Visual Field and Scotomas in Clinical Neuro Optometry

Visual Field

The total area in which objects can be seen in the peripheral vision while the eye is focused on a central point.

Relative Field of Vision

The usable part of the retina that can see light when the eye is looking straight ahead, limited by obstructions like the brow and nose.

Absolute Field of Vision

The total area of vision available to the eye, regardless of obstructions.

Scotoma

An area within the visual field where vision is absent or significantly reduced.

Central Scotoma

A blind spot located in the center of vision, commonly associated with macular disease.

Arcuate Scotoma

An arc-shaped blind spot that follows the path of nerve fibers, often seen in glaucoma.

Cecal Scotoma

A blind spot related to the optic disc, linked with optic nerve issues such as optic neuritis.

Localized Scotoma

A blind spot confined to a specific area, often resulting from focal retinal damage.

Diffused Scotoma

Widespread or blurry vision loss across the visual field, potentially caused by media opacities or optic nerve disease.

Peripheral Scotoma

A blind spot located in the outer vision, commonly associated with conditions like retinitis pigmentosa.

Paracentral Scotoma

A blind spot near the central vision, often an early sign of glaucoma.

Hemianopia

Loss of half of the visual field, either right or left, typically due to brain lesions.

Quadrantanopia

Loss of one-fourth of the visual field, often resulting from damage to optic radiation.

Sectoranopia

Loss of vision in a pie-shaped or wedge-like sector of the visual field, due to localized retinal or optic nerve damage.

Heteronymous Bitemporal Hemianopsia

A visual field defect where nasal fibers are affected, leading to loss of vision in the outer fields of both eyes.

Congruous Homonymous Hemianopsia

A type of visual field loss that is identical in shape and size in both eyes.

Congruous Homonymous Quadrantanopsia

Loss of one-fourth of the visual field that is the same in both eyes.

Positive Scotoma

A type of scotoma where the individual is aware of a dark spot or haze in their vision.

Negative Scotoma

A type of scotoma that is typically unnoticed until detected during vision testing.

Congruous Scotoma

Visual field loss that is identical in shape, depth, and size in both eyes.

Incongruous Scotoma

Visual field loss that differs in shape, depth, and size between the two eyes.

Homonymous Scotoma

A type of visual field loss where the same side of the visual field is affected in both eyes.

Heteronymous Scotoma

A type of visual field loss where different sides of the visual field are affected in each eye.

Absolute Scotoma

A complete loss of vision in a specific area due to damage to the optic nerve.

Heteronymous Binasal Hemianopsia

A visual field defect characterized by loss of vision in the nasal half of the visual field in both eyes, often due to damage to temporal fibers.

Sympathetic Nervous System

Part of the autonomic nervous system that prepares the body for 'fight or flight' responses, affecting ocular structures through pathways originating in the thoracic spinal cord.

Parasympathetic Nervous System

Part of the autonomic nervous system that promotes 'rest and digest' activities, affecting ocular structures through pathways originating in the midbrain and pons.

Preganglionic Neuron

A neuron that transmits impulses from the central nervous system to a ganglion in the autonomic nervous system.

Superior Cervical Ganglion

The largest sympathetic ganglion that innervates structures in the head and neck, including the eyes.

Cervical Spinal Cord

The upper part of the spinal cord that is involved in sympathetic control, particularly for ocular structures.

Lateral Gray Column

A region in the spinal cord where sympathetic fibers originate, specifically in the thoracic and upper lumbar segments.

Postganglionic fibers

Nerve fibers that exit a ganglion and innervate target organs or tissues.

Parasympathetic ganglia

Clusters of nerve cell bodies located near the target structures they innervate.

Iris dilator

A muscle that causes dilation of the pupil in response to sympathetic stimulation.

Ciliary muscle

A muscle that controls the shape of the lens for focusing, involved in accommodation.

Lacrimal gland

A gland responsible for the production of tears, with parasympathetic fibers promoting lacrimation.

Choroidal blood vessels

Blood vessels supplying the choroid layer of the eye, which can undergo vasoconstriction or vasodilation.

