Walsh & Hoyt: Psychophysical Tests

Light represents a very small portion of the electromagnetic spectrum (wavelengths between 400 and 700 nm), is emitted by natural and artificial sources, and is reflected by objects in the environment, thereby serving as the stimulus for vision. Light entering the eye is first refracted by the tear film, cornea, and lens to form an inverted image on the retina. Photoreceptors convert this light energy into electric signals that are subsequently processed by neural elements in the retina, optic nerve, and higher visual centers of the brain. The relationship between the physical properties of light and perceptual and behavioral responses is known as visual psychophysics, which serves as the foundation for the clinical assessment of visual function.