scholarly journals Linking Multi-Modal MRI to Clinical Measures of Visual Field Loss After Stroke

2022 ◽  
Vol 15 ◽  
Author(s):  
Anthony Beh ◽  
Paul V. McGraw ◽  
Ben S. Webb ◽  
Denis Schluppeck
Keyword(s):  
White Matter ◽  
Visual Field ◽  
Brain Imaging ◽  
Vision Loss ◽  
Receptive Fields ◽  
Visual Field Loss ◽  
Visual Pathway ◽  
Sensitivity Threshold ◽  
Treatment Pathways ◽  
Cortical Areas

Loss of vision across large parts of the visual field is a common and devastating complication of cerebral strokes. In the clinic, this loss is quantified by measuring the sensitivity threshold across the field of vision using static perimetry. These methods rely on the ability of the patient to report the presence of lights in particular locations. While perimetry provides important information about the intactness of the visual field, the approach has some shortcomings. For example, it cannot distinguish where in the visual pathway the key processing deficit is located. In contrast, brain imaging can provide important information about anatomy, connectivity, and function of the visual pathway following stroke. In particular, functional magnetic resonance imaging (fMRI) and analysis of population receptive fields (pRF) can reveal mismatches between clinical perimetry and maps of cortical areas that still respond to visual stimuli after stroke. Here, we demonstrate how information from different brain imaging modalities—visual field maps derived from fMRI, lesion definitions from anatomical scans, and white matter tracts from diffusion weighted MRI data—provides a more complete picture of vision loss. For any given location in the visual field, the combination of anatomical and functional information can help identify whether vision loss is due to absence of gray matter tissue or likely due to white matter disconnection from other cortical areas. We present a combined imaging acquisition and visual stimulus protocol, together with a description of the analysis methodology, and apply it to datasets from four stroke survivors with homonymous field loss (two with hemianopia, two with quadrantanopia). For researchers trying to understand recovery of vision after stroke and clinicians seeking to stratify patients into different treatment pathways, this approach combines multiple, convergent sources of data to characterize the extent of the stroke damage. We show that such an approach gives a more comprehensive measure of residual visual capacity—in two particular respects: which locations in the visual field should be targeted and what kind of visual attributes are most suited for rehabilitation.

scholarly journals What do patients with glaucoma see: a novel iPad app to improve glaucoma patient awareness of visual field loss

2020 ◽  
pp. bjophthalmol-2020-317034
Author(s):  
Meghal Gagrani ◽  
Jideofor Ndulue ◽  
David Anderson ◽  
Sachin Kedar ◽  
Vikas Gulati ◽  
...  
Keyword(s):  
Visual Field ◽  
Vision Loss ◽  
Peripheral Vision ◽  
Glaucoma Patient ◽  
Visual Field Loss ◽  
Sensitivity Threshold ◽  
Roc Curve Analysis ◽  
The Mean ◽  
Ipad App ◽  
Field Defects

PurposeGlaucoma patients with peripheral vision loss have in the past subjectively described their field loss as ‘blurred’ or ‘no vision compromise’. We developed an iPad app for patients to self-characterise perception within areas of glaucomatous visual field loss.MethodsTwelve glaucoma patients with visual acuity ≥20/40 in each eye, stable and reliable Humphrey Visual Field (HVF) over 2 years were enrolled. An iPad app (held at 33 cm) allowed subjects to modify ‘blur’ or ‘dimness’ to match their perception of a 2×2 m wall-mounted poster at 1 m distance. Subjects fixated at the centre of the poster (spanning 45° of field from centre). The output was degree of blur/dim: normal, mild and severe noted on the iPad image at the 54 retinal loci tested by the HVF 24-2 and was compared to threshold sensitivity values at these loci. Monocular (Right eye (OD), left eye (OS)) HVF responses were used to calculate an integrated binocular (OU) visual field index (VFI). All three data sets were analysed separately.Results36 HVF and iPad responses from 12 subjects (mean age 71±8.2y) were analysed. The mean VFI was 77% OD, 76% OS, 83% OU. The most common iPad response reported was normal followed by blur. No subject reported dim response. The mean HVF sensitivity threshold was significantly associated with the iPad response at the corresponding retinal loci (For OD, OS and OU, respectively (dB): normal: 23, 25, 27; mild blur: 18, 16, 22; severe blur: 9, 9, 11). On receiver operative characteristic (ROC) curve analysis, the HVF retinal sensitivity cut-off at which subjects reported blur was 23.4 OD, 23 OS and 23.3 OU (dB).ConclusionsGlaucoma subjects self-pictorialised their field defects as blur; never dim or black. Our innovation allows translation of HVF data to quantitatively characterise visual perception in patients with glaucomatous field defects.

