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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 -
Perception 2015
Topics: Depth Perception; Humans; Optic Flow; Optical Illusions; Photic Stimulation; Vision Disparity
PubMed: 26422897
DOI: 10.1068/p4405ed -
Philosophical Transactions of the Royal... Jun 2016Depth constancy is the ability to perceive a fixed depth interval in the world as constant despite changes in viewing distance and the spatial scale of depth variation....
Depth constancy is the ability to perceive a fixed depth interval in the world as constant despite changes in viewing distance and the spatial scale of depth variation. It is well known that the spatial frequency of depth variation has a large effect on threshold. In the first experiment, we determined that the visual system compensates for this differential sensitivity when the change in disparity is suprathreshold, thereby attaining constancy similar to contrast constancy in the luminance domain. In a second experiment, we examined the ability to perceive constant depth when the spatial frequency and viewing distance both changed. To attain constancy in this situation, the visual system has to estimate distance. We investigated this ability when vergence, accommodation and vertical disparity are all presented accurately and therefore provided veridical information about viewing distance. We found that constancy is nearly complete across changes in viewing distance. Depth constancy is most complete when the scale of the depth relief is constant in the world rather than when it is constant in angular units at the retina. These results bear on the efficacy of algorithms for creating stereo content.This article is part of the themed issue 'Vision in our three-dimensional world'.
Topics: Adult; Distance Perception; Female; Humans; Male; Vision Disparity; Young Adult
PubMed: 27269596
DOI: 10.1098/rstb.2015.0253 -
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 -
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 -
Attention, Perception & Psychophysics Aug 2021The hypothesis that perspective foreshortening leads to errors in the visual perception of angles, was tested in four experiments. An oblique to a z-dimension line was...
The hypothesis that perspective foreshortening leads to errors in the visual perception of angles, was tested in four experiments. An oblique to a z-dimension line was presented (a) on the ground in Experiments 1 and 2, and (b) on a wall in Experiments 3 and 4. Observers judged the acute angle between the oblique and the z-line. Foreshortening increased with the oblique's distance along the z-line and, in Experiments 2 and 4, shorter distances from the eye to the ground or wall. As distance and eye-height vary, so does the target's slant to the line of sight. We argue the apparent angles between the lines increased with foreshortening because vision underestimates the fast rate of foreshortening with elevation compared with the slower rates in azimuth.
Topics: Depth Perception; Distance Perception; Humans; Visual Perception
PubMed: 33904152
DOI: 10.3758/s13414-021-02299-w -
Investigative Ophthalmology & Visual... Jan 2022We developed a stereo task that is based on a motion direction discrimination to examine the role that depth can play in disambiguating motion direction.
PURPOSE
We developed a stereo task that is based on a motion direction discrimination to examine the role that depth can play in disambiguating motion direction.
METHODS
In this study, we quantified normal adults' static and dynamic (i.e., laterally moving) stereoscopic performance using a psychophysical task, where we dichoptically presented randomly arranged, limited lifetime Gabor elements at two depth planes (one plane was at the fixation plane and the other at an uncrossed disparity relative to the fixation plane). Each plane contained half of the elements. For the dynamic condition, all elements were vertically oriented and moved to the left in one plane and to the right in another plane; for the static condition, the elements were horizontally oriented in one plane and vertically oriented in another plane.
RESULTS
For the range of motion speed that we measured (from 0.17°/s to 5.33°/s), we observed clear speed tuning of the stereo sensitivity (P = 3.0 × 10-5). The shape of this tuning did not significantly change with different spatial frequencies. We also found a significant difference in stereo sensitivity between stereopsis with static and laterally moving stimuli (speed = 0.67°/s; P = 0.004). Such difference was not evident when we matched the task between the static and moving stimuli.
CONCLUSIONS
We report that lateral motion modulates human global depth perception. This motion/stereo constraint is related to motion velocity not stimulus temporal frequency. We speculate that the processing of motion-based stereopsis of the kind reported here occurs in dorsal extrastriate cortex.
Topics: Adult; Depth Perception; Female; Humans; Male; Motion Perception; Psychophysics; Reference Values; Vision Disparity; Vision, Binocular; Visual Cortex; Young Adult
PubMed: 35077551
DOI: 10.1167/iovs.63.1.32 -
Vision Research Mar 2021We describe a new unified model to explain both binocular fusion and depth perception, over a broad range of depths. At each location, the model consists of an array of...
We describe a new unified model to explain both binocular fusion and depth perception, over a broad range of depths. At each location, the model consists of an array of paired spatial frequency filters, with different relative horizontal shifts (position disparity) and interocular phase disparities of 0, 90, ±180, or -90°. The paired filters with different spatial profiles (non-zero phase disparity) compute interocular misalignment and provide phase-disparity energy (binocular fusion energy) to drive selection of the appropriate filters along the position disparity space until the misalignment is eliminated and sensory fusion is achieved locally. The paired filters with identical spatial profiles (0 phase disparity) compute the position-disparity energy. After sensory fusion, the combination of position and possible residual phase disparity energies is calculated for binocular depth perception. Binocular fusion occurs at multiple scales following a coarse-to-fine process. At a given location, the apparent depth is the weighted sum of fusion shifts combined with residual phase disparity in all spatial-frequency channels, and the weights depend on stimulus spatial frequency and stimulus contrast. To test the theory, we measured disparity minimum and maximum thresholds (Dmin and Dmax) at three spatial frequencies and with different intraocular contrast levels. The stimuli were Random-Gabor-Patch (RGP) stereograms consisting of Gabor patches with random positions and phases, but with a fixed spatial frequency. The two eyes viewed identical arrays of patches except that one eye's array could be shifted horizontally and could differ in contrast. Our experiments and modeling reveal two contrast normalization mechanisms: (1) Energy Normalization (EN): Binocular energy is normalized with monocular energy after the site of binocular combination. This predicts constant Dmin thresholds when varying stimulus contrast in the two eyes; (2) DSKL model Interocular interactions: Monocular contrasts are normalized before the binocular combination site through interocular contrast gain-control and gain-enhancement mechanisms. This predicts contrast dependent Dmax thresholds. We tested a range of models and found that a model consisting of a second-order pathway with DSKL interocular interactions and a first-order pathway with EN at each spatial-frequency band can account for both the Dmin and Dmax data very well. Simulations show that the model makes reasonable predictions of suprathreshold depth perception.
Topics: Contrast Sensitivity; Depth Perception; Humans; Vision Disparity; Vision, Binocular
PubMed: 33359897
DOI: 10.1016/j.visres.2020.11.009