Glaucoma: The 'silent thief' begins to tell its secrets

January 21, 2014

Glaucoma is sometimes called the "silent thief of sight" because it slowly damages the eyes and can cause irreparable harm before there is any vision loss. But this disease is stealthy in more ways than one. Glaucoma has been known at least since antiquity, and yet, researchers today still do not know what causes it in most cases. There are treatments to delay vision loss, but no cure, making it a leading cause of blindness all over the world.

Glaucoma is a group of diseases that damage the optic nerve, a cable at the back of each eye that connects it to the brain. It affects more than 2.7 million people in the United States and more than 60 million worldwide. There are many forms of the disease, but primary open-angle glaucoma is the most common form and the most mysterious.

Since January is Glaucoma Awareness Month, it's a good time to ask: Are researchers making progress in solving this mystery?

"Primary open-angle glaucoma remains a black box, but researchers are pursuing many avenues to investigate the underlying causes. As we develop a better understanding of the disease process, we hope this will lead to new, more effective treatments and possibly even preventive therapies for it," said Hemin Chin, Ph.D., director of the Glaucoma and Optic Neuropathies program at the National Eye Institute (NEI), part of the National Institutes of Health.

High-pressure research
If you've ever had an air-puff test, also known as tonometry, then you may have heard that glaucoma is linked to an increase in eye pressure, or intraocular pressure. The unique anatomy of the eye, when combined with other factors, can cause a rise in eye pressure that can in turn cause some types of glaucoma.

The eye is filled with fluid that drains through a gap between the cornea and iris. A build-up of fluid and eye pressure can damage the optic nerve.

 

The front of the eye, between the cornea (the eye's front window) and the iris (the colored part of the eye), is filled with a clear fluid. This fluid leaves the eye and enters the blood by passing through a gap at the angle where the cornea and iris meet. The gap is filled with a sponge-like tissue called the trabecular meshwork, which helps regulate fluid passage. Sometimes, eye infections, injuries, or certain medications can narrow the gap and compress this spongy tissue, producing a rapid buildup of fluid and eye pressure. This is called angle-closure glaucoma.

In the United States, open-angle glaucoma is more common than angle-closure glaucoma, affecting about three times as many people. It has a more gradual course and there are no clear signs of blockage within the eye's drainage system. Yet, researchers estimate that 50 to 80 percent of people with open-angle glaucoma have eye pressure that is higher than average. Others have normal pressure or even low pressure. On the flip side, many people have high eye pressure but never develop glaucoma.

Dr. Robert Weinreb. Credit: UCSD

 

"Elevated intraocular pressure is a leading risk factor for primary open-angle glaucoma," said Robert N. Weinreb, M.D., chair and distinguished professor of ophthalmology, and director of the Hamilton Glaucoma Center at the University of California, San Diego (UCSD). "The higher the intraocular pressure, the more likely the person is to develop glaucoma and the more likely it is to progress."
Because of these data, medications that lower eye pressure are a mainstay of glaucoma treatment. In some cases, a doctor may recommend surgery to increase fluid drainage from the eye. Drugs, surgery, or both approaches together are often successful at slowing the course of open-angle glaucoma. The NEI-funded Ocular Hypertension Treatment Study also found that pressure-lowering eye drops can delay the onset of glaucoma in people with high eye pressure. But even with medication or surgery, open-angle glaucoma usually continues to attack the optic nerve and cause gradual vision loss.

Other clues to glaucoma
There are other risk factors for open-angle glaucoma besides high eye pressure, and they may provide some clues about what causes it. For example, age is a clear risk factor. Open-angle glaucoma is rare among Americans under age 50, but affects nearly eight percent of Americans over 80.

Other risks come into play long before we grow old and even before we're born, including our ancestry. Open-angle glaucoma is about five times more common among African Americans and Mexican Americans compared to whites, and it has an earlier, more rapid course in African Americans. Family history also has a strong influence. A person's risk of developing open-angle glaucoma is about 10 times higher if a parent or sibling has it, and the risk is higher still if an identical twin has it.

These data from family and twin studies have prompted researchers to dig more deeply into the genetics of open-angle glaucoma. It turns out that sometimes open-angle glaucoma is passed from parent to child due to defects within a single gene. Eight such genes have been identified so far, and they tend to cause glaucoma with an early onset, before age 50. Thanks to these discoveries, there are now genetic tests that can help people with early-onset glaucoma determine the risk that their children will inherit the disease.

