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Perception Feb 2019We investigated artificial scotomas created when a moving object instantaneously crossed a gap, jumping ahead and continuing its otherwise smooth motion. Gaps of up to...
We investigated artificial scotomas created when a moving object instantaneously crossed a gap, jumping ahead and continuing its otherwise smooth motion. Gaps of up to 5.1 degrees of visual angle, presented at 18° eccentricity, either closed completely or appeared much shorter than when the same gap was crossed by two-point apparent motion, or crossed more slowly, mimicking occlusion. Prolonged exposure to motion trajectories with a gap in most cases led to further shrinking of the gap. The same gap-shrinking effect has previously been observed in touch. In both sensory modalities, it implicates facilitation among codirectional local motion detectors and motion neurons with receptive fields larger than the gap. Unlike stimuli that simply deprive a receptor surface of input, suggesting it is insentient, our motion pattern skips a section in a manner that suggests a portion of the receptor surface has been excised, and the remaining portions stitched back together. This makes it a potentially useful tool in the experimental study of plasticity in sensory maps.
Topics: Adolescent; Adult; Female; Humans; Male; Motion Perception; Photic Stimulation; Scotoma; Young Adult
PubMed: 30799731
DOI: 10.1177/0301006619825769 -
Indian Journal of Ophthalmology Jul 2020
Topics: Eyeglasses; Humans; Lenses, Intraocular; Scotoma
PubMed: 32587191
DOI: 10.4103/ijo.IJO_26_20 -
Canadian Journal of Ophthalmology.... Aug 2021
Topics: Humans; Moyamoya Disease; Scotoma; Visual Field Tests; Visual Fields
PubMed: 33539822
DOI: 10.1016/j.jcjo.2021.01.011 -
Current Opinion in Ophthalmology Nov 2018Neuroretinitis is an inflammatory disorder of the eye presenting with optic disc edema and the delayed development of a macular star secondary to optic nerve swelling... (Review)
Review
PURPOSE OF REVIEW
Neuroretinitis is an inflammatory disorder of the eye presenting with optic disc edema and the delayed development of a macular star secondary to optic nerve swelling toward the macular structures. Neuroretinitis can be divided into idiopathic, infectious (including neuroretinitis associated with cat scratch disease) and recurrent.
RECENT FINDINGS
The clinical presentation of neuroretinitis includes impaired visual acuity, dyschromatopsia, relative afferent pupillary defects and visual field abnormalities - particularly cecocentral and central scotomas. Features suggesting recurrent neuroretinitis include poorer visual recovery and visual field abnormalities representing damage to greater parts of the optic nerve. Treatment of neuroretinitis is based upon the cause of the disease. Specifically, in patients with cat scratch neuroretinitis, visual recovery is often favorable regardless of treatment with medication. However, some authors favor treatment with antibiotics early in the course of disease to limit progression and ensure eradication of the organism.
SUMMARY
Neuroretinitis can result from a number of infectious and noninfectious causes and it is essential that clinicians recognize the disease and determine the underlying etiology to ensure the best possible treatment and visual prognosis for the patient.
Topics: Bartonella henselae; Cat-Scratch Disease; Humans; Papilledema; Retinitis; Scotoma
PubMed: 30148725
DOI: 10.1097/ICU.0000000000000527 -
Optometry and Vision Science : Official... Mar 2017In this experiment, we tested whether perceptually delineating the scotoma location and border with a gaze contingent polygon overlay improves reading speed and reading...
PURPOSE
In this experiment, we tested whether perceptually delineating the scotoma location and border with a gaze contingent polygon overlay improves reading speed and reading eye movements in patients with bilateral central scotomas.
METHODS
Eight patients with age-related macular degeneration and bilateral central scotomas read aloud MNRead style sentences with their preferred eye. Eye movement signals from an EyeLink II eyetracker were used to create a gaze contingent display in which a polygon overlay delineating the area of the patient's scotoma was superimposed on the text during 18 of the 42 trials. Blocks of six trials with the superimposed polygon were alternated with blocks of six trials without the polygon. Reading speed and reading eye movements were assessed before and after the subjects practiced reading with the polygon overlay.
