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Lack of Sleep May Affect Your Eye Health

Have you been having trouble sleeping? Fatigue, concentration problems, and irritability aren't the only consequences of insomnia. Your eye health may also suffer if you can't fall asleep or stay asleep.

These Things Can Happen to Your Eyes if You Don't Get Enough Sleep

Most of us experience sleep problems from time to time. Stress, spicy foods, caffeinated beverages, illnesses, injuries, or the birth of a new baby can interfere with your ability to get a good night's sleep. Unfortunately, if sleep difficulties become chronic, you may be at risk of developing one of these eye issues:

• Dry Eye. Researchers who conducted a systematic literature review published in Investigative Ophthalmology and Visual Science in 2018 reported that almost half of patients with dry eye don't sleep well. Dry eye could be related to incomplete closure of your eyes when you sleep, problems with tear production, diabetes and other diseases, or hormonal changes due to menopause or pregnancy. Improving sleep quality and duration while using eye drops at night can help relieve dry eye, although you may still experience dry, irritated eyes from time to time. If you continue to have dry eye symptoms, your eye doctor can recommend treatment options.

• Eye Spasms. A twitching eyelid isn't usually a sign of a serious condition, although it's certainly annoying. Spasms may be more likely to occur if you don't get enough sleep, are stressed, have allergies, or spend many hours viewing digital screens. If your spasms don't go away after a week or two or make it hard to see or keep your eye open, get in touch with your optometrist.

• Circles, Bags, and Bloodshot Eyes. Dark circles, bags under your eyes, and red eyes may not damage your vision, but they can make you feel self-conscious about your appearance. Fluid retention due to poor sleep causes bags and circles, while dilated blood vessels can make your eyes look red and bloodshot.

• Glaucoma. The pressure inside your eye increases if you have glaucoma. If your condition isn't treated, the pressure may damage your optic nerve, causing permanent vision loss. Glaucoma can also occur even if your pressure is normal, in some cases. The amount of sleep you get may affect your glaucoma risk. Researchers who analyzed a survey of more than 6,000 glaucoma patients discovered that people who slept seven hours a night were three times more likely to develop glaucoma than those who slept 10 or more hours. Patients who took 30 minutes or more to fall asleep had twice the risk of developing glaucoma.

• Ischemic Optic Neuropathy (AION). One of the most serious effects of lack of sleep, AION can occur as a result of sleep apnea, a condition that causes hundreds of breathing pauses throughout the night. Oxygen deprivation caused by sleep apnea can eventually lead to optic nerve damage and vision loss. The optic nerve transmits electrical impulses from your retina to your brain and is essential for good vision. Continuous positive airway pressure (CPAP) machines or other treatments keep your airways open and stop breathing pauses that can damage your vision and your health.
   

Regular eye examinations are particularly important if you have sleep issues. Identifying and treating sleep-related eye problems promptly will reduce your risk of vision loss and ease discomfort and other symptoms. Contact our office if you're ready to schedule your appointment.

Sources:

Journal of Glaucoma: Association Between Sleep Parameters and Glaucoma in the United States Population: National Health and Nutrition Examination Survey, 2/19

American Academy of Ophthalmology: Eye-Opening Study: Relationship Between Glaucoma and Poor Sleep, 4/10/19

Investigative Ophthalmology and Visual Science: Sleep Disorders are a Prevalent and Serious Comorbidity in Dry Eye, 11/18

Cleveland Clinic: Anterior Ischemic Optic Neuropathy (AION)

All About Vision: Eye Twitching: Causes and Treatments

How Smoking Affects Your Eyes

Smoking increases the likelihood of developing many types of health issues, including conditions and diseases that may affect your vision. If you are a smoker or live with someone who smokes, your eye health may be at risk.

7 Diseases and Conditions Related to Smoking

Smoking can cause several eye-related problems, including:

• Diabetic Retinopathy. Diabetic retinopathy, one of the most devastating effects of diabetes, can rob you of your eyesight. The condition damages the tiny blood vessels in your retina, the layer of the light-sensing cells at the back of your eye. The vessels begin to leak fluid or blood, causing symptoms ranging from blurred vision to night vision problems to blind or dark spots in your visual field. A change in blood flow may be responsible in part for the changes. In a study published in Investigative Ophthalmology & Visual Science, retinal blood flow and blood velocity were lower in chronic smokers who had type 2 diabetes.

