What is AMD?
Age-Related Macular Degeneration is a common eye condition and a leading cause of vision loss among people age 50 and older. It causes damage to the macula, a small spot near the center of the retina and the part of the eye needed for sharp, central vision, which lets us see objects that are straight ahead. In some people, AMD advances so slowly that vision loss does not occur for a long time. In others, the disease progresses faster and may lead to a loss of vision in one or both eyes. As AMD progresses, a blurred area near the center of vision is a common symptom. Over time, the blurred area may grow larger or you may develop blank spots in your central vision. Objects also may not appear to be as bright as they used to be. AMD by itself does not lead to complete blindness, with no ability to see. However, the loss of central vision in AMD can interfere with simple everyday activities, such as the ability to see faces, drive, read, write, or do close work, such as cooking or fixing things around the house.

Who is at risk?
Age is a major risk factor for AMD. The disease is most likely to occur after age 50, but warning signs can occur earlier. Other risk factors for AMD include: • Smoking. Research shows that smoking doubles the risk of AMD. • Race. AMD is more common among Caucasians than among African-Americans or Hispanics/Latinos. • Family history and Genetics. People with a family history of AMD are at higher risk. At last count, researchers had identified nearly 20 genes that can affect the risk of developing AMD. Many more genetic risk factors are suspected.

Does lifestyle make a difference? Researchers have found links between AMD and some lifestyle choices, such as smoking. You might be able to reduce your risk of AMD or slow its progression by making these healthy choices: • Avoid smoking • Exercise regularly • Maintain normal blood pressure and cholesterol levels • Eat a healthy diet rich in green, leafy vegetables and fish

How is AMD detected?
During the exam, your eye care professional will look for drusen, which are yellow deposits beneath the retina. Most people develop some very small drusen as a normal part of aging. The presence of medium-to-large drusen may indicate that you have AMD.
Another sign of AMD is the appearance of pigmentary changes under the retina. In addition to the pigmented cells in the iris (the colored part of the eye), there are pigmented cells beneath the retina. As these cells break down and release their pigment, your eye care professional may see dark clumps of released pigment and later, areas that are less pigmented. These changes will not affect your eye color.

How is it treated? Early AMD. Currently, no treatment exists for early AMD, which in many people shows no symptoms or loss of vision. Your eye care professional may recommend that you get a comprehensive dilated eye exam at least once a year. The exam will help determine if your condition is advancing. As for prevention, AMD occurs less often in people who exercise, avoid smoking, and eat nutritious foods including green leafy vegetables and fish. If you already have AMD, adopting some of these habits may help you keep your vision longer.

Intermediate & Advanced AMD
Researchers at the National Eye Institute tested whether taking nutritional supplements could protect against AMD in the Age-Related Eye Disease Studies (AREDS and AREDS2). They found that daily intake of certain high-dose vitamins and minerals can slow progression of the disease in people who have intermediate AMD, and those who have advanced AMD in one eye. The first AREDS study showed that a combination of vitamin C, vitamin E, beta-carotene, zinc, and copper can reduce the risk of late AMD by 25 percent. The AREDS2 Trial tested whether this formulation could be improved by adding lutein, zeaxanthin or omega-3 fatty acids. Omega-3 fatty acids are nutrients enriched in fish oils. Lutein, zeaxanthin and beta-carotene all belong to the same family of vitamins, and are abundant in green leafy vegetables. The AREDS2 trial found that adding lutein and zeaxanthin or omega-three fatty acids to the original AREDS formulation (with beta-carotene) had no overall effect on the risk of late AMD. However, the trial also found that replacing beta-carotene with a 5-to-1 mixture of lutein and zeaxanthin may help further reduce the risk of late AMD. Moreover, while beta-carotene has been linked to an increased risk of lung cancer in current and former smokers, lutein and zeaxanthin appear to be safe regardless of smoking status. Even if you take a daily multivitamin, you should consider taking an AREDS supplement if you are at risk for AMD. The formulations tested in the AREDS trials contain much higher doses of vitamins and minerals than what is found in multivitamins. Tell your doctor or eye care professional about any multivitamins you are taking when you are discussing possible AREDS formulations. Finally, remember that the AREDS formulation is not a cure, and will** not restore vision already lost from AMD. But it may delay the onset of late AMD. It also may help slow vision loss in people who already have late AMD.

Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).

Amblyopia Defined
The brain and the eyes work together to produce vision. The eye focuses light on the back part of the eye known as the retina. Cells of the retina then trigger nerve signals that travel along the optic nerves to the brain. Amblyopia is the medical term used when the vision of one eye is reduced because it fails to work properly with the brain. The eye itself looks normal, but for various reasons the brain favors the other eye. This condition is also sometimes called lazy eye.

How common is it?
Amblyopia is the most common cause of visual impairment among children, affecting approximately 2 to 3 out of every 100 children. Unless it is successfully treated in childhood, amblyopia will persist into adulthood. It is also the most common cause of monocular (one eye) visual impairment among young and middle-aged adults.

