Perspective on Vision Science-Informed Interventions for Central Vision Loss.
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ABSTRACT:
SUBMITTER: Maniglia M
PROVIDER: S-EPMC8599964 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Better understanding of the extent and scope of visual cortex plasticity following central vision loss is essential both for clarifying the mechanisms of brain plasticity and for future development of interventions to retain or restore visual function. This study investigated structural differences in primary visual cortex between normally-sighted controls and participants with central vision loss due to macular degeneration (MD). Ten participants with MD and ten age-, gender-, and education-matched controls with normal vision were included. The thickness of primary visual cortex was assessed using T1-weighted anatomical scans, and central and peripheral cortical regions were carefully compared between well-characterized participants with MD and controls. Results suggest that, compared to controls, participants with MD had significantly thinner cortex in typically centrally-responsive primary visual cortex - the region of cortex that normally receives visual input from the damaged area of the retina. Conversely, peripherally-responsive primary visual cortex demonstrated significantly increased cortical thickness relative to controls. These results suggest that central vision loss may give rise to cortical thinning, while in the same group of people, compensatory recruitment of spared peripheral vision may give rise to cortical thickening. This work furthers our understanding of neural plasticity in the context of adult vision loss.
| S-EPMC4806312 | biostudies-other
Project description:To evaluate the effects of central vision loss (CVL) on mutual gaze perception (knowing whether somebody else is looking at you), an important nonverbal visual cue in social interactions.Twenty-three persons with CVL (visual acuity 20/50 to 20/200), 16 with a bilateral central scotoma and 7 without, and 23 age-matched control subjects completed a gaze perception task and a brief questionnaire. They adjusted the eyes of a life-size virtual head on a monitor at a 1-m distance until they either appeared to be looking straight at them or were at the extreme left/right or up/down positions at which the eyes still appeared to be looking toward them (defining the range of mutual gaze in the horizontal and vertical planes).The nonscotoma group did not differ from the control subjects in any gaze task measure. However, the gaze direction judgments of the scotoma group had significantly greater variability than those of the nonscotoma and control groups (p < 0.001). In addition, their mutual gaze range tended to be wider (p = 0.15), suggesting a more liberal judgment criterion. Contrast sensitivity was the strongest predictor of variability in gaze direction judgments followed by self-reported difficulties.Our results suggest that mutual gaze perception is relatively robust to CVL. However, a follow-up study that simulates less-than-optimal viewing conditions of everyday social interactions is needed. The gaze perception task holds promise as a research tool for investigating the effects of vision impairment on mutual gaze judgments. Self-reported difficulty and contrast sensitivity were both independent predictors of gaze perception performance, suggesting that the task captured higher-order as well as low-level visual abilities.
| S-EPMC4126164 | biostudies-literature
Project description:Late-stage macular degeneration (MD) often causes retinal lesions depriving an individual of central vision, forcing them to learn to use peripheral vision for daily tasks. To compensate, many patients develop a preferred retinal locus (PRL), an area of peripheral vision used more often than equivalent regions of spared vision. Thus, associated portions of cortex experience increased use, while portions of cortex associated with the lesion are deprived of sensory input. Prior research has not well examined the degree to which structural plasticity depends on the amount of use across the visual field. Cortical thickness, neurite density, and orientation dispersion were measured at portions of cortex associated with the PRL, the retinal lesion, and a control region in participants with MD as well as age-matched, gender-matched, and education-matched controls. MD participants had significantly thinner cortex in both the cortical representation of the PRL (cPRL) and the control region, compared with controls, but no significant differences in thickness, neurite density, or orientation dispersion were found between the cPRL and the control region as functions of disease or onset. This decrease in thickness is driven by a subset of early-onset participants whose patterns of thickness, neurite density, and neurite orientation dispersion are distinct from matched control participants. These results suggest that people who develop MD earlier in adulthood may undergo more structural plasticity than those who develop it late in life.