• Cataracts. Your smoking habit may cause cataracts to form in your eyes. Cataracts occur when the normally clear lens inside the eye becomes cloudy. The eye condition can cause blurred vision, halos around lights, glare, poor night vision, and faded colors. Swedish researchers discovered that men who smoked more than 15 cigarettes a day had a 42 percent increased risk of cataract surgery. Men who once smoked more than 15 cigarettes a day but had quit smoking more than 20 years earlier still had a 21 percent higher risk than non-smokers.

• Age-Related Macular Degeneration (AMD). AMD affects the macula, the area of the retina responsible for central and color vision. Cell deterioration is responsible for the "dry" form of AMD, while leaking blood vessels cause vision problems in the "wet" form. If you have AMD, you may notice blurred vision, blind spots in the center of your vision, faded colors, distortions, or straight lines that appear wavy. The Centers for Disease Control and Prevention note that smokers are twice as likely to develop the condition as non-smokers.

• Uveitis. Smoking may increase your risk of a painful eye disease that can cause vision loss. Inflammation of the uvea, the middle layer of the eye, can cause redness, eye pain, blurred vision, sensitivity to light, and floaters.

• Thyroid Eye Disease (TED). Smokers are more likely to get TED and may not respond to treatment as well as non-smokers. TED, also known as Grave's disease, causes bulging eyes, redness, pain, and dry eye. If the disease isn't treated promptly, swelling may damage the optic nerve.

• Difficulty Seeing Colors. Color vision problems may also be a consequence of smoking, according to researchers at Rutgers, the State University of New Jersey. Their study detailed how smoking affected blue-yellow and red-green vision and explored the difficulty heavy smokers had when trying to distinguish between certain colors and contrasts.

• Dry Eye. Smoking affects the tear film of your eyes and may cause dry, painful red eyes. Although dry eye may seem like a minor problem, you may be more likely to develop abrasions and ulcers in your cornea, the clear layer of tissue that covers the iris and pupil, if dry eye is a frequent problem.
   

You don't have to be a smoker to experience eye health issues. Exposure to secondhand smoke may increase your likelihood of developing dry eye, AMD, and other eye conditions and diseases.

What About Vaping?

Vaping may not produce noxious smoke, but it's not any safer for your eyes than smoking cigarettes or cigars. Although more studies need to be done on the effects of vaping, the habit can dry the eyes and may increase your risk of developing macular degeneration. In addition to nicotine, the chemicals used to flavor e-cigarettes may also cause eye issues.

If you're a smoker, live or work with a smoker, or have smoked in the past, yearly eye examinations are particularly important. Contact our office to schedule your appointment.

Sources:

JAMA Ophthalmology: Smoking Cessation and Risk of Cataracts, 3/14

Investigative Ophthalmology & Visual Science: Effects of Habitual Cigarette Smoking on Retinal Circulation in Patients with Type 2 Diabetes, 3/16

All About Vision: Vaping, Like Smoking, May Harm Your Eyes, 10/19

All About Vision: How Smoking Harms Your Eyes

Rutgers, The State University of New Jersey: Heavy Smoking Can Damage Vision, Rutgers Researcher Finds, 2/18/19

CDC: Vision Loss, Blindness, and Smoking

American Academy of Ophthalmology: Smoking and Eye Disease, 1/16/20

Have you noticed shadowy shapes drifting in and out of your field of vision lately? You may have floaters. Although floaters are usually harmless, they can be a sign of a serious eye condition in some cases.

What Are Floaters?

Floaters occur when the vitreous in the center of your eye begins to shrink. The clear, gel-like vitreous gives your eyeball its shape and helps hold the retina in place. The retina is the light-sensing layer of cells at the back of your eye. Light impulses reflected on your retina travel to the brain through the optic nerve, where they're transformed into recognizable images.

The vitreous is affected by aging, just like every other part of your body. As you get older, it shrinks slightly, causing stringy fibers to detach from the surface of the vitreous. Known as "floaters," the fibers cast shadows on your retina when you look at brightly lit objects. The more you move your eyes when looking at a bright background, the more you may notice floaters. Floaters may also be accompanied by flashes of light, particularly when you step into a dark room.