scholarly journals Minocycline-Associated Pseudotumor Cerebri with Severe Papilledema

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Simon R. Bababeygy ◽  
Michael X. Repka ◽  
Prem S. Subramanian
Keyword(s):  
Visual Field ◽  
Surgical Management ◽  
Vision Loss ◽  
Case Series ◽  
Visual Field Loss ◽  
Pseudotumor Cerebri ◽  
Drug Discontinuation ◽  
Unusual Complication ◽  
Limited Condition ◽  
Nonobese Patients

Background. Pseudotumor cerebri is an acknowledged but unusual complication of oral minocycline use. Vision loss and papilledema have been described as mild and transient, and some authors suggest that treatment is not needed.Methods. Case series of 2 patients with severe papilledema and visual field loss.Results. Severe pseudotumor cerebri developed in 2 nonobese patients taking minocycline. Their disease required further treatment even upon drug discontinuation because of visual field loss and papilledema.Conclusions. Minocycline-associated pseudotumor cerebri is not always a self-limited condition and may require aggressive medical or surgical management.

Design of Experiments for Exposure of Astrocytes to Elevated Hydrostatic Pressure and Hypoxia

2008 ◽  
Author(s):  
Shadi Rajabi ◽  
Craig A. Simmons ◽  
C. Ross Ethier
Keyword(s):  
Intraocular Pressure ◽  
Visual Field ◽  
Retinal Ganglion Cells ◽  
Vision Loss ◽  
Ganglion Cells ◽  
Visual Field Loss ◽  
Retinal Ganglion ◽  
Common Cause ◽  
Elevated Intraocular Pressure

Glaucoma, a chronic optic neuropathy, is the second most common cause of blindness, affecting 67 million people worldwide. The damage in glaucoma occurs at the optic nerve head (ONH), where the axons of the retinal ganglion cells leave the eye posteriorly. Glaucoma is frequently associated with elevated intraocular pressure (IOP), and visual field loss can be prevented by significant lowering of IOP. Hence, the role of pressure in glaucoma is important. Unfortunately, the mechanism by which pressure leads to vision loss in glaucoma is very poorly understood.

scholarly journals Patterns of functional vision loss in glaucoma determined with archetypal analysis

2015 ◽  
Vol 12 (103) ◽  
pp. 20141118 ◽  
Author(s):  
Tobias Elze ◽  
Louis R. Pasquale ◽  
Lucy Q. Shen ◽  
Teresa C. Chen ◽  
Janey L. Wiggs ◽  
...  
Keyword(s):  
Visual Field ◽  
Vision Loss ◽  
Optimal Solution ◽  
Visual Field Loss ◽  
Retinal Nerve Fibre Layer ◽  
Detailed Knowledge ◽  
Archetypal Analysis ◽  
Current Classification ◽  
Retinal Structure ◽  
Nerve Fibre Layer

Glaucoma is an optic neuropathy accompanied by vision loss which can be mapped by visual field (VF) testing revealing characteristic patterns related to the retinal nerve fibre layer anatomy. While detailed knowledge about these patterns is important to understand the anatomic and genetic aspects of glaucoma, current classification schemes are typically predominantly derived qualitatively. Here, we classify glaucomatous vision loss quantitatively by statistically learning prototypical patterns on the convex hull of the data space. In contrast to component-based approaches, this method emphasizes distinct aspects of the data and provides patterns that are easier to interpret for clinicians. Based on 13 231 reliable Humphrey VFs from a large clinical glaucoma practice, we identify an optimal solution with 17 glaucomatous vision loss prototypes which fit well with previously described qualitative patterns from a large clinical study. We illustrate relations of our patterns to retinal structure by a previously developed mathematical model. In contrast to the qualitative clinical approaches, our results can serve as a framework to quantify the various subtypes of glaucomatous visual field loss.

scholarly journals Spared perilesional V1 activity underlies training-induced recovery of luminance detection sensitivity in cortically-blind patients

