Topical review: optometric considerations in sports vs. e-sports

Electronic sports (e-sports) have recently emerged to become a rapidly growing form of videogame competition, requiring gamers to spend many hours in front of a visual display. The nature of this new modality raises important considerations for ocular health, and visual and perceptual functioning, compared to traditional sports. In general, sports performance has been associated with open spaces, gross motor movement, and balance, while electronic sports require visual and attentional stamina at near distances with fine motor control. From an optometric viewpoint, visual perception is specific to both the sports modality and the environment where sports take place. In this topical review, we consider e-sport optometric factors such as screen time and digital eyestrain, visual skill demands, and perceptual cognitive skills such as visual attention. We compare training considerations for traditional sports and training in gaming platforms, with recommendations for future research in this growing modality. The goal of this review is to raise awareness of the various elements to consider when providing vision care to e-sport participants.Peer ReviewedPostprint (author's final draft

Loss of blink regularity and its impact on ocular surface exposure

Background: Changes in blink parameters have been found to influence ocular surface exposure, eliciting symptoms of dry eye and ocular signs. The aim of the study was to highlight the relevance of including blink regularity as a new parameter to fully characterize blinking; (2) Methods: A novel characterization of blink parameters is described, including spontaneous eyeblink rate (SEBR), percentage of incomplete blinks, and blink regularity. A pilot study was designed in which tear film break-up time (TFBUT), blink parameters, and the time percentage of ocular surface exposure were determined in eight subjects (52.0 ± 16.6 years, 4 females) in three experimental conditions (baseline, reading a hard-copy text, and reading from an electronic display). Blink parameters were monitored through asynchronous image analysis of one minute video segments; (3) Results: All blink parameters were influenced by experimental conditions. A trend was observed in which both reading tasks resulted in an increase in ocular surface exposure, mainly related to a combination of reduced SEBR, increased percentage of incomplete blinks, and loss of blink regularity; (4) Conclusions: A complete characterization of blink parameters is relevant to better understand ocular dryness related to surface exposure and to advice patients towards a reeducation of their blinking habits.This research was supported by the Spanish Agencia Estatal de Investigación (project number PID2020-114582RB-I00)Postprint (published version

Functional connectivity of brain networks with three monochromatic wavelengths: a pilot study using resting-state functional magnetic resonance imaging

Exposure to certain monochromatic wavelengths can affect non-visual brain regions. Growing research indicates that exposure to light can have a positive impact on health-related problems such as spring asthenia, circadian rhythm disruption, and even bipolar disorders and Alzheimer’s. However, the extent and location of changes in brain areas caused by exposure to monochromatic light remain largely unknown. This pilot study (N = 7) using resting-state functional magnetic resonance shows light-dependent functional connectivity patterns on brain networks. We demonstrated that 1 min of blue, green, or red light exposure modifies the functional connectivity (FC) of a broad range of visual and non-visual brain regions. Largely, we observed: (i) a global decrease in FC in all the networks but the salience network after blue light exposure, (ii) a global increase in FC after green light exposure, particularly noticeable in the left hemisphere, and (iii) a decrease in FC on attentional networks coupled with a FC increase in the default mode network after red light exposure. Each one of the FC patterns appears to be best arranged to perform better on tasks associated with specific cognitive domains. Results can be relevant for future research on the impact of light stimulation on brain function and in a variety of health disciplines.Peer ReviewedPostprint (author's final draft

Spectral radiance of blue light filters on ophthalmic lenses

As a result of the recent improvement in light-emitting diode (LED) technology, the displays of the vast majority of electronic devices are now illuminated by LEDs. There are several advantages of this type of light source over its predecessors; however, recent research is giving support to the fact that prolonged exposition to the white LEDs emission in the blue spectrum may have a negative impact on visual health, as well as, on biological rhythms (circadian rhythms). As a consequence, ophthalmic lens manufacturers have recently introduced in the market innovative lenses that incorporate blue light filters, especially designed for electronic device users. In this work, the performance of different blue light filters present on commercially available ophthalmic lenses was tested and compared. Lenses were placed in front of a LED-based backlight tablet, in a similar way a common user would be reading a text on the electronic device. The absorption characteristics of the various samples from four different ophthalmic lens manufacturers were measured. Analysis of the different samples from the same manufacturer was conducted and blue light filters from different manufacturers were compared. © Sociedad Española de Óptica.Postprint (published version

