Write short notes on the normal visual field and how it can be measured

2018 ◽  
pp. 98-99
Author(s):  
Nathaniel Knox Cartwright ◽  
Petros Carvounis
Keyword(s):  
Visual Field ◽  
Normal Visual Field

Normal Visual Field

2016 ◽  
pp. 1-1
Author(s):  
Preeti Gupta ◽  
George Puthuran ◽  
Murali Ariga ◽  
Sneha Sharma
Keyword(s):  
Visual Field ◽  
Normal Visual Field

scholarly journals Glaucoma suspect & Humphrey Field Analyzer a correlation

2012 ◽  
Vol 8 (1) ◽  
pp. 23-28
Author(s):  
P Dahal ◽  
AP Rizal ◽  
DB Karki
Keyword(s):  
Visual Field ◽  
Visual Field Loss ◽  
Neural Retina ◽  
Medical Sciences ◽  
Significant Relation ◽  
Glaucoma Suspect ◽  
Humphrey Field Analyzer ◽  
Elevated Intraocular Pressure ◽  
Normal Visual Field ◽  
Primary Risk Factor

Glaucoma originally meant "clouded", in Greek.The term glaucoma refers to a group of diseases that have in common characteristic optic neuropathy with associated visual field loss for which elevated intraocular pressure is one of the primary risk factor. The purpose of the study is to correlate the clinically diagnosed cases of glaucoma suspect with the Humphrey Field Analyzer (HFA). Fifty cases of glaucoma suspect who attended the glaucoma clinic of Nepal Eye Hospital Tripureswor, Kathmandu, Nepal and who meets at least two criteria, among the four types of glaucoma suspects were advised for the HFA for the study. In this study out of 50 patient, 36 (72%) patients had normal visual field. 14 (28%) patients had thinning of the neural retinal rim (NRR) in both eyes. The significant relation with thinning of neural retina rim and glaucomatous hemifield test was found in the study. Journal of College of Medical Sciences-Nepal,2012,Vol-8,No-1, 23-28 DOI: http://dx.doi.org/10.3126/jcmsn.v8i1.6822

Behavioral evidence of filling-in at the blind spot of the monkey

1994 ◽  
Vol 11 (6) ◽  
pp. 1103-1113 ◽  
Author(s):  
Hidehiko Komatsu ◽  
Ikuya Murakami
Keyword(s):  
Visual Field ◽  
Human Subjects ◽  
Visual Fields ◽  
Blind Spot ◽  
Neural Mechanisms ◽  
Opposite Field ◽  
Normal Visual Field ◽  
Saccade Task ◽  
Behavioral Evidence ◽  
Blind Spots

AbstractIn human subjects, the blind spot is perceptually filled-in by color and brightness from the surrounding visual field. The present behavioral study examined the occurrence of color filling-in at the blind spot in monkeys. First, the location of the blind spot was determined using a monocular saccade task. The blind spots were located on the horizontal meridian at approximately 15–17 deg from the fixation point in the temporal visual field. Then, filling-in at the blind spot was tested by determining if the monkey could discriminate between an annulus presented on the blind spot and a homogeneous disk in the normal visual field. In this task, the monkey was required to make a saccade to a homogeneous disk of the same color and size as an annulus presented simultaneously in the opposite field. Both stimuli were large enough to cover the blind spot and the inner circle of the annulus was confined inside the blind spot. All four monkeys tested performed this task correctly in over 80% of the trials. However, when one eye was covered and the annulus was presented on the blind spot of the uncovered eye, performance deteriorated significantly. To confirm that these results reflected filling-in, one monkey was trained to maintain fixation when two identical homogeneous disks appeared in opposite visual fields. When only one eye was uncovered, and the annulus was presented on the blind spot of the uncovered eye, the monkey maintained fixation in most of the trials. These results show that monkeys were unable to distinguish an annulus from a homogeneous disk when the annulus was presented on the blind spot. This indicates that color filling-in occurs at the blind spot in monkeys and opens possibility to physiological experiments to study the neural mechanisms of filling-in.

Perceptual filling-in at the scotoma following a monocular retinal lesion in the monkey

1997 ◽  
Vol 14 (1) ◽  
pp. 89-101 ◽  
Author(s):  
Ikuya Murakami ◽  
Hidehiko Komatsu ◽  
Masaharu Kinoshita
Keyword(s):  
Visual Field ◽  
Receptive Fields ◽  
Macaque Monkey ◽  
Blind Spot ◽  
Retinal Lesion ◽  
Visual Inputs ◽  
Visual Attribute ◽  
Retinotopic Organization ◽  
Normal Visual Field ◽  
Behavioral Evidence

AbstractAlthough no visual inputs arise from the blind spot, the same visual attribute there as in the visual field surrounding the blind spot is perceived. Because of this remarkable “perceptual filling-in,” a hole corresponding to the blind spot is not perceived, even when one eye is closed. Does the same phenomenon occur in the case of a scotoma in which visual inputs are lost postnatally due to a retinal lesion? We report that it did: in the macaque monkey, behavioral evidence for filling-in at a scotoma produced by a laser-induced monocular retinal lesion was obtained. The visual receptive fields of neurons in the primary visual cortex (VI) in and around the representation of the visual field corresponding to the scotoma were also mapped, and no clear difference between the retinotopic organization of this part in VI and that found in the normal visual field was found. Also, perceptual filling-in was found to occur only two days after the lesion. These findings suggest that the normal visual system possesses a mechanism that yields filling-in when some part of the retina is damaged, and that such a mechanism requires no topographical reorganization in VI.