Unfortunately, it's rare that primary open-angle glaucoma can be traced to a single cause. In the vast majority of cases, experts theorize that the risk of the disease is influenced by many small genetic differences that vary from person to person. Alone, a single gene probably has a small impact on glaucoma risk.

Dr. Janey Wiggs.
Credit: Massachusetts Eye and Ear Infirmary.

 

"It's like tossing little pebbles into a pool," said Janey Wiggs, M.D., Ph.D., associate director of the Ocular Genomics Institute at the Massachusetts Eye and Ear Infirmary, part of Harvard Medical School in Boston. "They only have a big impact when a bunch of them are thrown in together."

The search for glaucoma genes
Dr. Wiggs and other researchers are conducting ambitious studies to compare the full genetic makeup—or genome—of people who have open-angle glaucoma to people who are free from the disease. They hope to sort out all of the suspected genetic differences that put people at risk.
This research began more than 20 years ago. Two of Dr. Wiggs' colleagues at Harvard—Susan Hankinson, Sc.D., and Louis Pasquale, M.D.—had begun monitoring for open-angle glaucoma cases and collecting genetic samples from participants in two large public health studies. Dr. Wiggs began another genetic study of open-angle glaucoma in 1996, based on patients seen through the glaucoma service at Massachusetts Eye and Ear. But progress in these studies was painstakingly slow.

The pace accelerated dramatically with the completion of the NIH-led Human Genome Project in 2003, and the advent of technology to rapidly and cheaply decode each person's unique genome. Soon, Dr. Wiggs and her Harvard colleagues merged their efforts, and began working with researchers at other sites. In 2012, with funding and additional guidance from NEI, Dr. Wiggs began leading the NEI Glaucoma Human Genetics Collaboration (NEIGHBOR). This consortium includes 12 institutions across the U.S., and has collected genetic samples from about 4,500 patients and about 20,000 (control) individuals without the disease. Recently, it has been expanded to include a number of other ongoing studies, and to build a database of genetic and clinical information on glaucoma cases and controls, called the NEIGHBOR Heritable Overall Operational Database (NEIGHBORHOOD). There are also major genetic studies of glaucoma based in the United Kingdom, Australia, Singapore, and Iceland.

So far, these efforts have uncovered five regions of the genome that are strongly associated with primary open-angle glaucoma, Dr. Wiggs said. Within each region, investigators have found specific genes that, together, form a line-up of suspects believed to contribute to the disease. "Every gene has its own story, but most of them divide neatly into two groups," she said. "There are some that impact eye pressure and others that impact the optic nerve."

Remember the trabecular meshwork, the spongy tissue that regulates fluid flow out of the eye? At least two of the genes linked to higher eye pressure and higher glaucoma risk appear to affect the function of this tissue, Dr. Wiggs said.

Genes affecting the cornea may also have an effect on glaucoma risk, she said. Many past studies have found that people with thin corneas are more likely to develop open-angle glaucoma. The NEIGHBOR consortium has found genetic factors that are associated with both a decrease in corneal thickness and an increase in the risk of open-angle glaucoma.

Linking genes with other risk factors
Another effort that is yielding data on glaucoma risk is the African Descent and Glaucoma Evaluation Study (ADAGES). This NEI-funded study was launched in 2002, in order to seek explanations for the high prevalence and rapid course of primary open-angle glaucoma in African Americans. Dr. Weinreb is leading it in collaboration with his UCSD colleague Linda Zangwill, Ph.D., and with Jeffrey Liebmann, M.D., at New York University Langone Medical Center, and Christopher Girkin, M.D., at the University of Alabama at Birmingham.

Soon after the study began, the researchers found that, compared to whites, African Americans have thinner corneas and subtle abnormalities in the visual field that aren't detected with standard diagnostic tests. (The visual field is the area of space a person can see at a given instant without moving the eyes.) These abnormalities may be an early sign of disease. Recently, the study has expanded to include a search for genetic factors that put African Americans at risk for open-angle glaucoma.

"By identifying genetic and non-genetic factors associated with glaucoma in this high-risk population, we hope to develop better means to diagnose it and detect progression, and improved drug targets that could benefit all patients," Dr. Weinreb said.