| S-EPMC10258531 | biostudies-literature
Project description:Loss of central vision can be partially compensated by increased use of peripheral vision. For example, patients experiencing central vision loss due to disease (macular degeneration) or healthy participants trained with simulated central vision loss, tend to develop eccentric fixation spots for reading or other visual tasks. In both patients and in simulated conditions, there are substantial individual variations in the effective use of the periphery. The factors driving these individual differences are still unclear. Although early approaches have described some dimensions of these strategies, the field is still in its initial stages and important elements are often conflated when examining gaze patterns. Here, we propose a systematic approach to characterize oculomotor strategies in cases of central vision loss that distinguishes different components: saccadic re-referencing, saccadic precision, first saccade landing dispersion, fixation stability, latency of target acquisition, and percentage of trials that are useful. We tested this approach in healthy individuals trained with a gaze-contingent display obstructing the central 10 degrees of the visual field. The use of simulated scotoma helps overcome known challenges in clinical research, from recruitment and compliance to the diverse extent and nature of the visual loss. Importantly, this approach offers the ability to examine oculomotor strategies as they develop in controlled settings where viewing conditions are similar across participants. Results show substantial differences in characteristics of peripheral looking strategies, both across trials and individuals. This more complete characterization of peripheral looking strategies can help us understand individual differences in rehabilitation after central vision loss.
| S-EPMC7521176 | biostudies-literature
Project description:Vision is the most powerful sense guiding our interaction with the environment. Its process starts with the retinal image as input and results in visually guided behaviors as output. This paper summarizes insights I gained over >40 years dealing with clinical ophthalmology, visual science, and vision rehabilitation, disciplines that all involve vision, but from different points of view. The retinal image contains 2-dimensional forms that have no inherent meaning. The brain matches this input to stored concepts, to create a Mental Model that is filled with 3-dimensional objects that are meaningful and linked to other senses. Ultimately this leads to the output of goal-directed visually guided behavior. The processes involved are too complex to be covered by a single practitioner. Optimal vision rehabilitation requires teamwork that includes contributions from various professions. It also requires an understanding, as well as possible, of the cerebral processes involved. The visual sciences study mostly the input-driven process from retinal image to visual percepts. Their studies deal mostly with groups and group averages and only occasionally with individual disease conditions. Clinical ophthalmology deals mostly with individuals, rather than group averages. The motto of the American Academy of Ophthalmology reminds us that the end point of patient care goes beyond "preserving sight." It also includes "empowering lives" by creating the conditions for goal-directed interaction with the environment through visually directed behavior. Traditionally, the study of vision has mainly involved the conscious part of vision, handled mostly in the ventral stream. However, the subconscious part of vision, handled mostly in the dorsal stream must also be considered. This is further stimulated by the demands of computer vision, image processing, and artificial intelligence. Vision rehabilitation traditionally deals with the input side through better illumination and various magnification devices. This is the domain of low vision aids. Increasingly, however, it must also address the output side, and the involvement of other senses (braille, long cane, and talking books). This requires better understanding of the goal-directed higher visual processes. The supplemental material covers the development of numerical scales to quantify not only visual acuity but also visual abilities, and the use of different tests.Financial disclosuresThe author(s) have no proprietary or commercial interest in any materials discussed in this article.
| S-EPMC11373033 | biostudies-literature
Project description:The experience of building and participating in women scientists' communities in Central America is a multi-layered topic worthy of study. Understanding the dynamics of these women's groups, associations, and other forms of collective participation, could assist in shedding light on why women are typically under-represented in Science, Technology, Engineering, and Mathematics (STEM) research in countries within this region. The objectives of this study are (i) to explore the experiences of participation in communities of women scientists in Guatemala, El Salvador, Honduras and Panama, and (ii) to systematize the challenges and opportunities derived from such activities. Additionally, this work elaborates on some best practices from the Science Diplomacy (SD) perspective, which could provide a helpful framework to encourage these types of collective participatory communities. The qualitative research methodology was based on the collection of primary data from semi-structured interviews and responses to an online survey sent out to Central American women scientists. The findings of this study revealed few cases of community building experiences among women scientists within the studied countries. Evidence also showed the emergence of shared patterns in terms of barriers and disincentives to participating in such communities. Meanwhile, data collected from the few existing community groups is used to identify successful incentives and motivations. The analysis of the collected data offered relevant implications for Science Diplomacy. Most respondents referred to the Organization of Women in Science for the Developing World (OWSD) as one of the main organizations that can impact and further Science Diplomacy. This organization promotes international engagement and networking among women scientists from developing countries across regions and this article shows how this has been used to foster women science community building in Central America. Exploring similar practices in-depth may offer opportunities to overcome traditional barriers and build further gender equality in science in Central America.
