Layers of the Retina

The retina at the back of the eye is essential for all vision. Each layer of cells in this tissue serves a specific purpose. As we prepare for Age-Related Macular Degeneration Awareness Month in February, a closer look at the layers of the retina and their function.

Layers of the Retina

Choroid – This is made up of a layer of blood vessels that supply oxygen and nutrients to the retina. Defect in the CHM gene can cause choroideremia, leaky blood vessels can expand in the retina causing wet age-related macular degeneration (AMD) and diabetic retinopathy.

Retinal pigment epithelium – This is a single layer of cells that provide essential nutrition and waste removal for the photoreceptor cells. Accumulation of waste can lead to AMD and Stargardt disease.

Photorecptors – This is where the rods and cones are located that convert light into electrical signals. Rods help you with night and peripheral vision. Cones are more concentrated in the macula (the central part of the retina) and proved central and color vision. Death of the rods can cause vision loss called retinitis pigmentosa, while AMD is the loss of central vision.

Horizontal cells – These cells are connect to the photoreceptors that surround the bipolar connected photoreceptor cells and help the help integrate and regulate the input from multiple photoreceptor cells, increasing your visual acuity.

Bipolar cells – The dependence of each layer of the retina on each other is exemplified here. These cells take the electrical information from the photoreceptor cells and pass it along to other retinal cells.

Ganglion cells – These cells extend to form an optic nerve that conveys information to the brain and take the electrical information from the bipolar cells and process it to determine shapes, contrast and color. Glaucoma vision loss results from high intraocular pressure that affects the optic nerve, interrupting the signals to the brain.

Wearing Contact Lenses in Winter

This has been a cold winter so far, and since it is only January, it is bound to get colder. The extreme cold, combined with winds, snow, rain and other environmental factors, can really take a toll on your eyes. And while it may be snowing or raining, winter air is actually drier than any other season. This can be especially difficult if you wear contact lenses. Here is what you should know about wearing contact lenses in winter.

Wear sunglasses for protection from UV rays and wind. Your eyes can become sunburned which cause blurry vision and can make your eyes feel like they are burning (think of your sunburned skin feels) for 24 to 72 hours. It will also protect your eyes from snow, rain or anything else the wind can send your way.
Avoid direct sources of heat such as heating vents and fireplaces. Indoor heating can draw the moisture out of the air, so consider a humidifier to help maintain the correct amount of moisture in the air to help keep eyes moist. Cool-air humidifiers have less of a tendency toward mold and bacteria.
Speaking of hydration, we also tend to drink less water in the winter months, so make a concentrated effort to keep up your water intake.
If it is so dry, why are my eyes watering? This is a common question and the answer may be a bit counter-intuitive. Anything that irritates your eyes, including dryness, causes a tearing reflex. Your tear glands go into overdrive trying to replace the moisture to your cornea. To try and reduce the tearing, you can use eye drops or artificial tears specifically designed for use with contact lenses.
Your eyes are not the only thing that dries out in the winter, so does your skin. Try to put in your contacts before moisturizing your skin, especially your hands. So wash your hands, put in your lenses and then use your creams and lotions.
Change out your contact lenses regularly in cold weather according to the recommended schedule, be it daily, every two weeks or monthly. This will allow them to better conduct oxygen, reduce irritation and increase comfort.
Take a break from your contacts and wear your eyeglasses. Putting them on when you get home from work can make a big difference. Contact lenses dry your eyes out on their own, when you add cold weather it gets that much worse.
Get plenty of sleep, which also helps with the dryness and fatigue. This will help you start the day with your eye refreshed and ready for the many things you will put them through throughout the day ahead.

Do you have any other suggestions that have helped you cope when wearing contact lenses in winter?

1/15/16

Susan DeRemer, CFRE Vice President of Development Discovery Eye Foundation

Silent Thief of Sight – Glaucoma

January is National Glaucoma Awareness Month. The National Eye Institute, through their education program NEHEP, have created this infographic to provide you with information you need to know about this blinding eye disease.

When adults reach their 40s, they often begin to notice small changes in their vision that can affect their daily lives and jobs. It could be difficulty in reading a book or working on a computer. This can be annoying, but it can often be addressed by seeing an eye care professional for comprehensive dilated eye exam. This allows the doctor to detect diseases and conditions that can cause vision loss and blindness and yet have no symptoms in their early stages.