Preganglionic fiber

A myelinated nerve fiber that originates in the central nervous system and terminates in an autonomic ganglion.

Sympathetic fibers

Nerve fibers that are part of the sympathetic nervous system, often involved in the 'fight or flight' response.

Ciliary ganglion

A parasympathetic ganglion located in the orbit, where synapses occur for ocular innervation.

Iris sphincter

A muscle that constricts the pupil in response to parasympathetic stimulation.

Vasoconstriction

The narrowing of blood vessels, which decreases blood flow to certain areas.

Vasodilation

The widening of blood vessels, which increases blood flow to certain areas.

Short ciliary nerves

Nerves that carry postganglionic fibers from the ciliary ganglion to the eye.

Long ciliary nerves

Nerves that carry sympathetic fibers to the iris dilator and ciliary muscle.

Cavernous sinus

A cavity at the base of the skull through which cranial nerves and the internal carotid artery pass.

Oculomotor nerve

A cranial nerve that carries parasympathetic fibers to the eye, including those that innervate the ciliary ganglion.

Sympathetic root

Fibers that enter the ciliary ganglion without synapsing and continue to the eye.

Inferior division

A branch of the oculomotor nerve that carries parasympathetic fibers to the ciliary ganglion.

Palpebral fissure

The opening between the eyelids, which can widen due to sympathetic stimulation.

Nasociliary nerve

A branch of the ophthalmic division of the trigeminal nerve that carries sensory and sympathetic fibers to the eye.

Edinger-Westphal Nucleus

A cluster of neurons in the midbrain that is responsible for parasympathetic innervation to the eye.

Parasympathetic Fibers

Nerve fibers that originate from the brain and are responsible for functions such as pupillary constriction and accommodation.

Pupillary Constriction

The process of the pupil becoming smaller, which is primarily controlled by parasympathetic stimulation.

Pupillary Dilation

The process of the pupil becoming larger, which is primarily controlled by sympathetic stimulation.

Afferent Pathway

The neural pathway that carries sensory information from the body to the brain.

Efferent Pathway

The neural pathway that carries motor commands from the brain to the body.

Accommodation

The process by which the eye adjusts its focus on near objects by changing the shape of the lens.

Convergence

The inward movement of both eyes toward each other to maintain single binocular vision when focusing on a near object.

Marcus Gunn Pupil

A condition where a light directed into one eye causes a less than normal constriction response due to a defect in the afferent pathway.

Amaurotic Pupil

A condition characterized by a complete lack of direct and consensual pupillary response to light due to severe disruption in the afferent pathway.

Pretectal Nucleus

A region in the midbrain involved in the pupillary light reflex, where afferent pupillary fibers synapse.

Sphincter Muscle

A muscle in the iris that constricts the pupil in response to parasympathetic stimulation.

Pupillary Light Reflex

The reflex that controls the diameter of the pupil in response to light intensity.

Posterior Commissure

A bundle of nerve fibers that connects the two sides of the brain, involved in the pupillary light reflex.

Near-Point Reaction

A response involving convergence, accommodation, and miosis when focusing on a nearby object.

Relative Afferent Pupillary Defect (RAPD)

A condition where one eye shows a diminished response to light compared to the other, detected through the swinging flashlight test.

Total Afferent Pupillary Defect (TAPD)

A condition where there is no constriction of the pupil in response to light in the affected eye, indicating a complete loss of sensory input.

Tonic Pupil

A pupil that is dilated and reacts poorly to light, characterized by a slow and sluggish response, often due to damage to the ciliary ganglion.

Argyll Robertson Pupil

A pupil that constricts poorly to light but reacts normally to accommodation, often associated with CNS lesions.

Horner's Syndrome

A neurological condition characterized by ptosis, miosis, and facial anhidrosis due to disruption of sympathetic innervation.

Iris Heterochromia

A condition where there is a difference in coloration of the irises, often seen in congenital cases of Horner's syndrome.

Consensual Reflex

The response of both pupils to light, where shining light in one eye causes both pupils to constrict.