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Davidova P, Biller M, Ademmer V, Kohnen T. Pupil size measurements with a multifunctional aberrometer/coherence interferometer/tomographer and two infrared-based pupillometers. J Cataract Refract Surg 2024; 50:631-636. [PMID: 38407983 PMCID: PMC11146177 DOI: 10.1097/j.jcrs.0000000000001432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 02/13/2024] [Accepted: 02/20/2024] [Indexed: 02/28/2024]
Abstract
PURPOSE To compare precision of pupil size measurements of a multifunctional device (Pentacam AXL Wave [Pentacam]) and 2 infrared-based pupillometers (PupilX, Colvard) and to compare repeatability of Pentacam and PupilX. SETTING Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany. DESIGN Prospective, comparative trial. METHODS Pupil diameter of healthy eyes was measured with Colvard once and Pentacam without glare (WO) and with glare (WG), PupilX in 0, 1, and 16 lux 3 times each. In a second series, measurements with Pentacam WO and PupilX in 0.06 and 0.12 lux were assessed. RESULTS 36 eyes of participants aged 21 to 63 years were included. Mean pupil diameter was 6.05 mm with Colvard, 5.79 mm (first series), 5.50 mm (second series) with Pentacam WO, 3.42 mm WG, 7.26 mm PupilX in 0, 4.67 mm 1, 3.66 mm 16, 6.82 mm in 0.06, and 6.39 mm in 0.12 lux. Measurements with Pentacam WO were significantly different to PupilX in 0, 0.06, 0.12, and 1 lux (all P < .001), but not to Colvard ( P = .086). Pupil size measured with Pentacam WG and PupilX in 16 lux was not significantly different ( P = .647). Consecutive measurements with Pentacam WO and WG had mean SD of 0.23 mm and 0.20 mm, respectively, and with PupilX 0.11 in 0, 0.24 mm 1, and 0.20 mm in 16 lux. CONCLUSIONS Pentacam provided good assessment of pupil size but was not equivalent to PupilX in low lighting conditions. Repeatability was more favorable for Pentacam.
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Affiliation(s)
- Petra Davidova
- From the Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany
| | - Marvin Biller
- From the Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany
| | - Vanessa Ademmer
- From the Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany
| | - Thomas Kohnen
- From the Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany
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2
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Dutta P, Baishya R. Pupillary dynamics, accommodation and vergence in concussion. Clin Exp Optom 2024; 107:385-394. [PMID: 38325849 DOI: 10.1080/08164622.2024.2311692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 01/22/2024] [Indexed: 02/09/2024] Open
Abstract
Concussion, which is usually associated with head injuries, has received considerable attention in recent years because of its possible long-term cognitive and visual consequences. The review summarised the mild traumatic brain injury literature. Pupillary dynamics, which are primarily mediated by the autonomic nervous system, play an important function in regulating the amount of light entering the eye, but they can be dramatically impacted after a concussion. This can result in aberrant pupillary responses, which may have ramifications for light sensitivity, a common post-concussion symptom. In concussed individuals, accommodation and vergence - the visual processes responsible for focusing on near and distant objects - might be interrupted, potentially leading to fuzzy vision, eyestrain, and difficulty with tasks that require precise visual coordination. Understanding the delicate interplay between these three components of vision in the setting of concussions is critical for creating more targeted diagnostic and rehabilitative techniques, ultimately enhancing the quality of life for those who have had head injuries.
