Advertisement

What is a refractory problem?

Dr. Michael Roizen, MD
Internal Medicine
One contributor to a decline in vision is refractory problems. Simply, refractory problems like near-sightedness (meaning you only see close things) or far-sightedness (meaning you can only see far away) stem from irregularities in the shape of the eye.

The normal eye is a perfect sphere in which the cornea and lens focus light to form the image on the retina. In near-sighted people, the eye is too long from front to back, so when the light travels through, the image it carries doesn't come into sharp focus on the retina as it should--but on the middle of the eye. In far-sighted people, the eye is too short, so the image would only come into a sharp focus well in back of the retina.

Eyeglasses or contact lenses can alter the light coming into the lens of the so that it correctly focuses on the retina. Nine out of 10 people can improve their eyesight with a corrective form of treatment, like glasses.

It's said that the Roman emperor Nero would look through an emerald to help focus on gladiator fights, and that's thought to be one of the first inventions of eyeglasses. I'm sure no one dared to make a "three eyes" joke in his presence.
YOU: The Owner's Manual, Updated and Expanded Edition: An Insider's Guide to the Body that Will Make You Healthier and Younger

More About this Book

YOU: The Owner's Manual, Updated and Expanded Edition: An Insider's Guide to the Body that Will Make You Healthier and Younger

Between your full-length mirror and high-school biology class, you probably think you know a lot about the human body. While it's true that we live in an age when we're as obsessed with our bodies as...

Continue Learning about Eye Conditions

Presbyopia: Correcting Age-Related Vision Loss
Presbyopia: Correcting Age-Related Vision Loss
Sometime around of after age 40, many people notice that it is getting more difficult for their eyes to focus on nearby objects. For many, the first s...
Read More
How are pterygium and pinguecula treated?
American Academy of Ophthalmology's EyeSmartAmerican Academy of Ophthalmology's EyeSmart
In many cases, no treatment is needed. When a pterygium or pinguecula becomes red and irritated, eye...
More Answers
What can help me manage map-dot fingerprint dystrophy?
Ivan A. Schwab, MDIvan A. Schwab, MD
Map-dot dystrophy of the cornea is relatively common and often has a genetic component. It consi...
More Answers
How Eye Health Is Influenced by Overall Health
How Eye Health Is Influenced by Overall Health

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.