Vision

12 pages, 1410 KiB

Open AccessArticle

Effects of Oral Antihistamines on Tear Volume, Tear Stability, and Intraocular Pressure

by Brian K. Foutch, Kyle A. Sandberg, Edward S. Bennett and Leonard L. Naeger

Vision 2020, 4(2), 32; https://doi.org/10.3390/vision4020032 - 20 Jun 2020

Cited by 2 | Viewed by 5407

The goal of this study was to investigate the effects of two commonly used oral antihistamines—diphenhydramine and loratadine—on tear volume, tear breakup time, and intraocular pressure. Placebo, diphenhydramine, and loratadine were administered for one week to 33 subjects experimentally blind to the treatment [...] Read more.

The goal of this study was to investigate the effects of two commonly used oral antihistamines—diphenhydramine and loratadine—on tear volume, tear breakup time, and intraocular pressure. Placebo, diphenhydramine, and loratadine were administered for one week to 33 subjects experimentally blind to the treatment given. All the subjects received all three treatments over a period of six weeks. The outcome measures were the change in phenol red thread test (PRT), the tear breakup time (TBUT), and the intraocular pressure (IOP) of both eyes evaluated by experimentally masked observers. Neither of the mean changes in TBUT or IOP depended on the treatment given, but there was a significant monocular decrease in tear volume from diphenhydramine use. While we used an adequate treatment washout period of seven days, our investigation was limited by the short treatment times and inclusion of only young healthy patients. Overall, however, these results suggest that systemic diphenhydramine use should be limited to increase the effectiveness of conventional therapies. Clinicians should have fewer reservations about recommending the use of loratadine concurrent with dry eye treatments. Full article

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Graphical abstract

10 pages, 7779 KiB

Open AccessCase Report

Time Course in Ocular Blood Flow and Pulse Waveform in a Case of Ocular Ischemic Syndrome with Intraocular Pressure Fluctuation

by Ryo Yamazaki, Ryuya Hashimoto, Hidetaka Masahara, Masashi Sakamoto and Takatoshi Maeno

Vision 2020, 4(2), 31; https://doi.org/10.3390/vision4020031 - 10 Jun 2020

Cited by 2 | Viewed by 3056

Abstract

We report on a 70-year-old Japanese man with complaints of worsening left visual acuity who was diagnosed with ocular ischemic syndrome (OIS) associated with internal carotid artery (ICA) stenosis. A gonioscopy examination showed rubeosis iridis and elevated intraocular pressure (IOP) in the left [...] Read more.

We report on a 70-year-old Japanese man with complaints of worsening left visual acuity who was diagnosed with ocular ischemic syndrome (OIS) associated with internal carotid artery (ICA) stenosis. A gonioscopy examination showed rubeosis iridis and elevated intraocular pressure (IOP) in the left eye (50 mmHg) at the baseline visit. The optic nerve head (ONH) and choroidal blood flow measured by laser speckle flowgraphy (LSFG) was impaired in the left eye compared with that in the right eye. Additionally, the blowout score (BOS), which indicates the variation of the mean blur rate (MBR) during systolic and diastolic periods, was decreased in the left eye. After treatment with an injection of bevacizumab and administration of Rho-associated kinase-inhibitor ripasudil eye drops, both ocular blood flow and BOS in each vascular bed gradually increased along with IOP reduction. The visual acuity also improved. The current case demonstrated increased blood flow and decreased fluctuation of blood flow in the ONH and choroid before and after the treatment in OIS with rubeosis iridis. The LSFG technique is useful to non-invasively assess the ocular circulation and pulse waveform in OIS. Full article

(This article belongs to the Special Issue Ocular Blood Flow and Visual Function)

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18 pages, 1586 KiB

Open AccessConcept Paper

Perspective-Taking: In Search of a Theory

by Geoff G. Cole, Abbie C. Millett, Steven Samuel and Madeline J. Eacott

Vision 2020, 4(2), 30; https://doi.org/10.3390/vision4020030 - 1 Jun 2020

Cited by 13 | Viewed by 4557

Abstract

Perspective-taking has been one of the central concerns of work on social attention and developmental psychology for the past 60 years. Despite its prominence, there is no formal description of what it means to represent another’s viewpoint. The present article argues that such [...] Read more.

