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Aperture. In biology, the pupil (appearing as a black hole) of the eye is its aperture and the iris is its diaphragm. In humans, the pupil can constrict to as small as 2 mm ( f/ 8.3) and dilate to larger than 8 mm ( f/ 2.1) in some individuals. In optics, the aperture of an optical system (including a system consisted of a single lens) is a ...
The human eye is a sensory organ in the visual system that reacts to visible light allowing eyesight. Other functions include maintaining the circadian rhythm, and keeping balance . Arizona Eye Model. "A" is accommodation in diopters. The eye can be considered as a living optical device. It is approximately spherical in shape, with its outer ...
Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its distance varies. In this, distances vary for individuals from the far point —the maximum distance from the eye for which a clear image of an object can be seen, to the near point —the minimum distance for a ...
Adaptation (eye) In visual physiology, adaptation is the ability of the retina of the eye to adjust to various levels of light. Natural night vision, or scotopic vision, is the ability to see under low-light conditions. In humans, rod cells are exclusively responsible for night vision as cone cells are only able to function at higher ...
Stereopsis. Stereopsis (from Ancient Greek στερεός ( stereós) 'solid' and ὄψις (ópsis) 'appearance, sight') is the component of depth perception retrieved through binocular vision. [ 1] Stereopsis is not the only contributor to depth perception, but it is a major one. Binocular vision happens because each eye receives a different ...
Depth perception. Perspective, relative size, occultation and texture gradients all contribute to the three-dimensional appearance of this photo. Depth perception is the ability to perceive distance to objects in the world using the visual system and visual perception. It is a major factor in perceiving the world in three dimensions.
Rod cells are photoreceptor cells in the retina of the eye that can function in lower light better than the other type of visual photoreceptor, cone cells. Rods are usually found concentrated at the outer edges of the retina and are used in peripheral vision. On average, there are approximately 92 million rod cells (vs ~6 million cones) in the ...
The functional unit of the eye is the photoreceptor cell, which contains the opsin proteins and responds to light by initiating a nerve impulse. The light sensitive opsins are borne on a hairy layer, to maximise the surface area. The nature of these "hairs" differs, with two basic forms underlying photoreceptor structure: microvilli and cilia. [26]