What causes it?
Amblyopia can result from any condition that prevents the eye from focusing clearly. Amblyopia can be caused by the misalignment of the two eyes—a condition called strabismus. With strabismus, the eyes can cross in (esotropia) or turn out (exotropia). Occasionally, amblyopia is caused by a clouding of the front part of the eye, a condition called cataract.
A common cause of amblyopia is the inability of one eye to focus as well as the other one. Amblyopia can occur when one eye is more nearsighted, more farsighted, or has more astigmatism. These terms refer to the ability of the eye to focus light on the retina. Farsightedness, or hyperopia, occurs when the distance from the front to the back of the eye is too short. Eyes that are farsighted tend to focus better at a distance but have more difficulty focusing on near objects. Nearsightedness, or myopia, occurs when the eye is too long from front to back. Eyes with nearsightedness tend to focus better on near objects. Eyes with astigmatism have difficulty focusing on far and near objects because of their irregular shape.

A patch is worn over the stronger eye in conjunction with correction for weeks to months. This therapy forces the child to use the eye with amblyopia. Patching stimulates vision in the weaker eye and helps parts of the brain involved in vision develop more completely. A combined program of patching and vision therapy is most effective.
Previously, studies thought that treating amblyopia would be of little benefit to older children. However, results from a clinical trial showed that many children from ages seven to 17 years old benefited from treatment for amblyopia. This study shows that age alone should not be used as a factor to decide whether or not to treat a child for amblyopia. And yes, adults may benefit as well.

Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).

What is astigmatism?
Astigmatism is a refractive error that causes blurred vision at distance and near. Astigmatism occurs at the cornea due to the irregular shape of it. For more information see the section on Eye Conditions and Terms. Toric contact lenses are specifically designed to provide clear vision for those who have it. Toric contact lenses can be more difficult to fit due to the fact that if it rotates while wearing it this will result in blurred vision. Not all toric contact lenses will fit the same person the same way each has its own design which may or may not help individuals. A severely astigmatic cornea may require specialty toric lenses. If you have a large amount of astigmatism and wear bifocal spectacles and would like to wear contact lens there are some options for you. A hybrid contact lens is the best option for astigmatics with presbyopia.

What is blepharitis?
Blepharitis is a common condition that causes inflammation of the eyelids. The condition can be difficult to manage because it tends to recur.

What causes blepharitis?
Blepharitis occurs in two forms: Anterior blepharitis affects the outside front of the eyelid, where the eyelashes are attached. The two most common causes of anterior blepharitis are bacteria (Staphylococcus) and scalp dandruff. Posterior blepharitis affects the inner eyelid (the moist part that makes contact with the eye) and is caused by problems with the oil (meibomian) glands in this part of the eyelid. Two skin disorders can cause this form of blepharitis: acne rosacea, which leads to red and inflamed skin, and scalp dandruff (seborrheic dermatitis).

What are the symptoms of blepharitis?
Symptoms of either form of blepharitis include a foreign body or burning sensation, excessive tearing, itching, sensitivity to light (photophobia), red and swollen eyelids, redness of the eye, blurred vision, frothy tears, dry eye, or crusting of the eyelashes on awakening.

How is blepharitis treated?
Treatment for both forms of blepharitis involves keeping the lids clean and free of crusts. Warm compresses should be applied to the lid to loosen the crusts, followed by a light scrubbing of the eyelid with a cotton swab and a mixture of water and baby shampoo. Because blepharitis rarely goes away completely, most patients must maintain an eyelid hygiene routine for life. If the blepharitis is severe, an eye care professional may also prescribe antibiotics or steroid eyedrops. In addition to the warm compresses, patients with posterior blepharitis will need to massage their eyelids to clean the oil accumulated in the glands. Patients who also have acne rosacea should have that condition treated at the same time.

Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).

What is a cataract?
A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. Cataracts are very common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery.

What causes cataracts?
The lens lies behind the iris and the pupil. It works much like a camera lens. It focuses light onto the retina at the back of the eye, where an image is recorded. The lens also adjusts the eye’s focus, letting us see things clearly both up close and far away. The lens is made of mostly water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it.
But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract. Over time, the cataract may grow larger and cloud more of the lens, making it harder to see. Researchers suspect that there are several causes of cataract, such as smoking and diabetes. Or, it may be that the protein in the lens just changes from the wear and tear it takes over the years.

What are the symptoms of a cataract?
The most common symptoms of a cataract are: • Cloudy or blurry vision. • Colors seem faded. • Glare. Headlights, lamps, or sunlight may appear too bright. A halo may appear around lights. • Poor night vision. • Double vision or multiple images in one eye. (This symptom may clear as the cataract gets larger.) • Frequent prescription changes in your eyeglasses or contact lenses.
These symptoms also can be a sign of other eye problems. If you have any of these symptoms, check with your eye care professional.

How is a cataract treated?
The symptoms of early cataract may be improved with new eyeglasses, brighter lighting, anti-glare sunglasses, or magnifying lenses. If these measures do not help, surgery is the only effective treatment. Surgery involves removing the cloudy lens and replacing it with an artificial lens.

A cataract needs to be removed only when vision loss interferes with your everyday activities, such as driving, reading, or watching TV. You and your eye care professional can make this decision together. Once you understand the benefits and risks of surgery, you can make an informed decision about whether cataract surgery is right for you. In most cases, delaying cataract surgery will not cause long-term damage to your eye or make the surgery more difficult. You do not have to rush into surgery.

