The visual field is "that portion of space in which objects are visible at the same moment during steady fixation of the gaze in one direction"; in ophthalmology and neurology the emphasis is mostly on the structure inside the visual field and it is then considered “the field of functional capacity obtained and recorded by means of perimetry”.Strasburger, Hans; Pöppel, Ernst (2002). Visual Field. In G. Adelman & B.H. Smith (Eds): ''Encyclopedia of Neuroscience''; 3rd edition, on CD-ROM. Elsevier Science B.V., Amsterdam, New York. However, the visual field can also be understood as a predominantly ''perceptual'' concept and its definition then becomes that of the "spatial array of visual sensations available to observation in

introspection Introspection is the examination of one's own conscious thoughts and feelings. In psychology, the process of introspection relies on the observation of one's mental state, while in a spiritual context it may refer to the examination of one's s ...

ist psychological experiments" (for example in van Doorn et al., 2013). The corresponding concept for

optical instrument An optical instrument is a device that processes light waves (or photons), either to enhance an image for viewing or to analyze and determine their characteristic properties. Common examples include periscopes, microscopes, telescopes, and camera ...

s and

image sensor An image sensor or imager is a sensor that detects and conveys information used to form an image. It does so by converting the variable attenuation of light waves (as they refraction, pass through or reflection (physics), reflect off objects) into s ...

s is the

field of view The field of view (FOV) is the angle, angular extent of the observable world that is visual perception, seen at any given moment. In the case of optical instruments or sensors, it is a solid angle through which a detector is sensitive to elec ...

(FOV). In humans and animals, the FOV refers to the area visible when eye movements – if possible for the species – are allowed. In

optometry Optometry is the healthcare practice concerned with examining the eyes for visual defects, prescribing corrective lenses, and detecting eye abnormalities. In the United States and Canada, optometrists are those that hold a post-baccalaureate f ...

ophthalmology Ophthalmology (, ) is the branch of medicine that deals with the diagnosis, treatment, and surgery of eye diseases and disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a ...

, and

neurology Neurology (from , "string, nerve" and the suffix wikt:-logia, -logia, "study of") is the branch of specialty (medicine) , medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the nervous syst ...

, a

visual field test A visual field test is an eye examination that can detect dysfunction in central and peripheral vision which may be caused by various medical conditions such as glaucoma, stroke, pituitary disease, brain tumours or other neurological deficits. V ...

is used to determine whether the visual field is affected by diseases that cause local

scotoma A scotoma is an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of normal – or relatively well-preserved – vision. Every normal mamm ...

or a more extensive loss of vision or a reduction in sensitivity (increase in threshold).

Normal limits

The normal (monocular) human visual field extends to approximately 60 degrees nasally (toward the nose, or inward) from the vertical meridian in each eye, to 107 degrees temporally (away from the nose, or outwards) from the vertical meridian, and approximately 70 degrees above and 80 below the horizontal meridian. The binocular visual field is the superimposition of the two monocular fields. In the binocular field, the area left of the vertical meridian is referred to as the left visual field (which is located temporally for the left, and nasally for the right eye); a corresponding definition holds for the right visual field. The four areas delimited by the vertical and horizontal meridian are referred to as upper/lower left/right quadrants. In the

European Union The European Union (EU) is a supranational union, supranational political union, political and economic union of Member state of the European Union, member states that are Geography of the European Union, located primarily in Europe. The u ...

, the minimum field requirement for driving is 50 degrees to either side of the vertical meridian and 120 degrees horizontally in total, and 20 degrees above and below the horizontal meridian. The

macula The macula (/ˈmakjʊlə/) or macula lutea is an oval-shaped pigmented area in the center of the retina of the human eye and in other animals. The macula in humans has a diameter of around and is subdivided into the umbo, foveola, foveal avas ...

corresponds to the central 17 degrees diameter of the visual field; the fovea to the central 5.2 degrees, and the

foveola The foveola is located within a region called the macula, a yellowish, cone photoreceptor filled portion of the human retina. Approximately 0.35 mm in diameter, the foveola lies in the center of the fovea and contains only cone cell C ...

to 1–1.2 degrees diameter. Note that in the clinical literature the fovea can refer to the central 1–1.2 deg, i.e. what is otherwise known as the foveola, and can be referred to as the "clinical fovea". The nose is situated in the field of view of both eyes, but due to later processing carried out in the brain, it is not noticed during normal visual tasks.

