Eyeglasses, Tints, Special Coatings, Bifocals Article

Article about Eyeglasses from The Second Wind

Dear Doctor Weaver,

I recently had my annual eye exam, and I have a lot of questions about getting new eyeglasses. My doctor recommended special features for my new bifocals to improve my problems with night-time driving and light sensitivity, but I’m confused about all of the different coatings and tints. Could you help explain what he’s talking about so that I can make a better decision about my new glasses?

Sincerely,
Frank

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Dear Frank,

When getting new eyeglasses, it can be daunting when trying to decide what kind of special tints and coatings you need on your eyeglass lenses, let alone selecting the style of frame that goes with them. I do not know your specific eye history, but I will give a general description of the special eyeglass lens options to help you make an informed decision.

The first choice is to decide between a bifocal and a trifocal option. A bifocal lens allows you to see at two separate points, far distance (driving, watching TV) and near (usually between 12 to 16 inches). A trifocal has a third section in the middle portion of the lens that allows a clearer view of an intermediate distance (between 2 to 3 feet) that is typically “washed-out” or blurred when trying to look through bifocals. The typical bifocal and trifocal are called “lined” bifocals or trifocals, because there is an actual line that is visible on the lens that separates the distance and near portions of the lens.

The next decision involves either choosing the “lined” bifocal/trifocal or going with a “no-line” progressive lenses. There are benefits to both types of lenses. With a line bifocal/trifocal, it is usually easier to switch between the reading and distance portion of the lens. The “lined” bifocals/trifocals are also usually less-expensive compared to the specialty design of progressive lenses and have a quicker adaptation period.

Progressive lenses are cosmetically appealing, because there are no lines visible on the lens. These types of lenses also provide the most complete range of vision, allowing you to see from far distance all of the way to your reading vision, depending on where you look through the lens. People typically had trouble adapting to the older styles of progressive lenses. However, progressive lens designs have gotten better over the last few years, causing less distortion and better adaptation.

After selecting the type of bifocal you would like, there are different types or lens materials, coatings and tinting options. What you decide on depends on your lifestyle and the type of work and hobbies in which you participate.

Most lens materials are made out of plastic, which is very safe, but not shatter-resistant. If you do a lot of work that requires a great deal of eye safety, polycarbonate is the most shatter-resistant material available. Children and those who are monocular should be in this material because it is the safest lens option. And in case you were wondering, glass lenses are still available. It is the most expensive option and most places have switched over to prescribing plastic and polycarbonate lenses due to their lighter weight and their safety. A high index plastic lens is lightweight and thinner than all other lens materials. Individuals with a very high prescription always had to deal with thick lens edges in glasses that would weigh heavily on the bridge of the nose. The high index can be used for any prescription, but it is especially recommended for those individuals with high prescriptions to allow the glasses to be lighter and more cosmetically appealing.

If you use your glasses extensively, or tend to throw them around a bit, you may want to consider a scratch-resistant coating. This can be placed on any type of lens material, but is always recommended for polycarbonate, since it tends to scratch more easily than other materials.

I always recommend an anti-reflective coating, which is also called an anti-glare coating. This coating reduces reflections on the eyeglass lenses, and helps in a variety of ways. The anti-glare coating reduces night-time glare from headlights or streetlamps, reduces eye fatigue from moderate reading or computer use, and can reduce light sensitivity during the day and at night. Some people refuse getting this because the coating “flaked-off” or “pealed-off.” Older types of coatings would do this after a few years. However, some of the new coatings are actually molded into the material itself, so that this problem is not a major issue anymore.

If you are outdoors a lot, you may want an ultraviolet coating, or UV coating. This is not a tint. It is a clear coating on the lens that protects your eyes while you are outside from harmful UV rays. From certain eye studies, UV rays are thought to play a role in the development of macular degeneration and cataracts. The UV coating is also a great option to help protect against any eye and eyelid lesions that can develop from extensive UV exposure.

Tinting is also a great feature if you spend a lot of time outdoors or are a person who is light sensitive. There are solid tints that are same color throughout the whole lens and graded tints that are darker at the top and lighter at the bottom of the lens. There are also many different color options when prescribing a tint. Certain colors are preferable to specific activities, such as fishing, hunting and playing golf to enhance contrast and reduce glare. There are also lenses that darken when activated by sunlight. These types of lenses are called transitions, or photograys. The older style of these lenses used to take a long while when changing from dark to light, but the newer technology allows this change to occur much faster.

Polarized lenses reduce the amount of reflected glare, allowing for clearer vision and reduced light sensitivity. It is definitely recommended for boaters or fishermen to reduce the issues caused by the sun reflecting off of the water’s surface. However, polarized lenses also reduce glare for many other activities, such as driving, skiing, golfing, and running.

So, as you can see, the added features are very helpful in a variety of ways. Your eye doctor, along the help with the optical department, can assist you in selecting the special features that would aid you the most.

Ocular Allergies, Allergic Conjunctivitis

Article about Ocular Allergies from The Second Wind

Dear Doctor Weaver,

I’ve been having a real problem with allergies this year, but the over-the-counter eye drops I typically use aren’t working well. Is there anything that you would recommend to help me out?

Sincerely,
Judy

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Dear Judy,

As you are already aware, Berks County is synonymous with allergies. The pollen from the blossoming plants in the Spring to the mold of decaying leaves in the Autumn can affect Berks County residents all year long.

