Chapter 3: The Eye and the Retina

Larry Hester

A person diagnosed with retinitis pigmentosa, a genetic disorder affecting vision.

Retinitis pigmentosa

A genetic disorder of the eye that leads to progressive vision decline.

Bionic eye

A device that uses an array of electrodes and a camera to send visual signals to the brain.

Visual process

The four steps involved in seeing, including distal stimulus, proximal stimulus, transformation of light, and processing of electrical signals.

Distal stimulus

The initial object in the environment that reflects light, such as a tree.

Proximal stimulus

The image created on the visual receptors after light is reflected from the distal stimulus.

Visual receptors

Cells in the eye that transform light into electrical signals.

Electrical signals

The transformed signals that travel through neurons for visual processing.

Light

The stimulus necessary for vision, part of the electromagnetic spectrum.

Electromagnetic spectrum

A continuum of electromagnetic energy produced by electric charges, radiated as waves.

Wavelength

The distance between the peaks of electromagnetic waves, determining the type of electromagnetic radiation.

Gamma rays

Extremely short-wavelength electromagnetic waves, measuring about one ten-billionth of a meter.

Radio waves

Long-wavelength electromagnetic waves, measuring about 10,000 meters.

Visible light

The portion of the electromagnetic spectrum that humans can perceive, associated with different colors.

Color perception

The association of visible light wavelengths with colors, where short wavelengths appear blue, and long wavelengths appear yellow, orange, and red.