each group, the software divides each image into multiple strips and calculates the Normalized Cross-Correlation with the reference frame using two substrips at both ends of the whole strip to estimate the strip translation, producing a registered image. Then, the software aligns the registered images of all groups also using a substrip based registration, thereby generating a montage with cell-for-cell precision in the overlapping areas of adjacent frames. The algorithm was evaluated with AOSLO images acquired in human subjects with normal macular health and patients with age-related macular degeneration (AMD). Images with a motion amplitude of up to 448 pixels in the fast scanner direction over a frame of 512 × 512 pixels can be precisely registered. Automatic montage spanning up to 22.6 degrees on the retina was achieved on a cell-to-cell precision with a low misplacement rate of 0.07% (11/16,501 frames) in normal eyes and 0.51% (149/29,051 frames) in eyes with AMD. Substrip based registration significantly improved AOSLO registration accuracy.
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Affiliation(s)
- Ruixue Liu
- Doheny Eye Institute, Pasadena, CA 91103, USA
| | | | - Sujin Hoshi
- Doheny Eye Institute, Pasadena, CA 91103, USA
- Department of Ophthalmology, University of California - Los Angeles, Los Angeles, CA 90024, USA
- Department of Ophthalmology, University of Tsukuba, Ibaraki, Japan
| | - Yuhua Zhang
- Doheny Eye Institute, Pasadena, CA 91103, USA
- Department of Ophthalmology, University of California - Los Angeles, Los Angeles, CA 90024, USA
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Sato W, Yoshikawa S. Influence of stimulus manipulation on conscious awareness of emotional facial expressions in the match-to-sample paradigm. Sci Rep 2023; 13:20727. [PMID: 38007578 PMCID: PMC10676436 DOI: 10.1038/s41598-023-47995-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 11/21/2023] [Indexed: 11/27/2023] Open
Abstract
The conscious perception of emotional facial expressions plays an indispensable role in social interaction. However, previous psychological studies have reported inconsistent findings regarding whether conscious awareness is greater for emotional expressions than for neutral expressions. Furthermore, whether this phenomenon is attributable to emotional or visual factors remains unknown. To investigate these issues, we conducted five psychological experiments to test the conscious perception of emotional and neutral facial expressions using the match-to-sample paradigm. Facial stimuli were momentarily presented in the peripheral visual fields while participants read simultaneously presented letters in the central visual fields. The participants selected a perceived face from nine samples. The results of all experiments demonstrated that emotional expressions were more accurately identified than neutral expressions. Furthermore, Experiment 4 showed that angry expressions were identified more accurately than anti-angry expressions, which expressed neutral emotions with comparable physical changes to angry expressions. Experiment 5, testing the interaction between emotional expression and face direction, showed that angry expressions looking toward participants were more accurately identified than those looking away from participants, even though they were physically identical. These results suggest that the conscious awareness of emotional facial expressions is enhanced by their emotional significance.
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Affiliation(s)
- Wataru Sato
- Psychological Process Research Team, Guardian Robot Project, RIKEN, 2-2-2 Hikaridai, Seika-cho, Soraku-gun, Kyoto, 619-0288, Japan.
- Field Science Education and Research Center, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo, Kyoto, 606-8502, Japan.
| | - Sakiko Yoshikawa
- Field Science Education and Research Center, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo, Kyoto, 606-8502, Japan
- Faculty of the Arts, Kyoto University of the Arts, 2-116 Uryuyama, Kitashirakawa, Sakyo, Kyoto, 606-8501, Japan
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González-Vides L, Hernández-Verdejo JL, Cañadas-Suárez P. Eye Tracking in Optometry: A Systematic Review. J Eye Mov Res 2023; 16:10.16910/jemr.16.3.3. [PMID: 38111688 PMCID: PMC10725735 DOI: 10.16910/jemr.16.3.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023] Open
Abstract
This systematic review examines the use of eye-tracking devices in optometry, describing their main characteristics, areas of application and metrics used. Using the PRISMA method, a systematic search was performed of three databases. The search strategy identified 141 reports relevant to this topic, indicating the exponential growth over the past ten years of the use of eye trackers in optometry. Eye-tracking technology was applied in at least 12 areas of the field of optometry and rehabilitation, the main ones being optometric device technology, and the assessment, treatment, and analysis of ocular disorders. The main devices reported on were infrared light-based and had an image capture frequency of 60 Hz to 2000 Hz. The main metrics mentioned were fixations, saccadic movements, smooth pursuit, microsaccades, and pupil variables. Study quality was sometimes limited in that incomplete information was provided regarding the devices used, the study design, the methods used, participants' visual function and statistical treatment of data. While there is still a need for more research in this area, eye-tracking devices should be more actively incorporated as a useful tool with both clinical and research applications. This review highlights the robustness this technology offers to obtain objective information about a person's vision in terms of optometry and visual function, with implications for improving visual health services and our understanding of the vision process.