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Affiliation(s)
- Pritam Dutta
- Department of Optometry, Ridley College of Optometry, a unit of Chandraprabha Eye Hospital, Assam, India
| | - Reeta Baishya
- Department of Physiology, Gauhati Medical College, Gauhati, India
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3
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Fernandez-Alonso M, Finch AP, Love GD, Read JCA. Ocular accommodation and wavelength: The effect of longitudinal chromatic aberration on the stimulus-response curve. J Vis 2024; 24:11. [PMID: 38411958 PMCID: PMC10910436 DOI: 10.1167/jov.24.2.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 01/06/2024] [Indexed: 02/28/2024] Open
Abstract
The longitudinal chromatic aberration (LCA) of the eye creates a chromatic blur on the retina that is an important cue for accommodation. Although this mechanism can work optimally in broadband illuminants such as daylight, it is not clear how the system responds to the narrowband illuminants used by many modern displays. Here, we measured pupil and accommodative responses as well as visual acuity under narrowband light-emitting diode (LED) illuminants of different peak wavelengths. Observers were able to accommodate under narrowband light and compensate for the LCA of the eye, with no difference in the variability of the steady-state accommodation response between narrowband and broadband illuminants. Intriguingly, our subjects compensated more fully for LCA at nearer distances. That is, the difference in accommodation to different wavelengths became larger when the object was placed nearer the observer, causing the slope of the accommodation response curve to become shallower for shorter wavelengths and steeper for longer ones. Within the accommodative range of observers, accommodative errors were small and visual acuity normal. When comparing between illuminants, when accommodation was accurate, visual acuity was worst for blue narrowband light. This cannot be due to the sparser spacing for S-cones, as our stimuli had equal luminance and thus activated LM-cones roughly equally. It is likely because ocular LCA changes more rapidly at shorter wavelength and so the finite spectral bandwidth of LEDs corresponds to a greater dioptric range at shorter wavelengths. This effect disappears for larger accommodative errors, due to the increased depth of focus of the eye.
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Affiliation(s)
- Maydel Fernandez-Alonso
- Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK
- Present address: Translational Sensory and Circadian Neuroscience Group, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | | | - Gordon D Love
- Department of Physics, Durham University, Durham, UK
- Department of Computer Sciences, Durham University, Durham, UK
- Present address: School of Computing, University of Leeds, Leeds, UK
| | - Jenny C A Read
- Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK
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4
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Romeo A, Leonovych O, Solé Puig M, Supèr H. Cognitive Vergence Recorded with a Webcam-Based Eye-Tracker during an Oddball Task in an Elderly Population. SENSORS (BASEL, SWITZERLAND) 2024; 24:888. [PMID: 38339605 PMCID: PMC10857309 DOI: 10.3390/s24030888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024]
Abstract
(1) Background: Our previous research provides evidence that vergence eye movements may significantly influence cognitive processing and could serve as a reliable measure of cognitive issues. The rise of consumer-grade eye tracking technology, which uses sophisticated imaging techniques in the visible light spectrum to determine gaze position, is noteworthy. In our study, we explored the feasibility of using webcam-based eye tracking to monitor the vergence eye movements of patients with Mild Cognitive Impairment (MCI) during a visual oddball paradigm. (2) Methods: We simultaneously recorded eye positions using a remote infrared-based pupil eye tracker. (3) Results: Both tracking methods effectively captured vergence eye movements and demonstrated robust cognitive vergence responses, where participants exhibited larger vergence eye movement amplitudes in response to targets versus distractors. (4) Conclusions: In summary, the use of a consumer-grade webcam to record cognitive vergence shows potential. This method could lay the groundwork for future research aimed at creating an affordable screening tool for mental health care.
