42 relations: Accommodation reflex, Accommodative infacility, Accommodative insufficiency, Adaptation (eye), Alexander Duane, Amplitude of accommodation, Aperture, Binocular vision, Catenary, Ciliary body, Ciliary muscle, Cycloplegia, Cyclospasm, D. Jackson Coleman, Depth of field, Dioptre, Diplopia, Edinger–Westphal nucleus, Emmetropia, Esotropia, Eye, Far point, Far-sightedness, Focus (optics), Hermann von Helmholtz, Lens (anatomy), Mandelbaum effect, Miosis, Near-sightedness, Negative relative accommodation, Optical power, Positive relative accommodation, Presbyopia, Pseudomyopia, Pupil, Sclera, Spasm of accommodation, Stewart Duke-Elder, Vergence, Vertebrate, Vision in fishes, Zonule of Zinn.
The accommodation reflex (or accommodation-convergence reflex) is a reflex action of the eye, in response to focusing on a near object, then looking at a distant object (and vice versa), comprising coordinated changes in vergence, lens shape and pupil size (accommodation).
Accommodative infacility is the inability to change the accommodation of the eye with enough speed and accuracy to achieve normal function.
Accommodative insufficiency (AI) involves the inability of the eye to focus properly on an object.
In ocular physiology, adaptation is the ability of the eye to adjust to various levels of light.
Alexander Duane (September 1, 1858 – June 10, 1926) was an American ophthalmologist who was a native of Malone, New York.
The amplitude of accommodation is the maximum potential increase in optical power that an eye can achieve in adjusting its focus.
In optics, an aperture is a hole or an opening through which light travels.
In biology, binocular vision is a type of vision in which an animal having two eyes is able to perceive a single three-dimensional image of its surroundings.
In physics and geometry, a catenary is the curve that an idealized hanging chain or cable assumes under its own weight when supported only at its ends.
The ciliary body is a part of the eye that includes the ciliary muscle, which controls the shape of the lens, and the ciliary epithelium, which produces the aqueous humor.
The ciliary muscle is a ring of smooth muscleSchachar, Ronald A. (2012). "Anatomy and Physiology." (Chapter 4). in the eye's middle layer (vascular layer) that controls accommodation for viewing objects at varying distances and regulates the flow of aqueous humour into Schlemm's canal. It changes the shape of the lens within the eye, not the size of the pupil which is carried out by the sphincter pupillae muscle and dilator pupillae.
Cycloplegia is paralysis of the ciliary muscle of the eye, resulting in a loss of accommodation.
Cyclospasm is the contraction of the ciliary muscle in the eye, in the accommodation of focus for near vision.
In optics, particularly as it relates to film and photography, the optical phenomenon known as depth of field (DOF), is the distance about the Plane of Focus (POF) where objects appear acceptably sharp in an image.
A dioptre (British spelling) or diopter (American spelling) is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres.
Diplopia, commonly known as double vision, is the simultaneous perception of two images of a single object that may be displaced horizontally, vertically, diagonally (i.e., both vertically and horizontally), or rotationally in relation to each other.
The Edinger–Westphal nucleus (accessory oculomotor nucleus) is the parasympathetic pre-ganglionic nucleus that innervates the iris sphincter muscle and the ciliary muscle.
Emmetropia is the state of vision where a faraway object at infinity is in sharp focus with the eye lens in a neutral or relaxed state.
Esotropia is a form of strabismus in which one or both eyes turns inward.
Eyes are organs of the visual system.
In visual perception, the far point is the point at which an object must be placed along the optical axis of the eye for its image to be focused on the retina when the eye is not accommodating.
Far-sightedness, also known as hyperopia, is a condition of the eye in which light is focused behind, instead of on, the retina.
In geometrical optics, a focus, also called an image point, is the point where light rays originating from a point on the object converge.
Hermann Ludwig Ferdinand von Helmholtz (August 31, 1821 – September 8, 1894) was a German physician and physicist who made significant contributions in several scientific fields.
The lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina.
The Mandelbaum effect is the tendency for the eye to focus nearby in conditions of poor visibility.
Miosis is excessive constriction of the pupil.
Near-sightedness, also known as short-sightedness and myopia, is a condition of the eye where light focuses in front of, instead of on, the retina.
Negative relative accommodation (NRA) was proposed by Joseph Kearney of Oxford University in 1967 as a measure of the maximum ability to relax accommodation while maintaining clear, single binocular vision.
Optical power (also referred to as dioptric power, refractive power, focusing power, or convergence power) is the degree to which a lens, mirror, or other optical system converges or diverges light.
Positive relative accommodation (PRA) is a measure of the maximum ability to stimulate accommodation while maintaining clear, single binocular vision.
Presbyopia is a condition associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects.
Pseudomyopia refers to an intermittent and temporary shift in refractive error of the eye towards myopia, in which the focusing of light in front of the retina is due to a transient spasm of the ciliary muscle causing an increase in the refractive power of the eye.
The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina.
The sclera, also known as the white of the eye, is the opaque, fibrous, protective, outer layer of the human eye containing mainly collagen and some elastic fiber.
A spasm of accommodation (also known as a ciliary spasm, an accommodation, or accommodative spasm) is a condition in which the ciliary muscle of the eye remains in a constant state of contraction.
Sir William Stewart Duke-Elder (22 April 1898 – 27 March 1978), a Scottish ophthalmologist who was a dominant force in his field for more than a quarter of a century.
A vergence is the simultaneous movement of both eyes in opposite directions to obtain or maintain single binocular vision.
Vertebrates comprise all species of animals within the subphylum Vertebrata (chordates with backbones).
Vision is an important sensory system for most species of fish.
The zonule of Zinn (Zinn's membrane, ciliary zonule) (after Johann Gottfried Zinn) is a ring of fibrous strands forming a zonule (little band) that connects the ciliary body with the crystalline lens of the eye.