Integrated visual fields: a new approach to measuring the binocular field of view and visual disability

2004 ◽  
Vol 243 (3) ◽  
pp. 210-216 ◽  
Author(s):  
David P. Crabb ◽  
Ananth C. Viswanathan
Keyword(s):  
Visual Fields ◽  
Field Of View ◽  
Visual Disability ◽  
New Approach ◽  
Binocular Field

External Design and Field of View of the Compound Eyes in a Raptorial Neuropteran Insect, Mantispa Styriaca

1990 ◽  
Vol 148 (1) ◽  
pp. 353-365 ◽  
Author(s):  
U. EGGENREICH ◽  
K. KRAL
Keyword(s):  
Dark Adaptation ◽  
Visual Fields ◽  
Field Of View ◽  
Compound Eyes ◽  
Praying Mantis ◽  
Binocular Field ◽  
Frontal Part

Visual fields and ommatidial angles of the compound eyes of Mantispa styriaca were determined using luminous pseudopupil and histological-anatomical techniques. The maximal horizontal overlap averaged 42.7° in femalesand 52.4° in males; females had only one overlap maximum, whereas males had two. In the dorsoventral direction, the binocular field had an overlap of 135.2° in the female and 142° in the male. In light-adapted eyes, optical acceptance angles reached values of 2.0°, and they reached 3.6° with dark adaptation; interommatidial angles were between 1.8° and 2.3°. The angles were very similar over the entire eye; no acute zone was found in the frontal part of the eye, as the large binocular overlap would suggest. The results are compared with those for the praying mantis: this animal is in no way related to Mantispa but resembles it in appearance and capture behaviour.

scholarly journals Vision and touch in relation to foraging and predator detection: insightful contrasts between a plover and a sandpiper

2008 ◽  
Vol 276 (1656) ◽  
pp. 437-445 ◽  
Author(s):  
Graham R Martin ◽  
Theunis Piersma
Keyword(s):  
Visual Fields ◽  
Skeletal Structure ◽  
Visually Guided ◽  
Sources Of Information ◽  
Predator Detection ◽  
Food Items ◽  
Binocular Field ◽  
Blind Area ◽  
Wide Range ◽  
Breeding Grounds

Visual fields were determined in two species of shorebirds (Charadriiformes) whose foraging is guided primarily by different sources of information: red knots ( Calidris canutus , tactile foragers) and European golden plovers ( Pluvialis apricaria , visual foragers). The visual fields of both species showed features that are found in a wide range of birds whose foraging involves precision pecking or lunging at food items. Surprisingly, red knots did not show comprehensive panoramic vision as found in some other tactile feeders; they have a binocular field surrounding the bill and a substantial blind area behind the head. We argue that this is because knots switch to more visually guided foraging on their breeding grounds. However, this visual field topography leaves them vulnerable to predation, especially when using tactile foraging in non-breeding locations where predation by falcons is an important selection factor. Golden plovers use visually guided foraging throughout the year, and so it is not surprising that they have precision-pecking frontal visual fields. However, they often feed at night and this is associated with relatively large eyes. These are anchored in the skull by a wing of bone extending from the dorsal perimeter of each orbit; a skeletal structure previously unreported in birds and which we have named ‘supraorbital aliform bone’, Os supraorbitale aliforme . The larger eyes and their associated supraorbital wings result in a wide blind area above the head, which may leave these plovers particularly vulnerable to predation. Thus, in these two shorebirds, we see clear examples of the trade-off between the two key functions of visual fields: (i) the detection of predators remote from the animal and (ii) the control of accurate behaviours, such as the procurement of food items, at close quarters.

scholarly journals Vision, touch and object manipulation in Senegal parrots Poicephalus senegalus

2011 ◽  
Vol 278 (1725) ◽  
pp. 3687-3693 ◽  
Author(s):  
Zoe P. Demery ◽  
Jackie Chappell ◽  
Graham R. Martin
Keyword(s):  
Visual Fields ◽  
Bird Species ◽  
Object Manipulation ◽  
Field Configuration ◽  
Tactile Information ◽  
Binocular Field ◽  
Prime Determinant ◽  
Tactile Cues ◽  
Foraging Method ◽  
Visual Coverage