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Affiliation(s)
- August Romeo
- Department Cognition, Development and Educational Psychology, University of Barcelona, 08035 Barcelona, Spain
| | - Oleksii Leonovych
- Bioinformatics and Biomedical Signals Laboratory, Polytechnical University of Catalonia, 08028 Barcelona, Spain
| | - Maria Solé Puig
- Assesment Unit of Cognition and Attention in Learning, Psychology Clinic, 08035 Barcelona, Spain;
| | - Hans Supèr
- Braingaze S.L., 08302 Mataró, Spain
- Institute of Neurosciences (UBNeuro), University of Barcelona, 08035 Barcelona, Spain
- Institut de Recerca Sant Joan de Déu (IRSJD), 08950 Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain
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5
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Kolnes M, Uusberg A, Nieuwenhuis S. Broadening of attention dilates the pupil. Atten Percept Psychophys 2024; 86:146-158. [PMID: 37801189 PMCID: PMC10770199 DOI: 10.3758/s13414-023-02793-3] [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] [Accepted: 09/14/2023] [Indexed: 10/07/2023]
Abstract
Inconclusive evidence suggests that the pupil is more dilated when the breadth of attention is broad compared to narrow. To further investigate this relationship, we recorded pupil size from healthy volunteers while inducing trial-wise changes in breadth of attention using a shape-discrimination task where participants had to remember the location of a gap in a small or a large circle. A visual search task with targets presented at different distances from the centre of the screen was used to behaviourally assess the success of the manipulation of breadth of attention. Data were analysed using a generalised additive mixed model to test the experimental effects on pupil size after controlling for the effects of gaze location and eye vergence. The results showed that the pupil was more dilated in the broad-breadth-of-attention condition compared to the narrow-breadth-of-attention condition. However, the effect of attentional breadth on visual search performance was not mediated by pupil size, suggesting that more research is needed to understand the functional role of pupil dilation in relation to breadth of attention.
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Affiliation(s)
- Martin Kolnes
- Department of Psychology Institute of Psychology, University of Tartu, Näituse 2, 50409, Tartu, Estonia.
- Institute of Psychology and Leiden Institute for Brain and Cognition, Leiden University, Leiden, The Netherlands.
| | - Andero Uusberg
- Department of Psychology Institute of Psychology, University of Tartu, Näituse 2, 50409, Tartu, Estonia
| | - Sander Nieuwenhuis
- Institute of Psychology and Leiden Institute for Brain and Cognition, Leiden University, Leiden, The Netherlands
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6
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Sparks S, Pinto J, Hayes G, Spitschan M, Bulte DP. The impact of Alzheimer's disease risk factors on the pupillary light response. Front Neurosci 2023; 17:1248640. [PMID: 37650103 PMCID: PMC10463762 DOI: 10.3389/fnins.2023.1248640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 07/31/2023] [Indexed: 09/01/2023] Open
Abstract
Alzheimer's disease (AD) is the leading cause of dementia, and its prevalence is increasing and is expected to continue to increase over the next few decades. Because of this, there is an urgent requirement to determine a way to diagnose the disease, and to target interventions to delay and ideally stop the onset of symptoms, specifically those impacting cognition and daily livelihood. The pupillary light response (PLR) is controlled by the sympathetic and parasympathetic branches of the autonomic nervous system, and impairments to the pupillary light response (PLR) have been related to AD. However, most of these studies that assess the PLR occur in patients who have already been diagnosed with AD, rather than those who are at a higher risk for the disease but without a diagnosis. Determining whether the PLR is similarly impaired in subjects before an AD diagnosis is made and before cognitive symptoms of the disease begin, is an important step before using the PLR as a diagnostic tool. Specifically, identifying whether the PLR is impaired in specific at-risk groups, considering both genetic and non-genetic risk factors, is imperative. It is possible that the PLR may be impaired in association with some risk factors but not others, potentially indicating different pathways to neurodegeneration that could be distinguished using PLR. In this work, we review the most common genetic and lifestyle-based risk factors for AD and identify established relationships between these risk factors and the PLR. The evidence here shows that many AD risk factors, including traumatic brain injury, ocular and intracranial hypertension, alcohol consumption, depression, and diabetes, are directly related to changes in the PLR. Other risk factors currently lack sufficient literature to make any conclusions relating directly to the PLR but have shown links to impairments in the parasympathetic nervous system; further research should be conducted in these risk factors and their relation to the PLR.