RESULTS
All of the subjects but one showed an increase in reading speed. A paired-samples t-test for the group as a whole revealed a statistically significant increase in reading speed of 0.075 ± 0.060 (SD) log wpm after reading with the superimposed polygon. Individual subjects demonstrated significant changes in reading eye movements, with the greatest number of subjects demonstrating a shift in the average vertical fixation locus. Across subjects, there was no significant difference between the initial and final reading eye movements in terms of saccades per second, average fixation duration, average amplitude of saccades, or proportion of non-horizontal saccades.
CONCLUSIONS
The improvement in reading speed (0.075 log wpm or 19%) over the short experimental session for the majority of subjects indicates that making the scotoma location more visible is potentially beneficial for improving reading speed in patients with bilateral central scotomas. Additional research to examine the efficacy of more extended training with this paradigm is warranted.
Topics: Aged; Aged, 80 and over; Eye Movements; Female; Humans; Macular Degeneration; Male; Reading; Scotoma; Visual Field Tests; Visual Fields; Visual Perception
PubMed: 28030516
DOI: 10.1097/OPX.0000000000001042 -
Canadian Journal of Ophthalmology.... Jun 2005Many patients with macular scotomas due to age-related macular degeneration do not perceive black spots in the visual field where the scotomas are located. Rather, they... (Review)
Review
Many patients with macular scotomas due to age-related macular degeneration do not perceive black spots in the visual field where the scotomas are located. Rather, they describe objects as "vanishing," "jumping out of nowhere" or "having blurry parts," or a combination of features. In addition, when the macular scotoma affects the fovea, the visual system uses 1 or more preferred retinal loci (PRLs) as a "pseudofovea" to perform visual tasks. Visual function testing with the scanning laser ophthalmoscope has provided a wealth of information regarding how patients perceive the visual world and how the oculomotor system directs eye movements. This article describes 2 specific functions of the oculomotor system, fixation stability and refixation precision, with data collected from normally sighted people and patients with visual field loss. The implications of the characteristics of PRLs and macular scotomas for clinical testing are discussed.
Topics: Eye Movements; Fixation, Ocular; Fovea Centralis; Humans; Macular Degeneration; Scotoma; Severity of Illness Index; Visual Fields
PubMed: 15947800
DOI: 10.1016/S0008-4182(05)80073-0 -
Journal of Neuro-ophthalmology : the... Jun 2023Transient vision loss can be an alarming symptom owing to potentially serious etiologies such as thromboembolism or giant cell arteritis. Transient monocular vision loss... (Observational Study)
Observational Study
BACKGROUND
Transient vision loss can be an alarming symptom owing to potentially serious etiologies such as thromboembolism or giant cell arteritis. Transient monocular vision loss (TVML) on awakening has been recently described as a benign phenomenon (Bouffard et al, 2017). Our objective was to describe the unique phenomenon of transient binocular vision loss (TBVL) on awakening.
METHODS
Retrospective observational case series of 5 patients who experienced TBVL on awakening seen in the neuro-ophthalmology clinic at the Mayo Clinic between 2016 and 2020. Patients who described generalized blurred vision and those with monocular transient vision loss were excluded.
RESULTS
The median age was 81.4 years (range, 68-92 years), and all were male. Every patient described a stereotyped transient bilateral central scotoma on awakening with slightly irregular borders and mild asymmetry between the 2 eyes lasting between 15 and 90 minutes. Frequency ranged from 3 to 7 times per week, and there was a median of 319 episodes (range, 126-728 episodes) before evaluation in the neuro-ophthalmology clinic. All patients had normal optic nerves, and no plaques were noted in the retinal vessels. All 5 had macular drusen, which were predominantly extrafoveal and mild. Two patients underwent electrophysiology testing, which were both normal on full-field electroretinogram (ERG), but there was blunted central wave forms on multifocal ERG. Two patients underwent dark adaptation testing, which showed both prolong and diminished dark adaptation. Neuroimaging and thromboembolic workup were unrevealing.