There is likely much more to glaucoma risk than a person's genes. Lifestyle, environment, and other factors are also believed to play a role, experts say. Various studies have examined the potential role of smoking, alcohol, caffeine, fat intake, and exercise in open-angle glaucoma, but so far, none of these has shown a strong relationship with the disease. In women, earlier age at menopause has been linked to a higher risk of the disease. In collaboration with Dr. Pasquale at Harvard, Dr. Wiggs has found that in women, but not men, open-angle glaucoma is associated with small variations in genes that regulate the reproductive hormone estrogen. These findings have led to speculation that estrogen replacement therapy may help protect older women from glaucoma, but research on this topic is inconclusive.

"As a community, there's still a lot we don't know about glaucoma," Dr. Wiggs said. "However, we've been able to achieve some success by pooling resources and ideas. I think we will see more rapid progress in the next few years."

Protecting yourself against glaucoma
Even though the risks of glaucoma aren't fully understood, remembering these tips can help you protect yourself and your family against it:

• People at higher risk include African Americans age 40 and older, everyone over age 60, especially Mexican Americans, and those with a family history of the disease.
• Because glaucoma often has no symptoms in its early stages, people at higher risk should have a comprehensive dilated eye exam every one to two years.
• With early detection and treatment, it is possible to slow progression of the disease and preserve vision.

NEI has more information about how to reduce your risk of vision loss from glaucoma, including this fact sheet and video. The NEIGHBORHOOD study is funded by NEI grant EY022305 and ADAGES is funded by NEI grant EY023704.

January is Glaucoma Awareness Month

Glaucoma, the “Sneak Thief of Sight,” May Strike Without Pain or Other Symptoms

The Oregon Optometric Physicians Association Offers Advice to Help Protect Against Vision Loss - Washington, DC (12/31/13)

January is National Glaucoma Awareness Month and the American Optometric Association (AOA) is urging people of all ages to take control of their eye health through early detection to help minimize the risk of developing glaucoma. Glaucoma leads to progressive damage to the optic nerve and a loss of nerve tissue resulting in loss of vision.

Currently, 2.7 million people in the United States over age 40 have glaucoma, one of the leading causes of blindness in the U.S., yet understanding and awareness of the disease is still relatively low. According to data from the AOA’s 2013 American EyeQ® consumer survey, Americans do not fully understand glaucoma:

● 72 percent think glaucoma has early warning signs—it does not –only a comprehensive eye exam administered by an eye doctor can detect the disease

● 86 percent don’t know what part of vision glaucoma affects— progressive deterioration to peripheral vision making it hard to see

● 47 percent think glaucoma is preventable—it is not preventable but it may be treated and progression can be slowed if it is detected and treated early

“Yearly, comprehensive eye exams play a critical role in detection and treatment of glaucoma,” said Robert Bittel, O.D., Chair of the AOA’s Health Promotion Committee. “Dilated eye exams allow eye doctors to thoroughly examine the pressure and nerves inside the eyes for potential signs of the disease. Early detection, prompt treatment and regular monitoring can help control glaucoma, and therefore, reduce the chances of progressive vision loss.”

Americans are also unaware if they are at risk for developing glaucoma: only 13 percent of Americans know that a person’s race could place them at a higher risk of developing glaucoma. According to the Glaucoma Research Foundation, glaucoma is six to eight times more common in African Americans than Caucasians. Additional factors that can increase the risk of developing glaucoma include those who have a family history of glaucoma, hypothyroidism, are over age 60 or individuals who have had severe eye trauma.

Treatment for glaucoma includes prescription eye drops and medicines to lower pressure in the eyes. In some cases, laser treatment or surgery may be effective in reducing pressure.

In addition to regular, comprehensive eye exams, the AOA recommends incorporating a few tips to help maintain overall eye health and clear, comfortable vision:

● Eat green, leafy vegetables and foods rich in nutrients like beta carotene, vitamin C and zinc to protect eyes from disease.

● Stop smoking and cut down on alcohol and caffeine when possible. .

● If you work in front of a computer, practice the 20/20 rule: every 20 minutes, take a 20 second break to help avoid eye strain and computer vision syndrome.

● Wear sunglasses with UVA and UVB protection year round.

● See your optometrist if you are experiencing stinging, itchy, or scratchy eyes, excessive tearing, or any eye discomfort or reduced vision; he or she may recommend artificial tears or tear substitutes, or prescribe medication.

New Year’s Resolutions - 2014!

1. New Year’s Resolutions #2: Maintaining Proper Eye Care

Now that the hustle and bustle of the holiday season is behind us, it is time to start packing up the Christmas decorations and preparing yourself and your family for the start of another year. Whether you are planning on ringing in 2013 with a festive party that counts down to midnight, or you prefer a quiet night at home to reflect on the past year, there is one common New Year's routine that is a tradition for people all over the world: RESOLUTIONS.