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Affiliation(s)
- Sierra Sparks
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
| | - Joana Pinto
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
| | - Genevieve Hayes
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
| | - Manuel Spitschan
- TUM Department of Sport and Health Sciences (TUM SG), Chronobiology and Health, Technical University of Munich, Munich, Germany
- TUM Institute for Advanced Study (TUM-IAS), Technical University of Munich, Garching, Germany
- Max Planck Institute for Biological Cybernetics, Translational Sensory and Circadian Neuroscience, Tübingen, Germany
| | - Daniel P. Bulte
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
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7
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Poudel S, Rahimi-Nasrabadi H, Jin J, Najafian S, Alonso JM. Differences in visual stimulation between reading and walking and implications for myopia development. J Vis 2023; 23:3. [PMID: 37014657 PMCID: PMC10080958 DOI: 10.1167/jov.23.4.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 02/11/2023] [Indexed: 04/05/2023] Open
Abstract
Visual input plays an important role in the development of myopia (nearsightedness), a visual disorder that blurs vision at far distances. The risk of myopia progression increases with the time spent reading and decreases with outdoor activity for reasons that remain poorly understood. To investigate the stimulus parameters driving this disorder, we compared the visual input to the retina of humans performing two tasks associated with different risks of myopia progression, reading and walking. Human subjects performed the two tasks while wearing glasses with cameras and sensors that recorded visual scenes and visuomotor activity. When compared with walking, reading black text in white background reduced spatiotemporal contrast in central vision and increased it in peripheral vision, leading to a pronounced reduction in the ratio of central/peripheral strength of visual stimulation. It also made the luminance distribution heavily skewed toward negative dark contrast in central vision and positive light contrast in peripheral vision, decreasing the central/peripheral stimulation ratio of ON visual pathways. It also decreased fixation distance, blink rate, pupil size, and head-eye coordination reflexes dominated by ON pathways. Taken together with previous work, these results support the hypothesis that reading drives myopia progression by understimulating ON visual pathways.
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Affiliation(s)
- Sabina Poudel
- Department of Biological and Visual Sciences, SUNY College of Optometry, New York, NY, USA
| | - Hamed Rahimi-Nasrabadi
- Department of Biological and Visual Sciences, SUNY College of Optometry, New York, NY, USA
| | - Jianzhong Jin
- Department of Biological and Visual Sciences, SUNY College of Optometry, New York, NY, USA
| | - Sohrab Najafian
- Department of Biological and Visual Sciences, SUNY College of Optometry, New York, NY, USA
| | - Jose-Manuel Alonso
- Department of Biological and Visual Sciences, SUNY College of Optometry, New York, NY, USA
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8
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Orman B, Benozzi G. Pharmacological Treatments for Presbyopia. Drugs Aging 2023; 40:105-116. [PMID: 36670320 DOI: 10.1007/s40266-022-01002-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2022] [Indexed: 01/22/2023]
Abstract
Accommodation is the change in dioptric power of the eye. It is a dynamic process that allows focusing on an object at all distances. In order to focus sharply, three physiological responses, known as the triad of accommodation, are produced by a change in pupil size, a change in shape and position of the lens, and ocular convergence. This is modulated by the autonomic nervous system, mainly the parasympathetic nervous system. Presbyopia is a refractive condition that occurs with aging, usually manifesting around 40-50 years of age, and is a result of the loss of accommodation in the eye, causing loss of visual performance when focusing on objects placed at different distances, starting with near vision. Glasses, contact lenses, surgical approaches and now pharmacological treatments are accepted methods of treating presbyopia. Pharmacological treatment is a promising new noninvasive option for treating presbyopia. Currently there are three pharmacological approaches to the treatment of presbyopia. The first one aims to produce miosis and, from a pinhole effect, increase depth of focus, and therefore improve uncorrected near visual acuity (UNVA). The second one addresses rehabilitating accommodation in a binocular way, allowing good vision at all distances. Finally, the third strategy uses lipoic acid to restore the lost elasticity of the lens. All of these pharmacological treatments are topical non-invasive eyedrops, with no serious adverse effects having been reported with any of the strategies, and require the right patient selection process to fulfill expectations and needs. The aim of this article is to provide an update on recent advances in this field.
