Depending on the material used to make a lens, between 4-16% of light striking the lens surface is ordinarily reflected back or "lost" by the lens. A multi-layer coating of metal oxides, just a few microns thick can significantly increase the amount of light transmitted through the lens by decreasing the percentage of light lost to reflection.

This multi-layer coating is called an anti-reflective or "AR" coating.

AR coatings are placed on microscopes and camera lenses to increase light transmission and maximize image quality. AR coatings can sometimes have a faint green or purple color. This color effect can be adjusted when necessary to create a pleasing cosmetic tint, as is often done for spectacle lenses.

AR coating for glasses

Cosmetic advantage - Eye contact is an important part of human interaction. If you glance at someone wearing glasses with ordinary clear lenses, it’s sometimes hard to see their eyes.

Even though the lenses are clear, their eyes are obscured by light reflected back toward you from both the front and back surfaces of the lenses.

Some light is actually being reflected from the back lens surfaces and bouncing back and forth inside the lens (between front and back surfaces), until it escapes. These "internal" reflections appear as a series of concentric reflections or rings. Thick lens edges, found in corrections for high degrees of myopia (nearsightedness), often produce rings which create a “coke bottle” look. Modern AR coatings can virtually eliminate these unsightly rings and make the lenses nearly invisible.

Nighttime advantage - Driving

Daytime advantage - Sunglasses

Reflections from back lens surfaces can also be annoying. This is most noticeable with sunglasses because a dark lens acts like a mirror. Under certain conditions, the wearer can actually see their own eyes reflected from the backs of the lenses. To see the effect a back-surface AR coating can have on your vision with sunglasses, cup both hands alongside your lenses, so that all light coming from behind you is blocked…the improvement may surprise you.

Improved technology

Lenses with antireflective (AR) coatings used to be hard to clean but no longer. Fingerprints and smudges have been a challenge for previous anti-reflective lenses but  many lenses now incorporate advanced surface treatments that make cleaning much easier. AR coatings are also more scratch-resistant than in the past.

The next time you order glasses, be sure to ask about what’s new in lens coatings and materials…a lot has changed! If you have a strong prescription, think about requesting an AR coating in conjunction with high-index lenses to make your glasses look and feel as thin as possible. You’ll not only look better but see better too!

Vision and Health Newsletter courtesy of:

Dr. Gordon Wong
Gordon G. Wong, O.D.
Wildon C. Wong, O.D.

7825 Fay Ave.
Suite 140
La Jolla, CA 92037

858-454-4699

When there are many light sources present, “ghost” images can be a real problemfor glasses wearers; the main example of this is driving a car at night. Headlights from other vehicles and streetlights can create distracting double images that make seeing difficult and contribute to eyestrain and fatigue. AR Coatings not only reduce the ghost images but actually increase the amount of light transmitted through the lenses to the eyes. There is an overall reduction in glare and halos around lights - a welcome addition to nighttime vision.

Diets Rich in Saturated Fat vs. Omega-3s

Eating foods rich in saturated fats has been associated with the development of degenerative diseases, including heart disease and even cancer. Polyunsaturated fatty acids, however, are actually good for you. Omega-3s (found primarily in cold-water fish) fall into this category, along with omega-6s, another type of polyunsaturated fatty acids found in grains, most plant-based oils, poultry and eggs.

Why "essential?" Omega-3s (and omega-6s) are termed essential fatty acids (EFAs) because they are critical for good health. However, the body cannot make them on its own. For this reason, omega-3s must be obtained from food, thus making outside sources of these fats "essential."

omega-6-rich foods excess - Nutritionists have come to recognize the importance of balancing omega-3 fatty acids with omega-6 fatty acids in the diet. Although the body needs both omega-3s and omega-6s to thrive, most people on a typical Western diet consume far more omega-6-rich foods (cereals, whole-grain bread, baked goods, fried foods, margarine and others.) This means for most Americans the the ratio is out of balance and more emphasis needs to be placed on increasing omega-3s.

Different types of omega-3s. Key omega-3 fatty acids include eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA), both found primarily in oily cold-water fish such as tuna, salmon and mackerel. Aside from fresh seaweed, a staple of many cultures, plant foods rarely contain EPA or DHA.

However, a third omega-3, called alpha-linolenic acid (ALA), is found primarily in dark green leafy vegetables, flaxseed oils, and certain vegetable oils. Although ALA has different effects on the body than EPA and DHA do, the body has enzymes that can convert ALA to EPA. All three are important to human health.

