Eye movements in visual impairment.

This Special Issue describes the impact of visual impairment on visuomotor function. It includes contributions that examine gaze control in conditions associated with abnormal visual development such as amblyopia, dyslexia and neurofibromatosis as well as disorders associated with field loss later in life, such as macular degeneration and stroke. Specifically, the papers address both gaze holding (fixation), and gaze-following behavior (single saccades, sequences of saccades and smooth-pursuit) that characterize active vision in daily life and evaluate the influence of both pathological and simulated field loss.

Suprathreshold length summation.

To investigate the mechanisms underlying elongated spatial summation with a pattern-masking paradigm, we measured the contrast detection thresholds for elongated Gabor targets situated at 3° eccentricity to either the left or right of the fixation and elongated along an arc of the same radius to access homogeneous retinal sensitivity. The mask was a ring with a Gabor envelope of the same 3° center radius containing either a concentric (iso-orientation mask) or a radial (orthogonal mask) modulation. The task of the observer was to indicate whether the target in each trial was on the left or the right of the fixation.

Noise estimation for head-mounted 3D binocular eye tracking using Pupil Core eye-tracking goggles.

Head-mounted, video-based eye tracking is becoming increasingly common and has promise in a range of applications. Here, we provide a practical and systematic assessment of the sources of measurement uncertainty for one such device - the Pupil Core - in three eye-tracking domains: (1) the 2D scene camera image; (2) the physical rotation of the eye relative to the scene camera 3D space; and (3) the external projection of the estimated gaze point location onto the target plane or in relation to world coordinates. We also assess eye camera motion during active tasks relative to the eye and the scene camera, an important consideration as the rigid arrangement of eye and scene camera is essential for proper alignment of the detected gaze.

ISCEV guidelines for calibration and verification of stimuli and recording instruments (2023 update).

This document developed by the International Society for Clinical Electrophysiology of Vision (ISCEV) provides guidance for calibration and verification of stimulus and recording systems specific to clinical electrophysiology of vision. This guideline provides additional information for those using ISCEV Standards and Extended protocols and supersedes earlier Guidelines. The ISCEV guidelines for calibration and verification of stimuli and recording instruments (2023 update) were approved by the ISCEV Board of Directors 01, March 2023.

Spatial cognition training rapidly induces cortical plasticity in blind navigation: Transfer of training effect & Granger causal connectivity analysis.

How is the cortical navigation network reorganized by the Likova Cognitive-Kinesthetic Navigation Training? We measured Granger-causal connectivity of the frontal-hippocampal-insular-retrosplenial-V1 network of cortical areas before and after this one-week training in the blind. Primarily top-down influences were seen during two tasks of drawing-from-memory (drawing complex maps and drawing the shortest path between designated map locations), with the dominant role being congruent influences from the egocentric insular to the allocentric spatial retrosplenial cortex and the amodal-spatial sketchpad of V1, with concomitant influences of the frontal cortex on these areas. After training, and during planning-from-memory of the best on-demand path, the hippocampus played a much stronger role, with the V1 sketchpad feeding information forward to the retrosplenial region.

Surreal space in René Magritte's Le Blanc-Seing (1965).

"The function of painting is to make poetry visible… to render thought visible." René Magritte Pictorial art reveals some of the visual brain's "neural rules" and processing hierarchy. This article examines one salient exemplar drawn from the vast oeuvre of the great Belgian surrealist, René Magritte (1898-1967).

Peripheral targets attenuate miniature eye movements during fixation.

Fixating a small dot is a universal technique for stabilizing gaze in vision and eye movement research, and for clinical imaging of normal and diseased retinae. During fixation, microsaccades and drifts occur that presumably benefit vision, yet microsaccades compromise image stability and usurp task attention. Previous work suggested that microsaccades and smooth pursuit catch-up saccades are controlled by similar mechanisms.

Getting in Touch With Tactile Map Automated Production: Evaluating impact and areas for improvement.

This study evaluated the impact the Tactile Maps Automated Production (TMAP) system has had on its blind and visually impaired (BVI) and Orientation and Mobility (O&M) users and obtained suggestions for improvement. A semi-structured interview was performed with six BVI and seven O&M TMAP users who had printed or ordered two or more TMAPs in the last year. The number of maps downloaded from the online TMAP generation platform was also reviewed for each participant.

Envisioning a Woman Scientist.

I entered science at a particularly lucky time. By the mid-1960s, women were being encouraged to pursue serious scientific careers. During the 60-year span of my career, women have become equal partners with men in scientific research, particularly in the biological sciences.

EVALUATION OF A NON-VISUAL AUDITORY CHOROPLETH AND TRAVEL MAP VIEWER.

The auditory virtual reality interface of Audiom, a web-based map viewer, was evaluated by thirteen blind participants. In Audiom, the user is an avatar that navigates, using the arrow keys, through geographic data, as if they are playing a first-person, egocentric game. The research questions were: What will make blind users want to use Audiom maps? And Can participants demonstrate basic acquisition of spatial knowledge after viewing an auditory map? A dynamic choropleth map of state-level US COVID-19 data, and a detailed OpenStreetMap powered travel map, were evaluated.

A Lightweight Approach to Localization for Blind and Visually Impaired Travelers.

Independent wayfinding is a major challenge for blind and visually impaired (BVI) travelers. Although GPS-based localization approaches enable the use of navigation smartphone apps that provide accessible turn-by-turn directions in outdoor settings, such approaches are ineffective in indoor and other GPS-deprived settings. We build on our previous work on a localization algorithm based on computer vision and inertial sensing; the algorithm is lightweight in that it requires only a 2D floor plan of the environment, annotated with the locations of visual landmarks and points of interest, instead of a detailed 3D model (used in many computer vision localization algorithms), and requires no new physical infrastructure (such as Bluetooth beacons).

