BLOCKING  99% OF ULTRAVIOLET RAYS

You should always buy sunglasses with this feature. Long-term exposure to ultraviolet (UV) radiation in sunlight is linked to eye disease. UVB radiation is considered more dangerous to the eyes and skin than UVA radiation. Both plastic and glass lenses absorb some UV light, but UV absorption can be improved by adding chemicals to the lens material during manufacturing or by applying special lens coatings.

Look for sunglasses that block 99% or 100% of all UV light. Some manufacturers’ labels say “UV absorption up to 400nm.” This is the same thing as 100% UV absorption.

BLOCKING  99% OF INFARED RAYS

Infrared wavelengths are invisible and produce heat. Sunlight has low levels of infrared rays, and the eye tolerates infrared well. Some sunglass manufacturers make health claims for their products based on infrared protection, but research has not shown a close connection between eye disease and infrared rays.

Some nonprescription glasses are ground and polished to improve the quality of the lenses. Nonprescription lenses that are not ground and polished will not hurt your eyes. You do want to make sure that the lenses you buy are made properly.

To judge the quality of nonprescription sunglasses, look at something with a rectangular pattern, such as floor tile. Hold the glasses at a comfortable distance and cover one eye. Move the glasses slowly from side to side, then up and down. If the lines stay straight, the lenses are fine. If the lines wiggle, especially in the center of the lens, try another pair.

DETERMINING LENS DARKNESS

A medium lens is good for day-to-day wear, but if you use the glasses for very bright conditions, choose a darker lens. The color and the degree of darkness do not tell you anything about the lenses’ ability to block UV light.

IMPACT-RESISTANT

All sunglasses must meet impact standards set by the Federal Food and Drug Administration (FDA) for safety. No lens is truly unbreakable, but plastic lenses are less likely than glass lenses to shatter when hit by a ball or stone.

Most nonprescription sunglass lenses are plastic. Polycarbonate plastic, used in many sports sunglasses, is especially tough, but it scratches easily. If you buy polycarbonate lenses, look for ones with scratch-resistant coatings.

POLARIZED LENSES

Polarized lenses cut reflected glare—sunlight that bounces off smooth surfaces like pavement or water. They can be particularly useful for driving and fishing. Polarization has nothing to do with UV light absorption, but many polarized lenses are now combined with a UV-blocking substance. Check the label to make sure the lenses provide maximum UV protection.

PHOTOCHROMIC LENSES

A photochromic glass lens automatically darkens in bright light and becomes lighter in low light. Most of the darkening takes place in about half a minute, while the lightening takes about five minutes. Photochromic lenses come in a uniform or gradient tint. Although photochromic lenses may be good UV-absorbent sunglasses (again, the label must state this benefit), it takes time for them to adjust to different light conditions.

WRAP-AROUND LENSES

Wrap-around glasses are shaped to keep light from shining around the frames and into your eyes. Studies have shown that enough UV rays enter around ordinary eyeglass frames to reduce the benefits of protective lenses. Large-framed wraparound sunglasses can protect your eyes from all angles.

GRADIENT LENSES

Gradient lenses are permanently shaded from top to bottom or from top and bottom toward the middle.

Single-gradient lenses (dark on top and lighter on the bottom) can cut glare from the sky but allow you to see clearly below. They are useful for driving because they don’t dim your view of the dashboard. They’re not as good, however, at reducing glare in snowy surroundings or at the beach.

Double-gradient lenses (dark on top and bottom and lighter in the middle) may be better for sports where light reflects up off the water or snow, such as sailing or skiing. Double-gradient lenses are not recommended for driving because they make the dashboard appear dim.

MIRROR COATED LENSES

Mirror finishes are thin layers of various metallic coatings on an ordinary lens. Although they do reduce the amount of visible light entering your eyes, do not assume they will fully protect you against UV radiation.

BLUE-BLOCKING LENSES

Whether blue light is harmful to the eye is still controversial. Lenses that block all blue light are usually amber colored and make your surroundings look yellow or orange. The tint supposedly makes distant objects appear more distinct, especially in snow or haze. For this reason, amber sunglasses are popular among skiers, hunters, boaters, and pilots.

Contacts are thin, clear disks of plastic that float on the tear film that coats the cornea, the curved front surface of the eye. The health of the corneal surface and tear film are very important to your comfort and the clarity of your vision when you are wearing contacts.

Contact lenses are used to correct the same conditions that eyeglasses correct:

• Myopia (nearsightedness)

• Hyperopia (farsightedness)

• Astigmatism

• Presbyopia

WHAT DOES THE PRICE OF CONTACT LENSES INCLUDE?

