Refractive errors are the most common eye conditions affecting the vision of Americans today. They occur when the shape of your eye is irregular, preventing your eye from properly bending light as it passes onto the retina.
A normal healthy eye can bend and focus light without the assistance of corrective lenses. However, when your eye needs help to properly focus light to display a sharp image, you are most likely suffering from a refractive error.
There are two factors affecting your eye’s ability to focus light on your retina:
Often, refractive errors such as myopia and hyperopia are genetically inherited. Myopia often develops in children between the ages of 8 and 12, and vision generally deteriorates during teenage years. By the age of 20, vision usually stabilizes. Hyperopia is frequently present in babies and very young children, but many people outgrow the condition as they get older and their eye becomes longer.
The four most common types of refractive errors are:
In myopia, your eye is too long or your cornea is too steep, causing light to focus in front of the retina. This makes far away objects seem blurry. In hyperopia, your eye is too short, causing light from close objects to be out of focus on your retina. Astigmatism can distort both near and far vision. This condition makes it seem as if you are viewing everything through a distorted mirror at a fun house. Presbyopia often develops after the age of 40 and causes you to experience blurry vision for close objects.
Your eye doctor will conduct an eye exam to diagnose the presence of a refractive error in your vision. He will use an instrument called a phoropter when evaluating your eyes. This instrument uses a set of lenses of varying power to identify the refractive error in your eye. By having you look through a series of these lenses, your eye doctor can estimate the amount of refractive error present. Your eye doctor will also use a retinoscope to shine a light into your eye so that he can view the reflection from the retina in the back of your eye.
Eyeglasses and contact lenses are still the most common ways to correct refractive errors. However, advances in refractive surgery technology have increased the popularity of surgical corrections in recent years. Some of the more common refractive surgery techniques used in correcting refractive errors include:
Please contact an eye doctor in your area if you need to schedule an eye exam or are interested in refractive surgery.