We see the world around us because of the way the cornea and lens of our eye helps us to focus.. The cornea and lens of your eye helps you focus. Refractive errors are optical imperfections that prevent the eye from properly focusing light, causing blurred vision.
The cause could be the length of the eyeball (longer or shorter), changes in the shape of the cornea, or aging of the lens. The main types of refractive errors are myopia (nearsightedness), hyperopia (farsightedness), presbyopia (loss of near vision with age), and astigmatism.
Myopia (nearsightedness, shortsightedness) is a very common condition affecting distance vision (seeing things that are far away). The light that enters the eye through the cornea and the crystalline lens is bent in such a way that the resulting image focuses not on the retina
Hyperopia, also known as farsightedness or long-sightedness, causes the individual to have difficulty seeing close objects. The eye focuses light behind the retina, instead of directly on the retina, thus causing the blurry near vision.
Eyes with Astigmatism have corneas that are shaped more like an rugby ball than like a soccer ball. This causes the light rays to bend differently across the corneal surface.