New Year’s resolutions are a chance for us to look back on what we wish we could have improved on in the past and finally pledge to change our bad habits going into a fresh new year. However, while many people typically create their resolutions around health and fitness goals―an improved diet, a regular fitness routine, becoming more active, etc.―why not spend this year focusing on improving the health and well-being of your vision?

Many people often assume that because their vision is stable, their eyes are healthy. However, this is not always the case. Regular eye examinations cannot only help to protect your vision and help prevent future problems, but it can also help to uncover evidence of many different diseases, including diabetes and hypertension.

However, eye exams are not the only way in which you should be taking care of your vision in the upcoming new year. We have put together several simple steps that will help to ensure that your eyes and your vision health stays strong in 2014, and beyond.

Contact Care
If you are a daily wearer of contact lenses, it is important that you follow necessary steps when it comes to cleaning and maintaining your contacts. For instance, you should always take out your contact lenses when you go to sleep at night and follow the FDA recommended replacement schedule when it comes time to change them out. You should also make a resolution to use only the recommended disinfection solution, and to change your contact case every three months to make sure that you are keeping your lenses clean.

Vision and Electronics
The amount of time that we spend in front of television and computer screens may not be able to permanently damage our vision, but it still can take a significant toll on your productivity and work performance. Eyes can become dry, irritated and red when they are in front of a screen for too long. Therefore, be sure to follow the 20-20-20 rule: Every 20 minutes, take a 20-second break and look at something 20 feet away. This will help to make sure that your eyes stay healthy and hydrated.

Sun Protection
It is no secret that UV rays can be very damaging to our vision and eye health. Therefore, why not invest in a protective pair of prescription sunglasses  this year so that you can prevent exposure to the dangerous sunlight when you are outside. If you are outside a lot, you may also wish to purchase a hat or any other kind of protective clothing that will give you an extra layer of protection against UV rays.

When it comes to our vision, preventative maintenance and regular eye exams can go a long way towards keeping your eyes healthy all year long. Therefore, be sure to follow these three simple steps to ensure that 2014 will be a year for healthy vision!

2. New Year's Resolutions #1: How to save money but not sacrifice the quality of your eyecare. 

 

Maintain a regular schedule for eye exams.
Many people feel that they are saving money by skipping their recommended eye exams.  Did you know that eye exams are primarily about eye health, not just clarity of sight?  There are some blinding conditions with no symptoms that can only be detected with a thorough eye exam. If caught early, they can often be treated early with much simpler treatments. This can save hundreds or thousands of dollars of complicated treatment, including ocular surgery. This doesn’t even factor in the lost income and quality of life that can come from the loss of vision.

Get the exam that you pay for.
This may seem very obvious, but you should be sure that you are getting a complete and thorough eye exam. After all, if you are paying for something, you should get it.  Sometimes people are reluctant to have their pupils dilated during an exam, but if they don’t, the doctor cannot look for signs of disease in the back of the eye. Find out if there is a charge to come back and finish the exam at a later date. If you bring your child to eye doctor because you have concerns that vision may be affecting school performance, ask beforehand what type of tests are included.  Not all vision plans will cover this specialized testing, so you should find out how much it costs.

Utilize InfantSEE.
As with all health issues, prevention is more cost effective than treatment. This is particularly true for infants. An eye early eye exam can detect potential problems such as extreme nearsightedness and farsightedness as well as strabismus and amblyopia. To assist in this, the American Optometric Association created the public health initiative called InfantSEE. Our office provides one visual and eye health exam to infants between six and twelve months old at no charge.

Understand your Vision Plan, Medical Insurance, Flex and HSAs.
Some medical plans have coverage for eye exams. Some plans specifically cover medical problems such as eye infections and glaucoma. Other plans are specifically for vision and will have coverage for a vision exam, glasses, or contacts, but not medical visits. If you or your employer pays for these benefits, use them wisely. Find out what the annual benefits are. Ask the doctor’s staff to help you maximize your benefits. For example, you are getting both glasses and contact lenses and your plan only covers one of these, you may save more money applying the benefits to the glasses.  Also know that you cannot ask that the vision plan be billed on a different date than you actually received the service.  However, you CAN use your Flex and HSA accounts for eyecare and optical purchases.

