Books or tablets: Which is better for your eyes?
For those of us who love to read, digital devices have opened up a rich new world of literary exploration. But as your mind expands, how are your eyes doing?
A refractive error is a condition caused by the shape of your eye that causes blurred vision. Nearsightedness, farsightedness, astigmatism and presbyopia are common refractive errors.
In a normal eye, light rays are bent (refracted) by the clear, outer covering of your eye (cornea) and the lens, then focused directly on the retina in the back of the eye. This results in clear vision. If you have a refractive error, light rays enter the eye in front of or behind the retina instead of directly on it, which causes blurred vision.
Refractive errors are very common — more than 150 million Americans have refractive errors.
Refractive errors are caused by having an abnormally shaped eyeball, which keeps you from focusing well. These abnormalities include:
Symptoms of the four common types of refractive errors include:
Other symptoms of refractive errors include double vision, hazy vision, squinting, seeing a glare or halo around bright lights, and trouble focusing when reading.
Your ophthalmologist or optometrist (eye doctor) will check for refractive errors as part of a comprehensive eye exam. Your doctor will ask you to read a vision chart while trying various lenses to find the best one to help you see clearly.
Part of a comprehensive exam includes dilating your eyes with eye drops so that your doctor can see inside your eyes. After your exam, you'll need sunglasses because your eyes will be sensitive to light for a few hours until your dilated pupils return to normal size.
Your ophthalmologist or optometrist may suggest one or more of the following treatments: