Refractive errors are a type of vision problem that makes it hard to see clearly. They happen when the shape of your eye keeps light from focusing correctly on your retina (a light-sensitive layer of tissue in the back of your eye). Refractive errors are the most common type of vision problem.

Nearsightedness (myopia)

Farsightedness (hyperopia)

Astigmatism

Presbyopia

Nearsightedness (myopia) :  Nearsightedness makes far-away objects look blurry. It happens when the eyeball grows too long from front to back, or when there are problems with the shape of the cornea (clear front layer of the eye) or the lens (an inner part of the eye that helps the eye focus). These problems make light focus in front of the retina, instead of on it.

Nearsightedness usually starts between ages 6 and 14. Children who spend more time outdoors during these years are less likely to develop nearsightedness, but experts aren’t sure why.

Severe nearsightedness (also called high myopia) can increase the risk of other eye conditions, like retinal detachment (when the retina is pulled away from its normal position).

the symptoms of a refractive error?

All refractive errors will make your vision worse. In addition to having trouble seeing clearly, your symptoms might include:

• Blurry vision either up close, at a distance or both.
• Double vision (diplopia).
• Headaches.
• Squinting.
• Eye strain.
• Eye pain.

An eye care specialist will diagnose refractive errors with an eye exam. They’ll look at your eyes (including inside them). They’ll also have you perform a visual acuity test. This will help determine which type of refractive error you have and how much it’s affecting your vision.

Treatments for refractive errors include:

• Eyeglasses.
• Contact lenses.
• Vision correction surgery such as LASIK and photorefractive keratectomy (PRK).

Usually, your eye care specialist will prescribe you glasses or contacts before you have vision correction surgery. However, you might be a good candidate for vision correction surgery right away. Talk to your eye care specialist about which treatment will work the best for you.

There’s usually nothing you can do to prevent a refractive error from developing in your eyes. Because they’re caused by the shape of your eye, cornea or lens — or changes to these parts of your eyes — there’s no way to prevent refractive errors. There’s also nothing you can do to prevent your child from being born with a refractive error.

Having your eyes and vision checked regularly can help your eye care specialist identify problems right away. How often you should get your eyes checked usually depends on your age:

• Kids: Your child’s pediatrician should check their eyes around the time they learn the alphabet, and then every one to two years.
• Adults younger than 40: Every five to 10 years.
• Adults between 40 and 54: Every two to four years.
• Adults older than 55: Every one to three years.

You might need your eyes checked more often than this if you wear glasses, contacts or need another type of visual aid. People with diabetes need their eyes checked more often than what’s listed here.

Ask your eye care specialist how often you need an eye exam.