Perspective-taking has been one of the central concerns of work on social attention and developmental psychology for the past 60 years. Despite its prominence, there is no formal description of what it means to represent another’s viewpoint. The present article argues that such a description is now required in the form of theory—a theory that should address a number of issues that are central to the notion of assuming another’s viewpoint. After suggesting that the mental imagery debate provides a good framework for understanding some of the issues and problems surrounding perspective-taking, we set out nine points that we believe any theory of perspective-taking should consider. Full article

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16 pages, 4448 KiB

Open AccessArticle

Effects of Spatial Frequency Filtering Choices on the Perception of Filtered Images

by Sabrina Perfetto, John Wilder and Dirk B. Walther

Vision 2020, 4(2), 29; https://doi.org/10.3390/vision4020029 - 26 May 2020

Cited by 17 | Viewed by 5998

Abstract

The early visual system is composed of spatial frequency-tuned channels that break an image into its individual frequency components. Therefore, researchers commonly filter images for spatial frequencies to arrive at conclusions about the differential importance of high versus and low spatial frequency image [...] Read more.

The early visual system is composed of spatial frequency-tuned channels that break an image into its individual frequency components. Therefore, researchers commonly filter images for spatial frequencies to arrive at conclusions about the differential importance of high versus and low spatial frequency image content. Here, we show how simple decisions about the filtering of the images, and how they are displayed on the screen, can result in drastically different behavioral outcomes. We show that jointly normalizing the contrast of the stimuli is critical in order to draw accurate conclusions about the influence of the different spatial frequencies, as images of the real world naturally have higher contrast energy at low than high spatial frequencies. Furthermore, the specific choice of filter shape can result in contradictory results about whether high or low spatial frequencies are more useful for understanding image content. Finally, we show that the manner in which the high spatial frequency content is displayed on the screen influences how recognizable an image is. Previous findings that make claims about the visual system’s use of certain spatial frequency bands should be revisited, especially if their methods sections do not make clear what filtering choices were made. Full article

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15 pages, 1974 KiB

Open AccessArticle

No Advantage for Separating Overt and Covert Attention in Visual Search

by W. Joseph MacInnes, Ómar I. Jóhannesson, Andrey Chetverikov and Árni Kristjánsson

Vision 2020, 4(2), 28; https://doi.org/10.3390/vision4020028 - 18 May 2020

Cited by 2 | Viewed by 3937

Abstract

We move our eyes roughly three times every second while searching complex scenes, but covert attention helps to guide where we allocate those overt fixations. Covert attention may be allocated reflexively or voluntarily, and speeds the rate of information processing at the attended [...] Read more.

We move our eyes roughly three times every second while searching complex scenes, but covert attention helps to guide where we allocate those overt fixations. Covert attention may be allocated reflexively or voluntarily, and speeds the rate of information processing at the attended location. Reducing access to covert attention hinders performance, but it is not known to what degree the locus of covert attention is tied to the current gaze position. We compared visual search performance in a traditional gaze-contingent display, with a second task where a similarly sized contingent window is controlled with a mouse, allowing a covert aperture to be controlled independently by overt gaze. Larger apertures improved performance for both the mouse- and gaze-contingent trials, suggesting that covert attention was beneficial regardless of control type. We also found evidence that participants used the mouse-controlled aperture somewhat independently of gaze position, suggesting that participants attempted to untether their covert and overt attention when possible. This untethering manipulation, however, resulted in an overall cost to search performance, a result at odds with previous results in a change blindness paradigm. Untethering covert and overt attention may therefore have costs or benefits depending on the task demands in each case. Full article

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8 pages, 501 KiB

Open AccessArticle

Plasma Levels of Matrix Metalloprotease MMP-9 and Tissue Inhibitor TIMP-1 in Caucasian Patients with Polypoidal Choroidal Vasculopathy

by Jakob Ø. Sørensen, Yousif Subhi, Christopher R. Molbech, Marie Krogh Nielsen and Torben L. Sørensen

Vision 2020, 4(2), 27; https://doi.org/10.3390/vision4020027 - 15 May 2020

Cited by 3 | Viewed by 2468

Abstract

Background: Matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinases 1 (TIMP-1) are regulating enzymes of the extracellular matrix. A systemic imbalance of MMP-9 and TIMP-1, thought to reflect an imbalance of the extracellular matrix homeostasis, is previously associated with polypoidal choroidal vasculopathy [...] Read more.