CONCLUSIONS
TBVL is a distinct phenomenon from TMVL on awakening, which has a different demographic and symptomology. The etiology is unclear but seems to be a focal macular process in conjunction with an autoregulatory failure resulting in a supply-demand mismatch during low-light conditions.
Topics: Aged, 80 and over; Female; Humans; Male; Electroretinography; Retrospective Studies; Scotoma; Vision Disorders; Visual Acuity
PubMed: 36255080
DOI: 10.1097/WNO.0000000000001718 -
Digital Journal of Ophthalmology : DJO 2021
Topics: Humans; Male; Middle Aged; Retinal Diseases; Scotoma; Visual Fields
PubMed: 34924885
DOI: 10.5693/djo.03.2021.08.004 -
Ophthalmic & Physiological Optics : the... Jan 2018This study evaluated the feasibility of using soft contact lenses (CLs) with an opaque centre to induce absolute central scotomas that move with the eye. We examined the...
PURPOSE
This study evaluated the feasibility of using soft contact lenses (CLs) with an opaque centre to induce absolute central scotomas that move with the eye. We examined the geometrical optics prediction that scotoma size will vary with the size of the CL's opaque centre and with ocular pupil size. We also tested the hypothesis that high environmental light levels will ensure that the ocular pupil will remain small enough, even with opaque centre CLs, to generate absolute scotomas representative of those experienced by patients with age-related macular disease.
METHODS
Using an Octopus 900 Perimeter ( www.Haag-Streit.com), kinetic visual fields (VFs) were measured in five normally-sighted subjects using a V4e Goldmann target with CLs that had central opaque areas with diameters of 2.8, 3.0, and 3.2 mm. To control pupil size, VFs were measured with background perimeter bowl luminances of 10, 585, and 1155 cd m . Subjects attempted to (i) fixate the bowl centre; and (ii) place the scotoma edge at the bowl fixation target (eccentric viewing).
RESULTS
As predicted, there was a direct relationship between scotoma size and both luminance level and diameter of the opacity. Mean scotoma diameters were 0°, 17.6° and 22°, for the low, medium and high bowl luminances, respectively. Scotoma size was determined primarily by the difference between the diameters of CL opacity and the entrance pupil of the eye and the axial separation between them, and between-subject differences in pupil diameters contributed most to the between-subject variability in scotoma diameter at each light level (SD: 6.01°). Scotoma displacement during eccentric fixation confirmed the gaze-contingent characteristics of this experimental model.
CONCLUSION
It is possible to induce a gaze-contingent absolute scotoma and hence mimic central vision loss using centrally-opaque CLs provided that the CL opacity is larger than the entrance pupil of the eye. This simulation tool will, therefore, be ineffective at low environmental light levels (as shown previously) if the entrance pupil of the eye is larger than the CL opacity.
Topics: Computer Simulation; Contact Lenses, Hydrophilic; Humans; Scotoma; Visual Acuity; Visual Field Tests; Visual Fields
PubMed: 29265475
DOI: 10.1111/opo.12422 -
Der Ophthalmologe : Zeitschrift Der... Jun 2012Syphilis is a sexually transmitted, chronic, systemic infection caused by the spirochete Treponema pallidum. If left untreated the disease progresses through 3 stages....
Syphilis is a sexually transmitted, chronic, systemic infection caused by the spirochete Treponema pallidum. If left untreated the disease progresses through 3 stages. The ocular manifestations are highly variable, including interstitial keratitis, anterior, intermediate and posterior uveitis, chorioretinitis, retinitis, retinal vasculitis and optic neuropathy which can occur at all stages. In patients with a suspected diagnosis it is mandatory to carry out serological tests, because an early treatment is essential for preserving visual acuity and ocular function.
Topics: Diagnosis, Differential; Humans; Scotoma; Tuberculosis, Ocular
PubMed: 22699950
DOI: 10.1007/s00347-012-2552-9