The Relationship Between Stereopsis and Visual Acuity After Occlusion Therapy for Amblyopia
Jan-Tjeerd de Faber in 28th European Strabismological Association Meeting, 2020
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.
Strabismus
Mostafa Khalil, Omar Kouli in The Duke Elder Exam of Ophthalmology, 2019
Ability to fuse images from both eyes to produce a single image. Characteristics of binocular vision are as follows. Simultaneous perception: An image formed simultaneously on each retina.Fusion Sensory fusion: The ability to unite the two images from each retina to form a single image.Motor fusion: The ability to align the eyes to maintain sensory fusion. Motor fusion occurs via version (conjugate movements) and vergence (disconjugate movements) in order to achieve binocular vision.Stereopsis: Perception of depth.
Overview of Mixed and Augmented Reality in Medicine
Terry M. Peters, Cristian A. Linte, Ziv Yaniv, Jacqueline Williams in Mixed and Augmented Reality in Medicine, 2018
The difficulties experienced when visualizing 3D scenes beneath a solid surface, as highlighted by Edwards et al., were further investigated by Johnson et al. (2003), who critically examined the use of stereoscopic displays to present surgeons with an accurate perception of surgical targets in 3D space. While the researchers noted that stereopsis is a powerful binocular cue that can supplement any monocular information in the scene, they also highlighted several difficulties. They showed that when employing a simple optical AR system that superimposes stereoscopic images onto a physical scene, an accurate sense of depth cannot be easily achieved from the stereoscopic images when the visualized target lies beneath a physical surface. In their AR system, they used stereo images of anatomical structures overlaid on the patient in a simulated surgical guidance scenario. The objective was to position the target stereoscopic image at a location beneath the patient surface to enable accurate localization in 3D space. However, when the stereo images were presented behind the transparent physical surface, they demonstrated that the perception of the depth of the images can become unstable and ambiguous despite appropriate system calibration, registration, and tracking.
Early post-operative angle as a predictor of surgical success in adult patients with intermittent exotropia
Published in Strabismus, 2023
Akshay Narayan, Surinder Dosanjh, Jonathan Dominic, Saurabh Jain
All patients underwent complete ophthalmological examination prior to surgery. The following preoperative characteristics were recorded for each patient: age at surgery, sex, visual acuity, spherical equivalent of current refractive prescription, type of exotropia, angle of deviation at near and distance, prism fusion range and stereopsis. The angle of deviation at near and distance was measured by using an alternate prism cover test at 1/3 m and 6 m respectively using spectacles or lenses that corrected for their refractive error. Near prism fusion range was measured using prism bars at 1/3 m. More specifically we looked at the convergence reserve by looking at the base out component of the range. We looked at the base out value after the exclusion of fused exotropia. We also measured stereopsis by predominately using the Frisby test for near with occasional use of the TNO test. Tests were performed at 1/3 m. We did not routinely carry out distance stereopsis testing due to variability in response. Refractive errors were measured either by conducting focimetry of their glasses or by using subjective or cycloplegic refraction when possible.
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.
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
Stereoacuity, representing one of the depth perceptions, is the highest form of binocular vision and has impacts on the performance of fine visuomotor actions and spatial representation. Poor stereopsis has negative impact on the neurodevelopmental performance, leading to reading difficulty in the kindergarten and poor intelligence in first grade children.1,2 As the development of stereopsis has a critical period,3,4 timely detection and treatment of stereoacuity disorder is important. If intervention for stereoacuity disorder is not provided in the critical period, the loss of stereopsis may become permanent.5 Therefore, it is of great importance to screen the stereoacuity disorder and provide timely interventions for preschoolers with poor stereoacuity.
Related Knowledge Centers
- Binocular Disparity
- Visual Cortex
- Binocular Vision
- Depth Perception
- Stereoscopy
- Parallax
- Stereoscopic Motion
- Horopter
- Crowding
- Infant Visual Development