The Optic Nerve And Its Visual Link To The Brain

The optic nerve, a cable–like grouping of nerve fibers, connects and transmits visual information from the eye to the brain. The optic nerve is mainly composed of retinal ganglion cell (RGC) axons. In the human eye, the optic nerve receives light signals from about 125 million photoreceptor cells (known as rods and cones) via two intermediate neuron types, bipolar and amacrine cells. In the brain, the optic nerve transmits vision signals to the lateral geniculate nucleus (LGN), where visual information is relayed to the visual cortex of the brain that converts the image impulses into objects that we see.

In the retinal tissues of the eye, more than 23 types of RGCs vary significantly in terms of their morphology, connections, and responses to visual stimulation. Those visual transmitting RGCs are the neuronal cells. They all share the defining properties of:

possessing a cell body (soma) at the inner surface of the retina
having a long axon that extends into the brain via the optic chiasm and the optic tract
synapsing with the LGN. The RGCs form multiple functional pathways within the optic nerve to mediate the visual signal

Human beings can see three primary colors: red, green, and blue. This is due to our having three different kinds of color sensitive cone cells: red cones, green cones, and blue cones.

The RGCs connecting to the red and green cones are midget RGCs. They are mainly located at the center of the retina (known as fovea). A single midget RGC communicates with as few as five photoreceptors. They transmit red-green color signals to the parvocellular layer in the LGN (see Figure). The midget-parvocellular pathway responds to color changes, but has little or no response to contrast change. This pathway has center-surround receptive fields, and slow conduction velocities. Because of this pathway, we can see objects precisely in detail and in full color.

The bistratified RGCs are likely involved in blue color vision. Bistratified cells receive visual information input originally from an intermediate numbers of cones and rods. The bistratified RGCs connect to the koniocellular layers in the LGN (see Figure). The koniocellular neurons form robust layers throughout the visual hemifield and have moderate spatial resolution, moderate conduction velocities, and can respond to moderate-contrast stimuli. They have very large receptive fields that only possess on-center regions (no off-surround regions).

Objects can be seen in the dark with motion and coarse outlines accentuated due to the parasol RGCs. At the periphery of the retina, a single parasol RGC connects to many thousands of photoreceptors (many rods and few cones). The parasol RGCs project their axons to the magnocellular layers of the LGN (see Figure) and are primarily concerned with visual perception. They have fast conduction velocities, can respond to low-contrast stimuli, but are not very sensitive to changes in color.

Finally, humans can see objects in three-dimension courtesy of the crossing over of optic nerve fibers at the optic chiasm. This anatomic structure allows for the human visual cortex to receive the same hemispheric visual field from both eyes (see Figure), thus making it possible for the visual cortex to generate binocular and stereoscopic vision.

Recently, a new type of RGC, called photosensitive RGCs, was discovered. The photosensitive RGCs contribute minimally to our vision, but play a key role in vision regulation. Photosensitive RGCs axons do not have connections to the LGN, but form the retino-hypothalamic tract, and synapse to three other locations in the brain for specific vision regulation functions:

Pretectal nucleus: involved in reflexive eye movements, thereby helping to target what we want to see
Midbrain nuclei: involved in controlling the size of the pupil, thus helping to adjust the brightness of objects; and coordinating movement of the eye for focusing
Suprachiasmatic nucleus: involved in regulating the sleep-wake cycle

A fully functional optic nerve is essential for vision. Obviously, any damage of the optic nerve will sever the precise transmission of visual information between the retina and brain, directly leading to vision distortion and/or vision loss. Damage to the optic nerve can result from:

Direct/indirect physical damage (e.g. ocular trauma)
Acute/sub-acute physiological lesion (e.g. infection or inflammation, or malignancy (cancer))
Chronic neuronal degeneration (e.g. glaucoma, a most common cause of optic nerve damage)

Moreover, the optic nerve is also a very important vivo model for studying central nervous protection and regeneration. At the cell biology level, the RGC axons are covered with myelin produced by oligodendrocytes (rather than Schwann cells of the peripheral nervous system) after exiting the eye on their way to the LGN and thus part of the central nervous system. Scientists have recently acquired more and more evidence that certain types of damage to the optic nerve may be reversible in the future. Therefore, the optic nerve provides a potential window to explore more complicated neuronal degenerative diseases, such as Alzheimer’s disease and Huntington disease.

3/12/15

Jun Lin, MD, PhD
Assistant Professor,
Department of Ophthalmology
New York Eye and Ear Infirmary of Mount Sinai
Icahn School of Medicine at Mount Sinai

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James Tsai, MD, MBA
Chair, National Eye Health Education Program Glaucoma
Subcommittee President, New York Eye and Ear Infirmary of Mount Sinai Chair
Department of Ophthalmology
Icahn School of Medicine at Mount Sinai

It’s All About ME – What to Know About Macular Edema

“You’ve got the macular? I’ve got some but my sister, she’s got all kinds!” Even as the word retina has become commonplace, the macula and its diseases are often feared and misunderstood. The retina is the light-sensitive layer of cells that line the inside of the eye. The many layers of the retina work together to convert what we see into an exquisitely coded signal that travels to the brain. There the message is decoded and directs us to take action – “that’s a fine looking piece of pie!”

