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Neuro-Ophthalmological Findings in Patients with Posterior Circulation Stroke
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Upper bank infarcts are much less common. The defects that result are in discerning the relationship of objects to each other and depth. Patients with bilateral inferior parietal lesions cannot revisualize where objects are located in space, for example, in picturing a map, or directions to a place. They reach for something they presume to be at a distance and hit into the object which is, in reality, very near. Stereoscopy, distance, and relationships can be tested by asking patients to look at a scene out of the window, or in the room, or even on a television screen. Three-dimensional pictures are especially useful to test for these abnormalities. The other common abnormalities are subserved under a condition termed Balint's syndrome (asimultagnosia, optic ataxia, and optic apraxia). These patients have difficulty seeing more than one object in a scene at the same time; they have difficulty coordinating hand and arm with eye movements.
Medical Linear Accelerators
Published in Eric Ford, Primer on Radiation Oncology Physics, 2020
The linac is coupled with an imaging system consisting of two kV X-ray tubes paired with two X-ray imaging panels in the floor (Figure 9.2.4). This system acquires two images simultaneously from two orthogonal directions which allows features like bony anatomy to be localized in 3D space. This is called stereoscopic imaging (see Chapter 21 for further details). This can also be used for respiratory tracking.
Three-dimensional ultrasound
Published in Peter R Hoskins, Kevin Martin, Abigail Thrush, Diagnostic Ultrasound, 2019
Peter R Hoskins, Tom MacGillivray
For stereoscopic viewing to work with ultrasound there must be sufficient contrast between the objects of interest and surrounding tissue. Some anatomical structures such as cysts, ventricles and abscesses as well as lesions surrounded by low echogenic tissue, i.e. some tumours and haematomas, provide good contrast in ultrasound images and are therefore well suited. Breast tumours and cardiac structures such as the mitral valve are also suitable for stereo display. In obstetrics stereoscopic viewing improves visibility of primary features such as fetal skull and spine (Nelson et al. 2008). Augmented stereoscopic vision has applications in surgery as it allows the combination of radiographic data from different sources (e.g. ultrasound, CT and MRI) with the surgeon's vision (Gronningsaeter et al. 2000).
The Effects of Binocular Visual Function Training after Concomitant Exotropia Surgery
Published in Current Eye Research, 2023
Jing Chen, Jin Xu, Huili Jia, Jing He, Zhengyang Tao, Ping Huang, Huahong Zhong, Hongwei Deng
The advanced 4D digital strabismus correction system that the authors employed for in-hospital training was developed according to high-tech three-dimensional (3D) multi-dimensional digital new media technology, based on the cognitive theory of visual attention in modern neuropsychology, and the principle of the synaptic plasticity-change mechanism in neurobiology. It is an approach that includes deinhibition training, abnormal retina-corresponding training, a fusion perceptual function training system, and a 3D spatial perceptual function training system, enabling it to provide targeted, individualized, and quantitative training to maximize visual stimulation according to individual patient visual function status. Moreover, it can also quantitatively provide simultaneous perceptual training for perception fusion, particularly fusion function training using random-dot stereograms. Because it can accurately capture the breakpoint of binocular single vision, it has better operability and practicality for detecting and training the fusion function using random-dot stereograms. Finally, the use of polarized light and liquid-crystal switching stereo imaging technology can be maximized for the inspection and training of stereoscopic vision. Patients were trained according to the film content and the range of the Arcsecond. Interesting training games can be developed according to different levels of stereoscopic acuity, thereby providing a diversified range of training modes and short treatment times, which can greatly improve the treatment compliance of children.
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.
Thoughts on digital microscopes
Published in British Journal of Neurosurgery, 2021
Depth perception is a big potential advantage of digital microscopy, but not one that has yet been exploited. This area is problematic because schemes to allow stereoscopic visualization involve projecting both images onto the same screen and using polarized glasses to present the left and right images to the correct eye. That is something that does not work equally well with all surgeons and it depends on having your head at the right orientation to the screen. Variations of this 3D system have been tried in cinema and television, but have repeatedly failed to catch on. And 3D viewing has been found to be associated with 21% of viewers reporting symptoms such as visual blurring, disorientation, headache, or motion sickness in that context.1 Current microscope systems use passive polarized glasses for 3D viewing. This works by presenting alternate lines of the image into either eye, which in turn reduces the resolution available to each eye. This is not as bad as it sounds as the brain interpolates between the images of each eye but that is variable between observers and result is some compromise to the already marginal resolution available on 4k screens. The glasses also impede vision for things outside of the microscope field and we have noted that non-scrubbed members of the team choose to repeatedly don and doff them, an option that is not convenient for the scrub team.