Improve heart health. Omega-3 fatty acids have been shown to play a part in keeping cholesterol levels low, stabilizing irregular heart beat (arrhythmia), and reducing blood pressure. Researchers now believe that alpha-linolenic acid (ALA), one of the omega-3s, is particularly beneficial for protecting against heart and vessel disease and for lowering cholesterol and triglyceride levels. Omega-3 fatty acids are also natural blood thinners, reducing the “stickiness” of blood cells (called platelet aggregation), which can lead to such complications as blood clots and stroke.

Reduce hypertension.Studies of large groups of people have found that the more omega-3 fatty acids people consume, the lower their overall blood pressure level is. This was the case with the Greenland Eskimos who ate a lot of oily, cold-water fish, for example.

Improve rheumatoid arthritis, lupus and other autoimmune diseases. Diets high in omega-3 fatty acids (such as fish oils) have been shown to increase survival in people with autoimmune diseases. This is probably because the omega-3s help the arteries–as well as many other parts of the body–stay inflammation free. EPA and DHA are successful at this because they can be converted into natural anti-inflammatory substances called prostaglandins and leukotrienes, compounds that help decrease inflammation and pain. In numerous studies over the years, participants with inflammatory diseases have reported less joint stiffness, swelling, tenderness and overall fatigue when taking omega-3s. Research has shown that getting more omega-3 fatty acids enables some participants to reduce their use of nonsteroidal anti-inflammatory drugs (NSAIDs).

Improve depression and symptoms of other mental health problems. The brain is remarkably fatty: In fact, this organ is 60% fat and needs omega-3s to function properly. Now researchers have discovered a link between mood disorders and the presence of low concentrations of omega-3 fatty acids in the body. Sometimes called "Prozac of the deep", The omega-3s are believed to help the brain’s entire traffic pattern of thoughts, reactions and reflexes run smoothly and efficiently. Interestingly, the oil used to help the child with a degenerative nerve disorder in the popular film Lorenzo’s Oil was an omega-3 fatty acid.

Aid cancer prevention and cancer support. Preliminary research from the University of California, Los Angeles, suggests that omega-3 fatty acids may help maintain healthy breast tissue and prevent breast cancer. Also, in a recent study, participants who supplemented their diet with fish oils produced fewer quantities of a carcinogen associated with colon cancer than did a placebo group. More research into this exciting use for omega-3s is underway.

Dosage Information - There is no established recommended daily intake for omega-3s,
but a healthy diet containing significant amounts of foods rich in this essential fatty acid is clearly wise. By increasing your intake of omega-3 fatty acids, you will naturally bring the ratio of omega-3 and omega-6 fatty acids back into a healthier, 2-1 or 1 -1 (optimal) balance. Try to reduce your consumption of omega-6-rich foods at the same time that you increase your intake of omega-3-rich foods in the following categories:

Plant sources: Canola oil, flaxseed, flaxseed oil, walnuts, and leafy green vegetables such as purslane are all good sources of alpha-linolenic acid (ALA), the plant-based omega-3. A quarter-cup (1 ounce) of walnuts supplies about 2 grams of plant-based omega-3 fatty acids, slightly more than is found in 3 ounces of salmon. Flax seed oil, at 53% Omega-3s, is, by far the most concentrated plant source.

Marine sources: Atlantic salmon and other fatty, preferably cold-water fish, including herring (both Atlantic and Pacific), sardines, Atlantic halibut, bluefish, tuna and Atlantic mackerel. The American Heart Association recommends that people eat tuna or salmon at least twice a week.

Cautions:

There are no known drug or nutrient interactions associated with increased consumption of omega-3 fatty acids through foods. However, if you decide to take omega-3s through supplements (especially those containing fish oils), be sure to check with your doctor first if you are taking a blood-thinner such as warfarin or heparin. Fish oil capsules do pose the risk of a “burp” factor. This harmless, although not exactly pleasant, fishy aftertaste that occurs with some brands of fish oil capsules.

Most sources recommend that fish consumption be limited to two to three servings weekly because so many fish are tainted with mercury and other contaminants. Fish oil capsules or plant sources don’t present this same risk.

Sources:

1. The American Heart Association
2. The Cleveland Clinic

Vision & Health Newsletter courtesy of:

Gordon G. Wong, O.D.
Wildon C. Wong, O.D.

7825 Fay Ave.
Suite 140
La Jolla, CA 92037858-454-4699

Our office is committed to offering quality eyewear at affordable prices.

This month we are extending a 30% courtesy on all Oakley and Christian Dior Eyewear.

If you do not have vision insurance we extend a 50% courtesy on the second pair of frames and lenses. For those covered under vision plans such as VSP, we offer a 30% courtesy on a second pair of frames and lenses.

For your convenience we will be open Friday November 28, the day after Thanksgiving and Saturday November 29 for appointments.

We look forward to seeing you and continuing to provide you with the best quality eyecare possible.

Sincerely,

Gordon G. Wong
Wildon C. Wong