Reading Speed under Real and Simulated Visual Impairment

1983 ◽  
Vol 77 (8) ◽  
pp. 386-388 ◽  
Author(s):  
Christof C. Krischer ◽  
Ralf Meissen
Keyword(s):  
Visual Acuity ◽  
Visual Field ◽  
Visual Impairment ◽  
Reading Speed ◽  
Visual Fields ◽  
Central Field ◽  
Normal Visual Field ◽  
Partially Sighted

The reading speed of subjects was studied under conditions of simulated and real visual impairment. For subjects with normal visual field and average reading speeds, two types of visual impairment were simulated: cataracts and deteriorated retinas. Three groups of partially sighted persons also were studied: those with normal visual fields, those with defects in peripheral fields, and those with defects in the central field. The results for these three groups were similar to those obtained under conditions of simulated visual impairment. The authors conclude that reading speed depends on visual acuity.

scholarly journals Is MRI follow-up relevant in patients with GH-secreting pituitary adenomas primarily treated and responsive to long-acting somatostatin analogues (SMSa)?

2020 ◽  
Vol 182 (1) ◽  
pp. 123-130
Author(s):  
Naia Grandgeorge ◽  
Giovanni Barchetti ◽  
Solange Grunenwald ◽  
Fabrice Bonneville ◽  
Philippe Caron
Keyword(s):  
Pituitary Adenoma ◽  
Visual Field ◽  
Pituitary Adenomas ◽  
First Generation ◽  
Somatostatin Analogues ◽  
Hormonal Control ◽  
Tumor Shrinkage ◽  
Normal Visual Field ◽  
Long Acting

Objective Primary SMSa treatment can be associated with hormonal control and tumor shrinkage in patients with GH-secreting pituitary adenomas. The aim of this study was to evaluate whether regular MRI follow-up was necessary in patients with acromegaly-treated and responsive to first-generation long-acting SMSa. Patients and methods In this retrospective monocentric study we included patients with GH/IGF-1 hypersecretion and pituitary adenomas with normal visual field, primarily treated with first-generation long-acting SMSa between 1995 and 2015 and regularly monitored (clinical evaluation, GH/IGF-1 levels and pituitary MRI) for at least 3 years. Results We included 83 patients (32 men and 51 women, mean age at diagnosis 50 ± 12 years) with mean GH = 19.3 ± 25.6 ng/mL, IGF-1 = 284 ± 110% ULN and pituitary adenoma height = 12.9 ± 4.7 mm. Mean follow-up was 8.9 ± 4.9 years in 36 controlled patients and 2.0 ± 1.6 years in 47 partial responders to SMSa alone. No significant increase in pituitary adenoma height was observed. Pituitary adenoma height decreased significantly in controlled patients (diagnosis: 11.9 ± 4.8 mm, SMSa: 9.6 ± 3.3 mm, P < 0.001), and in partially responders (diagnosis: 13.6 ± 4.5 mm, SMSa: 11.5 ± 4.5 mm, P < 0.001). Conclusion During SMSa treatment, no significant increase in GH-secreting adenoma size was observed. Primary SMSa treatment was associated with a significantly decrease in adenoma height in our population. Our cohort data suggest that regular MRI follow-up does not seem relevant in patients with acromegaly who are responsive to SMSa treatment.

scholarly journals Relationship between cortical resection and visual function after occipital lobe epilepsy surgery

2018 ◽  
Vol 129 (2) ◽  
pp. 524-532 ◽  
Author(s):  
Won Heo ◽  
June Sic Kim ◽  
Chun Kee Chung ◽  
Sang Kun Lee
Keyword(s):  
Visual Field ◽  
Visual Function ◽  
Peripheral Vision ◽  
Occipital Lobe ◽  
Linear Regression Models ◽  
Occipital Lobe Epilepsy ◽  
Related Quality ◽  
Normal Visual Field ◽  
Visual Cortical ◽  
The Relationship

OBJECTIVEIn this study, the authors investigated long-term clinical and visual outcomes of patients after occipital lobe epilepsy (OLE) surgery and analyzed the relationship between visual cortical resection and visual function after OLE surgery.METHODSA total of 42 consecutive patients who were diagnosed with OLE and underwent occipital lobe resection between June 1995 and November 2013 were included. Clinical, radiological, and histopathological data were reviewed retrospectively. Seizure outcomes were categorized according to the Engel classification. Visual function after surgery was assessed using the National Eye Institute Visual Functioning Questionnaire 25. The relationship between the resected area of the visual cortex and visual function was demonstrated by multivariate linear regression models.RESULTSAfter a mean follow-up period of 102.2 months, 27 (64.3%) patients were seizure free, and 6 (14.3%) patients had an Engel Class II outcome. Nineteen (57.6%) of 33 patients had a normal visual field or quadrantanopia after surgery (normal and quadrantanopia groups). Patients in the normal and quadrantanopia groups had better vision-related quality of life than those in the hemianopsia group. The resection of lateral occipital areas 1 and 2 of the occipital lobe was significantly associated with difficulties in general vision, peripheral vision, and vision-specific roles. In addition, the resection of intraparietal sulcus 3 or 4 was significantly associated with decreased social functioning.CONCLUSIONSThe authors found a favorable seizure control rate (Engel Class I or II) of 78.6%, and 57.6% of the subjects had good visual function (normal vision or quadrantanopia) after OLE surgery. Lateral occipital cortical resection had a significant effect on visual function despite preservation of the visual field.

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