Tint my world – what different sunglass tints do for my vision

Photo courtesy of Rebecca Bollwitt on Flickr

Photo courtesy of Rebecca Bollwitt on Flickr

Have you ever been shopping for new sunglasses and been asked, “what color lenses would you like?” If you look back over the past century, there have been many different colors of sunglass lenses that were popular. Back in the 1930’s, Ray-ban developed their B-15 brown lens to be used by US Airforce pilots. Followed up by the G-15 with grey-green sunglass lens, standard in the iconic Wayfarer in the 1950’s. In the 80’s, Vuarnet came out with the popular Px 2000 amber lens to increase contrast and the Px 5000 brown lens for extreme conditions of high mountains, glaciers and desert.

Revo – blue, Suncloud – red, what is the best color for your sunglass lenses?

The following is a guide to the benefits of different lens colors:

  • Grey – most common lens color; this tint is considered neutral because it maintains true colors while decreasing light levels. Good for general outdoor activities.
  • Green –works the same in any light condition; they can be used for just about any outdoor activity.
  • Brown and Amber –causes some color distortion, but also increases contrast. These lenses filter out distortion caused by scattered blue light thus are great for activities like tennis, skiing, boating, high-altitude sports, or other sports where distance vision is important. This tint is also great for golf, as it highlights varying contrasts of green on the golf course.
  • Yellow – like amber lenses, some color distortion, but increased contrast. Great for activities in lower light levels especially with changes from light to shadows. These are the lenses to choose when mountain biking, target shooting, skiing, playing tennis, or piloting an aircraft.
  • Pink, Rose and Red –block blue light, thereby improving contrast. Very soothing to the eyes, they provide good visibility on the road. Great for sports like cycling and racing.
  • Blue and Purple – a high contrast lens that reduces glare from visible white light. These lenses are endorsed by the USPTA for tennis professionals and linepersons in the sport because they block the glare from visible white light.
  • Polarization – though not a tint, polarized lenses offer significant glare reduction. Glare caused by light reflected off flat surfaces including roadways, water and snow is blocked by polarized filters, whereas tints can only decrease light intensity. A polarized lens can be combined with nearly any lens color.

No matter what color lenses you choose, the most important feature of your sunglasses is UV protection. Be sure to ask for 100% UV 400 eye protection to decrease the risk of certain eye diseases including macular degeneration, cataracts, and pterygium. According to the American Optometric Association, to provide adequate protection for your eyes, sunglasses should:

  • block out 99 to 100 percent of both UV-A and UV-B radiation;
  • screen out 75 to 90 percent of visible light;
  • be perfectly matched in color and free of distortion and imperfection

~ Steven Sage Hider, OD
California Optometric Association
http://eyehelp.org
http://www.coavision.org

You may have cataracts?

Courtesy of entirelysubjective on Flickr

Courtesy of entirelysubjective on Flickr

Cataracts are common

Not a day goes by in the office when I don’t tell a patient that he or she has a cataract, which is any kind of clouding in the crystalline lens of our eye. Some patients have heard of the term and understand that it’s a common occurrence as one ages. Other patients are terrified of the term and think it’s a disease that will make them blind. But the patients I relate to are the ones who hear the word cataract, and think “I’m old.”

Cataracts can affect your vision

If it helps, most cataracts develop over decades, from young adulthood onward. As early as 40 years old, we can start to notice the effects of this change over time. The crystalline lens in our eye, which is responsible for focusing light onto our retinas, begins to change shape and chemical structure over time. These changes result in more light scatter and dimming of vision. Usually, a patient will begin noticing glare from car headlights, double or ghost images around letters and lights or that night vision is not as clear or bright.

These are often initial symptoms and do not require treatment. As the cataracts continue to develop, patients’ eyeglass prescriptions may begin to change and they will also experience blurry or cloudy vision with worsening of the above symptoms. When they reach this point, which is about half of patients over the age of 65, cataract surgery may be indicated.

