scholarly journals Population receptive field analysis of the primary visual cortex complements perimetry in patients with homonymous visual field defects

2014 ◽  
Vol 111 (16) ◽  
pp. E1656-E1665 ◽  
Author(s):  
A. Papanikolaou ◽  
G. A. Keliris ◽  
T. D. Papageorgiou ◽  
Y. Shao ◽  
E. Krapp ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Receptive Field ◽  
Primary Visual Cortex ◽  
Field Analysis ◽  
Visual Field Defects ◽  
Field Defects

Computerized color perimetry in multiple sclerosis

1998 ◽  
Vol 4 (2) ◽  
pp. 79-84 ◽  
Author(s):  
N Accornero ◽  
S Rinalduzzi ◽  
M Capozza ◽  
E Millefiorini ◽  
G C Filligoi ◽  
...  
Keyword(s):  
Visual Field ◽  
Statistical Difference ◽  
Cost Effective ◽  
Quantitative Information ◽  
Field Analysis ◽  
Visual Field Defects ◽  
Highly Sensitive ◽  
The Subject ◽  
Color Perimetry ◽  
Field Defects

Color visual field analysis has proven highly sensitive for early visual impairments diagnosis in MS, yet it has never attained widespread popularity usually because the procedure is difficult to standardize, the devices are costly, and the test is fatiguing. We propose a computerized procedure running on standard PC, cost effective, clonable, and easy handled. Two hundred and sixty-four colored patches subtending 18 angle of vision, with selected hues and low saturation levels are sequentially and randomly displayed on gray equiluminous background of the PC screen subtending 2486408 angle of vision. The subject is requested to press a switch at the perception of the stimulus. The output provides colored maps with quantitative information. Comparison between normals and a selected population of MS patients with no actual luminance visual field defects, showed high statistical difference.

scholarly journals Functional Micro-Organization of Primary Visual Cortex: Receptive Field Analysis of Nearby Neurons

1999 ◽  
Vol 19 (10) ◽  
pp. 4046-4064 ◽  
Author(s):  
Gregory C. DeAngelis ◽  
Geoffrey M. Ghose ◽  
Izumi Ohzawa ◽  
Ralph D. Freeman
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Primary Visual Cortex ◽  
Field Analysis

scholarly journals Eye-tracking-based visual field analysis (EFA): a reliable and precise perimetric methodology for the assessment of visual field defects

2021 ◽  
Vol 6 (1) ◽  
pp. e000429
Author(s):  
Michael Christian Leitner ◽  
Florian Hutzler ◽  
Sarah Schuster ◽  
Lorenzo Vignali ◽  
Patrick Marvan ◽  
...  
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Eye Tracking ◽  
Field Analysis ◽  
Visual Field Defects ◽  
Test Duration ◽  
Automated Perimetry ◽  
The Individual ◽  
The Right ◽  
Field Defects

ObjectiveSeveral studies report evidence for training-related neuroplasticity in the visual cortex, while other studies suggest that improvements simply reflect inadequate eye fixation control during perimetric prediagnostics and postdiagnostics.Methods and analysisTo improve diagnostics, a new eye-tracking-based methodology for visual field analysis (eye-tracking-based visual field analysis (EFA)) was developed. The EFA is based on static automated perimetry and additionally takes individual eye movements in real time into account and compensates for them. In the present study, an evaluation of the EFA with the help of blind spots of 58 healthy participants and the individual visual field defects of 23 clinical patients is provided. With the help of the EFA, optical coherence tomography, Goldmann perimetry and a Humphrey field analyser, these natural and acquired scotomas were diagnosed and the results were compared accordingly.ResultsThe EFA provides a SE of measurement of 0.38° for the right eye (OD) and 0.50° for the left eye (OS), leading to 0.44° of visual angle for both eyes (OU). Based on participants’ individual results, the EFA provides disattenuated correlation (validity) of 1.00 for both OD and OS. Results from patients suffering from cortical lesions and glaucoma further indicate that the EFA is capable of diagnosing acquired scotoma validly and is applicable for clinical use.ConclusionOutcomes indicate that the EFA is highly reliable and precise in diagnosing individual shape and location of scotoma and capable of recording changes of visual field defects (after intervention) with unprecedented precision. Test duration is comparable to established instruments and due to the high customisability of the EFA, assessment duration can be shortened by adapting the diagnostic procedure to the patients’ individual visual field characteristics. Therefore, the saccade-compensating methodology enables researchers and healthcare professionals to rule out eye movements as a source of inaccuracies in pre-, post-, and follow-up assessments.

scholarly journals Functional MRI of visual cortex predicts training-induced recovery in stroke patients with homonymous visual field defects

2020 ◽  
Author(s):  
J.A. Elshout ◽  
D.P. Bergsma ◽  
A.V. van den Berg ◽  
Koen Haak
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Visual Stimulation ◽  
Daily Life ◽  
Visual Field Defects ◽  
Wide Field ◽  
Stroke Patients ◽  
Daily Life Activities ◽  
Humphrey Perimetry ◽  
Field Defects