Background: Matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinases 1 (TIMP-1) are regulating enzymes of the extracellular matrix. A systemic imbalance of MMP-9 and TIMP-1, thought to reflect an imbalance of the extracellular matrix homeostasis, is previously associated with polypoidal choroidal vasculopathy (PCV) in Asian patients. Previous studies suggest inter-ethnical differences in the genetic background and etiology of PCV. To further explore this issue, we studied the plasma levels of MMP-9 and TIMP-1 in Caucasian patients with PCV and compared to healthy age-matched controls. Methods: For this prospective case-control study, 60 participants were recruited who were either patients with PCV (n = 26) or healthy controls (n = 34). All participants underwent detailed clinical examination. We sampled fresh venous blood, isolated plasma, and quantified plasma concentrations of the extracellular matrix regulators MMP-9 and TIMP-1 using electrochemiluminescence immunoassays. Results: Plasma levels of MMP-9 (p = 0.4), TIMP-1 (p = 0.9), and MMP-9/TIMP-1 ratio (p = 0.4) did not differ significantly between patients with PCV and healthy controls. No differences appeared after adjusting for influencing co-variates in multivariate analyses. Conclusion: We demonstrate that Caucasian patients with PCV do not have altered levels of plasma MMP-9 or plasma TIMP-1. These findings suggest no strong evidence of a systemic imbalance of the extracellular matrix homeostasis in Caucasian patients with PCV. Our findings are in line with studies of other aspects of PCV that are also subject to significant inter-ethnical differences. Full article

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13 pages, 534 KiB

Open AccessArticle

Accident Vulnerability and Vision for Action: A Pilot Investigation

by Anthony J. Lambert, Tanvi Sharma and Nathan Ryckman

Vision 2020, 4(2), 26; https://doi.org/10.3390/vision4020026 - 13 May 2020

Cited by 3 | Viewed by 2976

Abstract

Many accidents, such as those involving collisions or trips, appear to involve failures of vision, but the association between accident risk and vision as conventionally assessed is weak or absent. We addressed this conundrum by embracing the distinction inspired by neuroscientific research, between [...] Read more.

Many accidents, such as those involving collisions or trips, appear to involve failures of vision, but the association between accident risk and vision as conventionally assessed is weak or absent. We addressed this conundrum by embracing the distinction inspired by neuroscientific research, between vision for perception and vision for action. A dual-process perspective predicts that accident vulnerability will be associated more strongly with vision for action than vision for perception. In this preliminary investigation, older and younger adults, with relatively high and relatively low self-reported accident vulnerability (Accident Proneness Questionnaire), completed three behavioural assessments targeting vision for perception (Freiburg Visual Acuity Test); vision for action (Vision for Action Test—VAT); and the ability to perform physical actions involving balance, walking and standing (Short Physical Performance Battery). Accident vulnerability was not associated with visual acuity or with performance of physical actions but was associated with VAT performance. VAT assesses the ability to link visual input with a specific action—launching a saccadic eye movement as rapidly as possible, in response to shapes presented in peripheral vision. The predictive relationship between VAT performance and accident vulnerability was independent of age, visual acuity and physical performance scores. Applied implications of these findings are considered. Full article

(This article belongs to the Special Issue Visual Orienting and Conscious Perception)

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33 pages, 9446 KiB

Open AccessArticle

MLGaze: Machine Learning-Based Analysis of Gaze Error Patterns in Consumer Eye Tracking Systems

by Anuradha Kar

Vision 2020, 4(2), 25; https://doi.org/10.3390/vision4020025 - 7 May 2020

Cited by 9 | Viewed by 6248

Abstract

Analyzing the gaze accuracy characteristics of an eye tracker is a critical task as its gaze data is frequently affected by non-ideal operating conditions in various consumer eye tracking applications. In previous research on pattern analysis of gaze data, efforts were made to [...] Read more.

