Mitochondria and Age-Related Macular Degeneration

Research on mitochondrial DNA shows promise for treating AMD

For the past few years, DEF Research Director Dr. M. Cristina Kenney has been researching the relationship of mitochondria and age-related macular degeneration (AMD). She found that damaged mitochondria from people with AMD send signals that can cause retinal cells to die at an increased rate, compared with people who had healthy mitochondria and no AMD. That research led to the exploration of stimulating mitochondria to support retinal cell health in an effort to retain or restore vision for people with AMD.

Mitochondria in Cells
Cells are the basic building blocks of all living things. The human body is composed of trillions of cells. They provide structure for the body, take in nutrients from food, convert those nutrients into energy and carry out specialized functions. Cells also contain the body’s hereditary material (DNA) and so they can make copies of themselves.

Mitochondria are tiny structures inside cells whose function is to produce energy, like a battery in a flashlight, to keep cells alive. Each cell contains hundreds to thousands of mitochondria, which are located in the fluid that surrounds the nucleus. Although most DNA is packaged in chromosomes within the nucleus of a cell (nuclear DNA), mitochondria also have a small amount of their own DNA, known as mitochondrial DNA or mtDNA.

Because only egg cells contribute mitochondria to a developing embryo, only females can pass on the mitochondrial DNA to their children.

Mitochondrial Haplogroups
The mtDNA can be classified into categories called haplogroups, which represent different ancient, geographically separated groups of people. For example, African-Americans and people of ancient African lineage have inherited L haplogroup mitochondria from their mothers no matter where they currently live.
mitochondria and age-related macular degeneration
Similarly, most Ashkenazi Jewish populations (primarily those Jews whose families originated in Eastern or Central Europe) possess mitochondria of the K haplogroup. People with this haplogroup of mtDNA seem to be susceptible to a variety of age-related diseases, including age-related macular degeneration (AMD).

The incidence of AMD varies a lot among different ethnic/racial populations. For example, in the United States, the likelihood of losing vision from AMD is very low for a person with an African maternal background but it is much higher in people of European descent. Similarly, in an Israeli eye clinic, of the people who had AMD, 96% were Jewish while only 4% were of Arab descent. This suggests that European mtDNA in retinal cells of Caucasians may be the reason they are more susceptible to AMD.

Mitochondria and Age-Related Macular Degeneration
Figure 1

It has been recognized that AMD is a very complex disease with many factors involved (Figure 1). There are more than 30 genes associated with AMD, representing many different biological pathways. In addition, mitochondrial damage and specific mtDNA haplogroups have been associated with AMD. Finally, it is recognized that environmental factors, such as smoking and obesity, increase the risk to develop AMD.

Although millions of dollars and thousands of man-hours have been invested in finding the causes and treatments for AMD, we still do not understand how to prevent the most common form of AMD. One major difficulty has been that when we study a diverse group of individuals, each with hundreds of different nuclear and mitochondrial genes, it is very difficult to identify the causes and pathways involved with developing AMD and determining effective treatments. One drug may not help everyone and different people develop different types and severities of AMD.

Mitochondria and Age-Related Macular Degeneration
Figure 2

Kenney’s approach to this dilemma has been to SIMPLIFY THE TESTING SYSTEM (Figure 2). In her research with different ethnic/racial groups, Kenney has found that the Ashkenazi Jewish population (K haplogroup) is an excellent group in which to study age-related diseases. This group has very well characterized nuclear and mitochondrial genes, the population tends to relatively homogenous and to marry within their community. Finally, the Ashkenazi Jewish population has longevity, which increases the likelihood that they will develop aging diseases, such as AMD.

Kenney’s laboratory has created a “cybrid” test system, which are cell lines with identical nuclei and nuclear DNA, but different mitochondrial DNA so that the differences in the cell behavior can be attributed to the different mitochondrial DNA (see the following cybrid story on 11/17/15). Using the cybrid system, Kenney has compared cell behavior of mitochondria from subjects with the K (Ashkenazi Jewish) haplogroups and the mitochondria from people of the H haplogroup (Figure 3), the most common European haplogroup.

Mitochondria and Age-Related Macular Degeneration
Figure 3

There are:

  • Major differences in production of cholesterol and lipid molecules
  • Altered levels of inflammation
  • Differences in their responses to toxic effects of amyloid-? (a toxic protein associated with AMD and Alzheimer’s disease)

These differences are important contributors to AMD and other age-related diseases.

Significance of the Findings
Maternally inherited mitochondrial DNA can influence how a person’s cells respond to stress and this can contribute to age-related diseases. This is a completely new way of thinking about common aging diseases and offers new approaches to treatment and prevention of those diseases.

Future Studies
Kenney’s laboratory will continue to use the K haplogroup cybrid model to study the mitochondrial DNA, with the goal of blocking the harmful events that cause early retinal cell death, such as that seen in AMD. An additional advantage of cybrids is that they are unique to the donor whose blood was used to make them. Therefore with these “personalized cybrids,” Kenney can test the responses of the personalized cybrids to drugs that are currently being used for AMD (Lucentis™, Avastin™ and Eylea™). They can also be used to identify novel, new drugs that can protect the cells from early cellular death, a major event in the dry form of AMD. This research shows great promise in developing personalized treatments for AMD and other age-related diseases.

11/12/15


Anthony B. Nesburn, MD FACSAnthony B. Nesburn, MD FACS
President/Medical Director
Discovery Eye Foundation

Technology for Vision

In just over 10 years, the technology that has been developed to help people see has been amazing. While medical research continues to move forward to find treatments and potential cures of the future, those with the technological know-how have created ways for people to see NOW. Here is a very brief look at some of these technologies.

Technology for Vision

Second Sight and the Argus II

One of the pioneers in the field of vision technology, Second Sight started in 1998, and they are now currently producing the second version of their device. It is made up of two parts:

The Implant: Requiring a 4-hour surgery, a device is surgically implanted in the eye on top of the retina, and along the outside of the eye. It includes an antenna, an electronics case, and an electrode array.
technology for vision
The External Equipment: It includes glasses, a video processing unit (VPU) and a cable.
technology for vision
In a healthy eye, photoreceptors (rods and cones) in the retina convert light into tiny electrochemical impulses that are sent to the brain, where they are translated into images. If the photoreceptors don’t function correctly your brain can’t produce images. The Argus II Retinal Prosthesis System (“Argus II”) is designed to bypass the damaged photoreceptors.

A miniature video camera housed in the patient’s glasses captures an object. The video is sent to the small VPU that the patient wears. It is then processed and transmitted back to the glasses via a cable. This information is sent wirelessly to the antenna in the implant and signals are sent to the electrode array, which emits small pulses of electricity. These pulses bypass the damaged photoreceptors and stimulate the retina’s remaining cells. The visual information is then sent to the brain to create the perception of patterns of light which patients can learn to interpret as objects. Significant training is required to use the system.

The implant is designed to give you a visual field of about 3.5 inches by 6.5 inches at arm’s length; however, the actual size of light you see may be larger or smaller. Since it is strictly based on light, there is no color perception.

eSight

Another system that relies upon the user wearing glasses is eSight which started in 2012. While the Argus II is for people that have very little or no vision, the eSight is for people with low vision or that are legally blind. eSight glasses require the individual to have a certain degree of sight remaining to be successful. If you can only see shadows you probably don’t have enough remaining sight for the glasses to work for them.

This system is also composed of two parts, but it does not require any surgery:

The Headset: It contains a high-definition camera, OLED screens, and the ability to capture and display a real-time video feed. The headset is mounted on carrier frames, which enables eSight’s “bioptic tilt” feature so the user can shift between viewing modes and engage their peripheral vision.
technology for vision
The Controller: A small, lightweight processing unit that adjusts every pixel of the video in real time. It also houses the battery, which powers eSight.
technology for vision
Because most legally blind individuals retain limited sight concentrated in their peripheral vision, their eyes do not receive an adequate signal for the brain to recognize what is being seen. This can create blind spots, blurriness, inability to detect contrast, and other symptoms that reduce vision. eSight is able to significantly corrects these issues by using a high-speed camera, video processing software, a computer processor and the high quality video OLED screens to project a real-time image on the inside of the glasses, allowing people to see.

eSight requires considerably less training than the Argus II. It is intuitive, but as with learning anything new, the more you use it the easier it is to use. It is best to practice on a daily basis.