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Wang Y, Wong J, Duncan JL, Roorda A, Tuten WS. Enhanced S-Cone Syndrome: Elevated Cone Counts Confer Supernormal Visual Acuity in the S-Cone Pathway. Invest Ophthalmol Vis Sci 2023; 64:17. [PMID: 37459066 PMCID: PMC10362924 DOI: 10.1167/iovs.64.10.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023] Open
Abstract
Purpose To measure photoreceptor packing density and S-cone spatial resolution as a function of retinal eccentricity in patients with enhanced S-cone syndrome (ESCS) and to discuss the possible mechanisms supporting their supernormal S-cone acuity. Methods We used an adaptive optics scanning laser ophthalmoscope (AOSLO) to characterize photoreceptor packing. A custom non-AO display channel was used to measure L/M- and S-cone-mediated visual acuity during AOSLO imaging. Acuity measurements were obtained using a four-alternative, forced-choice, tumbling E paradigm along the temporal meridian between the fovea and 4° eccentricity in five of six patients and in seven control subjects. L/M acuity was tested by presenting long-pass-filtered optotypes on a black background, excluding wavelengths to which S-cones are sensitive. S-cone isolation was achieved using a two-color, blue-on-yellow chromatic adaptation method that was validated on three control subjects. Results Inter-cone spacing measurements revealed a near-uniform cone density profile (ranging from 0.9-1.5 arcmin spacing) throughout the macula in ESCS. For comparison, normal cone density decreases by a factor of 14 from the fovea to 6°. Cone spacing of ESCS subjects was higher than normal in the fovea and subnormal beyond 2°. Compared to the control subjects (n = 7), S-cone-mediated acuities in patients with ESCS were normal near the fovea and became increasingly supernormal with retinal eccentricity. Beyond 2°, S-cone acuities were superior to L/M-cone-mediated acuity in the ESCS cohort, a reversal of the trend observed in normal retinas. Conclusions Higher than normal parafoveal cone densities (presumably dominated by S-cones) confer better than normal S-cone-mediated acuity in ESCS subjects.
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Affiliation(s)
- Yiyi Wang
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, California, United States
| | - Jessica Wong
- Department of Ophthalmology, University of California, San Francisco, California, United States
| | - Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, California, United States
| | - Austin Roorda
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, California, United States
| | - William S Tuten
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, California, United States
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de Castro A, Martínez-Enríquez E, Marcos S. Effect of fixational eye movements in corneal topography measurements with optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2023; 14:2138-2152. [PMID: 37206127 PMCID: PMC10191639 DOI: 10.1364/boe.486460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/24/2023] [Accepted: 03/25/2023] [Indexed: 05/21/2023]
Abstract
There is an increasing interest in applying optical coherence tomography (OCT) to quantify the topography of ocular structures. However, in its most usual configuration, OCT data is acquired sequentially while a beam is scanned through the region of interest, and the presence of fixational eye movements can affect the accuracy of the technique. Several scan patterns and motion correction algorithms have been proposed to minimize this effect, but there is no consensus on the ideal parameters to obtain a correct topography. We have acquired corneal OCT images with raster and radial patterns, and modeled the data acquisition in the presence of eye movements. The simulations replicate the experimental variability in shape (radius of curvature and Zernike polynomials), corneal power, astigmatism, and calculated wavefront aberrations. The variability of the Zernike modes is highly dependent on the scan pattern, with higher variability in the direction of the slow scan axis. The model can be a useful tool to design motion correction algorithms and to determine the variability with different scan patterns.
