There are some refractive errors or eye issues that could impair your vision, such as:
- Myopia (short-sightedness): inability to see distant objects clearly.
- Hyperopia (long-sightedness): inability to see close objects clearly.
- Astigmatism: blurry vision due to an irregular eye shape.
Myopia and hyperopia are the most common refractive eye errors. They are caused by eye abnormalities that affect the ability to focus light on the back part of the eye called the retina.
Light is bent (refracted) by the cornea, the clear surface at the front of your eye, and the crystalline lens inside it. Then, it ends up back at the retina, a fine layer of light-sensitive cells.
When the light doesn’t focus correctly or hit the retina properly, our brain interprets a blurred image.
Myopia is the most common refractive eye problem worldwide. If you suffer from short sight, you will have difficulty seeing distant objects clearly but will be able to perform close-up tasks, such as reading and using the computer.
Myopia occurs when the eyeball is too long. It causes light rays to focus in front of the retina instead of directly on the surface.
Short sight can also be caused by the cornea being too curved for the length of the eyeball.
Conversely, hyperopia is better known as far-sightedness and is the opposite of myopia. The eyeball is too short, causing light rays to be refracted behind it.
If you’re shortsighted, the first number on your eyeglasses prescription is preceded by a minus sign (–). The opposite applies to hyperopia.
Both refractive errors can be corrected using eyeglasses, contact lenses, or having refractive surgery. The latter includes laser eye surgery and lens surgery.