Refractive error in your eye happen when the shape of your eyeball prevents light from correctly focusing on your retina. If your eyeball is longer than normal (oblong) or shorter than normal, it changes the shape of your cornea and lens, causing an abnormal image to be projected on your retina in the back of your eye. This distorts the visual messages to your brain. The lens in your eye can also change shape with age — another cause of refractive error issues.
Refraction is normally defined as the bending of light rays passing through an object. Eye refraction is the same: the bending of light as it passes through your cornea and lens. Your vision works by bending light that passes through your cornea and lens, where it’s then focused on your retina. Your retina translates these light rays into electrochemical messages and sends them to your brain through the optic nerve. Your brain interprets this information into the imagery you see.
If you are having any abnormal visual symptoms, you should always be evaluated with a thorough consultation and examination by a physician for an accurate diagnosis and treatment plan as it may be a symptom or sign of a serious illness or condition.
Forms of Refractive Error
There are various types of refractive error that you may experience. They include:
- Nearsightedness: Also called myopia, this refractive error is caused by an elongation of your eyeball. With nearsightedness, light is focused in front of your retina instead of on it. In other words, the focal point occurs before reaching your retina. Myopia causes people to have difficulty seeing distant objects clearly. For children, myopia often increases until the child stops growing.
- Farsightedness: Known as hyperopia, this condition happens when your eyeball becomes too short for the light to be correctly focused on your retina. In this case, the focal point occurs behind your retina. Young adults and children that have mild hyperopia can often see clearly if their lens is flexible enough to refocus light on the retina. But as you age, your lens stiffens, and so it becomes more difficult to see nearby objects.
- Astigmatism: This refractive error stems from an abnormally shaped cornea or lens. When they’re not perfectly spherical or round, they can cause blurring of objects at any distance.
- Anisometropia: When you have a significant difference in refractive disorder from one eye to the other, it’s called anisometropia.
- Presbyopia: This refractive disorder occurs when you age. Lens stiffening occurs when you reach your early or mid-40s. As your lens stiffens, it can’t change its shape, so it’s not able to properly focus on nearby objects. As a result, you have difficulty seeing nearby objects. This is why many older adults purchase magnifying glasses to aid in their reading.
- Aphakia: This rare refractive disorder is a result of the absence of a lens resulting from an eye injury, eye surgery or from a birth defect.
Symptoms of Refractive Error
Typical symptoms of refractive disorders (refractive error) are:
- irritated eyes
- blurred vision (i.e.: when looking at close objects, objects that are far away or both)
- headaches that occur by frowning or squinting
Symptoms may appear with excessive reading. If a child is repeatedly rubbing his or her eyes or blinking, it may be a sign of refractive disorder.
- double vision
- a halo effect around bright lights
Diagnosis of Refractive Error
Refractive error typically are detected and diagnosed during a comprehensive dilated eye examination by an eye care professional. It’s likely you’ll visit your ophthalmologist complaining of blurry vision, unable to see as clear as normal, or with visual discomfort.
All adults and children should have regular eye exams by an ophthalmologist (read more).It’s important to have children screened to detect refractive disorders before their learning process in school becomes complicated and affects learning.
Treatment of Refractive Error
The most common treatment for refractive disorders are eyeglasses, contact lenses, or surgery. Eyeglasses are the most simple and safest way to correct refractive error issues. Your eye doctor can prescribe precise lens dimensions in your eyeglasses to change the refracted focal point and place it directly on your retina to provide you with optimal vision clarity.
CONTACT LENSES actually refract or bend the light before it reaches the lens and cornea, creating a more precise focus or refraction. People who wear contacts often experience a wider field of vision and clearer vision than people who wear eyeglasses. Contacts are effective and safe as long as they’re fitted properly and you take care of the contact lenses properly. It’s extremely important to follow the instructions and guidelines to wash your hands and clean your lenses to avoid infection. There are some eye conditions that prohibit the use of contacts. Ask your eye care professional to determine if you have any of these issues.
REFRACTIVE SURGERY is an option to permanently change the shape of your cornea. The improved shape of your cornea restores the focusing ability of your eye by permitting the light rays to correctly focus on your retina. Ask your ophthalmologist if refractive surgery is an appropriate option for you.