The macula is the part of the retina that helps us see fine detail, far away objects, and color. It’s packed with more photoreceptors than any TV or monitor which is why it is prized real estate. It is the small, central area of the retina that’s worth the most – the bullseye of sight. When things happen to the macula, it gets an “r”. Macular edema, macular degeneration, macular hole, pucker, drusen, scar, fibrosis, hemorrhage, and vitreomacular traction are common conditions that involve the macula. When present, distorted vision (metamorphopsia), blank spots (scotoma), and blurred vision are common symptoms.

Four. Ang. - Macular Edema — Figure 1: Fluorescein angiography: Macular edema may be seen as a pinpoint leak (left, large arrow) in mild cases. In serious cases, ME may diffusely involve the macula. Note how the image becomes brighter as more dye leaks from damaged macular capillaries. (Center and Right)

Macular edema refers to an abnormal accumulation of fluid in the layers of the macula. From the side, it looks like the snake that ate the pig. Like a droplet of water on your computer screen, images are distorted by the swollen retina – making it more difficult to see clearly. The more widespread, thicker, and severe the swelling becomes, more likely one will notice visual symptoms. If untreated, chronic macular edema can lead to irreversible damage to the macula and permanent vision loss.

OCT - Macular Edema — Figure 2: Optical Coherance Tomogrphy and Macular Edema: OCT is a useful test to study macular edema (ME)
-The top image has is normal. Note the even layers and gently sloping dip of the macula called the fovea. This eye has excellent vision.
– The middle OCT has ME, black-appearing cysts (arrows) which threaten the normal fovea. This eye also has good vision.
– The bottom OCT shows ME involving the macula. Because ME involves the macular center (the fovea), vision is poor (large red arrow).

Macular edema is not a disease but the result of one. As with other conditions where abnormal fluid accumulates (leg swelling, pulmonary edema, hives, and allergy), macular edema can be caused by many conditions including metabolic (diabetes), aging (macular degeneration), hereditary (retinitis pigmentosa), inflammatory (sarcoidosis, uveitis), toxic, neoplastic (eye tumors), traumatic, surgical, and unknown causes (idiopathic, macular hole, macular pucker, vitreomacular traction). Macular edema occurs when the retina’s ability to keep fluid out of the retina is overwhelmed by the fluid leaking into it. (If more rain falls on the lawn than it can handle, you get puddles of fluid. In the retina, blisters of fluid form and swell the retina – this is macular edema. Fluorescein angiography (Figure 1) and optical coherence tomography (Figure 2) are two common tests to evaluate macular edema.

Macular edema is typically caused by increased leakage or growth of abnormal blood vessels. The most effective treatment strategies address the underlying cause (diabetes, blood vessel occlusion, neovascularization, inflammation, etc) as well as the hyperpermeability of the capillaries in and around the macula. Eye drops, laser, placement of long-acting medication implants, and surgery are effective in many diseases but the mainstay of treatment is now intravitreal injections (IVI). The IVI is an office procedure painlessly performed under topical anesthesia in which medication is placed inside the eye by a very small needle. IVI should be performed by a trained retina specialist with meticulous monitoring of treatment efficacy and of extremely rare but potentially serious complications. IVI is considered one of the most commonly performed procedure in the world.
Lucentis, Eyelea, and Ozurdex are the trade names of the three most common FDA-approved medications for the treatment of the common conditions causing macular edema. Avastin is not FDA approved but has also been extensively studied in large, well-designed, federally-funded clinical trials and is felt to have efficacy and safety no less than any of the other available options. Each option has a considerable track record of success and works by decreasing the amount of fluid leaking from abnormal blood vessels.

Macular edema is a common finding in many diseases of the retina, most which can be treated to improve vision. The physician’s therapeutic armamentarium continues to expand. There has never been a more successful time in the treatment of macular edema and macular disease. While much has been discovered, many promising therapies await.

3/5/15

Suber S. Huang, MD, MBA
Chair, National Eye Health Education Program
Philip F. and Elizabeth G. Searle – Suber Huang MD Professor
Case Western Reserve University School of Medicine
Past-President American Society of Retina Specialists
CEO, Retina Center of Ohio

Selecting Your Best Vision Correction Options

Today technology has evolved to a point where patients either with normal refractive errors such as nearsightedness, farsightedness, astigmatism and presbyopia or those with ocular diseases that require specialized vision correction options such as those with keratoconus all have spectacular alternatives to maximize their visual performance. With the multitude of choices available, how does an individual make the decision which to take advantage of? Well let’s begin by saying that the input from your eye care professional is critically important. You need to be properly educated not only about the various options that are applicable to your individual situation but about the advantages and disadvantages of these options.

Normal Refractive Error Options

Let’s begin by discussing vision correction options available to those with normal refractive errors. Basically stated, these individuals have the ability to utilize spectacles, contact lenses or if they are appropriate candidates, consider the refractive surgical alternatives.

