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Yoked prism can move the image away from primary gaze without the need for a constant head tilt or turn. Prism correction is measured in prism dioptres. A prescription that specifies prism correction will also specify the "base". The base is the thickest part of the lens and is opposite from the apex.
Prism spectacles with a single prism perform a relative displacement of the two eyes, thereby correcting eso-, exo, hyper- or hypotropia. In contrast, spectacles with prisms of equal power for both eyes, called yoked prisms (also: conjugate prisms, ambient lenses or performance glasses) shift the visual field of both eyes to the same extent.
Vision therapy is a subset of behavioral optometry. In general, vision therapists attempt to improve the vision, and therefore day-to-day well-being, of patients using "eye exercises," prism, and lenses, with more emphasis on the patient's visual function.
It is also sometimes referred to as a forcing function or a behavior-shaping constraint . A poka-yoke is any mechanism in a process that helps an equipment operator avoid ( yokeru) mistakes ( poka) and defects by preventing, correcting, or drawing attention to human errors as they occur. [1] The concept was formalized, and the term adopted, by ...
Prisms or "field expanders" that bend light have been prescribed for decades in patients with hemianopsia. Higher power Fresnel ("stick-on") prisms are commonly employed because they are thin and lightweight, and can be cut and placed in different positions on a spectacle lens.
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.
The history of film technology traces the development of techniques for the recording, construction and presentation of motion pictures. When the film medium came about in the 19th century, there already was a centuries old tradition of screening moving images through shadow play and the magic lantern that were very popular with audiences in ...
A trial frame is a tool used by ophthalmic professionals like ophthalmologists and optometrists. It is basically an adjustable spectacle frame with multiple cells, used to hold corrective lenses, and other accessories in subjective refraction (finding the correct spectacle power) and retinoscopy .
A system of mirrors or prisms that projects a lateral view of the eye against a ruler that measures the distance from the lateral canthus to the anterior surface of the cornea: To evaluate the prominence of the eye, which increases in hyperthyroidism: Luedde exophthalmometer: A transparent ruler, held against the lateral rim of the orbit