Visual Perception and Color Theory

Nearsightedness

A condition where distant objects appear blurry because the eye is too long, causing light to focus before reaching the retina.

Farsightedness

A condition where close objects appear blurry because the eye is too short, causing light to focus behind the retina.

Astigmatism

A condition caused by an irregularly shaped cornea, leading to distorted or blurred vision at all distances.

Cornea

The clear front surface of the eye that provides most of the eye's focusing power.

Lens

A flexible structure in the eye that helps focus light onto the retina.

Ciliary muscles

Muscles that adjust the shape of the lens to focus on objects at various distances.

Fovea

The central part of the retina where visual acuity is highest.

Vitreous humor

The clear gel that fills the space between the lens and the retina, providing shape and support to the eye.

Glaucoma

A condition characterized by increased pressure in the eye, which can lead to damage of the optic nerve and vision loss.

Transduction

The process of converting physical stimuli (like light) into electrical signals that can be interpreted by the brain.

Rods

Photoreceptors in the retina that are sensitive to low light levels, mainly responsible for night vision.

Cones

Photoreceptors in the retina that detect color and are responsible for high acuity vision in bright light.

Trichromatic theory

A theory of color vision stating that color perception is based on the activation of three types of cones sensitive to short, medium, and long wavelengths.

Opponent process theory

A theory of color vision suggesting that colors are perceived in terms of opposing pairs (red-green, blue-yellow, black-white).

Afterimages

Visual sensations that persist after the initial stimulus has been removed, often used to demonstrate the opponent process theory.

Bottom up processing

A cognitive process that starts with sensory input, moving from the specific details to the general perception.

Top down processing

A cognitive process that starts with the general perception, influenced by context and prior knowledge, to interpret sensory information.

Retina

The light-sensitive layer at the back of the eye that converts light into neural signals, essential for visual perception.

Optic nerve

The bundle of nerve fibers that transmits visual information from the retina to the brain, where it is processed to create visual images.

Blind spot

The region on the retina where the optic nerve exits the eye, lacking photoreceptors, resulting in a gap in the visual field.

sensation

The process by which sensory receptors and the nervous system receive and represent stimulus energies from our environment, forming the basis of perception.

Retinex theory

A theory of color perception that explains how the brain perceives colors based on the relative intensity of light across different areas, accounting for variations in lighting conditions.