Question

in an old age , a bifocal lens is necessary for someone
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Answer 1

Answer:

In old age bifocal lens is necessary for person. In old age, sometimes person suffers both myopia and hypermetropia and then the person needs bifocal lens. In bifocal lens, upper part is concave lens to correct myopia and lower part is convex lens to correct hypermetropia

Answer 2

Answer:

who suffer from this

i mean jisko hypermetropia as well as myopia hai

unhe dono lense lagana padta hai concave or convex