Glasses
Today spectacle lens technology has evolved to the point where exceptional vision quality can be achieved with lens designs that allow for the selection of almost any frame size or shape. Thin lens technologies have enabled those with high prescription powers to not only see amazingly well, but to wear glasses that remain quite thin and attractive even with some of the most extreme prescription powers. Your eye care professional can discuss the various lens material options that best work for your situation. New high index materials are not only thin but are very light weight. A concern for some however can be the significantly higher costs associated with these lens materials. For those who need multifocals, new digital and free form progressive addition lenses (PALs) have dramatically increased the success rates associated with adaptation to PALs.

Contact Lenses
Contact lens alternatives for those with normal refractive errors have also dramatically developed technologically over the past years. Today virtually every patient with normal refractive error is a candidate to wear contact lenses. Developments such as astigmatic contacts, multifocal contacts, and hybrid (rigid center / soft periphery) contact lens designs along with the introduction and the tremendous growth in the use of single use daily disposable contacts has made one form or another of contact lenses something to consider for almost everyone. Today’s CLs are healthier, more comfortable and provide better vision than ever before. CLs have the advantage of superior peripheral vision, more natural vision “sensation” and obvious advantages for demanding physical activities. With contemporary contact lens materials and designs we have successfully addressed issues that limited many people in the past such as concerns of poor comfort due to dryness, contact lens vision instability and contact lens induced complications associated with over-wear and over-use of lenses. Your eye doctor should always present contact lens options to you regardless if you ask or not. So often patients think that they can’t wear contacts, so it does become the responsibility of your doctor to inform and educate you about CL alternatives.

Combination of Glasses and Contact Lenses
So how do you decide if you should be a contact lens wearer or a glasses wearer? Who said you have to? The two vision correction options are not mutually exclusive; in fact they are quite synergistic. All contact lens wearers should have an excellent pair of glasses to use. Contacts may be more cosmetically acceptable to many, they may be much better for various physical activities such as sports, however there are many times when glasses may be preferred such as at the end of a long day of contact lens wear, first thing in the morning before inserting your CLs, or on those days you just don’t want to bother with your CLs or simply prefer the look of your glasses for some situations. Today even the person who predominantly wears glasses can consider part time contact lens wear. Single use daily disposable (DD) CLs are the perfect option for such an individual. DD CLs are now even available in astigmatism and multifocal designs!

Refractive Surgery
Refractive surgery is also developing and is more effective and safer today than ever before. An experienced and skilled eye doctor is in the best position to consult with you in order to determine if you are an excellent candidate for the various refractive surgical options available. Again, having refractive surgery does not always eliminate your need for glasses or contact lenses. Although that would be the optimal outcome, many patients still use glasses and contact lenses after having refractive surgery. Typically the glasses and contact lenses are far less strong and are used significantly less often than prior to surgery. Some patients need them due to complications of surgery while others need them when outcomes did not perfectly correct vision and of course refractive surgery does not stop eyes from changing over the years, so many patients who had successful refractive surgery may experience vision changes years after surgery that require the use of glasses, contacts or both.

Irregular Refractive Error Options

Specialty Contact Lenses
Next let’s talk about choices in vision correction for those with irregular corneas and other conditions that are termed “medically necessary” vision correction cases. Individuals with irregular corneas such as those with keratoconus or post LASIK or other refractive surgery induced ectasias often require contact lenses that in essence “mask” the irregularity of the cornea. In the past this equated with the fitting of rigid corneal contact lenses, however today many other alternatives can be considered such as the fitting of scleral large diameter gas permeable contacts, hybrid CLs designed for irregular corneas and even combination systems of soft lenses with corneal gas permeable lenses (called “tandem” or “piggyback” CL systems). These CL alternatives provide advantages such as improved comfort, improved eye health response by limiting contact lens to cornea bearing, and improved contact lens positioning and stability which positively impacts visual performance.

Combination of Contact Lenses With Glasses
It should be clearly stated that spectacle lens alternatives still can have a significant role in the treatment of individuals with irregular corneas. Often glasses can be prescribed that provide adequate vision if even for part time and limited applications. While less severe cases may perform quite well with glasses as their primary modality of vision correction. Your doctor may need to modify the power of your glasses prescription in order for you to adapt to wearing glasses, however even a modified prescription power can frequently allow for some degree of visual function and allow for the ability to reduce the number of contact lens wearing hours during the day.

Surgical Procedures
Application of certain surgical and medical procedures such as intra-corneal ring segments (Intacs TM) or corneal collagen cross linking (CXL) for corneal irregularity can often help these patients in various ways and may allow for perhaps a less complex contact lens application or easier adaptation and improved function with glasses. Management of these diseases and conditions is quite complex and requires the expertise of doctors with extensive experience. Your doctor, if appropriately skilled and experienced can provide you with all of the required information and education so that you both can jointly decide on the best vision correction options for you.