Measuring the visual field

The visual field is measured by

perimetry A visual field test is an eye examination that can detect dysfunction in central and peripheral vision which may be caused by various medical conditions such as glaucoma, stroke, pituitary disease, brain tumours or other neurological deficits. V ...

. This may be kinetic, where spots of light are shown on the white interior of a half sphere and slowly moved inwards until the observer sees them, or static, where the light spots are flashed at varying intensities at fixed locations in the sphere until detected by the subject. Commonly used perimeters are the automated Humphrey Field Analyzer, Optopol Perimeters, Octopus, the Heidelberg Edge Perimeter, the Oculus or the Olleyes VisuALL. Another method is to use a

campimeter The campimeter is an instrument for examining the visual field. Campimeters have been in clinical use since the mid-nineteenth century. Initially, examination of the visual field was concerned only with the outer limits, or 'perimeter' of the visua ...

, a small device with a flat screen designed to measure the central visual field. Light spot patterns testing the central 24 degrees or 30 degrees of the visual field, are most commonly used. Most perimeters are also capable of testing up to 80 or 90 or even 120 degrees. Another method is for the practitioner to hold up one, two, or five fingers in the four quadrants and center of a patient's visual field (with the other eye covered). This is also known as confrontational field testing. If the patient is able to report the number of fingers properly as compared with the visual field of the practitioner, the normal result is recorded as "full to finger counting" (often abbreviated FTFC). The blind spot can also be assessed via holding a small object between the practitioner and the patient. By comparing when the object disappears for the practitioner, a subject's blind spot can be identified. There are many variants of this type of exam (e.g., wiggling fingers in the visual periphery on the cardinal axes).

Visual field loss

Visual field loss may occur due to many disease or disorders of the

eye An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

optic nerve In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual system, visual information from the retina to the brain. In humans, the optic nerve i ...

, or

brain The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...

. For the eye, e.g., Glaucoma causes peripheral field defects.

Macular degeneration Macular degeneration, also known as age-related macular degeneration (AMD or ARMD), is a medical condition which may result in blurred vision, blurred or vision loss, no vision in the center of the visual field. Early on there are often no sym ...

and other diseases affecting the macula cause central field defects. Lesions of the visual pathway cause characteristic forms of visual disturbances, including homonymous

hemianopsia Hemianopsia, or hemianopia, is a loss of vision or blindness ( anopsia) in half the visual field, usually on one side of the vertical midline. The most common causes of this damage are stroke, brain tumor, and trauma. This article deals only wi ...

quadrantanopsia Quadrantanopia, quadrantanopsia, refers to an anopia (loss of vision) affecting a quarter of the visual field. It can be associated with a lesion of an optic radiation. While quadrantanopia can be caused by lesions in the temporal and pariet ...

, and scotomata. The main classification of visual field defects is into #Lesions to the eye's retina (heteronymous field defects in Glaucoma and AMD) #Lesions of the optic nerve (heteronymous field defects) #Lesions in the chiasm (e.g. Bitemporal hemianopia, loss of vision at the sides) #Lesions after the chiasm (homonymous field defects like homonymous

hemianopia Hemianopsia, or hemianopia, is a loss of vision or blindness ( anopsia) in half the visual field, usually on one side of the vertical midline. The most common causes of this damage are stroke, brain tumor, and trauma. This article deals only wi ...