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Affiliation(s)
- Betina Orman
- Universidad de Buenos Aires, Facultad de Odontología, Cátedra de Farmacología, Buenos Aires, Argentina.
| | - Giovanna Benozzi
- Centro de Investigación Avanzada para la Presbicia, Buenos Aires, Argentina
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9
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Hashemi A, Leonovych O, Jiménez EC, Sierra-Marcos A, Romeo A, Valenzuala PB, Puig MS, Moliner JL, Tubau E, Supèr H. Classification of MCI patients using vergence eye movements and pupil responses obtained during a visual oddball test. AGING AND HEALTH RESEARCH 2023. [DOI: 10.1016/j.ahr.2023.100121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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10
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Abstract
The defocus curve (DC) has become the gold standard method for assessing the visual performance at different distances, and hence, to evaluate the depth of focus that is provided by modern presbyopia-compensating intraocular lenses that are used in cataract surgery. A former study, carried out by other authors, reported that the DC method, based on placing the chart at far distance and using trial negative lenses, underestimated the visual acuity that was measured by varying the test distance (VD) in pseudophakic patients. We have revisited the issue with pseudophakic subjects and have extended the study to include young phakic observers with their natural accommodation preserved. Our results show that both the VD and DC methods are equivalent in precision and accuracy and can be used indistinctly. However, the DC method is more practical in the clinics because it does not require further control of the chart positioning and illuminance.
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11
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Eberhardt LV, Strauch C, Hartmann TS, Huckauf A. Increasing pupil size is associated with improved detection performance in the periphery. Atten Percept Psychophys 2022; 84:138-149. [PMID: 34820766 PMCID: PMC8795034 DOI: 10.3758/s13414-021-02388-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2021] [Indexed: 11/08/2022]
Abstract
Visible light enters our body via the pupil. By changing its size, the pupil shapes visual input. Small apertures increase the resolution of high spatial frequencies, thus allowing discrimination of fine details. Large apertures, in contrast, provide a better signal-to-noise ratio, because more light can enter the eye. This should lead to better detection performance of peripheral stimuli. Experiment 1 shows that the effect can reliably be demonstrated even in a less controlled online setting. In Experiment 2, pupil size was measured in a laboratory using an eye tracker. The findings replicate findings showing that large pupils provide an advantage for peripheral detection of faint stimuli. Moreover, not only pupil size during information intake in the current trial n, but also its interaction with pupil size preceding information intake, i.e., in trial n-1, predicted performance. This suggests that in addition to absolute pupil size, the extent of pupillary change provides a mechanism to modulate perceptual functions. The results are discussed in terms of low-level sensory as well as higher-level arousal-driven changes in stimulus processing.
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Affiliation(s)
- Lisa Valentina Eberhardt
- General Psychology, Faculty of Engineering, Computer Science and Psychology, Ulm University, Albert-Einstein-Allee 47, 89069, Ulm, Germany.