| S-EPMC8344979 | biostudies-literature
Project description:PurposeTo examine whether perceptual learning can improve face discrimination and recognition in older adults with central vision loss.MethodsTen participants with age-related macular degeneration (ARMD) received 5 days of training on a face discrimination task (mean age, 78 ± 10 years). We measured the magnitude of improvements (i.e., a reduction in threshold size at which faces were able to be discriminated) and whether they generalized to an untrained face recognition task. Measurements of visual acuity, fixation stability, and preferred retinal locus were taken before and after training to contextualize learning-related effects. The performance of the ARMD training group was compared to nine untrained age-matched controls (8 = ARMD, 1 = juvenile macular degeneration; mean age, 77 ± 10 years).ResultsPerceptual learning on the face discrimination task reduced the threshold size for face discrimination performance in the trained group, with a mean change (SD) of -32.7% (+15.9%). The threshold for performance on the face recognition task was also reduced, with a mean change (SD) of -22.4% (+2.31%). These changes were independent of changes in visual acuity, fixation stability, or preferred retinal locus. Untrained participants showed no statistically significant reduction in threshold size for face discrimination, with a mean change (SD) of -8.3% (+10.1%), or face recognition, with a mean change (SD) of +2.36% (-5.12%).ConclusionsThis study shows that face discrimination and recognition can be reliably improved in ARMD using perceptual learning. The benefits point to considerable perceptual plasticity in higher-level cortical areas involved in face-processing. This novel finding highlights that a key visual difficulty in those suffering from ARMD is readily amenable to rehabilitation.
| S-EPMC7425703 | biostudies-literature
Project description:Regulatory science, a complex field which draws on science, law, and policy, is a growing discipline in medical-related applications. Competencies help define both a discipline and the criteria to measure high-quality learning experiences. This paper identifies competencies for regulatory science, how they were developed, and broader recommendations to enhance education and training in this burgeoning field, including a multifaceted training approach.
| S-EPMC5351091 | biostudies-literature
Project description:The central region of the human retina, the fovea, provides high-acuity vision. The oculomotor system continually brings targets of interest into the fovea via ballistic eye movements (saccades). Thus, the fovea serves both as the locus for fixations and as the oculomotor reference for saccades. This highly automated process of foveation is functionally critical to vision and is observed from infancy. How would the oculomotor system adjust to a loss of foveal vision (central scotoma)? Clinical observations of patients with central vision loss suggest a lengthy adjustment period, but the nature and dynamics of this adjustment remain unclear. Here, we demonstrate that the oculomotor system can spontaneously and rapidly adopt a peripheral locus for fixation and can rereference saccades to this locus in normally sighted individuals whose central vision is blocked by an artificial scotoma. Once developed, the fixation locus is retained over weeks in the absence of the simulated scotoma. Our data reveal a basic guiding principle of the oculomotor system that prefers control simplicity over optimality. We demonstrate the importance of a visible scotoma on the speed of the adjustment and suggest a possible rehabilitation regimen for patients with central vision loss.
| S-EPMC3773263 | biostudies-literature
Project description:PurposeChronic relapsing inflammatory optic neuropathy (CRION) is a type of idiopathic recurrent optic neuritis that responds to systemic corticosteroids and relapses on steroid withdrawal or dose reduction. Central serous chorioretinopathy (CSCR) is often associated with glucocorticoid therapy. This paper aims to highlight CSCR as a cause of visual loss in patients being treated with corticosteroids for optic neuritis.ObservationsWe describe the case of a 42-year-old woman with a history of CRION in her left eye who presented with painful vision loss in the right eye and diffuse right optic disc edema. Steroid therapy was initiated, leading to visual and perimetric improvement. Two months later however, the patient returned with painless visual loss, now related to CSCR. Despite oral steroids being continued, there was spontaneous tomographic and visual recovery after four months.Conclusions and importanceWe believe this is the first report of CSCR causing vision loss in a patient with CRION treated with oral corticosteroids. CSCR should be suspected in patients with optic neuritis of any cause who develop vision loss while on treatment with steroids.
| S-EPMC6031225 | biostudies-literature