In conclusion, patients today have numerous options for their vision correction. These options each have advantages and disadvantages but in most cases can be utilized synergistically. The role that your eye care professional plays in consultation and education of the vision correction alternatives applicable to you cannot be over stated. Vision is a precious gift and you should experience the highest quality of visual performance possible.

2/26/15

S. Barry Eiden, OD, FAAO
Medical Director, North Suburban Vision Consultants, Ltd.
NSCV Blog: www.nsvc.com/blog
President and Founder, International Keratoconus Academy of Eye Care Professionals

Watery, Red, Itchy Eyes

Do you have watery, red, itchy eyes?

As brutal winter weather continues to grip many parts of the US, we just want to remind you to protect your eyes – see our post on Winter Weather and Your Eyes. But there are other conditions that can cause excessive tearing and itchy eyes.

While tears are an important element in clear vision and healthy eyes, helping to keep eyes moist, wash away foreign objects and spread nutrients across the eye; this is not the case if there are too many tears and they are accompanied by redness, discharge, puffiness and an itchy, burning sensation.

Here are three common causes you should be aware of:

1. Allergies – In the US, eye allergies affect one in five people. There are two types of eye allergies, seasonal that generally happen early spring to late fall, and perennial that occurs throughout the year. Triggers for seasonal allergies include airborne pollens from grasses, trees and weeds. Perennial triggers include dust mites, feathers, animal dander, cosmetics, perfumes and smoke.

The first thing you should do is limit your exposure to the allergens. This could include:

Stay indoors when pollen count is highest, usually mid-morning or early evening.
Close all windows and use air conditioning in both your home and car.
Consider an air purifier for your home.
Wear wraparound sunglasses to help shield your eyes from pollen.
Limit exposure to dust mites by enclosing pillows, comforters, mattresses and seat cushions in allergen-impermeable covers.
Have your pet spend as much time outside as possible, and keep it out of your bedroom – don’t let it share your bed.
Clean floors with a damp mop – sweeping just stirs up the allergens.
Don’t rub your eyes as it will likely make the symptoms worse. Try a cold compress instead.
Remove your contact lenses and wear glasses during allergy season because the surface of the lens can attract and accumulate airborne allergens. If you must wear contacts, consider daily disposable contacts to avoid the build-up of allergens on your lens.
Sterile saline rinses and eye lubricants.
Oral antihistamines such as Claritin or Zyrtec.
Eye drops can also provide relief. In most cases you can use over the counter (OTC) eye drops, but be aware that overuse of decongestant eye drops can cause a “rebound effect” where the situation could get worse. You are better off asking your doctor to recommend an OTC eye drop. However, if the problem persists or gets worse, you need to contact your eye doctor for prescriptions eye drops tailored to your needs. Here you can learn more about types of eye drops and how to successfully get them in your eyes.

2. Dry Eyes – It seems counterintuitive, but if your eyes feel dry and gritty your tear glands go into overproduction as a protective response. This can become even more of a problem as you age and your tear ducts tend to shrink. For more information on dry eye and treatment options see Dr. Arthur Epstein’s article on Dry Eye and Tear Dysfunction.

3. Blepharitis – Chronic blepharitis is generally caused by seborrheic dermatitis, an oil build-up because of excessive oil secretion. While this results in dandruff on your scalp, near the eyes it leads to eye irritation, redness, burning, itchy and dry eyes. The best treatment is to keep the eyelid area clean and free of discharge. This is done with the application of a warm compress to the outer eyelid and cleansing the eyelids with eyelid cleaner. If a bacterial infection occurs you will need your eye doctor to prescribe an antibiotic ointment.

Blepharitis doesn’t usually damage your eye or affect your vision, but if a bacterial infection is left untreated you can develop ulcerative blepharitis which can result in the loss of eyelashes, eyelid scarring and inflammation of the cornea. Eyelid hygiene is the key with treating blephartis.

These are just three causes of watery, red, itchy eyes. While most are not a serious threat to your vision, you can relieve the discomfort yourself through lifestyle choices, good hygiene and OTC options. However, if you have tried to manage on your own and the condition does not seem to improve within a week, or gets worse, you should contact your eye care professional immediately.

2/24/15

Susan DeRemer, CFRE
Vice President of Development
Discovery Eye Foundation

GMO and the Nutritional Content of Food

Genetically Modified Organisms (GMO)

How do advances in biotechnology affect the nutritional quality of our food? Historically, humans have realized that the tastiest and most abundant fruit could be selected and replanted the next season. Food crop’s genes change continuously by natural mutation and recombination. Today, advances in our understanding of genetics and molecular biology are permitting scientists to find specific genes that can be moved from one species to another. Genetic material can be transferred from viruses, bacteria, plants, and animals to produce significant changes in the original species. Unlike traditional breeding, gene transfer allows the transfer of genes between organisms of different species. It also permits the transfer of only specifically selected genes to produce the desired outcome in a controlled laboratory setting. Terms frequently used to describe the gene transfer and modification of plants and animals include: Genetically Modified Organisms (GMO), Genetically Engineered (GE) and Biotechnology-Derived (BD).

