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  2. Eye chart - Wikipedia

    en.wikipedia.org/wiki/Eye_chart

    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.

  3. Snellen chart - Wikipedia

    en.wikipedia.org/wiki/Snellen_chart

    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 developed by his professor ...

  4. Abbe–Koenig prism - Wikipedia

    en.wikipedia.org/wiki/Abbe–Koenig_prism

    An Abbe–Koenig prism is a type of reflecting prism, used to invert an image (rotate it by 180°). They are commonly used in binoculars and some telescopes for this purpose. The prism is named after Ernst Abbe and Albert Koenig . The prism is made from two glass prisms, which are optically cemented together to form a symmetric, shallow Vee ...

  5. Eye color - Wikipedia

    en.wikipedia.org/wiki/Eye_color

    Eye color. Eye color is a polygenic phenotypic trait determined by two factors: the pigmentation of the eye 's iris [1] [2] and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris. [3] : 9. In humans, the pigmentation of the iris varies from light brown to black, depending on the concentration of ...

  6. 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.

  7. Correction fluid - Wikipedia

    en.wikipedia.org/wiki/Correction_fluid

    A correction fluid is an opaque, usually white fluid applied to paper to mask errors in text. Once dried, it can be handwritten or typed upon. It is typically packaged in small bottles, with lids attached to brushes (or triangular pieces of foam) that dip into the fluid. The brush applies the fluid to the paper.

  8. Roof prism - Wikipedia

    en.wikipedia.org/wiki/Roof_prism

    Roof prism. A roof pentaprism used in Single-lens reflex cameras; the lower right face is the roof ( dach ). A roof prism, also called a Dachkanten prism or Dach prism (from German: Dachkante, lit. "roof edge"), is a reflective prism containing a section where two faces meet at a 90° angle, resembling the roof of a building and thus the name.

  9. List of optometric abbreviations - Wikipedia

    en.wikipedia.org/wiki/List_of_optometric...

    Description ( notes ) AC. Anterior chamber. fluid-filled space between the iris and the endothelium. AC 4/4. Grade 4 anterior chamber angle. open angle between cornea and iris. AC 3/4. Grade 3 anterior chamber angle.