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Vision Research Nov 2020Recent work has transformed our ideas about the neural mechanisms, behavioral consequences and effective therapies for amblyopia. Since the 1700's, the clinical... (Review)
Review
Recent work has transformed our ideas about the neural mechanisms, behavioral consequences and effective therapies for amblyopia. Since the 1700's, the clinical treatment for amblyopia has consisted of patching or penalizing the strong eye, to force the "lazy" amblyopic eye, to work. This treatment has generally been limited to infants and young children during a sensitive period of development. Over the last 20 years we have learned much about the nature and neural mechanisms underlying the loss of spatial and binocular vision in amblyopia, and that a degree of neural plasticity persists well beyond the sensitive period. Importantly, the last decade has seen a resurgence of research into new approaches to the treatment of amblyopia both in children and adults, which emphasize that monocular therapies may not be the most effective for the fundamentally binocular disorder that is amblyopia. These approaches include perceptual learning, video game play and binocular methods aimed at reducing inhibition of the amblyopic eye by the strong fellow eye, and enhancing binocular fusion and stereopsis. This review focuses on the what we've learned over the past 20 years or so, and will highlight both the successes of these new treatment approaches in labs around the world, and their failures in clinical trials. Reconciling these results raises important new questions that may help to focus future directions.
Topics: Adult; Amblyopia; Child; Child, Preschool; Depth Perception; Humans; Infant; Video Games; Vision, Binocular; Visual Acuity
PubMed: 32866759
DOI: 10.1016/j.visres.2020.07.014 -
Asia-Pacific Journal of Ophthalmology... 2020Extended depth-of-focus (EDOF) is a new intraocular lens (IOL) technology in the treatment of presbyopia. In contrast to multifocal (MF) IOLs, EDOF lenses create a... (Review)
Review
Extended depth-of-focus (EDOF) is a new intraocular lens (IOL) technology in the treatment of presbyopia. In contrast to multifocal (MF) IOLs, EDOF lenses create a single elongated focal point, rather than several foci, to enhance depth of focus. In this way, EDOF IOLs aim to reduce photic phenomena, glare, and halos, which have been reported in MF IOLs. A potential disadvantage is a decrease of retinal image quality if the amount of the aberrations is excessively increased. Frequently, EDOF IOLs are combined with MF optical designs; for this reason, EDOF IOLs are commonly a subject of confusion with optical multifocality concepts. The aim of this article is to clarify what an EDOF IOL is and to discuss the recently reported outcomes with these IOLs. We propose naming lenses that have combined optical designs as "hybrid IOLs."
Topics: Aphakia, Postcataract; Depth Perception; Humans; Lenses, Intraocular; Prosthesis Design; Refraction, Ocular; Visual Acuity
PubMed: 32511121
DOI: 10.1097/APO.0000000000000296 -
Ophthalmology Nov 2021The intraocular lens (IOL) selection process for patients requires a complex and objective assessment of patient-specific ocular characteristics, including the quality... (Review)
Review
The intraocular lens (IOL) selection process for patients requires a complex and objective assessment of patient-specific ocular characteristics, including the quality and quantity of corneal astigmatism, health of the ocular surface, and other ocular comorbidities. Potential issues that could be considered complications after surgery, including dry eye disease, anterior or epithelial basement membrane dystrophy, Salzmann nodular degeneration, and pterygium, should be addressed proactively. Aspheric IOLs are designed to eliminate the positive spherical aberration added by traditional IOLs to the pseudophakic visual axis. Spherical aberration may be a consideration with patient selection. Patient desire for increased spectacle independence after surgery is one of the main drivers for the development of multifocal IOLs and extended depth-of-focus (EDOF) IOLs. However, no one single multifocal or EDOF IOL suits all patients' needs. The wide variety of multifocal and EDOF IOLs, their optics, and their respective impact on patient quality of vision have to be understood fully to choose the appropriate IOL for each individual, and surgery has to be customized. Patients who have undergone previous LASIK or who have radial keratotomy and ocular pathologic features, including glaucoma, age-related macular degeneration, and epiretinal membrane, require specific considerations for IOL selection. Subjectively, patient-centered considerations, including visual goals, lifestyle, personality, profession, and hobbies, are key elements for the surgeon to assess and factor into an IOL recommendation. This holistic approach will help surgeons to achieve optimal surgical outcomes and to meet (and exceed) the high expectations of patients.