Silent Thief of Sight – Glaucoma

Glaucoma is one of these age-related eye diseases that has no early symptoms, which is why it is called the silent thief of sight. It is actually a group of diseases that can damage the eye’s optic nerve and result in vision loss and blindness. Open-angle glaucoma is the most common form disease.

In addition to an eye exam, you can reduce your chances of losing your vision to glaucoma by also:

Live a healthy lifestyle that includes maintaining a proper weight, eating healthy foods, and not smoking.
Know your family history to determine if you are at a higher risk for some eye diseases.
Protect your eyes against harmful UV rays from the sun or your computer by wearing sunglasses when you are outdoors or computer glasses when using the computer for extended periods of time.

Silent thief of sight glacoma — Courtesy of NEI/NEHEP

1/5/16

Susan DeRemer, CFRE
Vice President of Development
Discovery Eye Foundation

9 Tips To Relieve Digital Eye Strain

Online shopping has continued to grow this year, which means more people are spending more time on computers, tablets and phones. While the convenience of online shopping can’t be beat, it could be costing us sleep, giving us headaches, making our vision blurry…and even affecting our posture.

Digital Eye Strain

Digital eye strain (DES), also known as computer vision syndrome (CVS), is a consequence of spending two or more hours at a time looking at a digital screen. Nearly 30% of adults spend more than 9 hours each day using digital devices, while 25% of children use digital devices more than 3 hours a day.

This can result in dry or itchy eyes, blurred vision, eye twitches, headaches and even back and neck pain. Using digital devices for an extended period of time increases your tendency to lean into the device, as you try to focus or compensate for glare from reflected light (room lighting or windows). Holding these positions for long periods of time are what create the back and neck pain.

As for the many eye symptoms, they can come from

poor lighting
improper viewing distance from device
not blinking often enough
poor screen contrast
glare on the screen
UV blue light

To help you deal with DES, here are 9 tips to relieve digital eye strain.

12/22/15

Susan DeRemer, CFRE
Vice President of Development
Discovery Eye Foundation

12 Thanksgiving Vision Tips

When you are giving thanks today, be sure to be thankful for your vision. In order to you keep your eyes healthy, here are 12 vision tips.

11/26/15

Susan DeRemer, CFRE
Vice President of Development
Discovery Eye Foundation

Smoking and Your Eyes

Smoking is the single largest preventable cause of eye disease.

On the third Thursday of November each year, smokers across the nation take part in the Great American Smokeout, sponsored by the American Cancer Society. This might be the ideal time for you to stop smoking and ACS has information and resources you may find helpful.

Here are some things you should know about smoking and your eyes.

Smoking at any age, even in your teens or twenties, increases your future risk for vision loss.

The more you smoke, the higher your risk for eye disease.

If you quit smoking, your risk for these eye diseases decreases considerably.

Smoking increases your risk for cardiovascular diseases that indirectly influence your eyes’ health.

Women who smoke during pregnancy increase their chance for a premature birth and a potentially blinding eye disease called retinopathy of prematurity (ROP).

A smoker is two times more likely to develop macular degeneration compared with a nonsmoker.

Smoking double your chance of forming cataracts and the risk continues to increase the more you smoke.

Smoking doubles your diabetes risk which can lead to the blinding eye disease, diabetic retinopathy.

Smokers are more than twice as likely to be affected by dry eye syndrome as a non-smoker.

Second-hand smoke also makes dry eye worse, especially for contact lens wearers and post-menopausal women.

If you smoke you can have a three-fold increase in the risk of developing AMD compared with people who have never smoked.

Smoking appears linked to the development of uveitis with smokers having more than twice the risk of non-smokers.

If you are looking to stop smoking you may also want to check out Smokefree.gov which provides free, accurate, evidence-based information and professional assistance to help support the immediate and long-term needs of people trying to quit smoking.

11/19/15

Susan DeRemer, CFRE
Vice President of Development
Discovery Eye Foundation

The Importance of An Eye Exam

Why You Need An Eye Exam

The end of the year is fast approaching – when was the last time you had an eye exam? Was it a comprehensive eye exam?

To keep your eyes healthy and maintain your vision, the American Optometric Association (AOA) recommends a comprehensive eye exam every two years for adults ages 18 to 60, and annual exams for people age 61 and older. However, if you have a family history of eye disease (glaucoma, macular degeneration, etc.), diabetes or high blood pressure, or have had an eye injury or surgery, you should have a comprehensive exam every year, unless otherwise indicated by your doctor.
Also, adults who wear contact lenses should have annual eye exams.