Cataract surgery – not as bad as you’d think

Cataract surgery is the most common surgery performed in the world. Nowadays, it can be a 15 minute out-patient procedure. The cataract is removed from the eye and replaced with an artificial lens implant, called an intraocular lens. With many advancements in this field, the lens implant can also have specialty optics which can correct for astigmatism or for both distance and reading.

What many don’t know is that cataract surgery is an optional procedure. A cataract is not malignant and does not always have to be removed. However, a patient’s vision will improve significantly with a successful cataract surgery. They will notice a much brighter and clearer environment. Some patients who have glaucoma or have a crowding of the internal structures of the eye would benefit from having cataract surgery.

Image

Photo courtesy of Community Eye Health on Flickr

Types of cataracts

There are many different forms of cataracts. In fact, I found a cataract in a 9-month old baby when his mom brought him in for a well-visit eye examination. In such a case where the eye is still developing, clouding of the lens can interfere with visual development and needs to be removed. Other congenital form of cataracts may simply be a cloudy spot on the lens which doesn’t interfere with vision. In this case, there is no need for cataract surgery.

Cataracts can also develop from trauma, use of certain medications and diabetes. Depending on the type, a cataract can slowly worsen over years, or change rapidly requiring surgical intervention within months. For patients whose vision is changing rapidly, I often like to follow them every few months to monitor for vision and cataract changes.

People often ask what can be done to prevent cataracts. Unfortunately, genetics plays a factor so if your parents required cataract surgery, you will most likely need one also. If you’re outdoors, wear a good quality pair of sunglasses that block UVA/UVB rays. This goes for kids as well since exposure to ultraviolet radiation is cumulative. If you’re outdoors for long periods of time, throw on a hat for added protection. Smoking has been shown to cause cataracts also, so limit your exposure to cigarette smoke. If you are currently being treated for diabetes or using steroid medications, be sure to see your internist regularly.

Why wait for your vision to blur? See your optometrist every year!

Most importantly, see your optometrist annually for an eye examination. They can check for cataracts but also determine if there are other factors that may be contributing to a reduction in your vision. It’s not just the lens that helps you to see but a whole network of related structures that work as a team to provide you with optimal vision.  If you require a new pair of glasses, always opt for an anti-glare coat on the lenses, which would further reduce disabling glare symptoms.

~Cindy P. Wang, OD, FAAO
http://eyehelp.org
http://www.coavision.org

 

What if my child’s eyes are crossed? Strabismus 411.

HELP! It looks like my child’s eye is turning in, or out or I’m not sure. What do I do? What is strabismus anyway?

Photo courtesy of mjtmail (tiggy) on Flickr

Photo courtesy of mjtmail (tiggy) on Flickr

Strabismus, or crossed eyes, is a condition in which both eyes do not look at the same place at the same time. It occurs when an eye turns in, out, up or down. Strabismus is classified by the direction the eye turns:
• Esotropia = Inward turn
• Exotropia = Outward turn
• Hypertropia = Upward turn
• Hypotropia = Downward turn

There are six muscles attached to each eye that control eye movement. Normally, the eyes work together so both eyes look at the same place at the same time. An eye turn may be visible when there are problems with eye movement control.
The eye turn may be present constantly or only at certain times such as when the person is tired, ill, or has done a lot of reading or close work. One eye or both eyes may alternate turning.

Proper eye alignment is important to avoid seeing double, for good depth perception, and to prevent the development of poor vision in the turned eye.

What causes strabismus?

There are many causes, including:

  • Eye muscle problems.
  • Problems with the nerves that transmit information to the muscles.
  • Trouble with the control center in the brain that directs eye movements.
  • General health conditions or eye injuries.

What are risk factors for developing strabismus?

  • Family history – Those with parents or siblings who have strabismus are more likely to develop it.
  • Refractive error – Especially a large amount of uncorrected farsightedness (hyperopia).
  • Medical conditions – Including Down syndrome, cerebral palsy, stroke or head injury.

