Sections
Glossary
Glossary
- aberration
- failure of rays to converge at one focus because of limitations or defects in a lens or mirror
- accommodation
- the ability of the eye to adjust its focal length is known as accommodation
- adaptive optics
- optical technology in which computers adjust the lenses and mirrors in a device to correct for image distortions
- angular magnification
- a ratio related to the focal lengths of the objective and eyepiece and given as
- astigmatism
- the result of an inability of the cornea to properly focus an image onto the retina
- color constancy
- a part of the visual perception system that allows people to perceive color in a variety of conditions and to see some consistency in the color
- compound microscope
- a microscope constructed from two convex lenses, the first serving as the ocular lens—close to the eye—and the second serving as the objective lens
- eyepiece
- the lens or combination of lenses in an optical instrument nearest to the eye of the observer
- far point
- the object point imaged by the eye onto the retina in an unaccommodated eye
- farsightedness
- another term for hyperopia, the condition of an eye where incoming rays of light reach the retina before they converge into a focused image
- hues
- identity of a color as it relates specifically to the spectrum
- hyperopia
- the condition of an eye where incoming rays of light reach the retina before they converge into a focused image
- laser vision correction
- a medical procedure used to correct astigmatism and eyesight deficiencies such as myopia and hyperopia
- myopia
- a visual defect in which distant objects appear blurred because their images are focused in front of the retina rather than being focused on the retina
- near point
- the point nearest the eye at which an object is accurately focused on the retina at full accommodation
- nearsightedness
- another term for myopia, a visual defect in which distant objects appear blurred because their images are focused in front of the retina rather than being focused on the retina
- numerical aperture
- a number or measure that expresses the ability of a lens to resolve fine detail in an object being observed. Derived by mathematical formula
9.28
where is the refractive index of the medium between the lens and the specimen and
- objective lens
- the lens nearest to the object being examined
- presbyopia
- a condition in which the lens of the eye becomes progressively unable to focus on objects close to the viewer
- retinex
- a theory proposed to explain color and brightness perception and constancies; is a combination of the words retina and cortex, which are the two areas responsible for the processing of visual information
- retinex theory of color vision
- the ability to perceive color in an ambient-colored environment
- rods and cones
- two types of photoreceptors in the human retina; rods are responsible for vision at low light levels, while cones are active at higher light levels
- simplified theory of color vision
- a theory that states that there are three primary colors, which correspond to the three types of cones