Parrots are exceptional among birds for their high levels of exploratory behaviour and manipulatory abilities. It has been argued that foraging method is the prime determinant of a bird's visual field configuration. However, here we argue that the topography of visual fields in parrots is related to their playful dexterity, unique anatomy and particularly the tactile information that is gained through their bill tip organ during object manipulation. We measured the visual fields of Senegal parrots Poicephalus senegalus using the ophthalmoscopic reflex technique and also report some preliminary observations on the bill tip organ in this species. We found that the visual fields of Senegal parrots are unlike those described hitherto in any other bird species, with both a relatively broad frontal binocular field and a near comprehensive field of view around the head. The behavioural implications are discussed and we consider how extractive foraging and object exploration, mediated in part by tactile cues from the bill, has led to the absence of visual coverage of the region below the bill in favour of more comprehensive visual coverage above the head.

The ipsilateral retinal projection in the fat-tailed dunnart, Sminthopsis crassicaudata

1998 ◽  
Vol 15 (4) ◽  
pp. 677-684 ◽  
Author(s):  
J. RODGER ◽  
S.A. DUNLOP ◽  
L.D. BEAZLEY
Keyword(s):  
Ganglion Cells ◽  
Visual Fields ◽  
Optic Tract ◽  
Retinal Ganglion ◽  
Retinal Projection ◽  
Binocular Field ◽  
Sminthopsis Crassicaudata ◽  
Area Centralis ◽  
Ipsilateral Projection ◽  
The Brain

The population of retinal ganglion cells which project ipsilaterally in the brain was examined in the fat-tailed dunnart, Sminthopsis crassicaudata, following injection of horseradish peroxidase into one optic tract. Retinae were examined as wholemounts and optic nerves as serial sections. In addition, visual fields were measured ophthalmoscopically. Ipsilaterally projecting ganglion cells were located temporal to a line which ran vertically through the middle of the area centralis and extended medially to define a ventrolateral crescent. Temporal to the naso-temporal division, a mean of 77% of ganglion cells projected ipsilaterally; these cells represented 20% of the total ganglion cell population. The magnitude and retinal location of the ipsilateral projection correlated with the extensive binocular field which measured 180 deg in the vertical (from 20 deg below the horizontal axis to 70 deg beyond the zenith) and 140 deg in horizontal meridian. Ipsilaterally projecting axons were restricted to the lateral third of the optic nerve along its length, sharing territory with contralaterally projecting axons.

scholarly journals Scaling of Discomfort Sensations in the Conditions of Performing Office Visual Tasks

2021 ◽  
Author(s):  
George Boos ◽  
Vladimir Budak ◽  
Ekaterina Ilyina ◽  
Tatyana Meshkova
Keyword(s):  
Physiological Model ◽  
Lighting Design ◽  
Field Of View ◽  
Distance Threshold ◽  
New Approach ◽  
Visual Tasks ◽  
Uniform Background ◽  
New Criterion ◽  
Work Done

Currently, computer graphics programs (CG) as a tool for designing lighting installations allows us to move to a fundamentally new approach to assessing the quality of lighting: to move away from designing based on illuminance values to designing based on synthetic images or lighting design. Modern CG programs allow us to calculate the spatial-angular distribution of luminance (SADL). Still, some criterion is needed for the assessment, which will allow us to uniquely determine the quality of lighting in terms of luminance distribution. In this paper, we consider constructing a physiological model of the visual sense scale for assessing the quality of lighting according to SADL based on an experiment to assess visual sense from the luminance of a light source in the field of view on a uniform background with different luminance. As a result of the work done, it is proposed to use a scale of sensations in the form of a certain space. The axis of space is the threshold contrast for the resulting sense of discomfort, depending on the observation conditions. All other sensations are separated from the axis at some distance. Threshold contrasts, at which visual sensations arise within the framework of the proposed scale, can be used in the future to assess the storm in the lighting scene using a new criterion and will allow analysing the quality of lighting using CG methods.

scholarly journals Visual Adaptations in Predatory and Scavenging Diurnal Raptors

Diversity ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 400
Author(s):  
Simon Potier
Keyword(s):  
Prey Capture ◽  
Foraging Ecology ◽  
Visual Fields ◽  
Blind Spot ◽  
Field Of View ◽  
Birds Of Prey ◽  
Ecological Diversity ◽  
Complex Interplay ◽  
Visual Systems ◽  
Central Fovea

