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Ophthalmic Injuries
Published in Ian Greaves, Keith Porter, Jeff Garner, Trauma Care Manual, 2021
Ian Greaves, Keith Porter, Jeff Garner
Ocular motility should be examined, looking especially for restriction of eye movement in any direction. The presence of diplopia (double vision), either in the primary position or gaze evoked, is a useful symptom, but it should be remembered that not all people have binocular vision (for example, those with a history of squint or a lazy eye) and eye injury causing loss of vision may prevent binocular diplopia. The presence of double vision on upward gaze or downward gaze and loss of sensation in the area of the infraorbital nerve point to an orbital floor fracture with involvement of the inferior rectus muscle and infraorbital nerve. In some cases, a degree of neurological trauma may also accompany orbital injuries, and the possibility of higher-level disruption of ocular motility, for example, from cranial neuropathies or brain stem damage, should also be considered. Any ocular motility findings should be taken in the context of the broader picture and correlated with other clinical findings.
Binocular vision problems after refractive surgery
Published in Jan-Tjeerd de Faber, 28th European Strabismological Association Meeting, 2020
D.J.M. Godts, M.J. Tassignon, L. Gobin
Binocular vision problems and also reading problems occur when accommodation is reduced what happened in one eye in patient I and in both eyes in patient II. Reduced stereopsis was seen in patient V due to the postoperative anisometropia. Decreased stereopsis after monovision and anisometropia has been described before (Bagolini et al. 1991; Brooks et al. 1996; Wright et al. 1999).
Monocular and Binocular Constraints on Eye Orientation
Published in Michael Fetter, Thomas Haslwanter, Hubert Misslisch, Douglas Tweed, Three-Dimensional Kinematics of Eye, Head and Limb Movements, 2020
A.V. van den Berg, P. Bruno, J.Tj.H.N. de Faber
Cyclovergence, or the difference between the torsional orientations of the eyes, depends on the head-centric distance and the elevation of the binocularly viewed target. This constraint on cyclovergence resembles the restriction that holds for the torsional position of a single eye which, according to Listing’s law, depends on the head-centric direction of the target. How do these constraints depend on binocular vision? We investigated this question by comparing cyclovergence for monocular and binocular viewing of nearby targets by normal subjects,by comparing the orientation of the eye of a monocular subject for fixation of distant and nearby targets andby an analysis of the eye orientation in subjects with intermittent exotropia.
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.
Binocular vision disorders in a geriatric population
Published in Clinical and Experimental Optometry, 2022
Hassan Hashemi, Payam Nabovati, Abbas Ali Yekta, Mohammadreza Agha Mirsalim, Shokoofeh Rafati, Hadi Ostadimoghaddam, Mehdi Khabazkhoob
Binocular vision disorders are a group of visual system abnormalities that impair visual performance by affecting clear single binocular vision.1 Various studies have reported a considerable prevalence of heterophoria in children and pre-presbyopic young adults. Accordingly, the prevalence of heterophoria has been reported in a wide range from 9.9 to 61.4% (median prevalence: 22.6%)2–15 this variability is mainly due to differences in diagnostic criteria and testing methods.1 According to a recent review in which the studies were also mostly related to children and young adults, the estimated global pooled prevalence of strabismus was 1.9%; 1.8% in subjects below 20 years and 3.3% in subjects above 20 years.16 Age-related changes in binocular vision status and the prevalence of binocular vision disorders in the elderly have received less attention.17
A 2020 Update on 20/20 X 2: Diplopia after Ocular Surgery Diplopia after Iatrogenic Monovision
Published in Journal of Binocular Vision and Ocular Motility, 2021
Binocular vision is the ability to incorporate images from the two eyes simultaneously, creating a single visual image in depth. The slight differences between the two images, seen from slightly different positions, make it possible to perceive stereopsis, a precise form of depth perception. Monovision correction, by virtue of optically or surgically produced anisometropia, results in dissimilar images projecting onto the two foveas. Iatrogenic monovision artificially induces a situation where the slight difference between the two images could become too much for the visual cortex to resolve. The two images can be so dissimilar in clarity, contrast, and size as to be un-fusible, resulting in loss of depth perception, double vision, severe asthenopia, and decompensation of strabismus.