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Eye care professionals use prism correction as a component of some eyeglass prescriptions. A lens which includes some amount of prism correction will displace the viewed image horizontally, vertically, or a combination of both directions. The most common application for this is the treatment of strabismus.
The prism cover test (PCT) is an objective measurement and the gold standard in measuring strabismus, i.e. ocular misalignment, or a deviation of the eye. It is used by ophthalmologists and orthoptists in order to measure the vertical and horizontal deviation and includes both manifest and latent components. [1]
Prism and Base Prism refers to a displacement of the image through the lens, often used to treat strabismus and other binocular vision disorders. The prism value is measured in prism diopters , and Base refers to the direction of displacement.
Chromatic aberration. In optics, chromatic aberration ( CA ), also called chromatic distortion and spherochromatism, is a failure of a lens to focus all colors to the same point. [1] It is caused by dispersion: the refractive index of the lens elements varies with the wavelength of light.
Aberrations of the eye. The eye, like any other optical system, suffers from a number of specific optical aberrations. The optical quality of the eye is limited by optical aberrations, diffraction and scatter. [1] Correction of spherocylindrical refractive errors has been possible for nearly two centuries following Airy's development of methods ...
Convergence Insufficiency. Other names. Convergence disorder. Specialty. Ophthalmology, optometry. Convergence insufficiency is a sensory and neuromuscular anomaly of the binocular vision system, characterized by a reduced ability of the eyes to turn towards each other, or sustain convergence .
Purpose. assess degree of binocular vision. The Worth Four Light Test, also known as the Worth's four dot test or W4LT, is a clinical test mainly used for assessing a patient's degree of binocular vision and binocular single vision. Binocular vision involves an image being projected by each eye simultaneously into an area in space and being ...
The Micro Four Thirds system cameras and lenses perform automatic distortion correction using correction parameters that are stored in each lens's firmware, and are applied automatically by the camera and raw converter software. The optics of most of these lenses feature substantially more distortion than their counterparts in systems that do ...
The Prentice position is an orientation of a prism, used in optics, optometry and ophthalmology. In this position, named after the optician Charles F. Prentice , the prism is oriented such that light enters it at an angle of 90° to the first surface, so that the beam does not refract at that surface.
A second peg, below it, can be moved back and forth until it is just detectably nearer than the fixed one. Stereoacuity is defined as the minimum angle detectable, calculated as the difference between the angles subtended by both positions, A and B. Stereoacuity is possible due to binocular disparity, i.e., the difference in their binocular ...