Sometimes a cataract should be removed even if it does not cause problems with your vision. For example, a cataract should be removed if it prevents examination or treatment of another eye problem, such as age-related macular degeneration or diabetic retinopathy.

Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).

What is color blindness?
Most of us share a common color vision sensory experience. Some people, however, have a color vision deficiency, which means their perception of colors is different from what most of us see. The most severe forms of these deficiencies are referred to as color blindness. People with color blindness aren’t aware of differences among colors that are obvious to the rest of us. People who don’t have the more severe types of color blindness may not even be aware of their condition unless they’re tested in a clinic or laboratory.
Inherited color blindness is caused by abnormal photopigments. These color-detecting molecules are located in cone-shaped cells within the retina, called cone cells. In humans, several genes are needed for the body to make photopigments, and defects in these genes can lead to color blindness.
There are three main kinds of color blindness, based on photopigment defects in the three different kinds of cones that respond to blue, green, and red light. Red-green color blindness is the most common, followed by blue-yellow color blindness. A complete absence of color vision —total color blindness – is rare.
Sometimes color blindness can be caused by physical or chemical damage to the eye, the optic nerve, or parts of the brain that process color information. Color vision can also decline with age, most often because of cataract - a clouding and yellowing of the eye’s lens.

Who gets color blindness?
As many as 8 percent of men and 0.5 percent of women with Northern European ancestry have the common form of red-green color blindness. Men are much more likely to be colorblind than women because the genes responsible for the most common, inherited color blindness are on the X chromosome. Males only have one X chromosome, while females have two X chromosomes. In females, a functional gene on only one of the X chromosomes is enough to compensate for the loss on the other. This kind of inheritance pattern is called X-linked, and primarily affects males. Inherited color blindness can be present at birth, begin in childhood, or not appear until the adult years.

How is color blindness diagnosed?
Eye care professionals use a variety of tests to diagnose color blindness. These tests can quickly diagnose specific types of color blindness. The Ishihara Color Test is the most common test for red-green color blindness. The test consists of a series of colored circles, called Ishihara plates, each of which contains a collection of dots in different colors and sizes. Within the circle are dots that form a shape clearly visible to those with normal color vision, but invisible or difficult to see for those with red-green color blindness.

Are there treatments for color blindness?
There is no cure for color blindness. However, people with red-green color blindness may be able to use a special set of lenses to help them perceive colors more accurately. These lenses can only be used outdoors under bright lighting conditions. Visual aids have also been developed to help people cope with color blindness. There are iPhone and iPad apps, for example, that help people with color blindness discriminate among colors. Some of these apps allow users to snap a photo and tap it anywhere on the image to see the color of that area. More sophisticated apps allow users to find out both color and shades of color. These kinds of apps can be helpful in selecting ripe fruits such as bananas, or finding complementary colors when picking out clothing.

Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).

What are floaters?
Floaters are little “cobwebs” or specks that float about in your field of vision. They are small, dark, shadowy shapes that can look like spots, thread-like strands, or squiggly lines. They move as your eyes move and seem to dart away when you try to look at them directly. They do not follow your eye movements precisely, and usually drift when your eyes stop moving. Most people have floaters and learn to ignore them; they are usually not noticed until they become numerous or more prominent. Floaters can become apparent when looking at something bright, such as white paper or a blue sky.

Floaters and Retinal Detachment
Sometimes a section of the vitreous pulls the fine fibers away from the retina all at once, rather than gradually, causing many new floaters to appear suddenly. This is called a vitreous detachment, which in most cases is not sight-threatening and requires no treatment. However, a sudden increase in floaters, possibly accompanied by light flashes or peripheral (side) vision loss, could indicate a retinal detachment. A retinal detachment occurs when any part of the retina, the eye’s light-sensitive tissue, is lifted or pulled from its normal position at the back wall of the eye. A retinal detachment is a serious condition and should always be considered an emergency. If left untreated, it can lead to permanent visual impairment within two or three days or even blindness in the eye.
Those who experience a sudden increase in floaters, flashes of light in peripheral vision, or a loss of peripheral vision should have an eye care professional examine their eyes as soon as possible.

What causes floaters?
Floaters occur when the vitreous, a gel-like substance that fills about 80 percent of the eye and helps it maintain a round shape, slowly shrinks. As the vitreous shrinks, it becomes somewhat stringy, and the strands can cast tiny shadows on the retina. These are floaters. In most cases, floaters are part of the natural aging process and simply an annoyance. They can be distracting at first, but eventually tend to “settle” at the bottom of the eye, becoming less bothersome. They usually settle below the line of sight and do not go away completely. However, there are other, more serious causes of floaters, including infection, inflammation (uveitis), hemorrhaging, retinal tears, and injury to the eye.

How are floaters treated?
For people who have floaters that are simply annoying, no treatment is recommended. On rare occasions, floaters can be so dense and numerous that they significantly affect vision. In these cases, a vitrectomy, a surgical procedure that removes floaters from the vitreous, may be needed. A vitrectomy removes the vitreous gel, along with its floating debris, from the eye. The vitreous is replaced with a salt solution. Because the vitreous is mostly water, you will not notice any change between the salt solution and the original vitreous. This operation carries significant risks to sight because of possible complications, which include retinal detachment, retinal tears, and cataract. Most eye surgeons are reluctant to recommend this surgery unless the floaters seriously interfere with vision.

Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).

What is Glaucoma?
Glaucoma is a group of diseases that damage the eye’s optic nerve and can result in vision loss and blindness. However, with early detection and treatment, you can often protect your eyes against serious vision loss.

How does the optic nerve get damaged by open-angle glaucoma?
Several large studies have shown that eye pressure is a major risk factor for optic nerve damage. In the front of the eye is a space called the anterior chamber. A clear fluid flows continuously in and out of the chamber and nourishes nearby tissues. The fluid leaves the chamber at the open angle where the cornea and iris meet. When the fluid reaches the angle, it flows through a spongy meshwork, like a drain, and leaves the eye. In open-angle glaucoma, even though the drainage angle is “open”, the fluid passes too slowly through the meshwork drain. Since the fluid builds up, the pressure inside the eye rises to a level that may damage the optic nerve. When the optic nerve is damaged from increased pressure, open-angle glaucoma-and vision loss—may result. That’s why controlling pressure inside the eye is important.

Can I develop glaucoma if I have increased eye pressure?
Not necessarily. Not every person with increased eye pressure will develop glaucoma. Some people can tolerate higher levels of eye pressure better than others. Also, a certain level of eye pressure may be high for one person but normal for another.
Whether you develop glaucoma depends on the level of pressure your optic nerve can tolerate without being damaged. This level is different for each person. That’s why a comprehensive dilated eye exam is very important. It can help your eye care professional determine what level of eye pressure is normal for you.

Can I develop glaucoma without an increase in my eye pressure?
Yes. Glaucoma can develop without increased eye pressure. This form of glaucoma is called low-tension or normal-tension glaucoma. It is a type of open-angle glaucoma.

Who is at risk for open-angle glaucoma?
Anyone can develop glaucoma. Some people, listed below, are at higher risk than others: • African Americans over age 40 • Everyone over age 60, especially people with Latino heritage • People with a family history of glaucoma
A comprehensive dilated eye exam can reveal more risk factors, such as high eye pressure, thinness of the cornea, and abnormal optic nerve anatomy. In some people with certain combinations of these high-risk factors, medicines in the form of eyedrops reduce the risk of developing glaucoma by about half.

Can glaucoma be cured?
No. There is no cure for glaucoma. Vision lost from the disease cannot be restored.

What is the Treatment?
Immediate treatment for early-stage, open-angle glaucoma can delay progression of the disease. That’s why early diagnosis is very important.
Glaucoma treatments include medicines, laser trabeculoplasty, conventional surgery, or a combination of any of these. While these treatments may save remaining vision, they do not improve sight already lost from glaucoma.

Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).

What is myopia?
Myopia, also known as nearsightedness, is a common type of refractive error where close objects appear clearly, but distant objects appear blurry. Myopia can also be the result of a cornea that is too curved for the length of the eyeball or a lens that is too thick. For some people, their myopia may be caused by a combination of problems in the cornea, lens, and length of the eyeball.

What are the symptoms of myopia?
If you have myopia, you have trouble seeing things far away, but you can see nearby things clearly. This is why myopia is commonly called nearsightedness.

How common is myopia?
About 40% of Americans are myopic. According to a 2009 study, the number of Americans with myopia has increased significantly from the 1970s to the early 2000s. The prevalence of myopia has also been increasing in many other countries around the world. It is particularly prominent among school-aged children living in urban areas in some Asian countries. In the past, people thought children might become myopic from spending too much time reading and writing, which require close-up vision, or from reading in poorly lit rooms. Recent studies suggest that the increase of myopia in children could be related to a decrease in the amount of time they spend outdoors.

What kinds of treatments are available for myopia?
The most common way to treat myopia is to prescribe eyeglasses or contact lenses. Refractive surgery, once the eyes have stopped growing, has become another option for many people.

Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).

What is hyperopia?
Hyperopia, also known as farsightedness, is a common type of refractive error where distant objects may be seen more clearly than objects that are near. However, people experience hyperopia differently. Some people may not notice any problems with their vision, especially when they are young. For people with significant hyperopia, vision can be blurry for objects at any distance, near or far.

Who is at risk for hyperopia?
Hyperopia can affect both children and adults. It affects about 5 to 10 percent of Americans. People whose parents have hyperopia may also be more likely to get the condition.

What are the signs and symptoms of hyperopia?
The symptoms of hyperopia vary from person to person. Your eye care professional can help you understand how the condition affects you. Commons signs and symptoms include headaches, eyestrain, squinting, and blurred vision.

How is hyperopia corrected?
Hyperopia can be corrected with eyeglasses, contact lenses, or surgery. Eyeglasses are the simplest and safest way to correct hyperopia. Your eye care professional can prescribe lenses that will help correct the problem and help you see your best. Contact Lenses work by becoming the first refractive surface for light rays entering the eye, causing a more precise refraction or focus. In many cases, contact lenses provide clearer vision, a wider field of vision, and greater comfort. They are a safe and effective option if fitted and used properly. However, contact lenses are not right for everyone. Discuss this with your eye care professional. Refractive Surgery aims to permanently change the shape of the cornea which will improve refractive vision. Surgery can decrease or eliminate dependency on wearing eyeglasses and contact lenses. There are many types of refractive surgeries and surgical options should be discussed with an eye care professional.

Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).

What is presbyopia?
Presbyopia is a common type of vision disorder that occurs as you age. It is often referred to as the aging eye condition. Presbyopia results in the inability to focus up close, a problem associated with refraction in the eye.

Can I have presbyopia and another type of refractive error at the same time?

Yes. It is common to have presbyopia and another type of refractive error at the same time. There are several other types of refractive errors: myopia (nearsightedness), hyperopia (farsightedness), and astigmatism.
An individual may have one type of refractive error in one eye and a different type of refractive error in the other.

What are the signs and symptoms of presbyopia?

Some of the signs and symptoms of myopia include: difficulty reading small print, having to hold reading material at arm's length or further, problem seeing objects close to you, headaches, and eyestrain.

How is presbyopia corrected?

Eyeglasses are the simplest and safest means of correcting presbyopia. Eyeglasses for presbyopia have higher focusing power in the lower portion of the lens. This allows you to read through the lower portion of the lens and see properly at distant through the upper portion of the lens. It is also possible to purchase reading eyeglasses. These types of glasses do not require a prescription and can help with reading vision.

Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).

Sports Vision and Eye Protection
Outdoor games and sports are an enjoyable and important part of most children's lives. Whether playing catch in the back yard or participating in team sports at school, vision plays an important role in how well a child performs. Specific visual skills needed for sports include: clear distance vision, good depth perception, wide field of vision, effective eye-hand coordination.
A child who consistently underperforms a certain skill in a sport, such as always hitting the front of the rim in basketball or swinging late at a pitched ball in baseball, may have a vision problem. If visual skills are not adequate, the child may continue to perform poorly. Correction of vision problems with eyeglasses or contact lenses, or a program of eye exercises called vision therapy can correct many vision problems, enhance vision skills, and improve sports vision performance. Eye protection should also be a major concern to all student athletes, especially in certain high-risk sports. Thousands of children suffer sports-related eye injuries each year and nearly all can be prevented by using the proper protective eyewear. That is why it is essential that all children wear appropriate, protective eyewear whenever playing sports. Eye protection should also be worn for other risky activities such as lawn mowing and trimming.
Regular prescription eyeglasses or contact lenses are not a substitute for appropriate, well-fitted protective eyewear. Athletes need to use sports eyewear that is tailored to protect the eyes while playing the specific sport.

Copyrighted information courtesy of the American Optometric Association.

News on Myopia Prevention
This topic is receiving much attention due to the number of studies completed recently. Based on a 2008 Archives of Ophthalmology study, experts at NIH estimate that at least 33 percent of Americans are nearsighted. According to a 2009 Archives of Ophthalmology study, the number of Americans with myopia has increased significantly from the 1970s to the early 2000s. The prevalence of myopia has also been increasing in many other countries around the world. It is particularly prominent among school-aged children living in urban areas in some Asian countries. In the past, people thought children might become myopic from spending too much time reading and writing, which require close-up vision, or from reading in poorly lit rooms. Recent studies suggest that the increase of myopia in children could be related to a decrease in the amount of time they spend outdoors 3. There are different methods to choose from for myopia prevention. The list includes: bifocal spectacles, bifocal contact lenses, RGP contact lenses (hard lenses), ortho-keratology, pharmaceutical options, and also emerging research on nutritional intervention as well. Each method has its pro's and con's. Discuss with your doctor the method that may work the best for you.

1.Arch Ophthalmol. 2008 Aug;126(8):1111-9. doi: 10.1001/archopht.126.8.1111.

  1. Arch Ophthalmol. 2009 Dec;127(12):1632-9. doi: 10.1001/archophthalmol.2009.303.

  2. Ophthalmology. 2012 Oct;119(10):2141-51. doi: 10.1016/j.ophtha.2012.04.020. Epub 2012 Jul 17.

What is binocular vision?
Binocular vision is how the eyes work together as a single entity. Unfortunately, for many people this is not always the case. Binocular vision encompasses many skills under the binocular vision umbrella such as: eye teaming, eye tracking, eye focusing, convergence, and visual motor integration. Eye teaming refers to the eyes ability to look at the same point or reference together as a team. For example, if you are reading a book both eyes should be directed together at the word you are reading. One eye should not be on word while the other eye on a different word. This can cause double vision and/or suppression. Eye tracking refers to the eyes ability to move across a page, or a vista in a smooth coordinated matter. Deficits with this skill may lead a loss of place while reading. Eye focusing (accommodation) refers to the eyes ability to produce a clear image on the back of the retina. Problems with this skill may result in blurred vision, headaches, eye strain, and an unusual reading distance. Convergence is eye teaming skill that specifically refers to the ability of the eyes to produce a single image up close, like a book or cell phone. Problems with this skill may result in shadows while reading, double vision, headaches, and eye strain just to name a few. Visual Motor Integration (hand eye coordination) is ofter referred to in sports, but has large implications in daily life. We use visual motor integration daily such as driving, copying from the board and yes sports. Problems with this area may result in the person being considered 'clumsy' or uncoordinated.