Ecological diversity among diurnal birds of prey, or raptors, is highlighted regarding their sensory abilities. While raptors are believed to forage primarily using sight, the sensory demands of scavengers and predators differ, as reflected in their visual systems. Here, I have reviewed the visual specialisations of predatory and scavenging diurnal raptors, focusing on (1) the anatomy of the eye and (2) the use of vision in foraging. Predators have larger eyes than scavengers relative to their body mass, potentially highlighting the higher importance of vision in these species. Scavengers possess one centrally positioned fovea that allows for the detection of carrion at a distance. In addition to the central fovea, predators have a second, temporally positioned fovea that views the frontal visual field, possibly for prey capture. Spatial resolution does not differ between predators and scavengers. In contrast, the organisation of the visual fields reflects important divergences, with enhanced binocularity in predators opposed to an enlarged field of view in scavengers. Predators also have a larger blind spot above the head. The diversity of visual system specializations according to the foraging ecology displayed by these birds suggests a complex interplay between visual anatomy and ecology, often unrelatedly of phylogeny.

Detecting Visual Field Progression in Glaucoma – Using the Right Tools for the Job

2013 ◽  
Vol 07 (01) ◽  
pp. 20 ◽  
Author(s):  
Luke J Saunders ◽  
Richard A Russell ◽  
David P Crabb ◽  
◽  
◽  
...  
Keyword(s):  
Visual Field ◽  
Visual Fields ◽  
Field Measurements ◽  
Automated Perimetry ◽  
Standard Automated Perimetry ◽  
Visual Disability ◽  
New Research ◽  
The Right ◽  
Over Time

Monitoring disease progression is at the centre of managing a patient with glaucoma. This article focuses specifically on how visual field measurements from standard automated perimetry (SAP) can be monitored over time. Various options for analysis on the Humphrey and Octopus perimeters are discussed, from summary indices to event and trend-based analyses; their respective merits and flaws evaluated. It is strongly recommended that quantitative analysis methods and software are used in assessing progression, as variability in threshold measurements makes detecting true deterioration non-trivial. Recommendations on the frequency of visual fields that should be taken per year are also discussed. The article concludes by putting the spotlight on new research being undertaken to improve the methods of measuring and predicting progression, as well as relating visual fields to patient visual disability and quality of life.

The visual fields of American horseshoe crabs: Two different eye shapes in Limulus polyphemus

1994 ◽  
Vol 11 (2) ◽  
pp. 333-346 ◽  
Author(s):  
William W. Weiner ◽  
Steven C. Chamberlain
Keyword(s):  
Adult Male ◽  
Visual Fields ◽  
Vertical Axis ◽  
Limulus Polyphemus ◽  
Field Of View ◽  
Male And Female ◽  
Maximum Resolution ◽  
Lateral Eye ◽  
Horseshoe Crabs ◽  
Optical Alignment

AbstractThe optical alignment of individual cuticular cones in the dioptric array of the lateral eye of Limulus polyphemus was determined with a precision two-circle goniometer constructed and mounted to the stage of a compound microscope and using a new formaldehyde-induced fluorescence procedure. All measurements were made from the corneal surface of the excised eye mounted in seawater through an air/water interface perpendicular to the optic axis of the microscope. Our results revealed two variants of visual field and eye curvature which can actually be discriminated in casual examination of adult animals. We call animals possessing these two variants “morlocks” and “eloi.” Adult male and female morlocks about 25 cm across the carapace have eyes which are relatively elongated, often darker in pigmentation, smaller, and relatively flatter in curvature. Morlocks have a monocular field of view of about 3.13 steradians or 50% of a hemisphere. The coverage averages 115 deg along the vertical axis and 168 deg along the horizontal axis of the eye, with maximum resolution in the anteroventral quadrant. Adult male and female eloi of comparable size have eyes which are relatively more round, often lighter in pigmentation, larger with more ommatidia, and relatively more bulged. Eloi have a monocular field of view of approximately 3.83 steradians or 61% of a hemisphere that covers 145 deg vertically and 185 deg horizontally. Eloi have more uniform resolution than morlocks with best resolution in the posteroventral quadrant. All horseshoe crabs examined, whether morlocks or eloi, have an identical orientation of the margin of the eye relative to the animals’ coordinates.

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