Post-chiasmatic damage to the visual system leads to homonymous visual field defects (HVDs), which can severely interfere with daily life activities. Visual Restitution Training (VRT) can recover parts of the affected visual field in patients with chronic HVDs, but training outcome is variable. An untested hypothesis suggests that training potential may be largest in regions with ‘neural reserve’, where cortical responses to visual stimulation do not lead to visual awareness as assessed by Humphrey perimetry—a standard behavioural visual field test. Here, we tested this hypothesis in a sample of twenty-seven hemianopic stroke patients, who participated in an assiduous 80-hour VRT program. For each patient, we collected Humphrey perimetry and wide-field fMRI-based retinotopic mapping data prior to training. In addition, we used Goal Attainment Scaling to assess whether personal activities in daily living improved. After training, we assessed with a second Humphrey perimetry measurement whether the visual field was improved and evaluated which personal goals were attained. Confirming the hypothesis, we found significantly larger improvements of visual sensitivity at field locations with neural reserve. These visual field improvements implicated both regions in primary visual cortex and higher order visual areas. In addition, improvement in daily life activities correlated with the extent of visual field enlargement but not sensitivity gain. Our findings are an important step toward understanding the mechanisms of visual restitution as well as predicting training efficacy in stroke patients with chronic hemianopia.

Improvement of visual field defects after focal resection for occipital lobe epilepsy: case report

2018 ◽  
Vol 128 (3) ◽  
pp. 862-866 ◽  
Author(s):  
Takahiro Yamamoto ◽  
Tadashi Hamasaki ◽  
Hideo Nakamura ◽  
Kazumichi Yamada
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Occipital Lobe ◽  
Neurological Deficits ◽  
Visual Field Defects ◽  
Epileptic Focus ◽  
Visual Aura ◽  
Occipital Lobe Epilepsy ◽  
The Right ◽  
Field Defects

Improvement of visual field defects after surgical treatment for occipital lobe epilepsy is rare. Here, the authors report on a 24-year-old man with a 15-year history of refractory epilepsy that developed after he had undergone an occipital craniotomy to remove a cerebellar astrocytoma at the age of 4. His seizures started with an elementary visual aura, followed by secondary generalized tonic-clonic convulsion. Perimetry revealed left-sided incomplete hemianopia, and MRI showed an old contusion in the right occipital lobe. After evaluation with ictal video-electroencephalography, electrocorticography, and mapping of the visual cortex with subdural electrodes, the patient underwent resection of the scarred tissue, including the epileptic focus at the occipital lobe. After surgery, he became seizure free and his visual field defect improved gradually. In addition, postoperative 123I-iomazenil (IMZ) SPECT showed partly normalized IMZ uptake in the visual cortex. This case is a practical example suggesting that neurological deficits attributable to the functional deficit zone can be remedied by successful focal resection.

scholarly journals A longitudinal observation of a patient with normal tension glaucoma

2017 ◽  
Vol 76 (1) ◽  
Author(s):  
Hlupheka L. Sithole
Keyword(s):  
Intraocular Pressure ◽  
Visual Field ◽  
Normal Tension Glaucoma ◽  
Field Analysis ◽  
Visual Field Defects ◽  
Due Diligence ◽  
Longitudinal Observation ◽  
Eye Examination ◽  
Field Defects

Normal tension glaucoma (NTG) is a disease associated with normal intraocular pressure (10 mmHg – 21 mmHg) that may lead to irreversible blindness if misdiagnosed or left untreated over a period of time. The author observed a patient with NTG over a period of 5 years (from 2013 to 2017). The initial visual field analysis results (2014) showed mild visual field defects because of NTG at the start of the 5-year period. Although the patient was also diagnosed with hydrocephalus, a condition associated with optic nerve head damage, following years of noncompliance to treatment of NTG and follow-up eye examination schedules, the patient’s visual field defects were found to have progressed by the year 2017. It is therefore important for optometrists to apply due diligence when examining patients with NTG in order to expedite intervention and prevention of visual impairment and blindness.

scholarly journals Statokinetic Dissociation (Riddoch Phenomenon) in a Patient with Homonymous Hemianopsia as the First Sign of Posterior Cortical Atrophy

2017 ◽  
Vol 9 (3) ◽  
pp. 256-260 ◽  
Author(s):  
Ryuichiro Hayashi ◽  
Shigeki Yamaguchi ◽  
Toshio Narimatsu ◽  
Hiroshi Miyata ◽  
Yasushi Katsumata ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Cortical Atrophy ◽  
Visual Field Defects ◽  
Posterior Cortical Atrophy ◽  
Unilateral Neglect ◽  
Homonymous Hemianopsia ◽  
Kinetic Perimetry ◽  
The Right ◽  
Field Defects

We report a 60-year-old woman with posterior cortical atrophy (PCA) who presented with left homonymous hemianopsia persisting for 5 years; the patient’s condition was observed using static, but not kinetic, perimetry. This statokinetic dissociation of hemianopsia, which is often called Riddoch syndrome, might have been caused by a dysfunction of the right primary visual and visual association cortices, representing a functional imbalance within a disturbed visual cortex. In patients with PCA and visual field defects, both static and kinetic perimetry may be useful for understanding the extent of degeneration in the visual cortex, in addition to examinations of unilateral neglect.

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