The Eye & The Vision Errors.
- A normal person or an Emmetrope sees well because rays from the outside world fall exactly on the light sensitive retina allowing them to see sharp and clear images of the world.
- In people with refractive error (or poor vision, such as nearsightedness or farsightedness), the light rays do not get focused on to the retina and blurred images are formed.
- The cornea is a part of the eye that helps focus light to create an image on the retina. It works in much the same way that the lens of a camera focuses light to create an image on film. The bending and focusing of light is also known as refraction.
- Usually the shape of the cornea and the eye are not perfect and the image on the retina is out-of-focus (blurred) or distorted.
- These imperfections in the focusing power of the eye are called refractive errors. There are three primary types of refractive errors: myopia, hyperopia and astigmatism.
- Persons with myopia, or nearsightedness, have more difficulty seeing distant objects as clearly as near objects.
- Persons with hyperopia, or farsightedness, have more difficulty seeing near objects as clearly as distant objects.
- Astigmatism is a distortion of the image on the retina caused by irregularities in the cornea or lens of the eye.
- Combinations of myopia and astigmatism or hyperopia and astigmatism are common.
Glasses or contact lenses are designed to compensate for the eye’s imperfections. If you are happy wearing contacts or glasses, you may not want to have refractive surgery. Together, you and your ophthalmologist can weigh the risks and rewards of LASER Procedures.
Surgical procedures aimed at improving the focusing power of the eye are called refractive surgery.