Quadrantanopia Quadrantanopia, quadrantanopsia, refers to an anopia (loss of vision) affecting a quarter of the visual field. It can be associated with a lesion of an optic radiation. While quadrantanopia can be caused by lesions in the Temporal lobe, tempora ...

, homonymous

ta) Other characterisations are: #Altitudinal field defects, loss of vision above or below the horizontal meridian – associated with ocular abnormalities #

Central scotoma A scotoma is an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of normal – or relatively well-preserved – vision. Every normal mamma ...

, loss of central vision #Peripheral field loss including

tunnel vision Tunnel vision is the loss of peripheral vision with retention of central vision, resulting in a constricted circular tunnel-like field of vision. Causes Tunnel vision can be caused by: Eyeglass users Eyeglass users experience tunnel vision ...

#Generalized depression of the entire field of vision

Visual field defects in glaucoma

glaucoma Glaucoma is a group of eye diseases that can lead to damage of the optic nerve. The optic nerve transmits visual information from the eye to the brain. Glaucoma may cause vision loss if left untreated. It has been called the "silent thief of ...

, visual field defects result from damage to the

retinal nerve fiber layer The retinal nerve fiber layer (RNFL) or nerve fiber layer, stratum opticum, is part of the anatomy of the eye. Physical structure The RNFL formed by the expansion of the fibers of the optic nerve; it is thickest near the optic disc, gradually d ...

. Field defects are seen mainly in primary open angle glaucoma. Because of the unique anatomy of the RNFL, many noticeable patterns are seen in the visual field. Most of the early glaucomatous changes are seen within the central visual field, mainly in Bjerrum's area, 10°-20° from fixation. Following are the common glaucomatous field defects: Bjerrums area and types of scotomas on the visual field

Bjerrums area and types of scotomas on the visual field

* Generalized depression: Generalized depression is seen in early stages of glaucoma and many other conditions. Mild constriction of the central and peripheral visual field due to isopter contraction comes under generalized depression. If all the isopters show similar depression to the same point, it is called a contraction of the visual field. Relative paracentral scotomas are the areas where smaller and dimmer targets are not detected by the patient. Larger and brighter targets can be seen. Small paracentral depressions, mainly superonasal, occur in normal-tension glaucoma (NTG). The generalized depression of the entire field may occur in cataract also. * Baring of blind spot: Baring of the blind spot means the exclusion of the blind spot from the central field due to inward curve of the outer boundary of the 30° central field. It is only an early, non-specific visual field change, without much diagnostic value in glaucoma. * Small wing-shaped paracentral scotoma: Small wing-shaped paracentral scotoma within Bjerrum's area is the earliest clinically significant field defect seen in glaucoma. It may also be associated with nasal steps. Scotoma may be seen above or below the blind spot. * Siedel's sickle-shaped scotoma: Paracentral scotoma joins with the blind spot to form Siedel's sickle-shaped scotoma. * Arcuate or Bjerrum's scotoma: This kind of scotoma is formed at later stages of glaucoma by extension of Seidel's scotoma in an area either above or below the fixation point to reach the horizontal line. Peripheral breakthrough may occur due to damage of nerve fibers. * Ring or double arcuate scotoma: Two arcuate scotomas join to form a ring or double arcuate scotoma. This defect is seen in advanced stages of glaucoma. * Roenne's central nasal step: It is created when two arcuate scotomas run in different arcs to form a right angled defect. This is also seen in advanced stages of glaucoma. * Peripheral field defects: Peripheral field defects may occur in early or late stages of glaucoma. Roenne's peripheral nasal steps occur due to contraction of peripheral isopter. * Tubular vision: Since macular fibers are the most resistant to glaucomatous damage, central vision remains unaffected until the end stages of glaucoma. It results in tubular vision, or

, by the loss of peripheral vision with retention of central vision, resulting in a constricted circular tunnel-like field of vision.