When comparing the price of contact lenses, it is important to consider what services are included. Does the fitting include a complete eye examination and follow-up? Can you exchange lenses during the initial fitting, and is insurance for lost lenses available?

If you need treatment for an eye condition not directly related to the contact lenses, such as inflamed eyelids or dry eyes, there may be additional charges.

Many different plastics are used in the manufacture of contact lenses, but basically there are two general types of lenses: hard and soft.

HARD LENSES

Include the PMMA contacts that were first developed in the 1960s

but are rarely used today; and rigid gas-permeable, or RGP, contacts. RGP contacts combine plastics with other materials such as silicone or fluoropolymers to produce a lens that holds its shape, yet allows the free flow of oxygen through the lens to the cornea. These lenses are more “wettable,” easier to adjust to and more comfortable to wear than the old PMMA hard lenses.

RGP LENSES

May be the best choice when the cornea has enough astigmatism (is shaped like an egg instead of an orange) that a soft lens will not provide sharp vision. They may also be  preferable when a person has allergies or tends to form protein deposits on his or her contacts.

SOFT LENSES

The choice of most contact lens wearers for their comfort as well as

for the great number of options available in soft contacts. These options include:

DAILY WEAR LENSES

Removed nightly and are replaced on an individualized schedule. They should not be used as an extended wear lens.

EXTENDED WEAR LENSES

Worn overnight but are removed at least weekly for thorough cleaning and disinfection. They are being recommended less frequently, since there is a greater risk of corneal infection with any overnight wear of contact lenses.

DISPOSABLE WEAR LENSES

The most popular type of contacts and generally the healthiest mode of contact lens use. They are replaced on a daily, weekly or monthly basis. Disposable lenses are sometimes recommended for people with allergies and for those who tend to form deposits on their lenses. Colored and toric lenses can be disposable as well.

COLORED CONTACT LENSES

Can change the appearance of your eye color to varying degrees.

TORIC WEAR LENSES

Can correct astigmatism, although sometimes not as well as RGP lenses. They usually cost more than other contact lenses.

Special uses for contact lenses include “bandage” lenses, to cover the corneal surface and provide comfort after injury or surgery; lenses for infants; RGP lenses, for people with very irregular corneas due to injury or disease. We offer our patients the latest in specialty contact lens fits for:

• Keratoconus

• Pellucid Marginal Degeneration

• Corneal scars

• Corneal implants

• Corneal transplants

• Irregular astigmatisms

• Severe dry eyes

As one ages, correction for near vision is often necessary because the lens of the eye can’t change shape as easily as it once did.

This common condition, called presbyopia, can be corrected in one of three ways:

• Wear your distance correction in the contacts, and wear reading glasses when needed.
  
  
• Wear one contact for distance vision, and one for near vision. This option is called "monovision,” and it works well for many people but not for everyone. You may need a trial period to decide if monovision is for you.
  
  
• Wear multifocal contacts, which are designed to allow distance, intermediate and near vision. These lenses may provide adequate vision without the need for spectacles for all distances.

Lenses that are not properly cleaned and disinfected increase the risk of eye infection. Lenses that are old or not properly fitted may scratch the eye or induce blood vessels to grow into the cornea. Because a lens can warp over time, and the cornea can change shape, the fit of the contact lens and the power should be re-evaluated on a regular basis.Your return visits will be scheduled depending on the condition of your eyes and visual needs. Any eyedrops can interact with all types of contact lenses. It is best to avoid the use of eyedrops while wearing lenses, except for wetting drops recommended by your eye doctor.

Any lens that is removed from the eye needs to be cleaned and disinfected before it is reinserted. Your doctor will discuss the best type of cleansing system for you, depending on the type of lens you use, any allergies you might have and whether or not your eye tends to form protein deposits. Care of contact lenses includes cleaning their case, since it is a potential source of infection. The case should be rinsed with water, wiped and allowed to dry. Daily wear lenses should not be worn while sleeping. Homemade saline (salt water) solutions have been linked to serious corneal infections and should not be used.

Consult your eye care professional at Lakeland Eye Clinic today, all of whom  are experienced with contact lenses and with whom you can discuss your needs and expectations. Your eye care professional should diagnose and treat any eye problems that may hinder healthy lens wear and be able to correct problems that arise during lens wear.

WHO SHOULD NOT WEAR CONTACT LENSES?

You may not be a good candidate for contacts if you have:

• Frequent eye infections
• Severe allergies
• Dry eye that is resistant to treatment
• A very dusty work environment
• An inability to handle and care for the lenses