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  2. Visual acuity - Wikipedia

    en.wikipedia.org/wiki/Visual_acuity

    Between these extremes is the pupil diameter that is generally best for visual acuity in normal, healthy eyes; this tends to be around 3 or 4 mm. If the optics of the eye were otherwise perfect, theoretically, acuity would be limited by pupil diffraction, which would be a diffraction-limited acuity of 0.4 minutes of arc (minarc) or 6/2.6 acuity.

  3. Corrective lens - Wikipedia

    en.wikipedia.org/wiki/Corrective_lens

    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.

  4. Base curve radius - Wikipedia

    en.wikipedia.org/wiki/Base_curve_radius

    Typical values for a contact lens are from 8.0 to 10.0 mm. The base curve is the radius of the sphere of the back of the lens that the prescription describes (the lower the number, the steeper the curve of the cornea and the lens, the higher the number, the flatter the curve of the cornea and the lens).

  5. MNREAD acuity chart - Wikipedia

    en.wikipedia.org/wiki/MNREAD_acuity_chart

    The MNREAD acuity chart or Minnesota low vision reading chart is a text based chart used to measure near visual acuity in people with normal or low vision. [1] It can also be used to measure maximum reading speed, critical print size and the reading accessibility index of a person. [2] Digital and printed types of charts are available.

  6. Snellen chart - Wikipedia

    en.wikipedia.org/wiki/Snellen_chart

    Snellen chart. Purpose. Snellen chart is used to estimate visual acuity (last three rows are 20/15, 20/13 and 20/10) A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen who developed the chart in 1862 as a measurement tool for the acuity formula ...

  7. Eye chart - Wikipedia

    en.wikipedia.org/wiki/Eye_chart

    Landolt C. Lea test. logMAR chart. An eye chart is a chart used to measure visual acuity comprising lines of optotypes in ranges of sizes. Optotypes are the letters or symbols shown on an eye chart. [ 1] Eye charts are often used by health care professionals, such as optometrists, physicians and nurses, to screen persons for vision impairment.

  8. Contact lens - Wikipedia

    en.wikipedia.org/wiki/Contact_lens

    Contact lens. A pair of contact lenses, positioned with the concave side facing upward. Putting contacts in and taking them out. One-day disposable contact lenses with blue handling tint in blister-pack packaging. Contact lenses, or simply contacts, are thin lenses placed directly on the surface of the eyes. Contact lenses are ocular prosthetic ...

  9. Progressive lens - Wikipedia

    en.wikipedia.org/wiki/Progressive_lens

    The gradient starts at the wearer's distance prescription at the top of the lens and reaches a maximum addition power, or the full reading addition, at the bottom of the lens. The length of the progressive power gradient on the lens surface depends on the design of the lens, with a final addition power between 0.75 and 3.50 dioptres .

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