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The usual recommendation for those needing iseikonic correction is to wear contact lenses. The effect of vertex distance is removed and the effect of center thickness is also almost removed, meaning there is minimal and likely unnoticeable image size difference. This is a good solution for those who can tolerate contact lenses.
Prentice's rule, named so after the optician Charles F. Prentice, is a formula used to determine the amount of induced prism in a lens: = where: P is the amount of prism correction (in prism dioptres) c is decentration (the distance between the pupil centre and the lens's optical centre, in millimetres)
Ophthalmology. Esotropia is a form of strabismus in which one or both eyes turn inward. The condition can be constantly present, or occur intermittently, and can give the affected individual a "cross-eyed" appearance. [1] It is the opposite of exotropia and usually involves more severe axis deviation than esophoria.
A liquid-crystal display ( LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly [1] but instead use a backlight or reflector to produce images in color or monochrome.
The Prentice position is an orientation of a prism, used in optics, optometry and ophthalmology. [1] 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. All the deviation caused by the prism ...
Esophoria is an eye condition involving inward deviation of the eye, usually due to extra-ocular muscle imbalance. It is a type of heterophoria. Cause. Causes include: Refractive errors; Divergence insufficiency; Convergence excess; this can be due to nerve, muscle, congenital or mechanical anomalies.
In materials science, effective medium approximations ( EMA) or effective medium theory ( EMT) pertain to analytical or theoretical modeling that describes the macroscopic properties of composite materials. EMAs or EMTs are developed from averaging the multiple values of the constituents that directly make up the composite material.
This method is a practical procedure to reduce celestial sights with the needed accuracy, without using electronic tools such as calculator or a computer. And it could serve as a backup in case of malfunction of the positioning system aboard.
The name horror fusionis (Latin phrase literally meaning "fear of fusion") arises from the notion that the brain is, or at least appears to be, actively preventing binocular fusion. The condition is an extreme type of binocular fusion deficiency. [1]
The mathematical derivation for the Eötvös effect for motion along the Equator explains the factor 2 in the first term of the Eötvös correction formula. What remains to be explained is the cosine factor. Because of its rotation, the Earth is not spherical in shape, there is an Equatorial bulge.