Nutritional Content of Food

Ways the nutrient profile and density of a food can be altered include: gene modification, agricultural growing and feeding practices, conventional plant breeding and selection, and vitamin biofortification. A gene selected for modification can increase or decrease the vitamin, mineral or fatty acid content found in the modified food. For example, golden rice is genetically altered to increase its beta carotene content. Sometimes when one nutrient is increased another will decrease as an unintended consequence. For example, canola oil genetically engineered to contain vitamin A has reduced vitamin E levels. Growing and feeding practices such as grass-fed versus corn-based animal husbandry, and wild versus farm-raised fish, alters the animal’s fatty acid profile. The amount of omega-3 fatty acids found in eggs varies depending upon the chicken’s diet. Conventional plant breeding and selection can also change the nutritional profile, and has been practiced for a very long time. Finally, grains and cereals are frequently fortified with iron and vitamins before being marketed without the need for genetic modification.

There are intended and unintended consequences of gene modification. Some of the intended goals driving the genetic modification of food include an altered nutritional profile, longer shelf life, and better texture and flavor. Other goals include improved agronomic characteristics such as insect and disease resistance, and herbicide and climate tolerance. For example, plant geneticists can isolate a gene responsible for drought tolerance and insert that gene into a different plant. The new genetically modified plant will then be drought tolerant as well. As the world population grows, perhaps genetic modification can increase crop yields.

The unintended consequences of genetic modification include an increased potential for new allergens in the food supply, antibiotic resistance, toxicity and environmental challenges. Genetic modification ultimately results in the introduction of new proteins into the food supply. True antibody mediated food allergies are an important health issue occurring in approximately 2% of adults and nearly 5% of children. Protecting people with food allergies from unwanted exposure to these new proteins represents a major public health challenge for genetically modified sources of food. Additionally, consumption of foods genetically modified by using “antibiotic resistance markers” may reduce the effectiveness of antibiotics to fight bacterial diseases. Antibiotic-resistant genes produce enzymes that degrade antibiotics and might be transferred to human or animal pathogens, also making them resistant to antibiotics. Finally, a gene selected for modification may have two functions, one with the desired effect and one that has an undesired effect like enhancing natural plant toxins. This occurs in legumes (protease inhibitors), lima beans (cyanogens) and canola species (goitrogens).

Environmental Risks

The unintended environmental risks of genetically modified crops include herbicide and insecticide resistance, gene transfer to wild and conventionally grown plants through cross pollination, crops that are too genetically uniform and thus susceptible to being wiped out by disease, farmer’s limited access to seeds due to patenting of genetically modified food plants, and hard to eradicate “super weeds.”As just one example of the unintended environmental consequences of genetically modified food, Bt corn has been genetically modified to create a toxin in the pollen which kills the European Corn Borer. However, when the pollen is disbursed by the wind, it can land on milkweed, the food plant of the Monarch butterfly, killing the caterpillars that feed on the milkweed. This is one of the reasons the Monarch butterfly population has decreased in recent years.

Lableing of GMO Foods

National and state organic certification rules do not allow genetically engineered foods to be labeled “organic.” Organic products cannot be grown from GMO seeds; an organic animal product like beef, chicken or eggs must not have fed on genetically modified food. Common sources of genetically modified food include sugar made from beets; corn, corn syrup and corn tortillas; papayas; tomatoes; rice; potatoes; soy, including tofu, soymilk, soy nuts, soy sauce; milk produced with rBGH ; zucchini and summer squash; and oils such as vegetable, canola, soybean, cottonseed and corn.

Read the labels and know your ingredients. It is a challenge to avoid genetically altered food. The PLU code on the sticker reveals if the fruit or vegetable was genetically modified, conventionally or organically grown. Bananas labeled with the four digit PLU code 4011 were conventionally grown with the use of pesticides. Bananas labeled with a five digit code beginning with ‘9’ are organically produced without genetic modification (eg. 94011). Genetically engineered produce has a five digit PLU code beginning with the number ‘8.’ For bananas, that code would be 84011.

While genetic modification can alter the nutritional profile of the foods we eat… are we ready to open Pandora’s Refrigerator?

2/19/15

Sandra Young, OD
Author: Visionary Kitchen: A Cookbook for Eye Health
www.visionarykitchen.com

February Is Low Vision Awareness Month

Help for People With Vision Loss

Here’s eye-opening news: Currently, 4.2 million Americans ages 40 and older are visually impaired. Of these, 3 million have low vision. By 2030, when the last baby boomers turn 65, the number of Americans who have visual impairments is projected to reach 7.2 million, with 5 million having low vision. For the millions of people who currently live or will live with low vision, the good news is there is help.

But first, what is low vision? Low vision is when even with regular glasses, contact lenses, medicine, or surgery, people have difficulty seeing, which makes everyday tasks difficult to do. Activities that used to be simple like reading the mail, shopping, cooking, and writing can become challenging.