Topics: Depth Perception; Humans; Lenses, Intraocular; Preoperative Period; Pseudophakia; Refraction, Ocular; Visual Acuity
PubMed: 32882308
DOI: 10.1016/j.ophtha.2020.08.025 -
Asia-Pacific Journal of Ophthalmology...In recent years, there has been an overwhelming influx of different types of intraocular lenses (IOLs) as treatment for presbyopia. The extended depth-of-focus (EDOF)...
In recent years, there has been an overwhelming influx of different types of intraocular lenses (IOLs) as treatment for presbyopia. The extended depth-of-focus (EDOF) technology creates a single elongated focal point to enhance depth of focus, in contrast to the multiple foci of multifocal (MF) lenses. In this way, the EDOF lenses aim to reduce photic phenomena, glare, and halos, which have been reported in MF IOLs. A potential disadvantage of this is a blur due to decreased retinal image quality when the amount of the aberrations is increased excessively. Multifocality and EDOF characteristics are not exclusive of each other. Frequently, EDOF IOLs are combined with MF optical designs, a bifocal IOL may exhibit EDOF characteristics, likewise an aspheric monofocal IOL or a diffractive or refractive trifocal IOL. Thus, EDOF lenses are commonly subjected to confusion. A wide range of different types of EDOF lenses are available on the market to surgeons. In this practical update, we aim to clarify what is a true EDOF lens, classify the different types of the EDOF lenses based on their optical principle and review their recently reported outcomes. Comprehensive patient examination and selection, combined with knowledge of the most updated options and adequate patient counseling, can avoid dissatisfaction and yield the desired outcomes.
Topics: Humans; Visual Acuity; Depth Perception; Prosthesis Design; Lenses, Intraocular; Refraction, Ocular
PubMed: 36706334
DOI: 10.1097/APO.0000000000000590 -
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 -
Philosophical Transactions of the Royal... Jan 2023Stereoscopic depth perception is possible with luminance-defined target velocities at least as high as 600° s, up to the limit of 30 Hz imposed by the high-temporal... (Review)
Review
Stereoscopic depth perception is possible with luminance-defined target velocities at least as high as 600° s, up to the limit of 30 Hz imposed by the high-temporal frequency cut-off of the eye. The limitation for perceiving depth from stereo disparity of moving targets is not their velocity but the temporal frequency bandwidth of the eye, which is affected by adaption state. Stereoacuity for a depth shift in a horizontally moving grating depends not on spatial disparity between corresponding luminance points in spatial units of arc min, but on the spatial shift as a fixed proportion of the period of the grating, in other words, on the phase angle difference between the two eyes, as is also the case for obliquely orientated, stationary gratings. Phase differences explain not only the classic Pulfrich stereophenomenon but its equivalent with dynamic visual noise, and a new effect in which depth results from interocular phase differences in luminance modulation. This article is part of a discussion meeting issue 'New approaches to 3D vision'.
Topics: Vision Disparity; Depth Perception; Visual Acuity; Vision, Ocular; Vision, Binocular; Motion Perception
PubMed: 36511411
DOI: 10.1098/rstb.2021.0462 -
Attention, Perception & Psychophysics Jan 2020Anne Treisman investigated many aspects of perception, and in particular the roles of different forms of attention. Four aspects of her work are reviewed here, including... (Review)
Review
Anne Treisman investigated many aspects of perception, and in particular the roles of different forms of attention. Four aspects of her work are reviewed here, including visual search, set mean perception, perception in special populations, and binocular rivalry. The importance of the breakthrough in each case is demonstrated. Search is easy or slow depending on whether it depends on the application of global or focused attention. Mean perception depends on global attention and affords simultaneous representation of the means of at least two sets of elements, and then of comparing them. Deficits exhibited in Balint's or unilateral neglect patients identify basic sensory system mechanisms. And, the ability to integrate binocular information for stereopsis despite simultaneous binocular rivalry for color, demonstrates the division of labor underlying visual system computations. All these studies are related to an appreciation of the difference between perceiving the gist of a scene, its elements or objects, versus perceiving the details of the scene and its components. This relationship between Anne Treisman's revolutionary discoveries and the concept of gist perception is the core of the current review.