How old does my child need to be for contacts?
I often get asked how old does a child have to be before they can be fit with contact lenses. The answer is - it depends. Several factors need to be considered when being evaluated for contact lenses. On the ocular side there is corneal curvature, refractive error (myopia, hyperopia, astigmatism), any irregularities to corneal surface, ocular moisture or dryness, what are they being used for - sports, a night out…, soft contact lenses, RGP's (hard contacts), and cost. After all that then let's go back to the child in question. The first thing to consider and biggest factor is the maturity of the child. Will they be able to deal with the responsibilities that come with contact lenses? If the child has a parent that wears contacts this helps greatly in educating the child all that will be expected of him. The second factor is motivation. Does the chlld want contact lenses or the parent? Often parents will push a child into contact lenses before she is ready. This will ultimately lead to frustration and failure when it comes to lens insertion and removal training.

What are monovision contact lenses?
Monovision contact lenses are a fitting option for some patients. It is considered an alternative to bifocal contact lenses. Monovision means one eye will be fitted with a contact lens to see distance while the fellow eye will be fitted with a contact lens that is suited for up close work, such as reading and computers. The pro's and con's are listed here. A benefit to monovision is convenience. You should be able to read items up close like a book and see far away like a street sign. The drawback to monovision is clarity. The convenience generally comes at the cost of sharp vision. Since a person is not using both eyes at the same time to view distant and near objects it is not as 'sharp as it could be.' Is monovision right for me? You won't know if you like monovision until you try it.

What are bifocal contact lenses?
Bifocal contact lenses are a great option for presbyopic contact lens wearers. The technology for bifocal contacts has improved dramatically over the last few years. What was once a niche product has become mainstream. A great use for bifocal contact lenses is for myopia progression control as well. What are the pro's and con's? The main drawback is astigmatism. If you have a large amount of astigmatism you will probably not be a candidate for traditional soft bifocal contact lenses. The benefits are convenience and clarity. Bifocal wearers gain clearer vision than monovision wearers because they are using both eyes to look far and near.

What is astigmatism?
Astigmatism is a refractive error that causes blurred vision at distance and near. Astigmatism occurs at the cornea due to the irregular shape of it. For more information see the section on Eye Conditions and Terms. Toric contact lenses are specifically designed to provide clear vision for those who have it. Toric contact lenses can be more difficult to fit due to the fact that if it rotates while wearing it this will result in blurred vision. Not all toric contact lenses will fit the same person the same way each has its own design which may or may not help individuals. A severely astigmatic cornea may require specialty toric lenses. If you have a large amount of astigmatism and wear bifocal spectacles and would like to wear contact lens there are some options for you. A hybrid contact lens is the best option for astigmatics with presbyopia.

Aren't all contact lens solutions the same?
Just get the cheapest one they're all the same. That's completely false! Todays contact lenses are made of newer materials that are more breathable and healthier for a patient eyes. So your contact lens solution must be compatible with the contact lens you are wearing. Generic contact lens solutions are usually not compatible with the newer generation of contacts and can cause irritation to the cornea after insertion of the lens. Peroxide contact lens solutions such as Clear Care are usually less irritating to the cornea and more effective at cleaning the contact lens.

What are RGP's?
RGP contact lenses are often referred to as hard contact lenses. While once they were the only option for contact lens wearers, now they have fallen out of favor due to the advent of soft contact lenses. RGP's will never go away because they still fill an important niche for lens wearers. As discussed in the myopia control section, they are still a good option for young wearers to slow the progression of their nearsightedness. The crisp vision that is achieved with a RGP lens is amazing, however most people are unable to wear them due to discomfort.

Which is best for me?
There has been a shift in the modality of contact lens wear with the newer technology that is available. Daily contact lenses have increased in popularity due to their convenience and being a healthy option. Daily contact lenses now come in bifocal, toric, and spherical to fit a wide array of patients. Monthly contact lenses have also benefitted from the newer lens materials. Provided the solution is compatible and the lens is not overworn, monthly options can be a healthy option as well.

What is diabetic eye disease?
Diabetic eye disease is a group of eye conditions that can affect people with diabetes. Diabetic retinopathy affects blood vessels in the light-sensitive tissue called the retina that lines the back of the eye. It is the most common cause of vision loss among people with diabetes and the leading cause of vision impairment and blindness among working-age adults. Diabetic macular edema (DME). A consequence of diabetic retinopathy, DME is swelling in an area of the retina called the macula. Diabetic eye disease also includes cataract and glaucoma: Cataract is a clouding of the eye’s lens. Adults with diabetes are 2-5 times more likely than those without diabetes to develop cataract. Cataract also tends to develop at an earlier age in people with diabetes. Glaucoma is a group of diseases that damage the eye’s optic nerve—the bundle of nerve fibers that connects the eye to the brain. Some types of glaucoma are associated with elevated pressure inside the eye. In adults, diabetes nearly doubles the risk of glaucoma.
All forms of diabetic eye disease have the potential to cause severe vision loss and blindness.