| | - Christoph Strauch
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, the Netherlands
| | - Tim Samuel Hartmann
- General Psychology, Faculty of Engineering, Computer Science and Psychology, Ulm University, Albert-Einstein-Allee 47, 89069, Ulm, Germany
| | - Anke Huckauf
- General Psychology, Faculty of Engineering, Computer Science and Psychology, Ulm University, Albert-Einstein-Allee 47, 89069, Ulm, Germany
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12
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Jiménez EC, Sierra-Marcos A, Romeo A, Hashemi A, Leonovych O, Bustos Valenzuela P, Solé Puig M, Supèr H. Altered Vergence Eye Movements and Pupil Response of Patients with Alzheimer's Disease and Mild Cognitive Impairment During an Oddball Task. J Alzheimers Dis 2021; 82:421-433. [PMID: 34024820 DOI: 10.3233/jad-201301] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) is characterized by progressive deterioration of cognitive functions and may be preceded by mild cognitive impairment (MCI). Evidence shows changes in pupil and vergence responses related to cognitive processing of visual information. OBJECTIVE Here we test the hypothesis that MCI and AD are associated with specific patterns in vergence and pupil responses. METHODS We employed a visual oddball task. In the distractor condition (80%of the trials), a blue stimulus was presented whereas in the target condition (20%of trials) it was red. Participants (23 Controls, 33 MCI patients, and 18 AD patients) were instructed to press a button when a target appeared. RESULTS Participants briefly converged their eyes 200 ms after stimulus presentation. In controls, this transient peak response was followed by a delay response to targets but not to distractor stimuli. In the patient groups, delay responses to distractors were noticed. Consequently, the differential vergence response was strong in the control group, weak in the MCI group, and absent in the AD group. Pupils started to dilate 500-600 ms after the appearance of a target but slightly contracted after the presentation of a distractor. This differential pupil response was strongest in the AD group. CONCLUSION Our findings support the idea of a role of vergence and pupil responses in attention and reveal altered responses in MCI and AD patients. Further studies should assess the value of vergence and pupil measurements as an objective support tool for early diagnosis of AD.
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Affiliation(s)
- Elizabeth Carolina Jiménez
- Department of Cognition, Development and Educational Psychology, University of Barcelona, Barcelona, Spain.,University of Guadalajara, Jalisco, México
| | - Alba Sierra-Marcos
- Department of Neurology and Neurophysiology, Hospital Sanitas CIMA, Barcelona, Spain
| | - August Romeo
- Department of Cognition, Development and Educational Psychology, University of Barcelona, Barcelona, Spain
| | - Amin Hashemi
- Department of Cognition, Development and Educational Psychology, University of Barcelona, Barcelona, Spain
| | - Oleksii Leonovych
- Department of Cognition, Development and Educational Psychology, University of Barcelona, Barcelona, Spain.,Braingaze SL, Mataró, Spain
| | - Patricia Bustos Valenzuela
- Department of Cognition, Development and Educational Psychology, University of Barcelona, Barcelona, Spain
| | - Maria Solé Puig
- Department of Cognition, Development and Educational Psychology, University of Barcelona, Barcelona, Spain
| | - Hans Supèr
- Department of Cognition, Development and Educational Psychology, University of Barcelona, Barcelona, Spain.,Institute of Neurosciences of the University of Barcelona (UBNeuro), Barcelona, Spain.,Braingaze SL, Mataró, Spain.,Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
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13
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Vergence eye movements during figure-ground perception. Conscious Cogn 2021; 92:103138. [PMID: 34022640 DOI: 10.1016/j.concog.2021.103138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 11/24/2022]
Abstract
Figure-ground, that is the segmentation of visual information into objects and their surrounding backgrounds, provides structure for visual attention. Recent evidence shows a novel role of vergence eye movements in visual attention. In the present work, vergence responses during figure-ground segregation tasks are psychophysically investigated. We show that during a figure-ground detection task, subjects convergence their eyes. Vergence eye movements are larger in figure trials than in ground trials. In detected figures trials, vergence are stronger than in trials where the figure went unnoticed. Moreover in figure trials, vergence responses are stronger to low-contrast figures than to high-contrast figures. We argue that these discriminative vergence responses have a role in figure-ground.