CentraSight from VisionCare Ophthalmic Technologies

The CentraSight uses a tiny telescope that is implanted inside the eye. The telescope implant was created to improve for people with end-stage age-related macular degeneration (AMD). The tiny telescope – about the size of a pea – is implanted inside one eye, behind the iris and is barely noticeable in your eye.
technology for vision
In end-stage AMD, the macula, where central vision occurs, is degenerated in both eyes without any healthy macular areas left for detailed central vision. There is no way for the individual to see around the central blind spot in their vision. It does not affect peripheral vision, which is blurry so you can’t use it to read, but you can use it to detect objects and movement.
technology for vision
Once implanted inside the eye, the tiny telescope works like a telephoto lens of a camera. It magnifies images onto the healthy areas of the retina to help improve central vision. Because the image is enlarged it reduces the effect the blind spot has on central vision. The surgical procedure is only performed on one eye because the peripheral (side) vision will be restricted in the eye with the telescope implant. This means the peripheral vision in the untreated eye will need to work in conjunction with the implanted eye. “A person uses the eye with the telescope implant for detailed central vision (such as reading “WALK” signs at a crosswalk). The other eye is used for peripheral vision (such as checking to see if cars are coming from the side).

Training with a CentraSight low vision specialist will be needed to develop the skills you need to use your new vision, such as how to switch your viewing back and forth between the eye with the telescope implant and the eye without the implant. You will still need to wear eye glasses and may need to use a hand-held magnifier with the telescope-implanted eye to read or see fine details clearly. However, in general, less magnification will be needed.

Ocumetics Bionic Lens

After eight years of research, a Canadian optometrist, Dr. Gareth Webb, has invented a tiny bionic lens that is able to enhance eyesight so that an individual can see three times better than the sharpness of 20/20 vision. The Ocumetics Bionic Lens is a button-shaped lens that can be injected into the eye in eight minutes in a procedure identical to cataract surgery.

As people get older, the lens inside the human eye becomes cloudy over time, causing blurred vision, known as cataracts. The Bionic Lens would be inserted, replacing the person’s clouded lens, similar to the intraocular lenses currently used in cataract surgery.

The Bionic Lens features a patented Ocumetics camera optics system, which is a tiny bio-mechanical camera that is able to shift focus from a close range object to optical infinity – as far as the eye can see – much faster than the human brain.

This device is still not available to the public, but Webb is hopeful that clinical trials will start soon. Depending on regulatory processes in each country, Webb hopes the Bionic Lens will be commercially available by 2017.

11/10/15


Susan DeRemerSusan DeRemer, CFRE
Vice President of Devlopment
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?
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 DeRemerSusan DeRemer, CFRE

Diabetic Eye Diseases

November is National Diabetes Month. Diabetes is a controllable condition that is growing in the US. In adults 20 and older more than one in 10 people have diabetes, while in seniors (65 and older) that number increases to more than one in four.

Diabetic Eye Diseases

One of the eye diseases that can result from diabetes is diabetic retinopathy, which will affect approximately 11 million people by 2030. Check the infographic below to learn more about diabetic eye diseases.

diabetic eye diseases

11/3/15

NEI LogoCourtesy of the National Eye Institute (NEI), a part of NIH.

Best’s Disease

In 1905, Friedrich Best presented a detailed pedigree of an inherited retinal condition referred to as vitelliform dystrophy, or Best’s disease. Best’s disease is an inherited dystrophy of the macula that primarily involves cells known as retinal pigment epithelium (RPE).

best's disease
Friedrich Best

Best’s typically affects both eyes and presents itself either in childhood or early adulthood. Visual acuity is usually minimally affected early on in the course. As the condition progresses, the vision can slowly begin to deteriorate. The rate of progression or the overall amount of progression is difficult to predict. The rate of progression may be also be asymmetric, with one eye progressing at a different rate than the other. Some patients may notice the development of scotoma, or “blind spot”, in their central vision as the condition progresses. Other patients may not progress to later stages or experience vision loss. Loss of peripheral, or side vision, is not expected with Best’s.

Best's disease
Best’s disease
The diagnosis of Best’s disease is primarily based on a careful clinical exam. Taking a careful family history is also important as Best’s is typically inherited in an autosomal dominant pattern. This means that an affected individual has a 50 percent chance of passing the gene to their offspring. It should be noted though that there is highly variable expression, which means there may be some affected individuals in whom the changes are so mild that they never notice any visual disturbance. The causative gene is located on chromosome 11 and has been labeled BEST1 (VMD2). This encodes for a protein known as bestrophin 1, which is located on the membrane of RPE cells. It is believed that this protein is involved in RPE metabolism through its control of chloride channels, although the details are still being elucidated. Thus far, there have been over 200 mutations of the BEST1 gene that have been described.