How is strabismus diagnosed?
Strabismus is diagnosed through a comprehensive eye exam. Testing may include:

  • Visual acuity, or vision – “Normal” distance visual acuity is 20/20.
  • Refraction – Determine the appropriate lens power needed to compensate for any refractive error (nearsightedness, farsightedness, or astigmatism).
  • Alignment and focusing testing – How well the eyes focus, track, move and work together.
  • Examination of eye health – This includes the front and back of the eyes. Eye pressure is also evaluated.

Because vision may change frequently during the school years, regular eye and vision care is important.

How is strabismus treated?
There are several treatment options to treat strabismus, including:

  • Eyeglasses or contact lenses – For some conditions, glasses alone will align the eyes.
  • Prism lenses – Prisms align the images seen by both eyes, so the eyes can fuse or see the same image, restoring visual clarity and depth perception.
  • Vision therapy – Vision therapy trains the eyes and brain to work together more effectively.
  • Eye muscle surgery – Surgery may be able to physically align the eyes so they appear straight. A vision therapy program may also be needed after surgery.

What can happen if the eye turn is not treated?

Photo courtesy of jmoneyyyyyyy on Flickr

Photo courtesy of jmoneyyyyyyy on Flickr

Potentially an untreated eye turn can lead to amblyopia, otherwise known as lazy eye. Amblyopia is permanently reduced vision in one eye.

When does a child develop strabismus?
Typically strabismus develops in infants and young children by age 3. It may be present in older children and adults. Children do not “outgrow” strabismus.

Most importantly…
If detected and treated early, strabismus can often be corrected with excellent results. Eye examinations are important for all children and adults, starting at 6 months of age. If any eye turn is in question, schedule a comprehensive eye examination immediately.

~Melissa Barnett, OD, FAAO
California Optometric Association
http://www.eyehelp.org
http://www.coavision.org

What did my doctor just say? Common terms your eye doctor will use and what they mean

Courtesy of riekhavoc (caughtup?) on Flickr

Courtesy of riekhavoc (caughtup?) on Flickr

Have you ever felt like you were not quite sure what just happened at your optometrist’s office? It is difficult enough to answer the “which is better, one or two?” questions and then at the end of the exam to try and understand the doctor’s explanations with difficult optometry terms without secretly worrying that you might have said something wrong!

Hopefully this blog will help you better understand some of the more common terms we use in our examinations.

1) First of all, most comprehensive exams will include a detailed case history. The doctor will want to know your family medical and ocular (eye) history. Some terms you may hear include the most common eye diseases – cataracts, glaucoma and macular degeneration.

  • Cataract is the term used when the natural lens of your eye becomes cloudy, causing blurred and distorted vision.
  • Glaucoma is the eye disease that causes your eye to have excessively high pressure, which can lead to long-term damage of the nerve in the eye.
  • Macular degeneration is a disease that affects your central or straight ahead vision.

Not only will the optometrist ask you about a family history of any of these conditions, they will also assess your eye health and your possible risk for developing any of them.

2) Next, the optometrist will perform a refraction to get you the best possible glasses or contacts that will correct your vision.

  • A refraction is just the process of determining for each individual what are the best lenses to give you maximum visual clarity and comfort at both distance and near.
  • Myopia – nearsightedness or the ability to see better at near than at far.
  • Hyperopia or farsightedness, really means that it is more difficult to focus at near and at far distances.
  • Astigmatism: this refers to the shape of the front surface of the eye being more football shaped rather than basketball shaped.

3) There are a few terms you might hear specifically in an child’s exam.

  • Pursuits: slow, smooth eye tracking.
  • Saccades: fast reading eye tracking.
  • Accommodation: focusing.
  • Binocularity: the ability of the eyes to work together as a team.

4) Finally, there are some terms regarding glasses that it might help to define.

  • Progressive lenses are the kind of “no line bifocal” that you might hear about on TV. But, unlike a bifocal, where there are two areas of vision, near and far, progressives have an unlimited amount of areas as you look from distance to near in the lens.
  • Transition lenses are the kind that change to dark outside. They undergo an anti-reflective treatment, which eliminates all glare and allows for crisper vision, especially at night.