An important part of the comprehensive eye exam is the dilated eye exam to look inside your eye. Drops are placed in each eye to widen the pupil and allow more light to enter the eye. This gives your doctor a clear view of important tissues at the back of the eye, including the retina, the macula, and the optic nerve. This allows for early diagnosis of sight-threatening eye diseases like age-related macular degeneration, diabetic retinopathy, glaucoma, etc.

To better understand the importance of the dilated eye exam, here is a video from the National Eye Institute (NE) that explains what to expect.

At the end of your comprehensive eye exam your doctor should raise any concerns he has with you. But it is up to you to be prepared to react and ask questions for peace of mind and to help save your vision.

Questions To Ask After Your Eye Exam

It is always important to know if anything about your eyes have changed since your last visit. If the doctor says no, then the only thing you need to know is when they want to see you again.

If the doctor says the have been some minor changes, you need to know what questions to ask, such as:

Is my condition stable, or can I lose more sight?
What new symptoms should I watch out for?
Is there anything I can do to improve or help my vision?
When is the next time you want to see me?

If the doctor sees a marked change in your vision or give you a diagnosis of eye disease, you would want to ask:

Are there treatments for my eye disease?
When should I start treatment and how long will it last?
What are the benefits of this treatment and how successful is it?
What are the risks and possible side effects associated with this treatment?
Are there any foods, medications, or activities I should avoid while I am undergoing this treatment?
If I need to take medication, what should I do if I miss a dose or have a reaction?
Are there any other treatments available?
Will I need more tests necessary later?
How often should I schedule follow-up visits? Should I be monitored on a regular basis?
Am I still safe to drive?

Your vision is a terrible thing to lose, but with proper diet, exercise and no smoking, along with regularly scheduled eye exams, you improve your chances of maintaining your sight.

11/5/15

Susan DeRemer, CFRE

General Differences Between Polarized and Absorptive Lenses

Polarized and Absorptive Lenses

Polarized lenses can be helpful in reducing glare; in fact, they were first developed to help with glare from outdoor sports and activities. Here is a passage from All About Vision that explains the basics of polarized lenses very well.

Light reflected from surfaces such as a flat road or smooth water generally is horizontally polarized. This means that, instead of light being scattered in all directions in more usual ways, reflected light generally travels in a more horizontally oriented direction. This creates an annoying and sometimes dangerous intensity of light that we experience as glare. Polarized lenses contain a special filter that blocks this type of intense reflected light, reducing glare.

Though polarized sunglasses improve comfort and visibility, you will encounter some instances when these lenses may not be advisable. One example is downhill skiing, where you don’t want to block light reflecting off icy patches because this alerts skiers to hazards they are approaching. In addition, polarized lenses may reduce the visibility of images produced by liquid crystal displays (LCDs) or light-emitting diode displays (LEDs) found on the dashboards of some cars or in other places such as the digital screens on automatic teller machines and self-service gas pumps. With polarized lenses, you also may be unable to see your cell phone or GPS device.

Boaters and pilots also have reported similar problems when viewing LCD displays on instrument panels, which can be a crucial issue when it comes to making split-second decisions based strictly on information displayed on a panel. (Some manufacturers of these devices have changed their products to solve the problem, but many have not yet done so.) Many polarized lenses are available in combination with other features that can enhance outdoor experiences.

Absorptive Sunlenses/Sunglasses do a little more than just reduce glare.

These are special wraparound sunglasses that filter out ultraviolet (UV) and infrared (IR) light. I explained those two types of light in my post. In addition to reducing glare, they can also increase contrast, which is important for visibility.

They also come in a variety of tints: dark gray-green, medium amber, medium gray, medium plum, yellow, orange, amber, and light orange. Many of the available tints/colors also have a percentage sign. The percentage sign represents the amount/percent of visible light that is transmitted through the lens. Here are some examples:

32% medium gray
10% medium amber
2% dark gray-green
20% medium plum
65% yellow
49% orange
16% amber
52% light orange

It is the tint – in combination with the amount of light transmission of each tint – that is helpful for people with glare issues. There are a few manufacturer websites that explain the range of absorptive lenses very well.

The first is NoIR Medical Technologies (NoIR stands for “No Infra-red” light.) You’ll see that there are different colors and tints, and many of the colors also have a percentage sign. The percentage sign represents the amount/percent of visible light transmitted through the lens.

