A complete sunglasses lens guide

Photo courtesy of Rebecca Bollwitt on Flickr

As the days get longer and summer approaches, you might just find yourself spending more time outdoors. Whatever you have planned, from driving on vacation, spending time on the beach or participating in your favorite sport, having the right type of sunglasses can make those activities more enjoyable. Understanding the available lens options will help to enhance the time you spend outside.

Whatever outdoor activity you partake in, utilizing glasses with ultraviolet (UV) protection can protect your eyes from the damaging effects of the sun. UV rays can cause early cataract formation, macular degeneration and other aging effects. All sunglasses lenses should provide protection from UVA and UVB rays.

The right tint color can enhance your outdoor activities by eliminating glare, reducing eyestrain and providing better depth perception. Lens tints may block certain colors while enhancing others. Contrast may be increased with certain tints.

• Grey lenses provide decreased brightness and glare while maintaining normal color perception; useful very bright conditions.
• Brown lenses block blue light to improve contrast and depth perception, but change color perception; great for overcast to sunny weather.
• Yellow lenses are useful in lowlight and hazy conditions and also enhance contrast; useful in indoor as well.
• Green lenses provide mild increase contrast with maintaining color perception; another good general-purpose lens.
• Pink and red lenses provide increased contrast but also alter color perception; can be useful in snowy conditions.
• Polarized lenses are another lens option for your sunglasses. These lenses are available in different tints and decrease glare by use special filter to block glare of flat surfaces such as roads or water; may block certain LCD or LED screens.
• Photochromatic lenses change colors or darken depending on the amount of UV light. These lenses are useful in variable or changing light conditions. However, these lenses may not fully darken while you are inside a vehicle.
• Anti-reflective coatings are often used on the back surface of sunglasses to eliminate reflected glare.

Finally, the right lens material is important. Certain glasses may provide the best optical clarity and scratch resistance, but are not impact resistant. Plastic lenses are tintable and more lightweight than glass lenses. Polycarbonate lenses are the lightest weight and most impact resistant making them suitable for sport settings. Regardless of your lens selection, be sure to stay safe and have fun this summer.

~ John Barrón, O.D.
California Optometric Association
http://www.coavision.org
http://www.eyehelp.org

Seven myths about contact lenses

1. 

   Photo courtesy of Valley Eyecare Center

   There is one “best” contact lens
   Do not think that if your first contact lens experience is less than ideal that you must be “contact lens intolerant”.   The truth is, what one patient loves another patient may hate.  It is all about how that contact’s shape and material interacts with your unique eyeball.  Not every contact lens and eyeball play well together.  There is no way to predict if you eye will like a particular lens until you give the lens a test drive for a few days in a trial pair.  Expect some trial and error with various lens brands.Every doctor will have their go-to contact lens that “on average” they find the most success with in their area.  However, you may not be average.  It is not unusual for the second or even third trial pair of different contact lens brands be the “ah-ha!” moment when great comfort is found.  Most doctors will have the patience as long as you do to find your “ah-ha!” contact lens.

2. All contact lens cleaners are alike
   The following is a very common conversation heard in an eye doctor’s office:
   Patient:  I suddenly noticed a month ago my contacts were not as comfortable anymore.
   Doctor:  Are you still using the same cleaner I prescribed when you ordered your contacts?
   Patient:  No. A month ago I found a generic cleaner for half the price so I started using that one.

   Contact lens cleaners are not alike.  Stick with the solution your doctors recommends when you order your contacts and the risk of solution-caused comfort issues will be greatly minimized.  Generic cleaners frequently will increase irritation with contact lens wear and reduce wear time.

3. Contacts can roll behind my eye into my brain
   There is an anatomical barrier called the conjunctiva which prevents the contact lens, or any foreign object, from getting behind the eye.
4. Swimming will cause the lens to float out of my eye into my brain
   To the contrary, swimming in contacts will actually adhere the contact lens to the eyeball tighter.  For this reason, it is recommended to not remove the lens for a half hour after swimming to allow it time to dry.  Trying to remove the lens too soon after swimming may cause a scratch on your eyeball from having to use extra force removing it.

   Although pool swimming in contacts is generally safe (hot tubs and ocean water being an exception and an absolute no-no), if you swim frequently most eye doctors will recommend you use daily disposable contact lenses so that you never have to use the same lens twice since pool chemicals and other impurities may build up on the lens, increasing the risk of infection.  If a daily disposable lens is not an option for you, your doctor will likely recommend a hydrogen peroxide based cleaning system.  Hydrogen peroxide cleaners provide extra-strength cleaning of most things the pool may leave behind on your contacts.  Wearing swim goggles is highly advised to reduce the risk of sight-threatening infections from wearing contacts while swimming.

5. Buying contact lenses online is always the most economical way to buy contacts
   Actually, this is rarely the case.  Historically, online retailers averaged a few dollars cheaper than doctor’s offices for the same contacts.  Recently, many of the most common contact lens manufactures now require “uniform pricing”, meaning online retailers and doctors now provide the exact same price for many brands of contacts.

   The real cost savings in purchasing contacts from your doctor’s office occur when manufacture rebates (typically not valid with online purchases) and insurance benefits are applied.

6. “I have allergy eyes, so I cannot wear contacts.”
   For contact lens wearers who suffer from allergies, Dr. Butterworth, an optometrist from University of Iowa Department of Ophthalmology, states she recommends daily disposable soft lenses for her allergy patients. “Not only does this allow the patient to have a fresh, clean lens on the eye every day, but it eliminates several factors that can make patients’ ocular allergies worse,” she said. “Daily disposables also minimize a lot of debris buildup, which can exacerbate allergies.”
7. Your eyes are too weird for contacts
   Many patients believe that astigmatism will keep them from being able to wear contacts.  However, we all have astigmatism to some degree.  Astigmatism is the amount by which your cornea (the front surface of the eye) is not perfectly spherical.  But nobody’s cornea is perfectly spherical, just like nobody’s head is perfectly round.  If your astigmatism is high enough, you will likely be placed in an astigmatism correcting contact lens.  For most doctors, more than half of their contact lens patients wear contacts specifically designed for astigmatism.   Whether it is a small amount or a larger amount, there is a contact lens out there for you.

~ David McCleary, O.D.
California Optometric Association
http://www.coavision.org
http://www.eyehelp.org