Ocular and developmental outcomes of a dosing study of bevacizumab for retinopathy of prematurity.

Purpose: To report 2-year ocular and developmental outcomes for infants receiving low doses of intravitreal bevacizumab for type 1 retinopathy of prematurity (ROP).

Methods: A total of 120 premature infants (mean birthweight, 687 g; mean gestational age, 24.8 weeks) with type 1 ROP were enrolled in a multicenter, phase 1 dose de-escalation study.

Bradykinesia and Its Progression Are Related to Interhemispheric Beta Coherence.

Objective: Bradykinesia is the major cardinal motor sign of Parkinson disease (PD), but its neural underpinnings are unclear. The goal of this study was to examine whether changes in bradykinesia following long-term subthalamic nucleus (STN) deep brain stimulation (DBS) are linked to local STN beta (13-30 Hz) dynamics or a wider bilateral network dysfunction.

Methods: Twenty-one individuals with PD implanted with sensing neurostimulators (Activa® PC + S, Medtronic, PLC) in the STN participated in a longitudinal 'washout' therapy study every three to 6 months for an average of 3 years.

VR Training to Facilitate Blind Photography for Navigation.

Smartphone-based navigation apps allow blind and visually impaired (BVI) people to take images or videos to complete various tasks such as determining a user 's location, recognizing objects, and detecting obstacles. The quality of the images and videos significantly affects the performance of these systems, but manipulating a camera to capture clear images with proper framing is a challenging task for BVI users. This research explores the interactions between a camera and BVI users in assistive navigation systems through interviews with BVI participants.

Mapping residual stereopsis in macular degeneration.

Individuals with macular degeneration typically lose vision in the central region of one or both eyes. A binocular scotoma occurs when vision loss occurs in overlapping locations in both eyes, but stereopsis is impacted even in the non-overlapping region wherever the visual field in either eye is affected. We used a novel stereoperimetry protocol to measure local stereopsis across the visual field (up to 25° eccentricity) to determine how locations with functional stereopsis relate to the scotomata in the two eyes.

Refractive error in unilateral Duane syndrome.

Purpose: To investigate whether chronic co-contraction of the medial and lateral rectus muscles leads to higher against-the-rule astigmatism in affected versus fellow eyes in Duane syndrome.

Methods: A database of 4,103 patients of Dr. Arthur Jampolsky was queried for diagnosis of Duane syndrome.

Non-Visual Access to an Interactive 3D Map.

Maps are indispensable for helping people learn about unfamiliar environments and plan trips. While tactile (2D) and 3D maps offer non-visual map access to people who are blind or visually impaired (BVI), this access is greatly enhanced by adding interactivity to the maps: when the user points at a feature of interest on the map, the name and other information about the feature is read aloud in audio. We explore how the use of an interactive 3D map of a playground, containing over seventy play structures and other features, affects spatial learning and cognition.

A novel method for utilizing dichoptic attention tasks in amblyopic training.

There is converging evidence of attention deficits in individuals with amblyopia. It has been reported that selective visual attention is allocated preferentially toward the non-amblyopic fellow eye in strabismic ambloypes. This attention allocation bias between the eyes is found related to visual suppression in amblyopia.

Measures and variability with age of low contrast acuity and near stereoacuity in children.

Clinical Relevance: Low contrast acuity (LCA) and near stereoacuity (NS) testing are integral to the comprehensive assessment of sensory visual function in children. However, routine ophthalmological evaluations seldom take these measures into consideration. Additionally, there is limited literature regarding the normative values of these parameters in children.

Saccades during visual search in macular degeneration.

Macular degeneration (MD) compromises both high-acuity vision and eye movements when the foveal regions of both eyes are affected. Individuals with MD adapt to central field loss by adopting a preferred retinal locus (PRL) for fixation. Here, we investigate how individuals with bilateral MD use eye movements to search for targets in a visual scene under realistic binocular viewing conditions.

The development of peak alpha frequency from infancy to adolescence and its role in visual temporal processing: A meta-analysis.

While it has been shown that alpha frequency increases over development (Stroganova et al., 1999), a precise trajectory has not yet been specified, making it challenging to constrain theories linking alpha rhythms to perceptual development. We conducted a comprehensive review of studies measuring resting-state occipital peak alpha frequency (PAF, the frequency exhibiting maximum power) from birth to 18 years of age.

The impact of early exposure to general anesthesia on visual and neurocognitive development.

Every year millions of children are exposed to general anesthesia while undergoing surgical and diagnostic procedures. In the field of ophthalmology, 44,000 children are exposed to general anesthesia annually for strabismus surgery alone. While it is clear that general anesthesia is necessary for sedation and pain minimization during surgical procedures, the possibility of neurotoxic impairments from its exposure is of concern.

A low-cost robotic oculomotor simulator for assessing eye tracking accuracy in health and disease.

Eye tracking accuracy is affected in individuals with vision and oculomotor deficits, impeding our ability to answer important scientific and clinical questions about these disorders. It is difficult to disambiguate decreases in eye movement accuracy and changes in accuracy of the eye tracking itself. We propose the EyeRobot-a low-cost, robotic oculomotor simulator capable of emulating healthy and compromised eye movements to provide ground truth assessment of eye tracker performance, and how different aspects of oculomotor deficits might affect tracking accuracy and performance.

Saccadic contributions to smooth pursuit in macular degeneration.

Saccades during smooth pursuit can help bring the fovea on target, particularly in cases of low pursuit gain. Individuals with macular degeneration often suffer damage to the central retina including the fovea, which impacts oculomotor function such as fixation, saccadic and smooth pursuit eye movements. We hypothesized that these oculomotor changes in macular degeneration (MD) would make saccades less appropriately directed (even if more numerous).