Topics: Attention; Depth Perception; Female; History, 20th Century; Humans; Male; Psychophysiology; Vision Disparity; Vision, Binocular; Visual Perception
PubMed: 31529208
DOI: 10.3758/s13414-019-01797-2 -
Journal of Robotic Surgery Oct 2023Stereopsis may be an advantage of robotic surgery. Perceived robotic ergonomic advantages in visualisation include better exposure, three-dimensional vision, surgeon... (Review)
Review
Stereopsis may be an advantage of robotic surgery. Perceived robotic ergonomic advantages in visualisation include better exposure, three-dimensional vision, surgeon camera control, and line of sight screen location. Other ergonomic factors relating to visualisation include stereo-acuity, vergence-accommodation mismatch, visual-perception mismatch, visual-vestibular mismatch, visuospatial ability, visual fatigue, and visual feedback to compensate for lack of haptic feedback. Visual fatigue symptoms may be related to dry eye or accommodative/binocular vision stress. Digital eye strain can be measured by questionnaires and objective tests. Management options include treatment of dry eye, correction of refractive error, and management of accommodation and vergence anomalies. Experienced robotic surgeons can use visual cues like tissue deformation and surgical tool information as surrogates for haptic feedback.
Topics: Humans; Robotic Surgical Procedures; Asthenopia; Depth Perception; Accommodation, Ocular; Ergonomics
PubMed: 37204648
DOI: 10.1007/s11701-023-01618-7 -
Journal of Refractive Surgery... Dec 2019To summarize the pharmacological strategies that are being explored for presbyopia correction. (Review)
Review
PURPOSE
To summarize the pharmacological strategies that are being explored for presbyopia correction.
METHODS
The review concentrates on pharmacologically induced pupillary miosis to increase depth-of-focus and lens softening or other measures to restore active accommodation.
RESULTS
Several studies suggest that near vision improves and distance vision is unaffected for many hours after either monocular or binocular instillation of any one of several drug combinations that cause miosis. Unfortunately, in most studies, measurements were limited to photopic visual acuity for near and distance vision, whereas it is anticipated that pupil constriction may have adverse effects on mesopic and scotopic vision. It is not clear whether improved near vision was due entirely to increased depth-of-focus, or whether, for example, a drug-induced myopic shift in refraction was also involved. Currently, no study has provided direct evidence for drug-induced restoration/enhancement of true accommodation involving an ocular power change.
CONCLUSIONS
Although it is possible that, in the future, pharmacological drops may offer a safe and reliable solution for presbyopia correction, more evidence of their effectiveness and limitations is required. [J Refract Surg. 2019;35(12):803-814.].
Topics: Accommodation, Ocular; Adrenergic alpha-Agonists; Anti-Inflammatory Agents, Non-Steroidal; Depth Perception; Histamine Antagonists; Humans; Miosis; Muscarinic Agonists; Parasympatholytics; Pharmaceutical Preparations; Presbyopia; Sympathomimetics
PubMed: 31830297
DOI: 10.3928/1081597X-20191010-04 -
BMC Psychology Dec 2022Studies have shown that viewing a cluster of dots evokes feelings of discomfort in viewers and that the discomfort becomes especially strong when the dots are placed on...
BACKGROUND
Studies have shown that viewing a cluster of dots evokes feelings of discomfort in viewers and that the discomfort becomes especially strong when the dots are placed on background images of human skin. This phenomenon has been explained by the physical properties and spatial and semantic relationships between the dots and the background. However, it was not known whether the perceived, as well as the physical, spatial relationships contributes to the generation of discomfort.
METHODS
We evoked illusory depth perception between black dots and the background face by drawing shadow-like gray dots around the black dots, while keeping the same black dots at the same positions, and examined whether illusory depth perception could increase or decrease discomfort. In each trial, participants viewed one of the following types of facial images: (a) face-only (face without dots), (b) a cluster of black dots on the face, (c) a cluster of gray dots on the face, and (d) a cluster of black dots and shadow-like gray dots on the face. After seeing each picture, they evaluated how much discomfort they felt from viewing the picture using a Likert scale and reported whether they perceived depth between the dots and the face.
RESULTS
Participants felt discomfort toward all three types of faces with dots, that is, faces with black dots, gray dots, and both. However, interestingly, participants felt less discomfort when both black and gray dots were presented on the face than when only black dots were presented. The participants perceived depth between the black dots and the face in 85% of the trials with black dots and shadow-like gray dots, and there was a significant correlation between discomfort and frequency of depth perception. However, in the trials with black dots only and gray dots only, they perceived depth in only 18% and 27% of the trials, respectively, and the correlations between the frequencies of depth perception and discomfort were not significant.
CONCLUSIONS
Our results suggest that the perceived spatial relationship, such as attached vs. separate, as well as the physical spatial relationship, contribute to the generation of discomfort.
Topics: Humans; Depth Perception
PubMed: 36474271
DOI: 10.1186/s40359-022-01006-0