This information was produced by the National Eye Institute to assist sufferers and their families seek for general knowledge about refractive errors. An eye care specialist who has studied the patient’s eyes and is familiar with his or her medical history is the best person to explain specific questions.
What are refractive errors?
Cross-section of the eye
Refractive errors happen when the size and shape of the eye prevent light from focusing directly on the retina. The length of the eyeball (longer or shorter), changes in the form of the cornea, or aging of the lens can cause refractive errors.
What is refraction?
Refraction is the bending of light as it passes through one object to another. Vision transpires when light rays are bent (refracted) as they pass through the cornea and the lens. The light is then focused on the retina. The retina changes the light-rays into messages that are sent through the optic nerve to the brain. The brain translates these messages into the images we see.
What are the different kinfd of refractive errors?
The most common types of refractive errors are hyperopia, myopia, astigmatism, and presbyopia.
Myopia (nearsightedness) is a condition where objects up close appear clearly, while objects far away seem blurry. With myopia, the light comes to focus in front of the retina rather than of on the retina.
Hyperopia (farsightedness) is a prevalent kind of refractive error in which further objects may be seen more distinctly than objects that are closer. Nevertheless, people encounter hyperopia conversely. Some individuals may not discern any dilemmas with their vision, particularly when they are young. For people with important hyperopia, vision can be blurry for objects at any range, near or far.
Astigmatism is a condition in which the eye does not adjust or focus light equally onto the retina, the light-sensitive tissue at the back of the eye. This can cause pictures to resemble blurry and stretched out.
Presbyopia is an age-related disease in which the ability to focus up near grows more difficult. As the eye ages, the lens can no longer change shape enough to permit the eye to focus on nearby objects.
Who is at risk for refractive errors?
Presbyopia affects the majority adults over age 35. Other refractive errors can impact both children and adults. People that have parents with specific refractive errors may be more inclined to get one or more refractive errors.
Symptoms and Detection
What are the symptoms and signs of refractive errors?
Blurred vision is the most common symptom of refractive errors. Other symptoms may include:
- Double vision
- Glare or halos around bright lights
- Eye strain
How are refractive errors diagnosed?
An eye care provider can diagnose refractive errors throughout a complete dilated eye examination. People with a refractive error often visit their eye care professional with issues of visual discomfort or blurred vision. However, some indivduals don’t know they aren’t seeing as clearly as they could.
How are refractive errors treated?
Refractive errors can be imporved with contact lenses, eyeglasses, o r surgery.
Eyeglasses are the easiest and safest way to fix refractive errors. Your eye care provider can recommned proper lenses to correct your refractive error and grant you optimal vision.
Contact Lenses work by forming the first refractive surface for light rays entering the eye, causing a more precise refraction or focus. In many cases, contact lenses provide clearer vision, a wider field of vision, and greater comfort. They are a safe and effective choice if fitted and used properly. It is very imperative to wash your hands and clean your lenses as directed to decrease the risk of infection.
If you have specific eye conditions you may not be able to wear contact lenses. Discuss this with your eye care professional.
Refractive Surgery purpose is to change the size and shape of the cornea permanently. This change in eye shape restores the focusing control of the eye by permitting the light rays to focus specifically on the retina for enhanced vision. There are various refractive surgeries. Your eye care provider can help you decide if surgery is an option for you.