Most people with low vision are age 65 or older. The leading causes of vision loss in older adults are age-related macular degeneration, diabetic retinopathy, cataract, and glaucoma. Among younger people, vision loss is most often caused by inherited eye conditions, infectious and autoimmune eye diseases, or trauma. For people with low vision, maximizing their remaining sight is key to helping them continue to live safe, productive, and rewarding lives. The first step is to seek help.

“I encourage anyone with low vision to seek guidance about vision rehabilitation from a low vision specialist,” advises Paul A. Sieving, MD, PhD, director of the National Eye Institute (NEI), one of the National Institutes of Health (NIH) and the federal government’s principal agency for vision research.

What is a low vision specialist? A low vision specialist is an ophthalmologist or optometrist who works with people who have low vision. A low vision specialist can develop a vision rehabilitation plan that identifies strategies and assistive devices appropriate for the person’s particular needs. “A vision rehabilitation plan helps people reach their true visual potential when nothing more can be done from a medical or surgical standpoint,” explains Mark Wilkinson, O.D., a low vision specialist at the University of Iowa Hospitals and Clinics and chair of the low vision subcommittee for the National Eye Health Education Program (NEHEP).

Vision rehabilitation can include the following:

Training to use magnifying and adaptive devices
Teaching new daily living skills to remain safe and live independently
Developing strategies to navigate around the home and in public
Providing resources and support

There are also many resources available to help people with low vision. NEI offers a 20-page, large-print booklet, titled What You Should Know About Low Vision, and companion DVD, featuring inspiring stories of people living with low vision. This booklet and DVD, among other resources, are available at
www.nei.nih.gov/lowvision.

With the aging of the population, eye diseases and vision loss have become major public health concerns in the United States. NEI is committed to finding new ways to improve the lives of people living with visual impairment. Aside from making information and resources readily available, NEI has dedicated more than $24 million to research projects on low vision, including learning how the brain adapts to vision loss; strategies to improve vision rehabilitation; and the development of new technologies that help people with low vision to read, shop, and find their way in unfamiliar places. Research like this will help people with low vision to make the most of their remaining vision and maintain their independence and quality of life.

2/17/15

The National Eye Health Education Program (NEHEP) of the National Eye Institute (NEI), a part of NIH, offers a 20-page, large-print booklet, titled What You Should Know About Low Vision, and a series of videos featuring patient stories about living with low vision. These and other resources are available at http://www.nei.nih.gov/lowvision.

Understanding and Treating Corneal Scratches and Abrasions

Corneal Scratches and Abrasions

Call it a scratch, an abrasion or erosion; no matter how you describe it or what the cause, damage to the cornea most always causes pain.

So what exactly is the cornea and why can even a small scratch hurt so much? The cornea is the clear dome at the very the front of the eye. Its primary job is to surface the tears and with them, focus light into the eye. It then passes through the crystalline lens and on to the retina where it is transformed into electrical impulses that are ultimately transformed by the brain into sight.

Because vision is so essential for survival and the cornea so critical to seeing, it is among the most richly innervated and exquisitely sensitive of all tissues. Even the smallest piece of dust that finds its way into the eye and touches the cornea can cause significant discomfort, irritation and copious tearing in an attempt to wash it away. A healthy cornea is transparent and consists of several layers that give the cornea its smooth dome like shape. The outermost layer, the epithelium, is designed to break away to protect the delicate deeper layers if scratched or abraded.

Looking For the Cause

The most common causes of corneal scratches are accidents. Tiny infant fingers and fingernails are a common cause of abrasions in young parents, tree branches are a frequent source of abrasions in hikers and lovers of the outdoors, and makeup brushes are a typical cause in women. Scratches can also be caused by foreign objects that get into the eye and then work their way on to the inside of the upper lid – causing a scratch that occurs with each blink. That’s why its important to carefully investigate the cause of every corneal scratch.

A scratch pr abrasion usually produces near instantaneous pain and tearing as the eye tries to wash away the irritant. Light sensitivity soon follows and can be so intense that the eye can involuntarily shut. This is actually nature’s way of “patching” the eye to facilitate healing.

To confirm you have a scratched cornea, a doctor or other health care professional will often apply a wetted fluorescein strip to the inside lid or white of the eye. Fluorescein is a dye that glows bright green when exposed to black light. The dye is absorbed by damaged areas, clearly showing the area if the scratch or abrasion.

Getting On the Mend

The good news is that most scratches will rapidly heal on their own, especially smaller and more superficial ones. The confocal microscope, a high tech device that provides extreme magnification views of living tissue, has been used to observe corneal healing in real time. The video captures are breathtaking as individual corneal cells can be seen literally stretching over each other to mend and seal the corneal surface.

If an abrasion is larger or deeper it may require patching to help healing. The traditional eye patch applied with tape to keep the eye shut has largely been replaced by the bandage contact lens which is far more comfortable and allows some vision and easier observation during follow up examination. It also allows medication to be applied if needed. Because there is a risk of infection whenever the outer boundaries of the body are breached, topical antibiotics are often used as a precaution in treating scratches of the cornea and ocular surface.

