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Non-Organic Vision Loss
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Ashwini Kini, Mangayarkarasi Thandampallayam Ajjeya, Padmaja Sudhakar
Stereopsis tests are based on the principle of binocular fusion and require a particular minimum level of vision to correlate to the degree of stereopsis (Table 13.1) (11). These tests can be administered to the patients without raising suspicion, i.e., Titmus test, Randot test (Stereo Optical Co., Inc., Chicago, IL). These could be used in patients reporting monocular loss and also with binocular loss to some extent (8). Some studies, however, state that commonly used visual acuity estimates based on stereo acuity might overestimate visual acuity (12).
Principles of neuromotor development
Published in Mijna Hadders-Algra, Kirsten R. Heineman, The Infant Motor Profile, 2021
Mijna Hadders-Algra, Kirsten R. Heineman
Two other visual functions are not present at term age: colour vision and stereopsis. Colour vision emerges at around two months (Burr et al. 1996). At three months, yellow-blue targets are easily detected, but it takes between 17 and 23 months before all infants are able to detect red-green targets (Mercer et al. 2014). The precursor of stereopsis (binocular summation) also emerges at two months, while stereopsis itself starts at four to five months. However, it takes till early adolescence for stereo-acuity to obtain its adult capacity (Norcia and Gerhard 2015).
The Relationship Between Stereopsis and Visual Acuity After Occlusion Therapy for Amblyopia
Published in Jan-Tjeerd de Faber, 28th European Strabismological Association Meeting, 2020
Se Youp Lee, Sherwin J. Isenberg
Stereopsis was quantitatively assessed with the Titmus test (Stereo Optical Inc, Chicago) with fly and graded circles. During the examination, the patients wore their regular spectacles underneath the polaroid lenses and the examiner used his index finger to guide fixation. The subject was enthusiastically asked to grab the wings of the fly and point to the circle that seemed to “jump” out of the book. When a mistake was made, the immediately preceding target was repeated. If a correct response was made on the preceding target, that target’s disparity was used as the measurement. If that response was incorrect, further steps backward on the target series were made until the correct response was obtained. The last correct target identified was used as the child’s stereopsis measurement.
Visual function impairment in patients suffering from visually induced motion sickness. A preliminary observational longitudinal study
Published in Hearing, Balance and Communication, 2023
Leonardo Gabriele, Sara De Angelis, Vittorio Roncagli, Marco Tramontano, Leonardo Manzari, Domenico Gabriele
Two evaluation sessions were carried out immediately before (T0) and after 16 weeks of visual rehabilitation training (T1) (Figure 1). Each evaluation aimed to evaluate participants’ visual function and sickness-related symptoms. Visual function evaluation consisted of vergence and accommodative tests, binocular vision, stereopsis and phoria. The function of the vergence eye movement system is to track objects moving in depth, to attain cortical fusion and bifoveation. Visual accommodation is a reflexive physical process in which the lens of the eye adjusts allowing images to become focussed. The stereopsis is the perception of depth produced by the reception in the brain of visual stimuli from both eyes in binocular vision. The phoria is characterized by a latent horizontal and vertical deviation of the visual axes.
Technology enhanced neuroanatomy teaching techniques: A focused BEME systematic review of current evidence: BEME Guide No. 75
Published in Medical Teacher, 2022
Hamish J. Newman, Amanda J. Meyer, Tim J. Wilkinson, Nalini Pather, Sandra. E. Carr
Assessed in three studies (Kockro et al. 2015; Goodarzi et al. 2017; Bernard et al. 2020), stereoscopic 3D video tools made no difference to overall knowledge acquisition compared to 2D videos of the same content. Stereoscopic resources were popularised for their use in neuroanatomy teaching in 2011 by Dr Albert Rhoton Jr, who designed an entire collection of images of the brain for use by neurosurgeons (Sorenson et al. 2016). Stereoscopy is a technique used to give the illusion of depth, or 3-dimensions, by using stereopsis for binocular vision. Traditionally, this is done by presenting two offset images to the left and right eye independently (practically, students wear glasses that are often red- and blue-coloured, anaglyph glasses) which are then combined by our visual cortex to give the perception of 3D. In stereoscopic 3D video tools, students watch audiovisual material while wearing a stereoscopic device (glasses or otherwise) allowing them to appreciate the video in 3D.
Stereoacuity and Related Factors in Healthy Preschool Children: The Nanjing Eye Study
Published in Ophthalmic Epidemiology, 2019
Shu Han, Xiaohan Zhang, Xiaoyan Zhao, Yue Wang, Qingfeng Hao, Rui Li, Dan Huang, Hui Zhu, Qigang Sun, Ji Chen, Yan Gao, Meng Li, Xuejuan Chen, Hu Liu
Previous studies found that poor stereopsis is associated with amblyopia, strabismus and significant refractive errors.6–12 When evaluating binocular visual function of children for these vision disorders, stereoacuity test is often performed. Though age-specific normative values of stereoacuity in healthy preschool children were reported in several studies,13–16 there has been still much controversy because some healthy children without vision disorders had significant poor stereopsis, and these children should be distinguished from those with ocular disorders that may need interventions. Therefore, it is important to determine the factors that are associated with poor stereoacuity in healthy preschoolers. Previous studies that evaluated the factors associated with stereoacuity included children with other vision disorders,17–20 no studies have evaluated factors associated with stereoacuity among healthy preschoolers without vision disorders.