Real-Time Non-Intrusive Assessment of Viewing Distance During Computer Use

Purpose: To develop and test the sensitivity of an ultrasound-based sensor to assess the viewing distance of visual display terminals operators in real-time conditions. Methods: A modified ultrasound sensor was attached to a computer display to assess viewing distance in real time. Sensor functionality was tested on a sample of 20 healthy participants while they conducted four 10-minute randomly presented typical computer tasks (a match-three puzzle game, a video documentary, a task requiring participants to complete a series of sentences, and a predefined internet search). Results: The ultrasound sensor offered good measurement repeatability. Game, text completion, and web search tasks were conducted at shorter viewing distances (54.4 cm [95% CI 51.3-57.5 cm], 54.5 cm [95% CI 51.1-58.0 cm], and 54.5 cm [95% CI 51.4-57.7 cm], respectively) than the video task (62.3 cm [95% CI 58.9-65.7 cm]). Statistically significant differences were found between the video task and the other three tasks (all p < 0.05). Range of viewing distances (from 22 to 27 cm) was similar for all tasks (F = 0.996; p = 0.413). Conclusions: Real-time assessment of the viewing distance of computer users with a non-intrusive ultrasonic device disclosed a task-dependent pattern. (C) 2016 American Academy of OptometryPostprint (author's final draft

Vergence and accommodation cues in stereo-localization during the Small-In Large-Out (SILO) effect

A typical procedure in vision therapy is the use of Quoits vectograms to train fusional vergence ranges by improving stereo-localization, which is the ability to correctly locate the target stimulus in space. With this procedure, the Small-In Large-Out (SILO) effect is usually reported in patients with normal binocular vision and accommodation. In this study, the influence of vergence and accommodation cues, as determined with the accommodative-convergence over accommodation (AC/A) ratio, to correctly locate the Quoits vectograms in space was investigated. Twenty participants, aged 29.2 ± 2.8 (mean ± standard deviation) years, without amblyopia or strabismus, were recruited. A geometrical formula was obtained to calculate the theoretical distance to the target stimulus for different vergence demands. Theoretical values were compared with measured distances to the perceived stimuli and stereo-localization accuracy was determined. Stereo-localization accuracy was significantly worse at 10¿ Base In vergence demand (p < 0.001). A statistically significant positive correlation was found between AC/A ratio and stereo-localization accuracy (i.e., worse accuracy) at 10¿ Base Out vergence demand (rho = 0.446, p = 0.049). These findings highlight that AC/A ratio may be a secondary cue for stereo-localization when using vectograms in which the SILO effect is manifest. These results assist in the understanding of the physiological basis of vision therapy procedures.Peer ReviewedPostprint (author's final draft

Comitant strabismus etiology: extraocular muscle integrity and central nervous system involvement—a narrative review

Strabismus is not a condition in itself but the consequence of an underlying problem. Eye misalignment can be caused by disease, injury, and/or abnormalities in any of the structures and processes involved in visual perception and oculomotor control, from the extraocular muscles and their innervations to the oculomotor and visual processing areas in the brain. A small percentage of all strabismus cases are the consequence of well-described genetic syndromes, acquired insult, or disease affecting the extraocular muscles (EOMs) or their innervations. We will refer to them as strabismus of peripheral origin since their etiology lies in the peripheral nervous system. However, in most strabismus cases, that is comitant, non-restrictive, non-paralytic strabismus, the EOMs and their innervations function properly. These cases are not related to specific syndromes and their precise causes remain poorly understood. They are generally believed to be caused by deficits in the central neural pathways involved in visual perception and oculomotor control. Therefore, we will refer to them as central strabismus. The goal of this narrative review is to discuss the possible causes behind this particular type of eye misalignment and to raise awareness among eyecare professionals about the important role the central nervous system plays in strabismus etiology, and the subsequent implications regarding its treatment. A non-systematic search was conducted using PubMed, Medline, Cochrane, and Google Scholar databases with the keywords “origins,” “causes,” and “etiology” combined with “strabismus.” A snowball approach was also used to find relevant references. In the following article, we will first describe EOM integrity in central strabismus; next, we will address numerous reasons that support the idea of central nervous system (CNS) involvement in the origin of the deviation, followed by listing several possible central causes of the ocular misalignment. Finally, we will discuss the implications CNS etiology has on strabismus treatment.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.Peer ReviewedPostprint (published version