Generally, NoIR recommends the following for people with glare problems:

32% Grey
13% Dark Grey
18% Grey
40% Grey-Green
20% Plum
16% Amber
10% Amber
54% Yellow

You can see from the list that the color does not have to be extremely dark for the lenses to reduce glare and light sensitivity.

Also, Eschenback Optik provides a good overview of Solar Shields, another type of absorptive lens product.

Most styles of absorptive lenses also can be fitted over prescription lenses. The bottom line is that it’s probably necessary to visit an office that carries a supply of these lenses and determine which color, tint, and percentage of light transmission is right for your wife. It’s helpful to compare several styles to determine what tint and percentage of light transmission work best.

10/27/15

Maureen A. Duffy, CVRT, LVT
Social Media Specialist, visionaware.org
Associate Editor, Journal of Visual Impairment & Blindness
Adjunct Faculty, Salus University/College of Education and Rehabilitation

Carrots For Healthy Eyes

Lately we have heard quite a bit about carrots and the positive effects they can have on your vision, such as slowing the progression of age-related macular degeneration (AMD). This is because carrots contain pigments called carotenoids. These pigments also give vegetables their colors, in this case orange. But carrots weren’t always orange.

The beginnings of carrots can be tracked back to the dry, hot lands of Iran and Afghanistan in 3000 BC, when the root vegetables were black, white, red and purple. They were bitter and used as a healing remedy for many illnesses, as well as an aphrodisiac.

The vegetable grew in popularity because it was still edible even after months of being stored in a variety of conditions. Carrot seeds were soon picked and sold to neighboring Middle Eastern, African and Asian populations. This is when the crossbreeding started and new types of carrots were created.

Across centuries and continents, the carrot evolved, improving the composition, look, flavor and size. After years of selective breeding, in the 17th century a Dutch yellow carrot was engineered to get rid of the bitterness, increase sweetness and minimalize the wooden core. This appears to be the origin of the orange carrot we enjoy today.

Americans didn’t fully use carrots until after World War I when soldiers returning home told about French and other European cuisine which included the carrot. However, it didn’t really become popular until World War II, when England actively encouraged home growing of carrots while the US was engaged in cultivating “Victory Gardens.”

Today the carrot is found around the world in temperate regions. They have a high nutrition value, presence of ?-carotene, dietary fiber, antioxidants, minerals and ability to be prepared in a wide variety of recipes. They have become a staple in many countries.

Currently, the largest producer and exporter of carrots in the world is China. In 2010, 33.5 million tons of carrots and turnips were produced worldwide, with 15.8 million tons from China, 1.3 million tons each from the US and Russia, 1 million tons from Uzbekistan and less than a million from Poland, the United Kingdom and Ukraine.

Because of the popularity and health benefits of carrots, they are now enjoyed in a variety of ways – beyond the simple salad. Here are some recipes you might find interesting to try:

Crab Toast with Carrot and Scallion – Forget your traditional bruschetta, wow your guests with the appetizer.

Potato-Carrot Latkes with Lemon-Raisin Topping – Seems perfect with Hanukkah just around the corner.

Roasted Carrot, Squash and Sweet Potato Soup – This is a more traditional carrot recipe, it is not that hard to find a carrot soup, but this one also has squash and sweet potatoes which are also eye healthy!

Carrot Farfalle Pasta with Lemon and Herbs – Not only are carrots good for flavor, but they add a nice color to this pasta that could be the base for any number of pasta dishes.

Carrot Ginger Layer Cake with Orange Cream Cheese Frosting – Most carrot cakes have no frosting or a traditional cream cheese frosting. The idea of an orange frosting makes this cake special.

Carrot, Ginger, and Lime Juice – Refreshing and healthy.

10/22/15

Susan DeRemer, CFRE
Vice President of Development
Discovery Eye Foundation

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Eye Health

Wearing Contact Lenses in Winter

Top 10 Articles of 2015

Silent Thief of Sight – Glaucoma

Silent Thief of Sight – Glaucoma

9 Tips To Relieve Digital Eye Strain

Digital Eye Strain

12 Thanksgiving Vision Tips

General Differences Between Polarized and Absorptive Lenses

Polarized and Absorptive Lenses

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Layers of the Retina

Silent Thief of Sight – Glaucoma

Digital Eye Strain

Here are some things you should know about smoking and your eyes.

Why You Need An Eye Exam

Questions To Ask After Your Eye Exam

Polarized and Absorptive Lenses

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