The classic exam finding in Best’s is a circular yellow lesion in the macula. This lesion resembles an “egg-yolk”, and is often referred to as such by ophthalmologists. As the condition progresses, the yellow material begins to break up and the pigmentation of the macula attains a more mottled appearance. This is often referred to as a “scrambled egg” appearance. After many years, there may be evidence of cell loss in the macula, which can negatively impact the visual acuity. In a relatively small proportion of cases, a complication can occur in which abnormal blood vessels grow underneath the macula and begin to leak fluid and/or blood into the macula. This is known as choroidal neovascularization (CNV), and can be vision threatening. Fortunately , CNV can be treated effectively with medications that are injected into the eye as part of a straightforward and low-risk office procedure. Typical signs of CNV would include distortion or blurring of the vision, and it is important to notify your doctor of any sudden changes in vision.

Diagnostic testing is sometimes used to confirm the diagnosis. The electro-oculogram (EOG) is universally abnormal in Best’s, and can be a valuable confirmatory test. Fluorescein angiography and optical coherence tomography can be valuable tests to better evaluate the macula and to also look for the development of CNV. Genetic testing for Best’s is now possible as well.

There is no established medical or surgical management for Best’s disease. In patients who develop CNV as a secondary complication, existing treatment options are effective. Future avenues of therapy hold significant promise, but are in their early stages of development. Stem cell based therapies, for example, have the potential to help restore healthy cells that may have been lost during the disease progression.

10/29/15

Dr. Esmaili posterior vitreous detachmentDaniel D. Esmaili, MD
Retina Vitreous Associates Medical Group

General Differences Between Polarized and Absorptive Lenses

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 Duffy, CVRTMaureen 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

Carrots forHealthy 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.
carrots for healthy eyes
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:

carrots for healthy eyesCrab Toast with Carrot and Scallion – Forget your traditional bruschetta, wow your guests with the appetizer.
 
 
 
 
 

carrots for healthy eyesPotato-Carrot Latkes with Lemon-Raisin Topping – Seems perfect with Hanukkah just around the corner.
 
 
 
 
 

carrots for healthy eyesRoasted 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!
 
 
 
 
 

carrots for healthy eyesCarrot 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.
 
 
 
 
 

carrots for healthy eyesCarrot 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.
 
 
 
 
 

carrots for healthy eyesCarrot, Ginger, and Lime Juice – Refreshing and healthy.
 
 
 
 
 

10/22/15

Susan DeRemerSusan DeRemer, CFRE
Vice President of Development
Discovery Eye Foundation

Tear Film Health is Essential for People with Keratoconus

People afflicted with keratoconus (KC) are often obligated to wear contact lenses in order to obtain functional vision. Unfortunately, wearing contact lenses can have detrimental effects on the ocular surface and tear film layers over the course of decades, ultimately reducing lens tolerance. Therefore, any intervention prolonging the comfortable wear time of contact lenses should be aggressively pursued. The tear film covers the surface of the eye, provides lubrication and is the primary defense against foreign bodies and infection. Without a robust and healthy tear film, safe and comfortable contact lens wear is not possible. This article will describe the structure of the tear film and review simple remedies that can keep it healthy throughout life.

Tear Film Layers

The tear film is a complex, triple layered structure comprised of mucus, water and oil. The surface of the cornea and conjunctiva contain cells specialized to secrete a sticky mucoid substance. These so called goblet cells produce the mucin layer of the tears, which creates a “Velcro” type interface and allows the overlying watery component to stick to the ocular surface without washing away.

The bulk of the tear film is comprised of the watery, or “aqueous” layer which is secreted primarily by the lacrimal gland. This specialized structure is located near the eyebrow. This gland continuously releases small amounts of watery fluid that also contains enzymes and antibodies to help fight infection and wash away contaminants.

The lipid layer is the final, outermost layer of the tears. If the tear film is the first line of defense for the ocular surface, then the lipid layer is the first line of defense for the entire tear film and the ocular surface combined. Because of that role, it is extremely important and helps stabilize the tear film by preventing evaporation. This thin, lipid based layer is released by the meibomian glands, which are modified sebaceous glands that reside in the upper and lower lids. In each lid there are 20-30 glands. These glands open up onto the lid margin and through the action of a complete blink, release the lipid secretion to ocular surface which gets spread with the upward motion of the upper eyelid.

