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  2. Prism correction - Wikipedia

    en.wikipedia.org/wiki/Prism_correction

    Prism correction. Prism lenses (here unusually thick) are used for pre-operative prism adaptation. 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.

  3. Prism cover test - Wikipedia

    en.wikipedia.org/wiki/Prism_Cover_Test

    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]

  4. Duochrome test - Wikipedia

    en.wikipedia.org/wiki/Duochrome_test

    A duochrome test is a test commonly used to refine the final sphere in refraction (undercorrection and overcorrection), which makes use of the longitudinal chromatic aberration of the eye. Because of the chromatic aberration of the eye, the shorter wavelengths (green) are focused in front of the longer red wavelengths.

  5. List of instruments used in ophthalmology - Wikipedia

    en.wikipedia.org/wiki/List_of_instruments_used...

    to correct refractive errors of the eye; a little invasive. Phoropter. used in refraction testing. Tonometers. used to determine the intraoccular pressure (IOP) - useful in glaucoma; video link for various types of tonometers. Speculum: to keep the eyes open during any operation. Universal eye speculum.

  6. Subjective refraction - Wikipedia

    en.wikipedia.org/wiki/Subjective_refraction

    It is a clinical examination used by orthoptists, optometrists and ophthalmologists to determine a patient's need for refractive correction, in the form of glasses or contact lenses. The aim is to improve current unaided vision or vision with current glasses.

  7. Eyeglass prescription - Wikipedia

    en.wikipedia.org/wiki/Eyeglass_prescription

    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.

  8. Aberrations of the eye - Wikipedia

    en.wikipedia.org/wiki/Aberrations_of_the_eye

    It has only recently [when?] become possible to measure the aberrations of the eye and with the advent of refractive surgery it might be possible to correct certain types of irregular astigmatism.

  9. Corrective lens - Wikipedia

    en.wikipedia.org/wiki/Corrective_lens

    A corrective lens is a transmissive optical device that is worn on the eye to improve visual perception. The most common use is to treat refractive errors: myopia, hypermetropia, astigmatism, and presbyopia. Glasses or "spectacles" are worn on the face a short distance in front of the eye.

  10. Prentice position - Wikipedia

    en.wikipedia.org/wiki/Prentice_position

    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. All the deviation caused by the prism takes ...

  11. Category:Corrective lenses - Wikipedia

    en.wikipedia.org/wiki/Category:Corrective_lenses

    A corrective lens is a lens worn on or before the eye. They are used to treat myopia, hypermetropia, astigmatism, and presbyopia