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Investigative Ophthalmology & Visual... Apr 2021The role of accommodation in myopia development and progression has been debated for decades. More recently, the understanding of the mechanisms involved in... (Review)
Review
The role of accommodation in myopia development and progression has been debated for decades. More recently, the understanding of the mechanisms involved in accommodation and the consequent alterations in ocular parameters has expanded. This International Myopia Institute white paper reviews the variations in ocular parameters that occur with accommodation and the mechanisms involved in accommodation and myopia development and progression. Convergence is synergistically linked with accommodation and the impact of this on myopia has also been critiqued. Specific topics reviewed included accommodation and myopia, role of spatial frequency, and contrast of the task of objects in the near environment, color cues to accommodation, lag of accommodation, accommodative-convergence ratio, and near phoria status. Aspects of retinal blur from the lag of accommodation, the impact of spatial frequency at near and a short working distance may all be implicated in myopia development and progression. The response of the ciliary body and its links with changes in the choroid remain to be explored. Further research is critical to understanding the factors underlying accommodative and binocular mechanisms for myopia development and its progression and to guide recommendations for targeted interventions to slow myopia progression.
Topics: Accommodation, Ocular; Convergence, Ocular; Disease Progression; Humans; Myopia; Refraction, Ocular; Vision, Binocular
PubMed: 33909034
DOI: 10.1167/iovs.62.5.4 -
Clinical & Experimental Optometry Sep 2019Smartphone and tablet use in Australia and worldwide is reaching saturation levels and associated visual and ocular discomfort such as headaches, eyestrain, dry eyes and... (Review)
Review
Smartphone and tablet use in Australia and worldwide is reaching saturation levels and associated visual and ocular discomfort such as headaches, eyestrain, dry eyes and sore eyes are widespread. This review synthesises the available literature and considers these symptoms in the context of a binocular vision and/or ocular surface aetiology. Eye discomfort with smartphones and tablets is discussed alongside similar symptoms reported with desktop computer use. Handheld devices differ from computers in viewing position and distance, screen size and luminance, and patterns of use. Accommodation is altered with handheld device use, with increased lag and decreased amplitude. Smartphone and tablet use results in reduced fusional convergence and possibly a receded near point of convergence. This is similar to what happens with computer use. Findings related to blink rate with smartphone and tablet use are contradictory, perhaps due to the influence of task difficulty, and there is limited evidence related to blink amplitude. Reduced blink rate and amplitude are consistently reported with computer use. Use of handheld digital devices, like computers, may adversely impact tear stability. There is insufficient evidence to support the impact of handheld devices on tear volume, although this is reduced with computer use. The available literature does not conclusively link eye and visual discomfort symptoms reported with handheld digital devices, with changes in binocular vision, blinking or ocular surface. However, there is a gap in our understanding of symptoms which occur with smartphone and tablet use in the context of how these devices are used. In addition, studies are required in high users such as teenagers, and in patients with dry eye or accommodative/binocular vision anomalies, all of whom may have a higher risk of symptoms. A better understanding of symptom aetiology can guide clinical advice to minimise adverse impacts on visual and ocular surface health and discomfort.
Topics: Asthenopia; Computers; Computers, Handheld; Dry Eye Syndromes; Humans; Smartphone; Vision Disorders; Vision, Binocular
PubMed: 30663136
DOI: 10.1111/cxo.12851 -
Indian Journal of Ophthalmology May 2023Amblyopia is a monocular or binocular reduction in visual acuity that results from prolonged visual deprivation in the early years of life. It is second only to... (Review)
Review
Amblyopia is a monocular or binocular reduction in visual acuity that results from prolonged visual deprivation in the early years of life. It is second only to refractive error as a cause of poor vision in children. The gold standard treatment of amblyopia includes patching and, less commonly, atropine penalization and filters. These therapies are aimed at improvements in the visual acuity of the amblyopic eye alone. They have compliance and psychosocial issues and gains are accrued after prolonged periods. Experimental studies have demonstrated the presence of binocular cortical communication even in amblyopes and neural plasticity in late childhood as well as adulthood. On this basis, binocular vision therapy aimed at the stimulation of both eyes rather than forced use of the amblyopic eye was developed. Such therapies involve visual tasks designed in such a way that they can be completed only by binocular viewing. These tasks vary from simple game play using red-green glasses, to engaging 3D games and movie viewing. Preliminary data suggest that binocular vision therapy has led to lasting improvements in visual acuity and can be a useful adjunct, if not replacement, to the conventional treatment of amblyopia. In this article, we aim to describe the various binocular vision therapies and review the available literature on the same.
Topics: Child; Humans; Adult; Amblyopia; Vision, Binocular; Visual Acuity; Eye; Vision, Low
PubMed: 37203032
DOI: 10.4103/IJO.IJO_3098_22 -
Contact Lens & Anterior Eye : the... Apr 2023To evaluate the benefits on the eyes of taking breaks based on the 20-20-20 rule.
PURPOSE
To evaluate the benefits on the eyes of taking breaks based on the 20-20-20 rule.
METHODS
Bespoke computer software using the laptop webcam to assess user breaks, eye gaze and blinking, and emitting personalized reminders of breaks based on the 20-20-20 rule, was downloaded onto the laptops of 29 symptomatic computer users. Digital eye strain (DES), binocular vision and dry eye were assessed before and after two weeks of using the reminders and one week after the discontinuation of the strategy. Binocular measurements included visual acuity, accommodative posture, stereopsis, fixation disparity, ocular alignment, accommodative facility, positive/negative vergences and near point of convergence. Symptoms were evaluated using the computer vision syndrome questionnaire, ocular surface disease index (OSDI), and symptom assessment in dry eye questionnaire (SANDE) versions one and two. Dry eye signs were assessed by measuring tear meniscus height, conjunctival redness, blink rate and incomplete blinking, lipid layer thickness, non-invasive keratograph break-up time, corneal and conjunctival staining and lid wiper epitheliopathy.