Each one of these layers contributes to the structure of the tear film, and a problem with any one of these structures (goblet cells, lacrimal gland or meibomian glands) will negatively impact the corresponding tear layer.

Tear Film
Image 1 -Layers of the tear film across the ocular surface & Meibomian glands of the eyelids. (Picture courtesy of TearScience™)

Tear Film Issues

Because the tear film is so thin, each individual component is necessary to maintain the integrity of the tears as a whole. When any layer of the tear film is deficient, the tear film becomes unstable and the ocular surface becomes irritated and can progress to developing classic symptoms of dry eye. This includes burning, stinging, redness, tearing, fatigue and contact lens intolerance.

Deficiencies in the mucin layer are uncommon, and are typically the result of chemical or thermal insult, or scarring. An aqueous deficiency, primarily from a lacrimal gland related etiology, is also relatively uncommon, and can arise from autoimmune and inflammatory causes such as Sjögren’s Syndrome. The most common reason for a poor tear film is linked with excessive evaporation of our tears due to a lack of sufficient lipid secretions from non-functioning or obstructed meibomian glands. It is understood that many factors contribute to why these glands stop performing optimally.

One factor has been linked to our habitual working environments. The compressive force exerted by the muscles of our eyelids that control blinking are essential for lipid secretion. However, the use of computers or wearing contact lenses has been shown to negatively impact our blinking habits, both by reducing the number of blinks and making blinks less complete. With an incomplete blink, the upper and lower lids do not make contact. The negative consequences of this are 1) the meibomian glands do not release their lipid contents, 2) the lower part of the eye is chronically exposed to the air, increasing evaporative stress and 3) dead skin cells accumulate on the lid margin which can clog the meibomian gland openings.

When increased evaporation of the tear film occurs chronically, the integrity of the entire ocular system becomes compromised over time and problems to the health of the eye become permanent attributes. This condition is known as Meibomian Gland Dysfunction or MGD and is linked with 86% of all dry eye sufferers.

Image 2 - Histology slide of a Meibomian gland with a terminal duct blockage
Image 2 – Histology slide of a Meibomian gland with a terminal duct blockage
Contact lenses have been shown in multiple studies to have a negative impact on the integrity of the tear film. To begin with, placement of a lens onto the eye divides the tears into two sections, referred to as the “post” (behind) and “pre” (in front) lens tear films.

The characteristics of the post lens tear film can differ depending on the type of lens that is worn. For example, soft lenses and scleral lenses have very little turnover of this post-lens tear film. This can cause issues related to the build up of toxic waste and bacterial elements that ultimately aggravate the corneal surface. Conversely, rigid gas permeable lenses are designed to have substantial tear turnover behind the contact lens with every blink.

The pre-lens tear film is also greatly affected by the type of lens material, as well as the interaction between the lid and the contact lens surfaces. Eye doctors know that without a healthy tear film, chances for contact lens intolerance increases. The rate of contact lens intolerance substantially increases as patients enter their fourth decade of life, primarily because of MGD caused by years of poor blinking habits.

Tear Film Care

Fortunately, simple interventions can prevent and/or limit the severity of MGD altogether or help to manage it once it occurs. Just like brushing and flossing one’s teeth can prevent gum disease, attention to complete blinking and lid margin hygiene can improve the tear film and prevent contact lens intolerance problems.

Because partial blinking is strongly linked with developing MGD, it is vitally important that the two lids touch when blinking. It is best to practice this several times throughout the day as well as when you are reading or using the computer.

Akin to flossing the teeth, it is also important to clean the lid margins with a Q-tip soaked in saline solution or a bit of mineral oil by gently brushing the Q-tip across the lid margin 10-20 times each night. It is easiest to get the lower lid.

Finally, performing warm compresses daily can provide heat to the Meibomian glands to soften the hardened oil that can plug the meibomian gland ducts. Warm compresses need to be done continuously for at least 10 minutes with consistent heat in order to attain a temperature that is sufficient to melt the oil that clogs the glands. We recommend folding 5-6 small towels or facecloths into a rectangular shape and wrapped together into a circular bundle, similar to the appearance of a cinnamon roll. The towels should be damp and moist, placed in a microwaveable safe dish with a lid and heated for approximately 1 minute and 50 seconds. After removal, wait a minute or two and then proceed to use the outermost cloth and cover the rest. Replace the first cloth after two minutes and grab the next outer most towel from the bundle, continuing this until all towels are used. In this way, the temperature can be adequately maintained for the full 10 minutes. The high temperatures applied to the lid are transferred to the cornea and very often cause temporary deformation, a phenomenon characterized by transient visual blur immediately following compress application. Therefore, it is vitally important, especially for patients with keratoconus, that pressure never be exerted onto the globe of the eye with a compress or massage administered to the lids of closed eyes after a compress.