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Antoine Barbot ◽  
Anasuya Das ◽  
Michael D. Melnick ◽  
Matthew R. Cavanaugh ◽  
Elisha P. Merriam ◽  
...  
Keyword(s):  
Visual Field ◽  
Visual Discrimination ◽  
Receptive Fields ◽  
Visual Field Loss ◽  
Detection Sensitivity ◽  
Perceptual Training ◽  
Visual Functions ◽  
Before And After ◽  
Plastic Changes ◽  
V1 Cortex

AbstractDamage to the primary visual cortex (V1) causes homonymous visual-field loss long considered intractable. Multiple studies now show that perceptual training can restore visual functions in chronic cortically-induced blindness (CB). A popular hypothesis is that training can harness residual visual functions by recruiting intact extrageniculostriate pathways. Training may also induce plastic changes within spared regions of the damaged V1. Here, we link changes in luminance detection sensitivity with retinotopic fMRI activity before and after visual discrimination training in eleven patients with chronic, stroke-induced CB. We show that spared V1 activity representing perimetrically-blind locations prior to training predicts the amount of training-induced recovery of luminance detection sensitivity. Additionally, training results in an enlargement of population receptive fields in perilesional V1, which increases blind-field coverage and may support further recovery with subsequent training. These findings uncover fundamental changes in perilesional V1 cortex underlying training-induced restoration of conscious luminance detection sensitivity in CB.

A Review of Learning Effect in Perimetry

2020 ◽  
pp. 23-30
Author(s):  
Aristeidis Chandrinos ◽  
Dorotheos-Dimitrios Tzamouranis
Keyword(s):  
Visual Field ◽  
Visual Impairment ◽  
Learning Effect ◽  
Vision Loss ◽  
Signal To Noise Ratio ◽  
Test Procedure ◽  
Field Tests ◽  
Visual Field Loss ◽  
Visual Field Defects ◽  
Specific Patient

Glaucoma is the second most common cause of visual impairment in the UK, with visual impairment registrations have increased by 22% since 2010. Glaucoma refers to a group of optic neuropathies leading to visual impairment and blindness. If glaucoma remains untreated, it may produce optic nerve damage, leading to vision loss. Consequently, visual field tests can be extremely valuable for glaucoma. At the same time, visual field assessment should be performed at baseline and periodically in the glaucoma follow-up or monitor the effectiveness of adopted therapeutic schemes. Any visual field test can be masked by one or more artefacts, which can either lead to the incorrect result of visual field loss or to the possible deterioration of existing loss. One of the most important factors is the perimetric learning effect that is present in almost all types of perimetry. To minimize the learning effect, we either have to conduct a practice test procedure, as a demonstration for the patient without collecting data, or to calculate and establish a learning index of the specific patient. By the establishment of such an index, assist the clinician in detecting possible masked or overestimated visual field defects or progression of glaucoma damage. Conclusion: Potentially, the intense data collection at a large number of locations throughout the field in a larger cohort of subjects (visually healthy and glaucomatous) would be required for a better index establishment. The incorporation of fatigue also may be required to form a robust index enough to simulate procedures of glaucoma prognosis. The low signal to noise ratio associated with perimetric testing suggests that improvements will always be difficult to make.

scholarly journals Quantitative Analysis of the Displacement of the Anterior Visual Pathway by Pituitary Lesions and the Associated Visual Field Loss

2016 ◽  
Vol 57 (8) ◽  
pp. 3576 ◽  
Author(s):  
Michael V. Boland ◽  
In Ho Lee ◽  
Elcin Zan ◽  
David M. Yousem ◽  
Neil R. Miller
Keyword(s):  
Quantitative Analysis ◽  
Visual Field ◽  
Visual Field Loss ◽  
Visual Pathway

scholarly journals Organization of Area hV5/MT+ in Subjects with Homonymous Visual Field Defects

2018 ◽  
Author(s):  
Amalia Papanikolaou ◽  
Georgios A. Keliris ◽  
T. Dorina Papageorgiou ◽  
Ulrich Schiefer ◽  
Nikos K. Logothetis ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Visual Perception ◽  
Activity Patterns ◽  
Receptive Fields ◽  
Visual Field Loss ◽  
Visual Sensitivity ◽  
Visual Field Defects ◽  
Temporal Area ◽  
Residual Capacity