Most commonly the cornea heals quickly and completely, but not always. In rare cases damaged areas of the cornea may not heal fully, leaving the outer layers of the cornea susceptible to coming off again for no apparent reason. This is thought to be more common after scratches caused by organic material such as a tree branch. Called recurrent corneal erosions, they often occur during sleep waking the person with a sudden sharp pain and excessive tearing. There are a variety of treatments for recurrent corneal erosion.

Conclusion

Most people will sooner or later experience a scratched cornea. Most scratches will be minor and will resolve with minimal treatment. However, some can be serious and have significant consequences. The best way to avoid problems is to be aware that they can occur and take measures to protect the eyes in situations where the risk of eye trauma is higher. This includes: wearing safety glasses while working with power tools, or sports where eye contact is possible. This includes cycling and sport shooting.

Be aware of active infants with little fingers that seem to have a magnetic attraction of their parents eyes. If you use eye makeup, leave enough time to properly apply it without rushing and potentially scratching your cornea in the process.

Finally, if you experience a scratched cornea and the pain doesn’t rapidly abate, see an eyecare specialist. Urgent care centers are fine for most things, but when it comes to the eyes finding a knowledgeable eye care professional is wise.

2/10/15

Arthur B. Epstein, OD, FAAO
co-founder of Phoenix Eye Care
and the Dry Eye Center of Arizona
Fellow of the American Academy of Optometry
American Board of Certification in Medical Optometry
Chief Medical Editor of Optometric Physician™

The Best Nutrition for Older Adults

Our bodies change as we age. Our metabolism slows down and we lose lean body mass. Changes occur in the kidneys, lungs, and liver. Total body fat typically increases. The digestive system slows down and changes, producing less of the fluids it needs to process food, thereby making it harder for the body to absorb important nutrients. We lose bone density, which can cause osteoporosis, fractures, and vertebral compression. Many of us lose some sense of taste and smell and our medications interfere with many vitamins. Because of these changes, older adults have very different nutritional needs than those who are younger. What is the best nutrition for older adults?

The basic challenge when one gets older is to meet the same nutrient needs as when we were younger, but doing it while consuming fewer calories. Extra weight and health issues may be the result if we don’t. We can meet the challenge by eating a healthy diet that provides the necessary nutrients and variables for good digestion and absorption of nutrients. A nutrient-dense (meaning foods high in nutrients in relation to their calories), fiber-filled, colorful and varied diet is key.

First, let’s look at some of the important vitamins and nutrients we need to insure healthy bodies:

WATER – of all the nutrients, this the most important. Drinking enough water reduces stress on kidney function, which can decline with age. It also eases constipation. Be aware that the ability to detect thirst declines with age. Instead of waiting to feel thirsty, drink water and other healthy fluids throughout the day. The goal should be about 8 glasses of water per day.

CALCIUM – Calcium’s most important role is for building and maintaining strong bones. Unfortunately, as we age, we tend to consume less in our diets. If you don’t get enough, your body will leach it out of your bones. If your diet includes dairy, three low-fat servings per day are recommended. But also consider plant alternatives such as collard greens, kale, and broccoli. In addition, tofu, almonds, sesame and chia seeds are other great non-dairy sources for calcium.

VITAMIN D – This vitamin helps the body absorb calcium, maintain bone density and prevent osteoporosis. Recent studies suggest it may also protect against some chronic diseases and vitamin D deficiency has been linked to an increased risk of falling in seniors. Vitamin D can be found in salmon, tuna, and eggs. You can also look for vitamin D fortified foods, including cereals, milk, some yogurts, and juices. Because aging skin becomes less efficient at producing the vitamin from sunlight, some experts believe seniors may need vitamin D supplements. You may want to discuss your vitamin D needs with your health care provider.

FIBER – Getting enough fiber in the diet will promote healthy digestion by moving foods though the digestive tract. It will also not interfere with the absorption of nutrients, which occurs with laxative use. Eating foods rich in fiber have additional benefits, including protecting against heart disease. So eat more whole grains, nuts, beans, fruits and vegetables.

POTASSIUM – Potassium is an essential mineral vital for cell function. It has been shown to reduce high blood pressure and the risk of kidney stones. It may also help keep bones strong. Older people can get the recommended daily amount by including fruits and/or vegetables in their diet at every meal. Banana, prunes, plums and potatoes with their skin are particularly potassium rich.

MAGNESIUM – Magnesium is important to many different physiological processes and keeps the immune system in good order. It also keeps the heart healthy and your bones strong. Absorption of magnesium decreases with age and some age-related medications, such as diuretics, may also reduce absorption levels. Eating as many unprocessed foods as possible, including fresh fruits, vegetables, nuts, seeds, grains, and beans will provide you a great source of magnesium.

VITAMIN B12 – Vitamin B12 is important in creating red blood cells and maintaining a healthy nerve function. Getting enough is the challenge for older people because of the decrease in absorption from food. The solution is to eat more food rich in B12 which includes fish, meat, poultry, eggs, and low-fat dairy. Also check with your health care provider about whether a supplement is in order.

