Explore the question in detail with explanation, related questions, and community discussions.
Presbyopia is a natural, age-related vision problem in which the eye gradually loses the ability to focus on nearby objects. It usually becomes noticeable after the age of 40, when people begin to experience difficulty in reading fine print or doing close work. The condition occurs because the lens of the eye loses elasticity with age, making it harder to adjust its shape (a process called accommodation) for near vision.
Unlike myopia (nearsightedness) or hypermetropia (farsightedness), which are caused by structural issues in the eye such as the length of the eyeball or the shape of the cornea, presbyopia is due to the stiffening of the eye’s crystalline lens. This means a single corrective lens is usually not sufficient.
The most effective correction for presbyopia is the bifocal lens. A bifocal lens is designed with two optical powers:
Upper part – for distant vision.
Lower part – for near vision (such as reading).
This dual correction allows the person to see clearly at both long and short distances, compensating for the natural loss of accommodation in the eye.
Other lenses play roles in different vision issues:
Convex lens corrects hypermetropia.
Concave lens corrects myopia.
Cylindrical lens corrects astigmatism, which is due to an irregular curvature of the cornea.
Therefore, bifocal lenses are specifically designed to handle the dual-vision challenge posed by presbyopia, making them the most suitable solution. In modern times, progressive lenses (multifocals) are also widely used, providing a smooth transition between near, intermediate, and distant vision without a visible dividing line.
Presbyopia = age-related loss of near vision
Caused by loss of elasticity of eye lens
Corrected by bifocal lenses
Convex lens → Hypermetropia, Concave lens → Myopia, Cylindrical lens → Astigmatism
Progressive lenses are a modern alternative to bifocals
👉 Correct Answer: Bifocal
Discussion
Leave a Comment