bifocal


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Related to bifocal: bifocal glasses

bifocal

 [bi´fo-kal]
of a lens, having two areas with different refractive powers.
bifocal glasses eyeglasses in which each lens is made up of two segments of different refractive powers, or strength. Generally, the upper part of the lens is used for ordinary or distant vision, and the smaller, lower section for near vision, for close work such as reading or sewing. Bifocal eyeglasses may be prescribed for presbyopia, which often occurs with aging.

bi·fo·cal

(bī-fō'kăl),
Having two foci.

bifocal

/bi·fo·cal/ (bi-fo´-) (bi´fo-k'l)
1. having two foci.
2. containing one part for near vision and another part for distant vision, as in a bifocal lens.

bifocal

(bī-fō′kəl, bī′fō′-)
adj.
1. Having two focal lengths.
2. Having one section that corrects for distant vision and another that corrects for near vision, as an eyeglass lens.
3. Having two distinct goals or objects of attention: a bifocal approach to the problem.
pl.n. bifocals (bī′fō′kəlz, bī-fō′-)
Eyeglasses with bifocal lenses.

bi·fo′cal·ism n.

bifocal

[bīfō′kəl]
Etymology: L, bis + focus, hearth
1 pertaining to the characteristic of having two foci.
2 (of a lens) having two areas of different focal lengths.

bi·fo·cal

(bī-fō'kăl)
Having two foci.

bifocal

Having two different foci. In bifocal spectacles each lens has a lower segment of greater power for convenience in reading.
References in periodicals archive ?
Surprisingly, the children with bifocals also accommodate more accurately when looking over the top of their bifocals through the distance part of the lens.
In the past, presbyopia meant having to wear bifocals or carry around the kind of reading glasses that perch on the end of your nose.
Table 117: Japanese Historic Review for Lenses by Design Type - Single Vision, Bifocal, and Progressive Addition Markets Independently Analyzed with Annu
They allow bifocal wearers to switch between different prescription settings for reading and more distant viewing.
For bifocal contact lenses wearers, there are a variety of design options in soft lenses, gas-permeable lenses, and specialty designs for astigmatism.
The researchers fitted two groups of children with Down's syndrome, matched for everything which could influence the success of failure of bifocals, with either bifocal lenses or ordinary lenses.
In addition to inventing the "apple a day" phrase, bifocal lenses, and the second hand on the clock, Ben Franklin also helped to start a hospital, a fire department, and a post office that delivers mail directly to people's houses.
Bifocals, trifocals, and special contact lenses are among your options.
For details of where the lenses can be fitted call Acuvue Bifocals 0800 200 256.
The sub product segments analyzed under the Lenses segment include Glass Lenses (Single-Vision, Bifocal, and Progressive Addition), Plastic Lenses (Single-Vision, Bifocal, and Progressive Addition), Polycarbonate (Single-Vision, Bifocal, and Progressive Addition).
67 SV lenses, round top bifocal lenses, flat top bifocal lenses, progressive lenses, photochromic lenses, sunglass lenses and lenticular lens.
Washington, Jan 12 (ANI): Bifocal glasses can prove effective in slowing down the progression of myopia in children with high rates of progression, according to a new study.