Analyzing the gaze accuracy characteristics of an eye tracker is a critical task as its gaze data is frequently affected by non-ideal operating conditions in various consumer eye tracking applications. In previous research on pattern analysis of gaze data, efforts were made to model human visual behaviors and cognitive processes. What remains relatively unexplored are questions related to identifying gaze error sources as well as quantifying and modeling their impacts on the data quality of eye trackers. In this study, gaze error patterns produced by a commercial eye tracking device were studied with the help of machine learning algorithms, such as classifiers and regression models. Gaze data were collected from a group of participants under multiple conditions that commonly affect eye trackers operating on desktop and handheld platforms. These conditions (referred here as error sources) include user distance, head pose, and eye-tracker pose variations, and the collected gaze data were used to train the classifier and regression models. It was seen that while the impact of the different error sources on gaze data characteristics were nearly impossible to distinguish by visual inspection or from data statistics, machine learning models were successful in identifying the impact of the different error sources and predicting the variability in gaze error levels due to these conditions. The objective of this study was to investigate the efficacy of machine learning methods towards the detection and prediction of gaze error patterns, which would enable an in-depth understanding of the data quality and reliability of eye trackers under unconstrained operating conditions. Coding resources for all the machine learning methods adopted in this study were included in an open repository named MLGaze to allow researchers to replicate the principles presented here using data from their own eye trackers. Full article

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6 pages, 1059 KiB

Open AccessCase Report

Delayed Onset Scleromalacia and Conjunctival Bleb Formation Following Intraoperative Mitomycin C Application during Conjunctival Melanoma Excision

by Syed Naqib Ahmed, Syed Mohammed Shahid and Mayank A. Nanavaty

Vision 2020, 4(2), 24; https://doi.org/10.3390/vision4020024 - 6 May 2020

Cited by 1 | Viewed by 3326

Abstract

Purpose: To present a case of delayed onset scleromalacia and conjunctival bleb formation one year after conjunctival melanoma excision with intraoperative use of mitomycin-C (MMC) and double-freeze-thaw technique. Methods: Case report. Results: A 69-year-old woman had a conjunctival melanoma excised by the ‘no [...] Read more.

Purpose: To present a case of delayed onset scleromalacia and conjunctival bleb formation one year after conjunctival melanoma excision with intraoperative use of mitomycin-C (MMC) and double-freeze-thaw technique. Methods: Case report. Results: A 69-year-old woman had a conjunctival melanoma excised by the ‘no touch technique’ with intraoperative application of 0.02% MMC for 3 min on bare sclera, freeze-thaw cryotherapy and amniotic membrane transplant performed elsewhere. Three months later, she presented to us with a red, sore and painful right eye. Examination revealed severe scleritis. She was treated with lubricants and oral steroids for 6 weeks. She settled well with no recurrence of melanoma. At one year, she developed scleromalacia and conjunctival blebs in the inferonasal quadrant of right eye. She remains under closer observation as she is at high risk of perforation. Conclusion: Caution should be exercised with intraoperative use of MMC on bare sclera during excision and cryotherapy of conjunctival melanoma. As published in the literature, when using MMC, it is recommended to use the lowest dose topically in the form of eye drops in the postoperative period for the shortest time to avoid any sight-threatening complications. Full article

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24 pages, 673 KiB

Open AccessArticle

Tracking the Migraine Cycle Using Visual Tasks

by A.J. Shepherd

Vision 2020, 4(2), 23; https://doi.org/10.3390/vision4020023 - 30 Apr 2020

Cited by 10 | Viewed by 3403

Abstract

There are a number of reports that perceptual, electrophysiological and imaging measures can track migraine periodicity. As the electrophysiological and imaging research requires specialist equipment, it has few practical applications. This study sought to track changes in performance on four visual tasks over [...] Read more.