Hopefully, this quick explanation helps with some of the confusing terms in an eye exam. As for any others, always ask your optometrist to explain something that does not make sense.

~Lisa Weiss, OD, MEd, FCOVD
California Optometric Association
http://www.coavision.org

Common myths about eyeglasses debunked!

Photo courtesy of Ben Andreas Harding on Flickr.

Photo courtesy of Ben Andreas Harding on Flickr.

As an optometrist, I often hear a variety of misconceptions about eyeglasses from my patients. Most concerns fall into a few broad categories with a few bizarre ones sprinkled in. I would like to take a brief moment to address some of the most common ones I hear:

  1. “Wearing glasses will make your eyes weaker.” This is probably the one myth I hear the most often and it is absolutely false. The biggest thing people forget to account for when they notice they are more reliant on their prescription glasses is that they are a bit older. As a person gets older, their ability to continue to see clearly without prescription glasses deteriorates. While this applies to everyone, it is most pronounced in my far-sighted patients in particular.
  2. “Not wearing your prescription glasses will make your eyes get worse.” This also is not true. Not wearing your glasses will not damage your eyes, but it can cause a significant amount of eyestrain. Extended viewing of computer monitors, smart phones, tablets or televisions without a proper prescription can lead to significant eyestrain and may cause you to discontinue viewing sooner than you planned.

    Photo Courtesy of TempusVolat on Flickr

    Photo Courtesy of TempusVolat on Flickr

  3. You can’t play sports with glasses on.” Not true! Glasses for sports can be made to protect your eyes and clear your vision at the same time. Protective lenses such as polycarbonate plastic can be put into sports goggles to allow a person to wear glasses when participating in sporting activities. Many patients prefer to wear contacts when they play sports, but it is a personal preference. Be sure to talk to your optometrist if you need specialty lenses for any of the activities you participate in.
  4. “Over the counter readers are just as good as prescription glasses.” This myth is not necessarily untrue. For a small group of patients, over the counter readers do work just as well as prescription reading glasses. The bad news is it’s an extremely small group of patients and those glasses work only when they are reading. Proper prescription glasses can correct each eye individually for the distance so both eyes are in focus and balanced. Once the eyes are balanced and working together, your optometrist can determine the proper power you need for your computer monitor or for reading materials. For the overwhelming majority of patients, there is a difference between the prescriptions between their eyes or some astigmatism in their correction that you cannot find in over the counter glasses.

I hope these answers help open your eyes to how prescription glasses can help you see clearly.

~Ranjeet S. Bajwa, OD, FAAO
California Optometric Association
http://www.coavision.org

“What if 1 and 2 look the same?!”

Courtesy of riekhavoc (caughtup?) on Flickr

Courtesy of riekhavoc (caughtup?) on Flickr

A common concern for some of my patients is if they don’t tell me the correct choice of lens, then their prescription for that year will be off and not work properly. This is not true. When an optometrist is switching between lenses (which we in “the business” call a refraction), we are fine-tuning a prescription using the patient’s input to find the lenses that are the most clear and comfortable.

Optometrists are trained to filter out incorrect answers from our patients as we double and sometimes triple check on your responses to make sure we have the right powers. Many optometrists do this by bracketing the lens choices presented to patients. Bracketing means we pick two lenses with a noticeable difference in powers and move towards the most clear of the two. By doing so, the lenses in 1 and 2 may end up being the same lens or lenses in choices 7 and 8, etc.

Additionally, when we bracket the lens choices our goal (or “end point”) is when the two choices look just about the same. So if your optometrist is checking your eyes and the two choices look about the same, tell them- that’s what we want to know.

Another thing that we as optometrists don’t want is to give you a glasses prescription that are too strong for you. That is why it is important for you to relax and try not to squint when your optometrist is checking your prescription. If you are constantly squinting when we try to refract you, then you are more likely to end up with glasses that only work well when you squint, but are too strong for you when you don’t.