It is becoming apparent that MGD is developing in patients at earlier ages. Because of this, the condition has likely been present for decades by the time the patient becomes symptomatic. It may take significant time and effort to rehabilitate not only the glands themselves, but also to reduce the resulting inflammation of the ocular surface.

Meibography is the technique used to image Meibomian glands. In chronic cases of MGD, we see abnormal changes to gland structure, in the form of atrophy or loss of gland tissue and/or dilation of glands where obstructed material causes glands to become widened. In severe cases, the prognosis for recovery is guarded.

The visual clarity that contact lenses provide for patients with keratoconus is incredibly important. But the ability to comfortably wear contact lenses is reliant on our body’s ability to provide a sufficiently thick protective tear film. Taking a small amount of time daily to attend to the lipid producing Meibomian glands by proper blinking habits, exfoliation of the lid margin with a Q-tip and warm compresses will help to extend the number of hours, and ultimately the number of years, that contact lenses can be safely and comfortably worn.

10/20/15

tear filmAmy Nau, OD
Korb and Associates, Boston, MA
Contact lens fitting for keratoconus, other ocular surface disorders and dry eye
 
 
 
 
 
 

tear filmDavid Murakami, MPH, OD, FAAO
Tear Science, Inc.
Researcher, Dry Eye

Increased Awareness for Saving Vision

The following is a survey done by Essilor (a French company that produces ophthalmic lenses along with ophthalmic optical equipment) and a large marketing research firm in the UK, YouGov. While the focus in on people living in the UK, the results would probably be similar to the US population. Even with increased access to the Internet, many people are still not aware of the risks associated with eye disease and what they can do to help retain their vision. Increased awareness of informational resources are important for saving vision.
saving vision
There are a number of websites with easy to understand information about taking care of your vision that I have listed under Resources to Help Save Vision at the bottom of this article. And while there are eye diseases that are hereditary, you can slow the onset and progression by making good lifestyle choices about smoking, diet and exercise. Your eye care specialist is also an excellent source of information about what you can to do reduce your risk of vision loss, at any age.

Increased Awareness for Saving Vision

A YouGov poll conducted with Essilor reveals that most Britons are unaware of damage to their eyes by surrounding objects, activities, and devices. This widespread lack of awareness means fewer people seeking methods of prevention and avoidance, and for those that are aware of risks, most are not informed of existing preventative measures.

The poll has shown* that many British people remain uninformed about the various ways in which eyes are damaged by common daily factors, despite evidence that eye health is affected by blue light, UV rays (reflected from common surfaces), diet, obesity, and smoking.
Of the 2,096 people polled, the percentage of respondents aware of the link between known factors affecting and eye health were:

  • Poor diet – 59%
  • Obesity – 35%
  • Smoking tobacco – 36%
  • UV light, not just direct from the sun but reflected off shiny surfaces – 54%
  • Blue light from low energy lightbulbs and electronic screens – 29%

More than one in ten people were completely unaware that any of these factors could affect your eyesight at all.
saving vision
72% of respondents own or wear prescription glasses but only 28% knew that there were lenses available (for both prescription and non-prescription glasses) to protect against some of these factors; specifically, blue light from electronic devices and low energy light bulbs, and UV light from direct sunlight and reflective surfaces.

76% admitted they haven’t heard of E-SPF ratings – the grade given to lenses to show the level of protection they offer against UV.

Just 13% have lenses with protection from direct and reflected UV light, and only 2% have protection from blue light (from screens, devices, and low energy bulbs).

Poll results showed that younger people were most aware of the dangers of UV and blue light, yet least aware of how smoking tobacco and obesity can affect your eye health. Within economic sectors, middle to high income people are more aware of the effects of smoking & obesity on eyesight than those with low income –

  • 39% of people with middle to high income compared to 33% of people with low income are aware of the impact of smoking tobacco.
  • 38% of people with middle to high income compared to 31% of people with low income are aware of the impact of obesity.