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Vergence, accommodation, and visual tracking in children and adolescents evaluated in a multidisciplinary concussion clinic. Vision Res 2021; 184:30-36. [PMID: 33838503 DOI: 10.1016/j.visres.2021.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 02/22/2021] [Accepted: 03/03/2021] [Indexed: 11/23/2022]
Abstract
Many patients with concussion experience visual symptoms following injury that lead to a diagnosis of convergence insufficiency, accommodative insufficiency, or saccadic dysfunction. However, these diagnostic categories are based on aggregates of clinical tests developed from a non-concussed population and therefore may not accurately describe visual deficits in the concussed population. Thus, we sought to understand individual metrics of visual dysfunction in chronically symptomatic post-concussion patients. This retrospective cross-sectional study included patients examined at the multidisciplinary concussion clinic (MDCC) at Boston Children's Hospital over four years. Patients aged 5-21 years who had a complete assessment of eye alignment, vergence, accommodation, and visual tracking, and had visual acuity better than or equal to 20/30 in each eye were included. Patients with history of amblyopia, strabismus, or ocular pathology were excluded. Chart review yielded 116 patients who met inclusion criteria (median age 15 years, 64% female). The majority of patients (52%) experienced a single concussion and most were sports-related (50%). Clinical data show vergence, accommodation, or visual tracking deficits in 95% of patients. A receded near point of convergence (NPC, 70/116) and reduced accommodative amplitude (63/116) were the most common deficits. Both NPC and accommodative amplitude were significantly correlated with one another (r = -0.5) and with measures of visual tracking (r = -0.34). Patients with chronic post-concussion symptoms show deficits in individual metrics of vergence, accommodation and visual tracking. The high incidence of these deficits, specifically NPC and accommodative amplitude, highlights the need for a detailed sensorimotor evaluation to guide personalized treatment following concussion.
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15
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Is accommodation a confounder in pupillometry research? Biol Psychol 2021; 160:108046. [PMID: 33581231 DOI: 10.1016/j.biopsycho.2021.108046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 02/07/2021] [Accepted: 02/07/2021] [Indexed: 11/24/2022]
Abstract
Much psychological research uses pupil diameter measurements to investigate the cognitive and emotional effects of visual stimuli. A potential problem is that accommodating at a nearby point causes the pupil to constrict. This study examined to what extent accommodation is a confounder in pupillometry research. Participants solved multiplication problems at different distances (Experiment 1) and looked at line drawings with different monocular depth cues (Experiment 2) while their pupil diameter, refraction, and vergence angle were recorded using a photorefractor. Experiment 1 showed that the pupils dilated while performing the multiplications, for all presentation distances. Pupillary constriction due to accommodation was not strong enough to override pupil dilation due to cognitive load. Experiment 2 showed that monocular depth cues caused a small shift in refraction in the expected direction. We conclude that, for the young student sample we used, pupil diameter measurements are not substantially affected by accommodation.
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16
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Close facial emotions enhance physiological responses and facilitate perceptual discrimination. Cortex 2021; 138:40-58. [PMID: 33677327 DOI: 10.1016/j.cortex.2021.01.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 09/22/2020] [Accepted: 01/26/2021] [Indexed: 11/21/2022]
Abstract
Accumulating evidence indicates that the peripersonal space (PPS) constitutes a privileged area for efficient processing of proximal stimuli, allowing to flexibly adapt our behavior both to the physical and social environment. Whether and how behavioral and physiological signatures of PPS relate to each other in emotional contexts remains, though, elusive. Here, we addressed this question by having participants to discriminate male from female faces depicting different emotions (happiness, anger or neutral) and presented at different distances (50 cm-300 cm) while we measured the reaction time and accuracy of their responses, as well as pupillary diameter, heart rate and heart rate variability. Results showed facilitation of participants' performances (i.e., faster response time) when faces were presented close compared to far from the participants, even when controlling for retinal size across distances. These behavioral effects were accompanied by significant modulation of participants' physiological indexes when faces were presented in PPS. Interestingly, both PPS representation and physiological signals were affected by features of the seen faces such as the emotional valence, its sex and the participants' sex, revealing the profound impact of social context onto the autonomic state and behavior within PPS. Together, these findings suggest that both external and internal signals contribute in shaping PPS representation.
