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2. Eyeglass prescription - Wikipedia

   en.wikipedia.org/wiki/Eyeglass_prescription

   This specifies the part of the prescription designed primarily to improve far vision. In a bifocal lens, this generally indicates what is to be placed in the top segment. NV is an abbreviation for near vision. This may represent a single-vision lens prescription to improve near work, or the reading portion of a bifocal lens.

3. Eyepiece - Wikipedia

   en.wikipedia.org/wiki/Eyepiece

   The lenses are called the eye lens and the field lens. The focal plane is located between the two lenses. It was invented by Christiaan Huygens in the late 1660s and was the first compound (multi-lens) eyepiece. [ 2 ]

4. Condenser (optics) - Wikipedia

   en.wikipedia.org/wiki/Condenser_(optics)

   As with objective lenses, a condenser lens with a maximum numerical aperture of greater than 0.95 is designed to be used under oil immersion (or, more rarely, under water immersion), with a layer of immersion oil placed in contact with both the slide/coverslip and the lens of the condenser. An oil immersion condenser may typically have NA of up ...

5. Dioptre - Wikipedia

   en.wikipedia.org/wiki/Dioptre

   It is normally used to express the optical power of a lens or curved mirror, which is a physical quantity equal to the reciprocal of the focal length, expressed in metres. For example, a 3-dioptre lens brings parallel rays of light to focus at 1 ⁄ 3 metre. A flat window has an optical power of zero dioptres, as it does not cause light to ...

6. Corrective lens - Wikipedia

   en.wikipedia.org/wiki/Corrective_lens

   Higher Abbe numbers mean a better lens material, and lower Abbe numbers result in the presence of chromatic aberration (i.e., color fringes above/below or to the left/right of a high contrast object), especially in larger lens sizes and stronger prescriptions (beyond ±4.00D). Generally, lower Abbe numbers are a property of mid and higher index ...

7. Farsightedness - Wikipedia

   en.wikipedia.org/wiki/Farsightedness

   Aphakia correction: High degree hypermetropia due to absence of lens (aphakia) is best corrected using intraocular lens implantation. [ citation needed ] Refractive lens exchange (RLE): A variation of cataract surgery where the natural crystalline lens is replaced with an artificial intraocular lens ; the difference is the existence of abnormal ...