AbstractDamage to the primary visual cortex (V1) leads to a visual field loss (scotoma) in the retinotopically corresponding part of the visual field. Nonetheless, a small amount of residual visual sensitivity persists within the blind field. This residual capacity has been linked to activity observed in the middle temporal area complex (V5/MT+). However, it remains unknown whether the organization of hV5/MT+ changes following V1 lesions. We studied the organization of area hV5/MT+ of five patients with dense homonymous defects in a quadrant of the visual field as a result of partial V1+ or optic radiation lesions. To do so, we developed a new method, which models the boundaries of population receptive fields directly from the BOLD signal of each voxel in the visual cortex. We found responses in hV5/MT+ arising inside the scotoma for all patients and identified two possible sources of activation: 1) responses might originate from partially lesioned parts of area V1 corresponding to the scotoma, and 2) responses can also originate independent of area V1 input suggesting the existence of functional V1-bypassing pathways. Apparently, visually driven activity observed in hV5/MT+ is not sufficient to mediate conscious vision. More surprisingly, visually driven activity in corresponding regions of V1 and early extrastriate areas including hV5/MT+ did not guarantee visual perception in the group of patients with post-geniculate lesions that we examined. This suggests that the fine coordination of visual activity patterns across visual areas may be an important determinant of whether visual perception persists following visual cortical lesions.

The nature of the boundary between cortical visual areas II and III in the cat

1977 ◽  
Vol 199 (1136) ◽  
pp. 445-462 ◽  
Keyword(s):  
Visual Field ◽  
Receptive Fields ◽  
Horizontal Meridian ◽  
Vertical Meridian ◽  
Reversal Point ◽  
Cortical Areas ◽  
Visual Areas ◽  
Primate Visual Cortex ◽  
Visual Cortical ◽  
Cortical Visual Areas

The representation of the visual field in the second and third visual cortical areas (V II and V III) of the cat was examined by microelectrode recording. The position of the field maps and the arrangement of the map within V II were found to vary greatly from one cat to another so that no single composite map can be made. The horizontal meridian of the visual field was found to run laterally and forward from V I across V II to V III. The reversal of field sequence, which indicates the V II/V III boundary, was very variable both from cat to cat and in the same cat for points above and below the horizontal meridian. The commonest situation was one in which the reversal point was 40° for some lines of latitude, but for others the reversal point was only 6- 15° out. This means an ‘island’ of representation of points 40° out was bounded by areas of representation much closer to the vertical meridian. In some cats one ‘island’ was plotted, in one there were two completely plotted and in others there were two ‘islands’, one complete, one incompletely plotted. In one cat no ‘island’ was found, and the boundary between V II and V III seemed to be formed anteriorly and posteriorly by the vertical (longitudinal) meridian 20° out. The islands contain many units with markedly elongated receptive fields whose particular function is not yet clear. The arrangement of the V II/V III boundary found in these experiments is compared to that previously suggested and to present knowledge of the mapping in primate visual cortex.

Design for Simulator Performance Evaluations of Driving with Vision Impairments and Visual Aids

2005 ◽  
Vol 1937 (1) ◽  
pp. 128-135 ◽  
Author(s):  
E. Peli ◽  
A. R. Bowers ◽  
A. J. Mandel ◽  
K. Higgins ◽  
R. B. Goldstein ◽  
...  
Keyword(s):  
Visual Field ◽  
Vision Loss ◽  
Driving Simulator ◽  
Small Sample Size ◽  
Visual Field Loss ◽  
Small Sample ◽  
Visual Aids ◽  
Pilot Studies ◽  
Strong Basis ◽  
The Impact

Driving simulator technology provides a safe method for evaluating the impact of vision loss on different components of the driving task and the potential efficacy of visual aids intended to compensate for a particular type of vision loss. Most previous investigations have used general driving scenarios. It is proposed here that scenarios with different task requirements be designed specifically to address the condition under investigation. As an example, the design of driving scenarios and tasks that are specific for the evaluation of one type of visual field loss, homonymous hemianopia, is described. Results of pilot studies show that even with a small sample size, the design is sufficiently sensitive to differentiate individuals with hemianopic visual field loss from control drivers. These results suggest that careful design of test situations, measurements, and analyses provides a strong basis for investigations of driving performance of individuals with specific types of vision impairment and could be used to evaluate the efficacy of low-vision driving aids.

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