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Accommodative Exercises to Lower Intraocular Pressure. J Ophthalmol 2020; 2020:6613066. [PMID: 33489336 PMCID: PMC7803153 DOI: 10.1155/2020/6613066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 12/09/2020] [Indexed: 02/02/2023] Open
Abstract
Purpose This study investigated how a conscious change in ocular accommodation affects intraocular pressure (IOP) and ocular biometrics in healthy adult volunteers of different ages. Methods Thirty-five healthy volunteers without ocular disease or past ocular surgery, and with refractive error between −3.50 and +2.50 diopters, were stratified into 20, 40, and 60 year old (y.o.) age groups. Baseline measurements of central cornea thickness, anterior chamber depth, anterior chamber angle, cornea diameter, pupil size, and ciliary muscle thickness were made by autorefraction and optical coherence tomography (OCT), while IOP was measured by pneumotonometry. Each subject's right eye focused on a target 40 cm away. Three different tests were performed in random order: (1) 10 minutes of nonaccommodation (gazing at the target through lenses that allowed clear vision without accommodating), (2) 10 minutes of accommodation (addition of a minus 3 diopter lens), and (3) 10 minutes of alternating between accommodation and nonaccommodation (1-minute intervals). IOP was measured immediately after each test. A 20-minute rest period was provided between tests. Data from 31 subjects were included in the study. ANOVA and paired t-tests were used for statistical analyses. Results Following alternating accommodation, IOP decreased by 0.7 mmHg in the right eye when all age groups were combined (p = 0.029). Accommodation or nonaccommodation alone did not decrease IOP. Compared to the 20 y.o. group, the 60 y.o. group had a thicker ciliary muscle within 75 μm of the scleral spur, a thinner ciliary muscle at 125–300 μm from the scleral spur, narrower anterior chamber angles, shallower anterior chambers, and smaller pupils during accommodation and nonaccommodation (p's < 0.01). Conclusion Alternating accommodation, but not constant accommodation, significantly decreased IOP. This effect was not lost with aging despite physical changes to the aging eye. A greater accommodative workload and/or longer test period may improve the effect.
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He S, Dai C, Shigemasu H. Role of vergence eye movements in the visual recognition of long time duration. OPTICS EXPRESS 2020; 28:6594-6608. [PMID: 32225904 DOI: 10.1364/oe.380606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/30/2020] [Indexed: 06/10/2023]
Abstract
When viewing dichoptic stimuli in long time duration, visual percepts are always the alternation between the left and right eye inputs, while not the combination. This is known as binocular rivalry. An efficient coding theory reported that binocular visual inputs can be combined into binocular summation (S+) and difference (S-) channels in V1 brain area. In this study, we used specially designed stimuli as the previous study, in which monocular inputs caused ambiguous percepts, but S+ and S- channels had unambiguous percepts. We aim to investigate whether the visual percepts alter between S+ and S- channels in long time duration and whether vergence eye movements are involved in the process. To do so, the stimuli were presented in 300-s time duration in a trial, and a binocular eye tracker was used to record eye information. Participants' real-time behavioral responses about the visual percepts and binocular information were recorded simultaneously. The results show there are perceptual flips between S+ and S- channels in both central and long time viewing conditions. More importantly, in central vision there are vergence eye movements before perceptual flips, suggesting the involvement of high level visual attention; the time of a perceptual flip from S+ is shorter than that of a flip from S-, which might be due to different involvements of visual attention, indicating a bias of feedback connection from higher brain areas for visual attention to S+ channel. Since S+ and S- dominated signals can be carried by different types of binocular neurons, our results provide new insights into high level visual attention and binocular neurons in V1 brain area by using specially designed dichoptic stimuli and eye vergence as measuring tools.
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Sulutvedt U, Mannix TK, Laeng B. Gaze and the Eye Pupil Adjust to Imagined Size and Distance. Cogn Sci 2018; 42:3159-3176. [DOI: 10.1111/cogs.12684] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 05/23/2018] [Accepted: 07/03/2018] [Indexed: 10/28/2022]
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