Search results
Results from the WOW.Com Content Network
Prentice's rule is a formula to calculate the amount of prism correction in a lens based on decentration and lens power. It can be used for prescribing, tolerance control, or determining unprescribed prism in eyeglasses.
A cover test is an objective determination of the presence and amount of ocular deviation, such as strabismus or phoria. It involves covering and uncovering one eye while observing the movement of the other eye with a fixation target at different distances.
Esophoria is an eye condition involving inward deviation of the eye, usually due to extra-ocular muscle imbalance. It is a type of heterophoria and can be caused by refractive errors, divergence insufficiency or convergence excess.
The prism cover test (PCT) is an objective method to measure ocular misalignment or deviation of the eye. It involves using prism bars, occluder, and targets to neutralise the deviation and record the angle and base of the prism.
Learn about the different types of optical prisms, such as dispersive, reflective, beam-splitting and polarizing prisms, and how they refract, reflect or split light. Find out how prisms are made of transparent materials like glass, acrylic or fluorite, and how they can create spectra, images or polarizations.
The Maddox rod test is a subjective method to measure horizontal and vertical deviations of the eyes, using a red line and a white light. The double Maddox rod test can also assess torsion and cyclotropias, by comparing the angles of two red lines.
Diplopia is the simultaneous perception of two images of a single object, which may be voluntary or involuntary. It can result from various ophthalmologic, neurological, or systemic disorders, and can be classified as monocular or binocular, acute or chronic, and suppressed or not.
Maddox wing is an instrument for measuring strabismus (eye misalignment) by dissociating the eyes with septa and arrows. Learn about its indications, equipment, method, interpretation, advantages, disadvantages and considerations.