Courtesy of Lyn Kelley Author on Flickr

Courtesy of Lyn Kelley Author on Flickr

Something I have found to help patients give better responses is remembering to blink often. Occasionally, a patient will get so fixated on telling me which lens looks better that they don’t blink as often as they normally would. This can cause your tear film on the surface of your eyes to start to break up and affect your ability to tell which lens looks better. Blinking often lets your eyelids put a smooth layer of tears over the front of your eyes. It is similar to polishing a lens, and a polished lens is always easier to see out of than a scratched lens.

Your optometrist can check on the health and structures of your eyes as well as check the function of your two eyes working together when you go in for your annual eye exam. The art of determining a person’s prescription is not easy, but an optometrist is trained to work with the responses of their patients. Don’t worry about getting it wrong! If you just remember some of the tips mentioned above, you can be sure your optometrist find your proper prescription.

~Ranjeet S. Bajwa OD
California Optometric Association
http://www.coavision.org

Night blindness 101

The term night blindness sounds alarming, as though some people are actually blind at night.  There is a small percentage of the population that does in fact experience true night blindness, but it is rare and often the result of late stage eye disease.  In optometry, it is not common to use the term night blindness although we do encounter a significant number of patients who complain of poor night vision.  The symptoms are usually blur and dimming of vision at night, glare and haloes around lights and poor adaptation from light to dark environments.  How do you know if what you are experiencing is normal or a result of something more serious?

There are a handful of eye conditions that can create symptoms of poor night vision.

Photo Courtesy of kenleewrites on Flickr

Photo Courtesy of kenleewrites on Flickr

  1.  Patients who have had surgery to the corneas such as LASIK or corneal transplants may notice glare and haloes around light.  They may also experience diminished contrast sensitivity which can cause images in the evening to appear more dim.  Unfortunately, surgical results usually cannot be reversed.
  2. Cataracts are the number one cause of decreased night vision.  Patients over the age of 40 will begin developing mild cataracts.  This is when the natural lens inside the eye becomes more yellow and opaque as a result of age and ultraviolet exposure.  Cataracts can cause haloes and dimming of vision in the dark and decreased contrast sensitivity.  Fortunately, cataracts are easily removed thereby restoring problems with night vision.
  3. Corneal diseases such as keratoconus and severe dry eyes may also affect one’s vision in the evenings causing double vision or haloes.  For some of these patients, specialty contact lenses or eyedrops will alleviate these symptoms.
  4. Newer technology has also allowed optometrists to detect higher order aberrations in some patients.  For these patients, standard spectacle lenses may not improve night vision problems.  An instrument to detect higher order aberrations will determine whether a patient requires a specialty custom-made spectacle lens to improve night vision.

Some patients do in fact have true night blindness caused by an eye disease in its late stage.  Usually, symptoms begin slowly over time and progress to an inability to see in the dark.  These patients usually suffer from one of two eye conditions.

  1.  Retinitis pigmentosa is an inherited eye disease of the retina, the tissue that lines the back wall of the eye and captures visual images.  Retinitis pigmentosa affects the rods of the retina and causes slow deterioration of these structures.  The rods (unlike the cones) are responsible for night vision and for peripheral vision.  As the disease progresses, patients will notice a decrease in their ability to see in the dark and in the periphery.  Unfortunately, there is no current cure for retinitis pigmentosa.
  2. Glaucoma is an eye disease where the optic nerve slowly degenerates.  Patients with glaucoma usually have no symptoms in the early stages of the disease.  As the disease progresses, nerve fibers in the retina begin to deteriorate resulting in a decrease in peripheral vision as well as night vision.  Usually, patients do not experience symptoms of poor night vision and poor peripheral vision until the late stages of the disease.

Now that you know the causes, what are some ways to alleviate or improve poor night vision?  The simplest solution is to wear an updated pair of prescription glasses (if you have a prescription) with higher index lenses and an anti-glare coat.  Your optometrist can also inform you if you require customized lenses to correct for higher-order aberrations.  If your night vision problems are not a result of surgery or any eye diseases that you are aware of, then it is important that you visit your optometrist for a comprehensive eye examination.

– Cindy P. Wang, O.D., F.A.A.O.
California Optometric Association
www.coavision.org