FOLATE/FOLIC ACID – Anemia is the result of not enough of this essential B vitamin, which is related to B12 absorption and may improve hearing. Eat plenty of fruits and vegetables and/or make sure your breakfast cereals are fortified to ensure you are getting enough.

OMEGA-3 FATS – Primarily found in fish, these unsaturated fats have a wide range of benefits, including possibly reducing symptoms in rheumatoid arthritis and slowing the progression of age-related macular degeneration. They may also reduce the risk of Alzheimer’s disease and may even keep the brain sharper as we age. Strive toward at least two servings of fish a week and choose salmon, tuna, sardines, and mackerel which are especially high in omega-3. Plant sources of omega-3 include soybeans, walnuts, flaxseed, chia, hemp and sesame seeds, and cauliflower.

IRON – Iron intake sometimes appears to be low in many older adults. To improve absorption, include vitamin C-rich fruits and vegetables with iron-rich foods such as red meats, fish, and poultry.

ZINC – Along with vitamins C and E, lutein and zeaxanthin, it may help slow the progression of age-related macular degeneration. Eat lots of fruits and vegetables, especially those that are dark green, orange or yellow in color, such as kale, spinach, broccoli, peas, oranges, and cantaloupes.

VITAMIN E – This vitamin may have a potential role in the prevention of Alzheimer’s disease. Including whole grains, peanuts, nuts and seeds in your diet may help reduce the risk of this disease.

Now, how do we get these into our diet to ensure optimal nutrition? Strive to have your diet look like this:

Colorful and varied. Have three to five different colors of food on your plate at each meal. This will translate into getting the most variety of nutrients. Eat more veggies than fruit.
More natural and unprocessed. This will give you more fiber. Choose whole fruit over juice; whole grains over processed flours; include seeds, nuts, whole grains and beans in your salads and soups. Look at labels – choose foods with five or fewer ingredients you can pronounce.
The majority of your food should be complex carbohydrate foods – vegetables, fruits, grain products, seeds, legumes and nuts. Choose more vegetables to keep the calorie count down.
High-quality protein – eat less processed and high-fat choices and go for fish, lean meats, skinless poultry, low-fat dairy and plant-based protein sources.
Less sodium, sugar, and “bad” carbs (such as white flour, refined sugars, and white rice). Too much of these things can lead to many age-related health issues and diseases.
More steaming and sautéing and less battering and/or frying.
Use of good fats such as olive oil, avocados, salmon, walnuts, flaxseed, and other monounsaturated fats to protect your body against heart disease.
Try not to skip meals (it slows down your metabolism), eat smaller portions (we don’t need the extra calories), and exchange unhealthy snacks with healthier choices (raw veggies instead of potato chips, piece of fruit instead of a candy bar, etc).
Lastly, don’t forget to drink your water!

2/10/15

Michelle Moore, CHHC
Natural Style Health

Understanding Ocular Herpes

Ocular herpes is caused by the type 1 herpes simplex virus, and is a common, recurrent viral infection affecting the eyes. This type of herpes virus can cause inflammation and scarring of the cornea. Herpes of the eye can be transmitted through close contact with an infected person whose virus is active.

The National Eye Institute (NEI) says an estimated 400,000 Americans have experienced some form of ocular herpes, with close to 50,000 new and recurring cases occurring each year, ranging from a simple infection to a condition that can possibly cause blindness. There are several forms of eye herpes:

Herpes keratitis is the most common form of eye herpes and is a viral corneal infection. Ocular herpes in this form generally affects only the top layer which is called the epithelium, of the cornea, and usually heals without scarring.
Stromal keratitis occurs when the infection goes deeper into the layers of the cornea. This can lead to scarring, loss of vision and, occasionally, blindness. Although the condition is rare, the NEI reports that stromal keratitis is the leading cause of corneal scarring that subsequently causes blindness in the United States.
Iridocyclitis is a serious form of eye herpes where the iris and surrounding tissues inside the eye become inflamed, causing severe sensitivity to light, blurred vision, pain and redness.

Treatment for eye herpes depends on where the infection is located in the eye – in the corneal epithelium, corneal stroma, or iris, etc.

Some ocular herpes treatments could aggravate the outbreak and therefore should be considered on a case-by-case basis.

If the corneal infection is only superficial, it can normally be alleviated by using antiviral eye drops or ointments, or oral antiviral pills over a two to three week period. In some patients, both drops/ointments and pills are used. Steroid drops can help decrease inflammation and prevent corneal scarring when the infection appears deeper in the corneal layers. Steroid drops are almost always used in conjunction with and simultaneously with antiviral drops. For those relatively few eyes where, despite the best of treatment, the virus has caused vision-impairing scars, corneal transplantation surgery is often a highly successful solution.

Although eye herpes has no cure, treatment can help control outbreaks. Studies are underway to determine better methods for managing the disease.

1/27/15

Susan DeRemer
Vice President of Development
Discovery Eye Foundation

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