Final answer:
Cataracts are a leading cause of blindness, especially prevalent in those aged 65 to 74, and are treated by removing the clouded lens and prescribing a spectacle lens of 16 D for vision correction. Conditions like myopia and hyperopia are corrected with concave and convex lenses, respectively. Post-cataract surgery, reading glasses are often still required for near tasks, and UV protection is crucial to prevent cataracts.
Step-by-step explanation:
Cataracts and Vision Correction
Cataracts are a common condition where there is cloudiness in the lens of the eye, which can lead to a loss of vision. Factually, cataracts are responsible for 50% of all cases of blindness. They are especially prevalent among those aged 65 to 74, with about 60% of individuals in this age group developing cataracts. When the lens of an eye with a cataract is removed, a spectacle lens of about 16 diopters (D) is often prescribed to compensate for the loss of the eye's natural lens. This artificial lens helps to refocus light onto the retina, allowing the individual to see clearly.
In terms of vision correction, there are various eye conditions like myopia (nearsightedness) and hyperopia (farsightedness). Myopia is corrected by lenses that are concave, which make light rays converge less before they enter the eye. On the other hand, hyperopia is corrected by convex lenses to help the light rays converge more. Presbyopia, which often occurs with age, is a condition where the eye loses the ability to focus on close objects, necessitating the use of reading glasses.
When it comes to removing cataracts, replacing the clouded lens with a plastic one can restore vision. However, without the natural accommodation of the lens, reading glasses may still be needed for near vision tasks. It is also essential to protect the eyes from UV light as exposure to UV-B can also lead to the formation of cataracts.