Final answer:
The eye focuses on near and far objects through a process called accommodation, which involves adjusting the lens to change its focal length. Nearsightedness (myopia) and farsightedness (hyperopia) can be corrected with diverging and converging lenses, respectively.
Step-by-step explanation:
The way the eye focuses on near and far objects is through a process called accommodation. Accommodation is the adjustment of the lens in the eye to change its focal length. For near objects, the lens becomes more rounded to increase its refractive power, allowing the image to be focused on the retina. For far objects, the lens becomes flatter to decrease its refractive power and focus the image on the retina.
In the case of nearsightedness, or myopia, the images of distant objects are focused in front of the retina. This can be corrected with a diverging lens to reduce the optical power of the eye. Hyperopia, or farsightedness, is the inability to see close objects clearly because their images are focused behind the retina. It can be corrected with a converging lens to increase the optical power of the eye. For older individuals, there is a condition called presbyopia, where the lens of the eye becomes progressively unable to focus on near objects. This happens due to the loss of elasticity in the lens as we age.