Awareness of the impacts of smoking and obesity on eye health is significantly higher in Scotland (47% & 49% respectively) than anywhere else in the UK (35% & 33% in England and 40% & 38% in Wales).
Essilor’s Professional Relations Manager, Andy Hepworth, has commented: “The lack of awareness about these common risks to people’s eyes is concerning. Not only would many more glasses wearers be better protected, but also many people who do not wear glasses would likely take precautions too, if made aware of the dangers and the existence of non-prescription protective lenses.”

To see the full results of the poll, please visit the Essilor website.

For more information on the protection offered from blue light and UV through specialist lens coatings, for both prescriptions and non-prescription glasses, please see here for UV & Blue Light Protection options.

*All figures, unless otherwise stated, are from YouGov Plc. Total sample size was 2,096 adults. Fieldwork was undertaken between 21st and 24th August 2015. The survey was carried out online. The figures have been weighted and are representative of all GB adults (aged 18+).

Resources To Help Save Vision
All About Vision
Macular Degeneration Partnership
National Eye Institute (NEI)
Prevent Blindness

10/16/15


Susan DeRemerSusan DeRemer, CFRE
Vice President of Development
Discovery Eye Foundation

Business Opportunity for Blind Adults

Food for Thought – Business Opportunity for Blind Adults

For those not in the know, the acronym sounds like a popular sandwich. However, for Louisville, KY resident, George Bouquet, The Hadley School for the Blind’s and the National Association of Blind Merchants’ joint“BEPLT” program (Business Enterprise Program Licensee Training) is more like a dream come true.

George Bouquet - Business Opportunity for Blind
George Bouquet

Hadley is the largest provider of distance education for people who are blind and visually impaired worldwide and the BEPLT program is part of the school’s Forsythe Center for Employment (FCE) and Entrepreneurship. Under the Randolph-Sheppard Act, legally blind adults are given first right of refusal on operating state and federal government vending facilities including cafeterias, snack bars, convenience stores, micro markets, and vending machines and rest stop vending areas nationwide. In February 2014, Hadley’s FCE partnered with the National Association of Blind Merchants (NABM) and the National Federation of the Blind Entrepreneurs’ Initiative (NFBEI) to bring the academic portion of training to would-be blind vendors. Individual state Business Enterprise Programs provide the hands-on component of the blind vendor training. Bouquet is Hadley’s first graduate from the school’s new BEPLT program.

Born with both Pierre Robin Syndrome, which often results in a smaller-than-normal lower jaw, a cleft palate, a tongue that falls back in the throat, and difficulty breathing, as well as Stickler Syndrome, which causes hearing loss, eye abnormalities and joint problems, Bouquet has struggled with health issues throughout his 54 years. Although he was born without eye lenses, he was not born blind. Rather, his vision worsened over time. Bouquet worked in several food service positions since high school and had wanted to become a Randolph-Sheppard vendor even before he would have qualified as legally blind!

There are only so many blind vendor licensee training slots available and many more people compete for them than such programs can accommodate. The first time Bouquet applied to receive the training was in February 2014. Unfortunately, he was not accepted into a program. However, he was fortunate to gain some blind vendor experience by working under friends who already held the license. In early 2015, Bouquet’s counselor told him of another opportunity to apply for vendor training. This time he was accepted and Bouquet began Hadley’s BEPLT program in April 2015. Bouquet was so motivated to graduate from the program that he completed approximately two modules (one-lesson online courses) per week. Hadley’s BEPLT students complete a 10-module program and then take their state’s physical training component. After passing both elements, graduates are eligible to bid for the opportunity to become a blind vendor in their community.
George Bouquet - Business Opportunity for Blind
“The [Hadley BEPLT] program offers a lot of useful information. It will really help anyone wanting to undertake vending,” he said. Bouquet then acknowledged that the material about food borne illnesses helped him to realize the tremendous responsibility he would be accepting by running a government food service area. “As a manager, you need to decide what you are willing to delegate to other people,” he added.

For Bouquet, becoming a blind vendor allows him to hire and train his 25 year-old unemployed son, who inherited most of his visual and hearing problems. This training is Bouquet’s first step toward creating a legacy of financial independence.

10/13/15

Sheryl BassSheryl Bass, MA, MSW
The Hadley School for the Blind