The relationship between fixation stability and retinal structural parameters in children with anisometropic, strabismic and mixed amblyopia

Background: Amblyopia is an ocular condition leading to structural and functional changes. The relationship between these changes is complex and remains poorly understood. (2) Methods: Participants included 31 children aged 5 to 9 years with strabismic (n = 9), anisometropic (n = 16) and mixed (n = 6) unilateral amblyopia, and 14 age-matched non-amblyopic children. The 95% and 63% Bivariate Contour Ellipse Area (BCEA), axial length, Foveal Avascular Zone (FAZ) area, center macular thickness and volume were assessed. The relationship between these parameters was explored. (3) Results: Statistically significant differences were found among the four groups in best corrected distance visual acuity (BCVA) (p < 0.001), BCEA 95% (p = 0.002) and BCEA 63% (p = 0.002), but not in the FAZ area, central macular thickness, central macular volume and axial length. Eyes with amblyopia had poorer BCVA and larger fixation instability than controls. Inter-ocular differences were more significant in patients with strabismic amblyopia, particularly in BCVA (p = 0.003), central macular thickness (p < 0.001) and central macular volume (p = 0.002). In amblyopic eyes, BCEA 95% and 63% were correlated with BCVA, but not with the FAZ area. (4) Conclusion: Amblyopia is associated with a reduction in fixation stability and BCVA, although there is a general lack of correlation with structural changes, suggesting a complex interaction between anatomy and function in amblyopia.Peer ReviewedPostprint (published version

Impact of strabismus and binocular dysfunctions in the developmental eye movement test and test of visual perception skills: A multicentric and retrospective study

Purpose To compare the performance in the Developmental Eye Movement test (DEM) and the Test of Visual Perceptual Skills (TVPS) between three groups: individuals with strabismus and amblyopia, patients with binocular and accommodative dysfunctions, and subjects with normal binocular and accommodative function. Methods A multicentric, retrospective study including 110 children aged 6–14 years old was conducted to investigate the potential impact of strabismus, amblyopia, and different binocular conditions in DEM results (adjusted time in vertical and horizontal parts) and TVPS (percentiles in the seven sub-skills). Results No significant differences were found in the different subtests of the vertical and horizontal DEM and all the sub-skills in the TVPS between the three groups of the study. We found high variability of performance in the DEM test between participants with strabismus and amblyopia compared with binocular and accommodative problems. Conclusion DEM and TVPS scores have not been found to be influenced by the presence of strabismus with or without amblyopia, nor by binocular and accommodative dysfunctions. A slightly correlation tendency with horizontal DEM and degree of exotropia deviation was observed.Peer ReviewedPostprint (author's final draft

Moviments oculars, atenció visual i procés lector

Descripció del recurs: 15 maig 2020Aquest llibre pretén ser una guia per aprofundir en els processos visuals implicats durant la lectura, com es veuen afectats en casos de dificultats lectores i quins estudis hi han hagut on es podria observar un efecte positiu en treballar les habilitats de moviments oculars, atenció visual i vergències en el rendiment lector. El text base forma part de l’assignatura Dificultats de l’aprenentatge que s’imparteix en el Màster d’Optometria i Teràpia Visual de la Universitat Politècnica de Catalunya. També és una font d’interés per tota persona relacionada en el camp de l’optometria i l’educació.Primera edici