Retinitis pigmentosa Retinitis pigmentosa (RP) is a member of a group of genetic disorders called inherited retinal dystrophy (IRD) that cause loss of vision. Symptoms include trouble seeing at night and decreasing peripheral vision (side and upper or lower visua ...

is another disease that causes tubular vision. * Temporal island of vision: It is also seen in end stages of glaucoma. The temporal islands lie outside of the central 24 to 30° visual field, so it may not be visible with standard central field measurements done in glaucoma.

Field defects in macular degeneration (AMD)

The

of the

retina The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...

is the central area in the visual field of about 10 to 17 deg diameter (in visual angle). It is responsible for high-resolution vision in good light, in particular for ''reading''. Many diseases affecting the macula may cause defects in the central field of vision, among them

metamorphopsia Metamorphopsia (from , ) is a type of distorted vision in which a grid of straight lines appears wavy or partially blank. In addition, metamorphopsia can result in misperceptions of an object's size, shape, or distance to the viewer. People can f ...

and central

Field defects in visual pathway lesions

The

visual pathway The visual system is the physiological basis of visual perception (the ability to detect and process light). The system detects, transduces and interprets information concerning light within the visible range to construct an image and build ...

consists of structures that carry visual information from the

to the

. Lesions in the pathway cause a variety of visual field defects. The type of field defect can help localize where the lesion is located (see figure). *A lesion in the

of one eye causes partial or complete loss of vision in the same eye, with an intact field of vision in other eye. *A lesion at the proximal part of

of one eye cause, central field defect in one eye and temporal half-field defect in the other eye (not shown in the figure). *A lesion in the center of the

optic chiasma In neuroanatomy, the optic chiasm, or optic chiasma (; , ), is the part of the brain where the optic nerves cross. It is located at the bottom of the brain immediately inferior to the hypothalamus. The optic chiasm is found in all vertebrates, ...

causes bitemporal hemianopia *A lesion to the

optic tract In neuroanatomy, the optic tract () is a part of the visual system in the brain. It is a continuation of the optic nerve that relays information from the optic chiasm to the ipsilateral lateral geniculate nucleus (LGN), pretectal nuclei, and su ...

, or involving the complete

optic radiation In neuroanatomy, the optic radiation (also known as the geniculocalcarine tract, the geniculostriate pathway, and posterior thalamic radiation) are axons from the neurons in the lateral geniculate nucleus to the primary visual cortex. The optic ...

causes

homonymous hemianopia In linguistics, homonyms are words which are either; '' homographs''—words that mean different things, but have the same spelling (regardless of pronunciation), or '' homophones''—words that mean different things, but have the same pronunciat ...

*When part of the optic radiation in the

parietal lobe The parietal lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus. The parietal lobe integra ...

is affected, the resulting field defect may be inferior quadrant hemianopia

Neurological causes of visual field defects

Cerebral palsy Cerebral palsy (CP) is a group of movement disorders that appear in early childhood. Signs and symptoms vary among people and over time, but include poor coordination, spasticity, stiff muscles, Paresis, weak muscles, and tremors. There may b ...

: Field loss due to cerebral palsy may be hemianopic affecting even upper or lower half, central scotoma, peripheral scotoma, or islands of vision. *

Epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...

: Although field defects are rarely associated with epilepsy, defects may occur after temporal lobe surgery for epilepsy. *

Periventricular leukomalacia Periventricular leukomalacia (PVL) is a form of white-matter brain injury, characterized by the necrosis (more often coagulation) of white matter near the lateral ventricles. It can affect newborns and (less commonly) fetuses; premature infants ...

(PVL): Bilateral inferior visual field defects may occur due to damage of the

Other causes of field defects

* Generalized depression is seen in

cataract A cataract is a cloudy area in the lens (anatomy), lens of the eye that leads to a visual impairment, decrease in vision of the eye. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colours, blurry or ...

* Central visual field loss is seen in

Optic neuritis Optic neuritis (ON) is a debilitating condition that is defined as inflammation of cranial nerve II which results in disruption of the neurologic pathways that allow visual sensory information received by the retina to be able to be transmitted to ...