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Affiliation(s)
- Alberto de Castro
- Instituto de Óptica, Consejo Superior de Investigaciones Científicas, Madrid, Madrid, Spain
| | | | - Susana Marcos
- Instituto de Óptica, Consejo Superior de Investigaciones Científicas, Madrid, Madrid, Spain
- Center for Visual Science, The Institute of Optics, Flaum Eye Institute, University of Rochester, Rochester, NY, USA
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Reeves SM, Otero-Millan J. The influence of scene tilt on saccade directions is amplitude dependent. J Neurol Sci 2023; 448:120635. [PMID: 37031623 DOI: 10.1016/j.jns.2023.120635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 01/13/2023] [Accepted: 03/24/2023] [Indexed: 03/28/2023]
Abstract
When exploring a visual scene, humans make more saccades in the horizontal direction than any other direction. While many have shown that the horizontal saccade bias rotates in response to scene tilt, it is unclear whether this effect depends on saccade amplitude. We addressed this question by examining the effect of image tilt on the saccade direction distributions recorded during freely viewing natural scenes. Participants (n = 20) viewed scenes tilted at -30°, 0°, and 30°. Saccade distributions during free viewing rotated by an angle of 12.1° ± 6.7° (t(19) = 8.04, p < 0.001) in the direction of the image tilt. When we partitioned the saccades according to their amplitude we found that small amplitude saccades occurred most in the horizontal direction while large amplitude saccades were more oriented to the scene tilt (p < 0.001). To further study the characteristics of small saccades and how they are affected by scene tilt, we looked at the effect of image tilt on small fixational saccades made while fixating a central target amidst a larger scene and found that fixational saccade distributions did not rotate with scene tilt (-0.3° ±1.7° degrees; t(19) = -0.8, p = 0.39). These results suggest a combined effect of two reference frames in saccade generation: one egocentric reference frame that dominates for small saccades, biases them horizontally, and may be common for different tasks, and another allocentric reference frame that biases larger saccades along the orientation of an image during free viewing.
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Hu X, Yang Q. Real-time correction of image rotation with adaptive optics scanning light ophthalmoscopy. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2022; 39:1663-1672. [PMID: 36215635 DOI: 10.1364/josaa.465889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 08/03/2022] [Indexed: 06/16/2023]
Abstract
Fixational eye motion includes typical translation and torsion. In the registration of images from adaptive optics scanning light ophthalmoscopy (AOSLO), image rotation due to eye torsion and/or head rotation is often ignored because (a) the amount of rotation is trivial compared to translation within a short duration of imaging or recording time and (b) computational cost increases substantially when the registration algorithm involves simultaneous detection of rotation and translation. However, it becomes critically important under cases such as long exposure, functional measurements, and precise motion tracking. We developed a fast method to detect and correct rotation from AOSLO images, together with the detection of strip-level motion translation. The computational cost for rotation detection and correction alone is about 5 ms/frame (512×512 pixels) on an nVidia GTX960M GPU. Image quality is compared with and without rotation correction from 10 healthy human subjects and 8 diseased eyes with a total of 180 videos. The results show that residual image motions between the reference images and the registered images with rotation correction are a fraction of those without rotation correction, and the ratio is 0.74-0.89 at the image center and 0.37-0.51 at the four corners of the images.
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Roshandel D, Sampson DM, Mackey DA, Chen FK. Impact of Reference Center Choice on Adaptive Optics Imaging Cone Mosaic Analysis. Invest Ophthalmol Vis Sci 2022; 63:12. [PMID: 35446344 PMCID: PMC9034713 DOI: 10.1167/iovs.63.4.12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Foveal center marking is a key step in retinal image analysis. We investigated the discordance between the adaptive optics (AO) montage center (AMC) and the foveal pit center (FPC) and its implications for cone mosaic analysis using a commercial flood-illumination AO camera. Methods Thirty eyes of 30 individuals (including 15 healthy and 15 patients with rod–cone dystrophy) were included. Spectral-domain optical coherence tomography was used to determine the FPC, and flood-illumination AO imaging was performed with overlapping image frames to create an AO montage. The AMC was determined by averaging the (0,0) coordinates in the four paracentral overlapping AO image frames. Cone mosaic measurements at various retinal eccentricities were compared between corresponding retinal loci relative to the AMC or FPC. Results AMCs were located temporally to the FPCs in 14 of 15 eyes in both groups. The average AMC–FPC discordance was 0.85° among healthy controls and 0.33° among patients with rod-cone dystrophy (P < 0.05). The distance of the AMC from the FPC was a significant determinant of the cone density (β estimate = 218 cells/deg2/deg; 95% confidence interval [CI], 107–330; P < 0.001) and inter-cone distance (β estimate = 0.28 arcmin/deg; 95% CI, 0.15–0.40; P < 0.001), after adjustment for age, sex, axial length, spherical equivalent, eccentricity, and disease status. Conclusions There is a marked mismatch between the AMC and FPC in healthy eyes that may be modified by disease process such as rod–cone dystrophy. We recommend users of AO imaging systems carefully align the AO montage with a foveal anatomical landmark, such as the FPC, to ensure precise and reproducible localization of the eccentricities and regions of interest for cone mosaic analysis.
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Affiliation(s)
- Danial Roshandel
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Perth, Western Australia, Australia.,Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Danuta M Sampson
- Surrey Biophotonics, Centre for Vision, Speech and Signal Processing and School of Biosciences and Medicine, The University of Surrey, Guildford, United Kingdom
| | - David A Mackey
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Perth, Western Australia, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Perth, Western Australia, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia.,Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
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