Protecting Your Eyes from Everyday Hazards : Part 2

by Food and Drug Administration (FDA)

(Page 2 of 2)

Routine Eye Care

Basic eye care can go far to protect eyes on a day-to-day basis. Disease prevention begins in childhood. Ideally, children's eyes should be checked periodically by their health-care practitioners, with the first thorough examination by the time the child enters school. Children who have hereditary or congenital problems such as "lazy eye" might need earlier and more frequent monitoring.

From adolescence through adulthood, barring any problems, eyes should be examined every five years, not merely to check for vision changes, but for early detection of diseases such as glaucoma. People with impaired vision should be followed at intervals recommended by their eye-care practitioners. If a change in vision is noticed between regularly scheduled visits, more frequent examinations may be required.

Eye-care practitioners include ophthalmologists, optometrists and opticians. Ophthalmologists are physicians and surgeons who specialize in the diagnosis and treatment of eye disease. They also perform vision tests and prescribe glasses and contact lenses.

Optometrists are state-licensed professionals who examine for visual defects and prescribe glasses and contact lenses. Optometrists can diagnose eye diseases, and in some states are licensed to prescribe medicines and manage certain eye diseases, but they do not perform surgery. Opticians fill prescriptions for eyeglasses, and in some states are licensed to fill prescriptions for contact lenses as well.

The most common vision defects that require corrective lenses are myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. As the name suggests, a nearsighted person can see close-up objects clearly, while those at a distance become less distinct. Farsightedness is the opposite condition and may result in blurriness at all distances. In both conditions light does not focus properly on the retina. In myopia, the eyeball is elongated and light focuses in front of the retina. In hyperopia, the eyeball is shortened and light focuses at a point in back of the retina. Astigmatism is caused by an irregularity in the shape of the cornea that causes light to focus in different planes. Corrective lenses reduce the multiple images and refocus them to the retina.

Eyeglass frames can also play a role in eye safety. Well-fitted frames should neither pinch the bridge of the nose nor lietoo heavily behind the ears. Thicker lenses require heavier frames. The ideal color for tinted lenses is gray because it is the most neutral in the color spectrum, letting most colors appear in their natural hue. Green and brown are considered next best. Darkly tinted lenses should be limited to outdoor use because they can severely limit visibility indoors.

Contact Lenses

Contact lenses require greater care than eyeglasses because they come into direct contact with the eye. Whatever is on the lens — dust, pollen, bacteria, and chemicals — also reaches the eye's surface. Always follow the eye-care practitioner's directions, as well as all manufacturer's instructions. The eye-care practitioner should also be consulted about the various types of solutions and cleaning methods for contact lenses.

There are three types of contact lenses: hard, soft, and oxygen- (gas) permeable. Each is fashioned out of a slightly different material, requiring different care.

Hard lenses were the first type marketed. According to James Saviola, an optometrist in FDA's division of ophthalmic devices, hard lenses are fashioned from the same material originally used to make airplane windshields. Of the contact lens types, they are best able to correct astigmatism because they form a new front surface to counteract the irregular cornea. It takes several weeks for the wearer to become adjusted to hard lenses, however, and they should be worn according to a schedule for maximum benefit.

Because the material from which hard lenses are made does not admit oxygen to the eye, after a few hours the eye will begin to swell. Hard lens wearers must remove their lenses after about 12 hours of use and rely on eyeglasses for the rest of the day. To overcome this problem, oxygen-permeable lenses were developed. Because these are actually a type of hard lens, the period of adjustment and routine wearing schedules are similar to the break-in period of regular hard lenses.

Soft contact lenses are made of various types of water-absorbing plastics that allow oxygen to reach the eye. They are easier to adjust to than hard contact lenses, usually requiring no more than a week until they are comfortable. They are less likely than hard lenses to dislodge when playing sports, but they are less durable and may need to be replaced every year.

Soft lenses require careful attention to cleaning, rinsing and disinfection. Daily-wear soft contact lenses need to be cleaned daily and, as with hard and oxygen-permeable lenses, must be removed for sleeping. Extended-wear soft contact lenses can be left in the eye while sleeping, but, as mentioned previously, must be removed at least once a week for cleaning.

Educating Yourself

Don't be afraid to ask eye-care professionals whatever questions are necessary to understand their instructions. Make sure you know what brand of lenses you have and what eye-care products are specifically formulated for those lenses. Learn to recognize signs of trouble that can alert you to serious problems:

• red or painful eyes
• sudden changes in vision
• repeated irritation of the eye
• excess secretions from the eyes.

If you develop any unusual or severe symptoms, see an eye-care specialist immediately, even if that means a trip to a hospital emergency room.

Eye safety requires only a little education and a lot of common sense. Take care of your windows to the world, and they will reward you with all that world's visual delights.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.