What causes diabetic retinopathy?
Chronically high blood sugar from diabetes is associated with damage to the tiny blood vessels in the retina, leading to diabetic retinopathy. The retina detects light and converts it to signals sent through the optic nerve to the brain. Diabetic retinopathy can cause blood vessels in the retina to leak fluid or hemorrhage (bleed), distorting vision. In its most advanced stage, new abnormal blood vessels proliferate (increase in number) on the surface of the retina, which can lead to scarring and cell loss in the retina. Diabetic retinopathy may progress through four stages: 1. Mild nonproliferative retinopathy. **Small areas of balloon-like swelling in the retina’s tiny blood vessels, called microaneurysms, occur at this earliest stage of the disease. These microaneurysms may leak fluid into the retina. **2. Moderate nonproliferative retinopathy. As the disease progresses, blood vessels that nourish the retina may swell and distort. They may also lose their ability to transport blood. Both conditions cause characteristic changes to the appearance of the retina and may contribute to DME. 3. Severe nonproliferative retinopathy. Many more blood vessels are blocked, depriving blood supply to areas of the retina. These areas secrete growth factors that signal the retina to grow new blood vessels. 4. Proliferative diabetic retinopathy (PDR). At this advanced stage, growth factors secreted by the retina trigger the proliferation of new blood vessels, which grow along the inside surface of the retina and into the vitreous gel, the fluid that fills the eye. The new blood vessels are fragile, which makes them more likely to leak and bleed. Accompanying scar tissue can contract and cause retinal detachment—the pulling away of the retina from underlying tissue, like wallpaper peeling away from a wall. Retinal detachment can lead to permanent vision loss.

What are the symptoms of diabetic retinopathy and DME?
The early stages of diabetic retinopathy usually have no symptoms. The disease often progresses unnoticed until it affects vision. Bleeding from abnormal retinal blood vessels can cause the appearance of “floating” spots. These spots sometimes clear on their own. But without prompt treatment, bleeding often recurs, increasing the risk of permanent vision loss. If DME occurs, it can cause blurred vision.

How can people with diabetes protect their vision?
Vision lost to diabetic retinopathy is sometimes irreversible. However, early detection and treatment can reduce the risk of blindness by 95 percent. Because diabetic retinopathy often lacks early symptoms, people with diabetes should get a comprehensive dilated eye exam at least once a year. People with diabetic retinopathy may need eye exams more frequently. Women with diabetes who become pregnant should have a comprehensive dilated eye exam as soon as possible. Additional exams during pregnancy may be needed. Studies such as the Diabetes Control and Complications Trial (DCCT) have shown that controlling diabetes slows the onset and worsening of diabetic retinopathy. DCCT study participants who kept their blood glucose level as close to normal as possible were significantly less likely than those without optimal glucose control to develop diabetic retinopathy, as well as kidney and nerve diseases. Other trials have shown that controlling elevated blood pressure and cholesterol can reduce the risk of vision loss among people with diabetes.

Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).

Information is coming soon.

What is dry eye?
Dry eye occurs when the eye does not produce tears properly, or when the tears are not of the correct consistency and evaporate too quickly. In addition, inflammation of the surface of the eye may occur along with dry eye. If left untreated, this condition can lead to pain, ulcers, or scars on the cornea, and some loss of vision. However, permanent loss of vision from dry eye is uncommon. Dry eye can make it more difficult to perform some activities, such as using a computer or reading for an extended period of time, and it can decrease tolerance for dry environments, such as the air inside an airplane. Other names for dry eye include dry eye syndrome, keratoconjunctivitis sicca (KCS), dysfunctional tear syndrome, lacrimal keratoconjunctivitis, evaporative tear deficiency, aqueous tear deficiency, and LASIK-induced neurotrophic epitheliopathy (LNE).

What are the causes of dry eye?
Dry eye can be a temporary or chronic condition: • Dry eye can be a side effect of some medications, including antihistamines, nasal decongestants, tranquilizers, certain blood pressure medicines, Parkinson’s medications, birth control pills and anti-depressants. • Skin disease on or around the eyelids can result in dry eye. • Diseases of the glands in the eyelids, such as meibomian gland dysfunction, can cause dry eye. • Dry eye can occur in women who are pregnant. • Women who are on hormone replacement therapy may experience dry eye symptoms. Women taking only estrogen are 70 percent more likely to experience dry eye, whereas those taking estrogen and progesterone have a 30 percent increased risk of developing dry eye. • Dry eye can also develop after the refractive surgery known as LASIK. These symptoms generally last three to six months, but may last longer in some cases.
• Dry eye can result from chemical and thermal burns that scar the membrane lining the eyelids and covering the eye. • Allergies can be associated with dry eye. • Infrequent blinking, associated with staring at computer or video screens, may also lead to dry eye symptoms. • Both excessive and insufficient dosages of vitamins can contribute to dry eye. • Homeopathic remedies may have an adverse impact on a dry eye condition. • Loss of sensation in the cornea from long-term contact lens wear can lead to dry eye. • Dry eye can be associated with immune system disorders such as Sjögren’s syndrome, lupus, and rheumatoid arthritis. Sjögren’s leads to inflammation and dryness of the mouth, eyes, and other mucous membranes. It can also affect other organs, including the kidneys, lungs and blood vessels. • Dry eye can be a symptom of chronic inflammation of the conjunctiva, the membrane lining the eyelid and covering the front part of the eye, or the lacrimal gland. Chronic conjunctivitis can be caused by certain eye diseases, infection, exposure to irritants such as chemical fumes and tobacco smoke, or drafts from air conditioning or heating. • If the surface area of the eye is increased, as in thyroid disease when the eye protrudes forward or after cosmetic surgery if the eyelids are opened too widely, dry eye can result. • Dry eye may occur from exposure keratitis, in which the eyelids do not close completely during sleep.