The hallmark symptom of allergic conjunctivitis is itching. Other common symptoms include excessive tearing, as well as redness and swelling of the conjunctiva and eyelids. Many individuals seek ocular allergy relief with over-the-counter eye drops, but most non-prescription drops have a short duration of action, can cause rebound redness, and can potentially cause symptoms to last longer than they should.

Your primary care physician may also prescribe oral anti-histamines if you suffer from seasonal allergies. These medications work very well to reduce the systemic symptoms of allergies, such as congestion, sneezing, and runny nose. However, the action of the oral anti-histamine medications can actually cause dry eye symptoms to occur, which can mimic allergic conjunctivitis. These added symptoms can include irritation, burning, tearing, and foreign body sensation, which are especially dreadful to contact lens wearers.

The simplest way to self-treat mild allergic conjunctivitis is with the use of lubricating, preservative-free artificial tears and cold compresses. The artificial tears should be preservative-free because some preservatives can cause a sensitivity reaction to cause redness and irritation. The artificial tears will wash away the allergens that can accumulate on the surface of your eye and in your natural tears. The cold compresses helps to constrict the blood vessels to decrease the amount of redness and also aids in reducing swelling and itching.

If this doesn’t help, and your over-the-counter eye drops aren’t relieving your symptoms, I would seek an eye examination in order to obtain a prescription allergy eye drop medication. Your doctor will probably prescribe a combination allergy eye drop that is a mast cell stabilizer and an anti-histamine. These two mode of actions greatly reduce symptoms of acute ocular allergy in a short amount of time. If you suffer from chronic allergies, your eye doctor may also add steroid eye drops to relieve your symptoms.

The ocular allergy treatment is tailored to each individual, so what may work for someone may not work for you. So if your over-the-counter eye drops aren’t working, I would take a break from them and use plenty of cold compresses and preservative-free artificial tears. Then, if you are still having issues, go seek an eye examination to obtain professional advice and treatment.

Diabetes and the Eyes

Dear Doctor Weaver,

Recently, I was diagnosed with diabetes and my family doctor recommended that I get an eye examination. Could you please explain?

Sincerely,
Felicia

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Dear Felicia,

Diabetes is a condition that affects your entire body. It is a result of the body not being able to regulate appropriate blood sugar levels, due to the poor production or deficient activity of insulin. Your doctor has probably explained to you the different types of diabetes, which are type 1 (insulin dependent) and type 2 (non-insulin dependent).

Those with type 1 require the use of insulin to modulate suitable blood sugar levels in the body. Individuals with type 2 typically have the ability to control their blood sugar levels by changing their lifestyle habits, by eating a healthy diet, losing weight and exercising. If the blood sugar levels are still high, oral medications would be used to control blood glucose.

The best way to see if your blood sugar levels are in the normal range is to see your family doctor for a physical evaluation. Your doctor would then order blood tests that would include a fasting blood glucose and hemoglobin A1c. The fasting blood sugar is taken in the morning, prior to eating anything that day. This is similar to the home-screening tests that diabetics have to monitor their blood sugar levels throughout the day. The fasting blood glucose shows how your body processed sugar from your diet the day before. The hemoglobin A1c provides greater information to the physician, for it shows how well your body processed glucose over the previous three months.

Uncontrolled blood sugar from diabetes can cause cardiovascular disease with an increased risk of stroke, neuropathy that can result in limb amputations, kidney failure, skin ulcerations, depression, ocular complications, as well as many other problems.

The most common ocular complication is fluctuating vision. If a patient has diabetes and comes in for an eye examination, it is important for his/her blood sugar levels to be normal and stable to get an accurate eyeglass prescription. If the patient had high or fluctuating blood glucose the time of the exam, his/her vision will change when the blood sugar level normalizes. Therefore, the eyeglasses prescribed during the eye exam would be useless.

More seriously, diabetes affects the eyes by causing the blood vessels in the retina to become “leaky.” Early changes in the retina from diabetes would include microaneurisms and very small, pinpoint hemorrhages, called diabetic retinopathy. These signs usually resolve in time, and do not progress as long as the blood glucose is maintained at normal and stable levels. If the blood sugar remains high or fluctuates, the blood vessels can allow even more fluid to escape, which can cause retinal edema that can potentially result in vision loss or even blindness. These advanced changes in the retina would require co-management with a retinal specialist for treatment.

Diabetes can also accelerate the formation of cataracts as well. If you remember from a previous article, cataracts cause decreased vision as well as light sensitivity problems, such as haloes and glare. If glasses or contact lenses no longer provide clear, crisp vision, cataract surgery would be recommended.

High uncontrolled blood sugar levels can also cause the formation of new “leaky” vessels in a process called neovascularization. The vessels can grow in different parts of the eye. If in the retina, they can contribute to fluid accumulation or large hemorrhages in the retina. The neovascularization can also occur in the iris and in the angle, the drainage area of the eye. This will raise the intraocular pressure and cause neovascular glaucoma, which is a severe form of glaucoma that can lead to blindness.

It is advised for those with diabetes to have an annual dilated eye examination to monitor for any ocular changes related to this disease. It is possible that many of these signs can occur with no symptoms experienced by the patient, so it is important to seek routine care with your eye doctor and family physician to ensure that diabetes is diagnosed and treatment is initiated when necessary.