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Contrast adaptation
Published in Pablo Artal, Handbook of Visual Optics, 2017
It is interesting that binocular summation can improve visual performance only when the highest spatial frequencies are not represented in the retinal image. If retinal images are defocused in both eyes, binocular visual acuity is superior to monocular visual acuity. However, under fully corrected conditions, binocular summation does not provide additional benefit, neither during visual acuity testing nor in VEP recordings (Plainis et al. 2011; Figure 21.28). Similarly, if the retinal image is corrected for chromatic aberration and higher-order aberrations with adaptive optics, no further benefit can be gained when the input from both eyes is combined (Schwarz and Artal 2013, Schwarz et al.2014; Figure 21.28).
ENTRIES A–Z
Published in Philip Winn, Dictionary of Biological Psychology, 2003
The process by which information from the two eyes is combined. Binocular summation is not necessarily limited to linear summation of local contrasts; various combination rules apply in different circumstances, ranging from summing the squares of local contrast to no difference between the binocular and monocular impression (FECHNER'S PARADOX). Recent evidence has revealed that binocular summation may occur between dissimilar images in the same location in the two eyes if they are brief, low contrast or high spatial frequency. Under other conditions, such dissimilar images engender BINOCULAR RIVALRY.
Normal and Abnormal Development of the Neuronal Response Properties in Primate Visual Cortex
Published in Jon H. Kaas, Christine E. Collins, The Primate Visual System, 2003
Yuzo M. Chino, Hua Bi, Bin Zhang
Anisometropia is a condition in which a significant difference in refractive error exists between the two eyes. In primates, which typically begin life with modest hyperopic refractive errors in both eyes, uncorrected anisometropia early in life leads to constant defocus in one eye. As a result, stereo-deficiencies, abnormal binocular summation, and/or amblyopia may develop.78103-105×100×84×
Emerging therapies for amblyopia
Published in Seminars in Ophthalmology, 2021
Michelle M. Falcone, David G. Hunter, Eric D. Gaier
Dichoptic amblyopia treatments employ use of both eyes together in order to target reduction of interocular suppression.19 There are three different techniques that utilize dichoptic presentation, where eye-selective modified visual stimuli are presented to achieve this goal.20 In anti-suppression therapy, the fellow, non-amblyopic eye is exposed to images with significantly reduced contrast compared to that of the amblyopic eye. Balanced binocular viewing employs blurring of images seen by the non-amblyopic eye. Interactive binocular treatment presents different parts of a visual scene to each eye as the patient watches a video or plays a game that requires binocular summation.20 Each of these techniques can be used alone or in combination. Binocular amblyopia therapy has been applied through different platforms which we will discuss here (Table 1).
Effect of Pupil Size and Binocular Viewing on Accommodative Gain in Emmetropia and Myopia
Published in Journal of Binocular Vision and Ocular Motility, 2020
Chun Tang Huang, Tsukasa Satou, Takahiro Niida
In this study, measurement of the refractive value and pupil size with various accommodative stimuli was performed under three conditions. Condition 1 (monocular): Monocular status with complete occlusion of the non-viewing eye. Participants were asked to cover the non-viewing eye (i.e., non-dominant eye) completely using a black occluder (cover-testing type). This condition induces pupil dilation and deactivates binocular viewing. Condition 2 (translucent): Monocular status with occlusion of the non-viewing eye by a translucent occluder (cover-testing type). Participants were asked to cover their non-dominant eye using a translucent occluder with which retinal illumination was kept constant in both eyes. The translucent occluder kept light illumination at 93% and visual acuity <0.01. This condition deactivates binocular viewing but keeps the pupil size constant, which was verified in a preliminary experiment. Condition 3 (binocular): Binocular status. This condition induces binocular viewing and binocular summation. Examination order among conditions was randomized.
The Role of Binocularity in Anisometropic Amblyopia
Published in Journal of Binocular Vision and Ocular Motility, 2019
Sarah J. Murray, Charlotte J. Codina
There are three distinct methods of binocular therapy being tested in amblyopia treatment:7Anti-suppression techniques reduce the image contrast in the fellow eye to equal the perceived contrast of the amblyopic eye when viewing an image at 100% contrast. Some elements of the visual scene are shown only to the amblyopic eye, requiring both eyes to contribute equally to achieve an accurate perception of the image.Balanced binocular viewing (BBV) blurs the image in the fellow eye to equal the acuity of the amblyopic eye.Interactive binocular treatment (I-Bit) presents different aspects of a visual scene rapidly between each eye requiring accurate and constant binocular summation to see the presented image.