How is dry eye treated?
Depending on the causes of dry eye, your doctor may use various approaches to relieve the symptoms. Dry eye can be managed as an ongoing condition. The first priority is to determine if a disease is the underlying cause of the dry eye (such as Sjögren’s syndrome or lacrimal and meibomian gland dysfunction). If it is, then the underlying disease needs to be treated. Cyclosporine, an anti-inflammatory medication, is the only prescription drug available to treat dry eye. It decreases corneal damage, increases basic tear production, and reduces symptoms of dry eye. It may take three to six months of twice-a-day dosages for the medication to work. In some cases of severe dry eye, short term use of corticosteroid eye drops that decrease inflammation is required. If dry eye results from taking a medication, your doctor may recommend switching to a medication that does not cause the dry eye side effect. If contact lens wear is the problem, your eye care practitioner may recommend another type of lens or reducing the number of hours you wear your lenses. In the case of severe dry eye, your eye care professional may advise you not to wear contact lenses at all. Another option is to plug the drainage holes, small circular openings at the inner corners of the eyelids where tears drain from the eye into the nose. Lacrimal plugs, also called punctal plugs, can be inserted painlessly by an eye care professional. The patient usually does not feel them. These plugs are made of silicone or collagen, are reversible, and are a temporary measure. In severe cases, permanent plugs may be considered. In some cases, a simple surgery, called punctal cautery, is recommended to permanently close the drainage holes. The procedure helps keep the limited volume of tears on the eye for a longer period of time.
In patients with dry eye, supplements or dietary sources (such as tuna fish) of omega-3 fatty acids (especially DHA and EPA) may decrease symptoms of irritation. The use and dosage of nutritional supplements and vitamins should be discussed with doctor.

Courtesy: National Eye Institute, National Institutes of Health (NEI/NIH).

What is high energy blue light?
The spectrum of visible light is 400-700 nanometers (nm). This is easily remembered by the mnemonic ROYGBIV. Blue, indigo, violet are at the end of the higher energy wavelengths, around the 380-500 nm spectrum. The light beyond the visible violet portion is called ultraviolet. There are 2 classes of UV, UV-A and UV-B. UV-A wavelength is 315 to 400 nm. UV-B is 280 to 315 nm.

Can it harm your eyes?
Wavelengths shorter than 295 nm are blocked by the cornea. While UV-A and UV-B are blocked by the lens inside your eye. Several studies have shown that short term and chronic long term exposure may be harmful to your eyes. An association between UV light and cataracts has been found. 1,2,3,4. The light that passes through the cornea and lens that reaches the retina, 400-480nm, can damage the retina. Exposure to light at this wavelength, that is emitted from digital devices like tablets, smartphones, and LED lights, are 50-80 tomes more efficient at causing photoreceptor death than green light. 5. In the same article researchers showed that damage to RPE layer or the retina and results in AMD. 6. Algvere PV, Marshall J, Seregard S. Age-related maculopathy and the impact of blue light hazard. Acta Ophthalmology. 2006 Feb;84(1):4-15.

What about sleep?
The effects appear to be mediated through the intrinsically photosensitive retinal ganglion cells (iprgc). These cells appear to be important components of the circadian pacemaker. Stimulation of the iprgc’s can suppress melatonin levels in the circulation. The iprgc’s have a peak wavelength sensitivity around 480 nm and have a fairly wide spectral sensitivity around the peak wavelength similar to other retinal photoreceptors (rods and cones). Stimulation of these cells by blue colored light (or from strong white light with a substantial blue component) can inhibit sleep and keep one alert. 7.

What about contact lenses?
Contact lenses have an edge over spectacles with UV protection since the entire pupil is covered from all angles of light. However, contact lenses (hard or soft) are unable to filter out high energy blue light.

What can be done to protect your eyes from blue light?
The best way to protect your eyes from high energy blue light is limit the amount the screen time. Unfortunately, with our modern society this is not always a solution. Newer spectacle technology allows the wearer to protect their eyes by a filter applied to the lenses to protect the wearer from this light spectrum. Also, nutritional intervention can be helpful as well. Studies have shown that AMD sufferers have a low amount of macular pigment. People who supplement a healthy diet with lutein and zeaxanthin, are able to combat the effects of oxidative stress placed on their retina.

  1. Chesapeake Watermen Study Taylor et al. New Engl J Med. 1988; 391:1429-33.
  2. Beaver Dam Eye Study Cruickshanks et al. Am J Public Health 1992; 82:1658-62
  3. Salisbury Eye Evaluation West et al. J Am Med Assoc. 1998; 280:714-8
  4. Blue Mountains Eye Study Mitchell et al. Ophthalmology 1997; 104:581-8.
  5. Age-related maculopathy and the impact of blue light hazard. Algvere PV, Marshall J, Seregard S. Acta Ophthalmology. 2006 Feb;84(1):4-15
  6. Age-related maculopathy and the impact of blue light hazard. Algvere PV, Marshall J, Seregard S. Acta Ophthalmology. 2006 Feb;84(1):4-15
  7. Light and Eye Damage. Good, Gregory W. American Optometric Association White Paper. December 2014.