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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. Light will be bent towards the base and the ...
Eyeglass prescription. An eyeglass prescription is an order written by an eyewear prescriber, such as an optometrist, that specifies the value of all parameters the prescriber has deemed necessary to construct and/or dispense corrective lenses appropriate for a patient. If an eye examination indicates that corrective lenses are appropriate, the ...
Lenticular lenses are sometimes used as corrective lenses for improving vision. A bifocal lens could be considered a simple example. Lenticular eyeglass lenses have been employed to correct extreme hyperopia (farsightedness), a condition often created by cataract surgery when lens implants are not possible.
Flint glasses are arbitrarily defined as having an Abbe number of 50 to 55 or less. The currently known flint glasses have refractive indices ranging between 1.45 and 2.00. Traditionally, flint glasses were lead glasses containing around 4–60% lead(II) oxide ; however, the manufacture and disposal of these glasses were sources of pollution .
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. [1] It is used by ophthalmologists and orthoptists in order to measure the vertical and horizontal deviation and includes both manifest and latent components. [1]
The calculation of glass properties allows "fine-tuning" of desired material characteristics, e.g., the refractive index.. The calculation of glass properties (glass modeling) is used to predict glass properties of interest or glass behavior under certain conditions (e.g., during production) without experimental investigation, based on past data and experience, with the intention to save time ...