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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.
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.
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.
Scintillating scotoma is a visual aura that may precede a migraine headache, but can also occur without headache. It causes flickering spots or patterns in the visual field, often resembling zigzag lines or fortifications, and lasts less than 60 minutes.
Learn about the band of electromagnetic radiation that is visible to the human eye, and how it is dispersed by a prism into colors. Explore the history, properties, and applications of the visible spectrum, and the difference between spectral and unsaturated colors.
The direct effect adaptation observed as a result of prism exposure persists and results in what is known as the prism adaptation negative after-effect. The negative after-effect causes the initial attempts in pointing to the visual target during the post-test to be in the direction opposite that of the visual shift.
The Four Prism Dioptre Reflex Test (also known as the 4 PRT, or 4 Prism Dioptre Base-out Test) is an objective, non-dissociative test used to prove the alignment of both eyes (i.e. the presence of binocular single vision) by assessing motor fusion. [1]
Learn about the optical aberrations that affect the quality of vision in the human eye, such as spherical, coma and trefoil aberrations. Find out how they are measured, corrected and influenced by factors such as age, accommodation and pupil size.