, Leber hereditary optic neuropathy, Macular hole, Cone dystrophy,

Branch retinal artery occlusion Branch retinal artery occlusion (BRAO) is a rare retinal vascular disorder in which one of the branches of the central retinal artery is obstructed. Although often grouped together under one term, the condition consists of two distinct subtypes: pe ...

etc. * Peripheral visual field loss including tunnel vision is seen in

Retinal detachment Retinal detachment is a condition where the retina pulls away from the tissue underneath it. It may start in a small area, but without quick treatment, it can spread across the entire retina, leading to serious vision loss and possibly blindness. ...

Branch retinal vein occlusion Branch retinal vein occlusion is a common retinal vascular disease of the elderly. It is caused by the occlusion of one of the branches of central retinal vein. Signs and symptoms Patients with branch retinal vein occlusion usually have a sudden ...

etc. * Hemianopia and quadrantanopia are seen in patients with

stroke Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...

traumatic brain injury A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity ranging from mild traumatic brain injury (mTBI/concussion) to severe traumati ...

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

etc. * Altitudinal visual field defect is seen

anterior ischemic optic neuropathy Anterior ischemic optic neuropathy (AION) is a medical condition involving loss of vision caused by damage to the anterior portion of the optic nerve as a result of insufficient blood supply (ischemia). This form of ischemic optic neuropathy ...

, compressive neuropathy (due to a tumor or aneurysm), Branch retinal artery occlusion, Branch retinal vein occlusion,

Coloboma A coloboma (from the Greek , meaning "defect") is a hole in one of the structures of the eye, such as the iris, retina, choroid, or optic disc. The hole is present from birth and can be caused when a gap called the choroid fissure, which is ...

Papilloedema Papilledema or papilloedema is optic disc swelling that is caused by increased intracranial pressure due to any cause. The swelling is usually bilateral and can occur over a period of hours to weeks. Unilateral presentation is extremely rare. In ...

, lesions in

visual cortex The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalam ...

etc.

Gallery

The following illustrations are a rough attempt at visualizing a number of visual field defects. Note that they do not (and cannot) visualize the percept (i.e. what is seen by the observer). For example, the visual fields for the two eyes are seen as one field. The depiction is (necessarily) much too small. The missing areas are not seen as white or black, or grey – they are simply invisible to the observer, who is, furthermore, typically unaware that they are invisible. File:fullvf.png, Paris as seen with full visual fields File:bitempvf.png, Paris as seen with

bitemporal hemianopsia Bitemporal hemianopsia is the medical description of a type of partial blindness where vision is missing in the outer half of both the right and left visual field. It is usually associated with lesions of the optic chiasm, the area where the opt ...

File:binasalvf.png, Paris as seen with

binasal hemianopsia Binasal hemianopsia is the medical description of a type of partial blindness where vision is missing in the inner half of both the right and left visual field. It is associated with certain lesions of the eye and of the central nervous system, ...

File:Paris as seen with left homonymous hemianopsia.png, Paris as seen with left

homonymous hemianopsia Hemianopsia, or hemianopia, is a visual field loss on the left or right side of the vertical midline. It can affect one eye but usually affects both eyes. Homonymous hemianopsia (or homonymous hemianopia) is hemianopic visual field loss on the s ...

File:rhvf.png, Paris as seen with right

File:Eye disease simulation, retinitis pigmentosa.jpg, Tubular vision File:Eye disease simulation, age-related macular degeneration.jpg, Central field defect in

macular degeneration Macular degeneration, also known as age-related macular degeneration (AMD or ARMD), is a medical condition which may result in blurred vision, blurred or vision loss, no vision in the center of the visual field. Early on there are often no sym ...

References

External links

*
Patient Plus
*Strasburger, Hans; Rentschler, Ingo; Jüttner, Martin (2011). Peripheral vision and pattern recognition: a review
Journal of Vision, 11(5):13, 1–82

{{Authority control Ophthalmology Vision Visual system