RESULTS
A decrease in the duration of computer work and the duration of breaks, along with an increase in the number of breaks taken per day was observed as a result of the 20-20-20 rule reminders (p ≤ 0.015). No changes on any binocular parameter were observed after the management period (p ≥ 0.051), except for an increase in accommodative facility (p = 0.010). Dry eye symptoms and DES decreased with the rule reminders (p ≤ 0.045), although this improvement was not maintained one week after discontinuation (p > 0.05). No changes on any ocular surface and tear film parameter were observed with the rule reminders (p ≥ 0.089).
CONCLUSIONS
The 20-20-20 rule is an effective strategy for reducing DES and dry eye symptoms, although 2 weeks was not enough to considerably improve binocular vision or dry eye signs.
Topics: Humans; Vision, Binocular; Dry Eye Syndromes; Tears; Cornea; Conjunctiva
PubMed: 35963776
DOI: 10.1016/j.clae.2022.101744 -
Romanian Journal of Ophthalmology 2017Diplopia (seeing double) is an ophthalmologic complaint found mainly in elder patients. It can have both ocular and neurological causes. A careful history and clinical... (Review)
Review
Diplopia (seeing double) is an ophthalmologic complaint found mainly in elder patients. It can have both ocular and neurological causes. A careful history and clinical examination must detail the type of diplopia (monocular/ binocular), onset, and progression, associated and relieving factors. In case of monocular diplopia, refraction and biomicroscopic examination of the ocular media are mandatory. The cause of ocular misalignment for binocular diplopia must be determined and life-threatening conditions (such as posterior communicating artery aneurysm) must imply an immediate treatment. Management and treatment is always according to the specific cause of diplopia.
Topics: Diplopia; Humans; Ophthalmologic Surgical Procedures; Ophthalmology; Vision Tests; Vision, Binocular
PubMed: 29450393
DOI: 10.22336/rjo.2017.31 -
Visual Neuroscience Jan 2018There are many levels of disorder in amblyopic vision, from basic acuity and contrast sensitivity loss to abnormal binocular vision and global perception of motion and... (Review)
Review
There are many levels of disorder in amblyopic vision, from basic acuity and contrast sensitivity loss to abnormal binocular vision and global perception of motion and form. Amblyopia treatment via patching to restore acuity often leaves other aspects of vision deficient. The source for these additional deficits is unclear. Neural correlates of poor binocular function and acuity loss are found in V1 and V2. However, they are generally not sufficient to account for behaviorally measured vision loss. This review summarizes the known cortical correlates of visual deficits found in association with amblyopia, particularly those relevant to binocular vision and higher-order visual processing, in striate and extrastriate cortex. Recommendations for future research address open questions on the role of suppression and oculomotor abnormalities in amblyopic vision, and underexplored mechanisms such as top-down influences on information transmission in the amblyopic brain.
Topics: Amblyopia; Contrast Sensitivity; Humans; Vision, Binocular; Visual Acuity; Visual Cortex
PubMed: 29905122
DOI: 10.1017/S0952523817000232 -
Vision Research Apr 2022
Topics: Depth Perception; Humans; Vision Disparity; Vision, Binocular
PubMed: 34973631
DOI: 10.1016/j.visres.2021.107989 -
Vision Research Nov 2022Stereopsis provides us with a vivid impression of the depth and distance of objects in our 3- dimensional world. Stereopsis is important for a number of everyday visual... (Review)
Review
Stereopsis provides us with a vivid impression of the depth and distance of objects in our 3- dimensional world. Stereopsis is important for a number of everyday visual tasks, including (but not limited to) reaching and grasping, fine visuo-motor control, and navigating in our world. This review briefly discusses the neural substrate for normal binocular vision and stereopsis and its development in primates; outlines some of the issues and limitations of stereopsis tests and examines some of the factors that limit the typical development of stereopsis and the causes and consequences of stereo-deficiency and stereo-blindness. Finally, we review several approaches to improving or recovering stereopsis in both neurotypical individuals and those with stereo-deficiency and stereo-blindness and outline some emerging strategies for improving stereopsis.
Topics: Animals; Blindness; Depth Perception; Learning; Vision, Binocular
PubMed: 35841717
DOI: 10.1016/j.visres.2022.108082 -
Annual Review of Vision Science Sep 2021Most animals have at least some binocular overlap, i.e., a region of space that is viewed by both eyes. This reduces the overall visual field and raises the problem of... (Review)
Review
Most animals have at least some binocular overlap, i.e., a region of space that is viewed by both eyes. This reduces the overall visual field and raises the problem of combining two views of the world, seen from different vantage points, into a coherent whole. However, binocular vision also offers many potential advantages, including increased ability to see around obstacles and increased contrast sensitivity. One particularly interesting use for binocular vision is comparing information from both eyes to derive information about depth. There are many different ways in which this might be done, but in this review, I refer to them all under the general heading of stereopsis. This review examines the different possible uses of binocular vision and stereopsis and compares what is currently known about the neural basis of stereopsis in different taxa. Studying different animals helps us break free of preconceptions stemming from the way that stereopsis operates in human vision and provides new insights into the different possible forms of stereopsis.
Topics: Animals; Contrast Sensitivity; Depth Perception; Vision, Binocular; Vision, Ocular
PubMed: 34283925
DOI: 10.1146/annurev-vision-093019-113212 -
Journal of Optometry 2021
Topics: Depth Perception; Humans; Vision, Binocular
PubMed: 34176573
DOI: 10.1016/j.optom.2021.06.001