Select your eyewear carefully.
When you are picking out eyewear, try on the styles and brands that you like. But keep in mind the purpose of each pair of glasses you buy. You might love the Dior frames with crystals, but if you work or play hard, it might make more sense to get some less expensive frames that are built to be durable. RayBan sunglasses are durable, but if you are prone to losing them (or dropping them in the gulf!) spend a extra few dollars on a glasses strap. And when shopping  around, be sure you compare apples to apples. A discount store or online retailer may be cheaper,  but consider material quality and customer service when making your choice.  Will your optical service remake lenses in the case of an error?  What happens if the coating flakes off within a few months? Our office prides itself on personalized frame and lens selection and high quality products with generous warranties!

Get the right lens materials and coatings.
Find out what the doctor or optician recommends for lens options, but don’t just assume that more expensive is better. Some lens options are worth a little extra: The newer anti-reflective coatings will improve the clarity of your lenses, reduce glare, and resist scratches.  Some fabulously high-tech lens materials are essential for someone with a very high prescription but may be a waste of money if you have a low prescription. We always recommend UV protection for all general purpose glasses, but if you only use glasses for reading indoors, then it may not be needed.  On the other hand the anti-reflective coatings are a necessity for computer use.  If the optical staff do not explain your options to your satisfaction – ask. They may be able to help you save money when they understand how the glasses are to be used.

Try multipurpose lenses.
Do you own just one pair of shoes? Not likely, because most people have different shoes for different purposes. Your eyes also have different needs and no one single pair of glasses will meet all those needs.  But you don’t need to own a baker’s dozen pairs of glasses either. If you have a different prescription for reading and distance (like most people over 45), save money with just one pair of bifocals or progressives. It is best to have a dedicated pair of prescription sunglasses.  But eyewear with clip-on sunglasses or Transitions (that darken in the sun) are a cost-effective and protect your eyes from UV and bright sun.

Make use of your warranties.
If you are spending hard-earned money on glasses, you expect them to work well for you. Always inquire about what warranty is included in your purchase. At Uptown EyeCare, most of our eyewear frames come with a 2-year breakage warranty. If you get premium anti-reflective coating, it also includes a 2-year scratch warranty.

Learn about your contacts.
Talking to your optometrist about your contact lens options.  Monthly lenses may be a cost-saving option for full-time wearers;  daily lenses are a good deal for occasional contact wearers, especially when you factor in the solution costs.  RGP (hard) contacts frequently outperform their soft counterparts and can be up to half as expensive.

Consider financing options or just planning ahead.
Many offices, including ours, accept cash, checks and multiple credit cards.  This is helpful for spreading the cost around so you do not have to pay it all at once for extra pairs or spare pairs of glasses.  We also have many patients pick out two pair of glasses and order one pair of glasses now and get the second pair in a month and take advantage of our multiple pairs discounts.

3. New Year Resolutions for Parents and Teachers! 

**Parents – I resolve:

To play catch with my child and help strengthen his/her visual skills.

To make sure my child doesn’t use a smart phone, iPad or laptop with poor posture.

To realize that signs of dyslexia could also be the signs of a vision problem.

To make sure my child uses the Harmon Distance (the distance from the big knuckle on the middle finger to the tip of the elbow) when doing near work.

To schedule next year’s vision test before school starts.

To use these summer activities to give my child meaningful visual experiences.

To realize that school screenings don’t provide the complete picture on a child’s vision, as they don’t test functional vision.

To make sure that my child, when using a computer screen, is sitting on a chair with his/her feet flat on the floor and legs at a ninety-degree angle.

To take action if I get bad news at a parent-teacher conference.

To understand why my gifted child hates school.

To understand the difference between crossed eye and lazy eye.

To watch my child for headaches, excessive eye-rubbing and a short attention span – telltale signs of a vision problem.

To consider vision as a reason your child says, “I hate school.”


Teachers – I resolve:

To ensure my classroom has proper lighting for computer use.

To have my children take vision breaks when they are using computers.  Every 15 minutes, they should look at an object 20 feet away for 20 seconds.

To have my students use a slant board or a three-ring binder as a slant board.

To understand the impact vision has on standardized testing.

To improve my understanding of how vision relates to math.

To make parents aware of the connection between vision and learning.

To learn how vision impacts spelling.

To use visualization to help struggling readers.

To modify my classroom for children with vision problems.

To understand that a child can have 20/20 eyesight but still have a vision problem.

A big list, we know.  Try and shoot for 1 or 2 (or 3 or 4).  It will be a big difference in a child’s life and learning. Happy New Year from all of us at Uptown EyeCare!