There are a number of reports that perceptual, electrophysiological and imaging measures can track migraine periodicity. As the electrophysiological and imaging research requires specialist equipment, it has few practical applications. This study sought to track changes in performance on four visual tasks over the migraine cycle. Coherence thresholds were measured for two motion and two orientation tasks. The first part of the study confirmed that the data obtained from an online study produced comparable results to those obtained under controlled laboratory conditions. Thirteen migraine with aura, 12 without aura, and 12 healthy controls participated. The second part of the study showed that thresholds for discriminating vertical coherent motion varied with the migraine cycle for a majority of the participants who tested themselves multiple times (four with aura, seven without). Performance improved two days prior to a migraine attack and remained improved for two days afterwards. This outcome is as expected from an extrapolation of earlier electrophysiological research. This research points to the possibility of developing sensitive visual tests that patients can use at home to predict an impending migraine attack and so take steps to try to abort it or, if it is inevitable, to plan their lives around it. Full article

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18 pages, 4510 KiB

Open AccessArticle

Pulvinar Modulates Synchrony across Visual Cortical Areas

by Nelson Cortes, Bruno O. F. de Souza and Christian Casanova

Vision 2020, 4(2), 22; https://doi.org/10.3390/vision4020022 - 10 Apr 2020

Cited by 14 | Viewed by 3741

Abstract

The cortical visual hierarchy communicates in different oscillatory ranges. While gamma waves influence the feedforward processing, alpha oscillations travel in the feedback direction. Little is known how this oscillatory cortical communication depends on an alternative route that involves the pulvinar nucleus of the [...] Read more.

The cortical visual hierarchy communicates in different oscillatory ranges. While gamma waves influence the feedforward processing, alpha oscillations travel in the feedback direction. Little is known how this oscillatory cortical communication depends on an alternative route that involves the pulvinar nucleus of the thalamus. We investigated whether the oscillatory coupling between the primary visual cortex (area 17) and area 21a depends on the transthalamic pathway involving the pulvinar in cats. To that end, visual evoked responses were recorded in areas 17 and 21a before, during and after inactivation of the pulvinar. Local field potentials were analyzed with Wavelet and Granger causality tools to determine the oscillatory coupling between layers. The results indicate that cortical oscillatory activity was enhanced during pulvinar inactivation, in particular for area 21a. In area 17, alpha band responses were represented in layers II/III. In area 21a, gamma oscillations, except for layer I, were significantly increased, especially in layer IV. Granger causality showed that the pulvinar modulated the oscillatory information between areas 17 and 21a in gamma and alpha bands for the feedforward and feedback processing, respectively. Together, these findings indicate that the pulvinar is involved in the mechanisms underlying oscillatory communication along the visual cortex. Full article

(This article belongs to the Special Issue Role of the Pulvinar in Visual Processing)

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16 pages, 2044 KiB

Open AccessArticle

Examining the Role of Familiarity in the Perception of Depth

by Elizaveta Mischenko, Ippei Negishi, Elena S. Gorbunova and Tadamasa Sawada

Vision 2020, 4(2), 21; https://doi.org/10.3390/vision4020021 - 2 Apr 2020

Cited by 4 | Viewed by 3924

Abstract

Bishop Berkeley suggested that the distance of an object can be estimated if the object’s size is familiar to the observer. It has been suggested that humans can perceive the distance of the object by using such “familiarity” information, but most or many [...] Read more.

Bishop Berkeley suggested that the distance of an object can be estimated if the object’s size is familiar to the observer. It has been suggested that humans can perceive the distance of the object by using such “familiarity” information, but most or many of the prior experiments that found an effect of familiarity were not designed to minimize or eliminate potential influences of: higher cognitive factors on the observers’ responses, or the influences of low-level image features in the visual stimuli used. We looked for the familiarity effect in two experiments conducted both in Russia and Japan. The visual stimuli used were images of three coins used in Russia and Japan. The participants’ depth perception was measured with a multiple-choice task testing the perceived depth-order of the coins. Our expectation was that any effect of “familiarity” on depth perception would only be observed with the coins of the participant’s country. We expected a substantial familiarity effect based on our meta-analysis of the “familiarity” effects observed in prior experiments. But, our results in both experiments showed that the familiarity effect was virtually zero. These findings suggest that the importance of a familiarity effect in depth perception should be reconsidered. Full article

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Vision, Volume 4, Issue 2 (June 2020) – 12 articles

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