human eye

Table of Contents

Introduction
Anatomy of the visual apparatus
- Structures auxiliary to the eye
  - The orbit
  - The eyelids
    - The conjunctiva
    - The fibrous layer
    - The muscles of the lids
    - The skin
  - The glandular apparatus
  - Extraocular muscles
- The eye
  - General description
  - Outer and middle tunics of the globe
    - The outermost coat
    - The uvea
  - The inner tunic of the globe
    - The epithelia
    - The retina
  - The transparent media
    - The aqueous humour
    - The vitreous body
    - The crystalline lens
The visual process
- The work of the auxiliary structures
  - The protective mechanisms
    - Innervation
    - Blink reflexes
    - Normal rhythm
    - Secretion of tears
  - Movements of the eyes
    - The axes of the eye
    - Actions of muscles
    - Binocular movements
    - Nervous control
    - Reflex pathways
    - Voluntary centre
    - The nature of eye movements
    - Vision suppression during a saccade
- The work of the optical lens system
  - Refraction by cornea and lens
  - Normal sightedness and near- and farsightedness
  - Accommodation
    - Effects of accommodation
    - Mechanism of accommodation
    - Nerve action
  - The pupil
  - The near response
The work of the retina
- Some basic facts of vision
  - Measurement of the threshold
  - Scotopic sensitivity curve
  - Loss of dark adaptation
  - Bleaching of rhodopsin
- Synaptic organization of the retina
  - Plexiform layers
  - Convergence of the messages
- Absolute threshold and minimum stimulus for vision
  - Quantum fluctuations
  - Spatial summation
  - Temporal summation
- Inhibition
- Flicker
- Visual acuity
  - Measurement
  - Anatomical basis: the retinal mosaic
  - The retinal image
- Electrophysiology of the retina
  - Neurological basis
  - Anatomical basis
  - Direction-sensitive ganglion cells
  - The electroretinogram
  - Flicker
  - Visual acuity
- Colour vision
  - Spectral sensitivity curve
  - Colour mixing
  - Colour defectiveness
  - Responses of uniform population of photoreceptors
  - Young-Helmholtz theory
  - The nervous messages
  - Lateral geniculate cells
- The photochemical process
  - Rhodopsin
  - The transduction process
  - Cone pigments
The higher visual centres
- The visual pathway
  - Fusion of retinal images
  - The visual field
  - Lateral geniculate body
  - Striate area
  - Pupillary pathways
  - Point-to-point representation
  - Visuopsychic or circumstriate areas
- Integration of the retinal halves
  - Corpus callosum
  - Stereopsis in the midline
  - Callosal transfer
  - Superior colliculi
Some perceptual aspects of vision
- Projection of the retina
  - Relative positions of objects
  - Position in relation to observer
- Visual estimates
  - The directions of lines
  - Comparison of lengths
  - Optical illusions
- The perception of depth
  - Monocular cues
  - Binocular vision
- Retinal rivalry
  - Ocular dominance
  - Binocular brightness sensation
Electrophysiology of the visual centres
- Ganglion cells
- Geniculate neurons
- Cortical neurons
  - Eye dominance
  - Cortical architecture
  - Complex neurons
- Stereoscopic vision

References & Edit History Related Topics

Images, Videos & Interactives

cross section of the human eye

Human body systems interactive

structure of the retina

muscles of the right eye

visual pathways in the human brain

visual field of the human eye

For Students

human eye summary

Read Next

Hand washing. Healthcare worker washing hands in hospital sink under running water. contagious diseases wash hands, handwashing hygiene, virus, human health

17 Questions About Health and Wellness Answered

Discover

Orange basketball on black background and with low key lighting. Homepage 2010, arts and entertainment, history and society

The 10 Greatest Basketball Players of All Time

Fish. Lionfish. Lion-fish. Turkey fish. Fire-fish. Red lionfish. Pterois volitans. Venomous fin spines. Coral reefs. Underwater. Ocean. Red lionfish swims by seaweed.

10 of the World’s Most Dangerous Fish

Watergate scandal. Richard M. Nixon. President Nixon gives a press conference and talks to the press, March 12, 1971.

9 American Political Scandals

Scottish fold cat. A genetic mutation caused (in the original cat-1961) the ears to bend forward and down.

Shorthair Cat Breeds

Stylish light blue jeans on wooden background, closeup of inset pocket

Why Do Jeans Have That Tiny Pocket?

Close-up of ostriches (Struthio camelus) necks and heads; location unknown.

6 of the World's Most Dangerous Birds

Saint Lucia Day. Young girl wears Lucia crown (tinsel halo) with candles. Holds Saint Lucia Day currant laced saffron buns (lussekatter or Lucia's cats). Observed December 13 honor virgin martyr Santa Lucia (St. Lucy). Luciadagen, Christmas, Sweden

7 Winter Solstice Celebrations From Around the World

cross section of the human eye — cross section of the human eye A horizontal cross section of the human eye, showing the major parts of the eye, including the protective covering of the cornea over the front of the eye.

human eye

anatomy

Written by Hugh Davson, Edward S. Perkins•All

Fact-checked by The Editors of Encyclopaedia Britannica

Last Updated: Dec 16, 2024 • Article History

Related Topics:: eyeball; tear duct and glands; optic nerve; eyelid; visual pigment

See all related content

human eye, in humans, specialized sense organ capable of receiving visual images, which are then carried to the brain. The eye is protected from mechanical injury by being enclosed in a socket, or orbit, which is made up of portions of several of the bones of the skull to form a four-sided pyramid, the apex of which points back into the head. Thus, the floor of the orbit is made up of parts of the maxilla, zygomatic, and palatine bones, while the roof is made up of the orbital plate of the frontal bone and, behind this, by the lesser ...(100 of 31643 words)

Access the full article

Help support true facts by becoming a member.