Floaters take a variety of shapes and may look like cobwebs, specks, threads or spots. Although it may be a little alarming when you notice floaters for the first time, the phenomenon isn't usually a cause for concern.

Floaters occur as a normal part of aging but are more likely to happen after cataract surgery, if you are very nearsighted or have diabetes, according to the National Eye Institute.

You may also notice floaters if you experience bleeding or inflammation in the back part of your eye. Bleeding can be can caused by leaking blood vessels, injuries or high blood pressure.

When Should I Be Concerned About Floaters?

Seeing more floaters than normal doesn't necessarily indicate a problem, but a sudden increase in the number of floaters should be reported to your optometrist. Sometimes, you'll see a flurry of new spots if several fibers detach from the vitreous at the same times.

New floaters can also be a sign that your retina has torn or begun to detach from the back of your eye. Retinal tears and detachments are emergencies and can result in permanent loss of vision if they're not treated promptly.

If your retina tears or detaches, you may notice:

• Many New Floaters

• A Dark Area That Covers Part of Your Visual Field

• Flashing Lights

• Loss of Side Vision
   

Call your optometrist immediately if you notice any of these symptoms. If you can't get in touch with your eye doctor, go to the emergency room.

How Are Floaters Treated?

Although floating spots can be annoying, floaters don't usually require treatment. If you have so many floaters that your vision is affected, you may benefit from a vitrectomy, a surgical procedure that removes your vitreous and replaces it with a saline solution or gas bubble.

Retinal tears and detachments are repaired by reattaching the retina to the back of the eye. One or more of these procedures may be used if you have a tear or detachment:

• Laser Surgery. Laser heat creates tiny scars that hold the torn or detached retinal tissue firmly in place.

• Cryopexy. Cryopexy also creates small scars that seal the retina to the back of the eye but uses freezing temperatures rather than heat.

• Scleral Buckling. Scleral buckles are often used in conjunction with laser surgery or cryopexy. Small silicone or plastic bands are sewn on to the white part of the eye. The bands reduce traction on the retina and help it reattach.

• Pneumatic Retinopexy. During pneumatic retinopexy, a gas bubble is injected into the vitreous. The bubble presses against the retina, facilitating healing.

• Vitrectomy. A vitrectomy not only removes floaters but also offers another way to repair tears.
   

Whether you're concerned about your floaters or it's time for your next eye exam, we can help you care for your eyes. Contact us to schedule your appointment.

Sources:

All About Vision: Eye Floaters, Flashes and Spots, 3/17

https://www.allaboutvision.com/conditions/spotsfloats.htm

National Eye Institute: Facts About Floaters

https://nei.nih.gov/health/floaters/floaters

Mayo Clinic: Retinal Detachment, 3/12/19

https://www.mayoclinic.org/diseases-conditions/retinal-detachment/symptoms-causes/syc-20351344

American Society of Retina Specialists: Posterior Vitreous Detachment

https://www.asrs.org/patients/retinal-diseases/9/posterior-vitreous-detachment

The goal of vision therapy is to treat vision problems that cannot be fully addressed through eyeglasses, contact lenses or surgery. For example, studies show that vision therapy may be beneficial for addressing eyestrain and other issues that can affect a child’s reading abilities. The human brain has significant neuroplasticity, which means it can change its structure and function in response to external stimuli. This neuroplasticity is present not only in childhood, but also into adulthood. As a result, custom vision therapy programs can help bring about neurological changes that correct vision problems for improved visual perception and performance.

What It Treats

Vision therapy addresses vision problems that include amblyopia (“lazy eye”), strabismus, binocular vision problems, eye movement disorders, and accommodative (focusing) disorders. For example, if one eye fails to attain normal visual acuity due to eye teaming problems, vision therapy can help improve this teaming and reduce an eye’s perceived “laziness”. Studies show that vision therapy can improve the accuracy of eye movements required for close-up work and reading, as well as minimizing eyestrain and eye fatigue.

Vision therapy is not a “cure all” for vision issues and it is not a replacement for glasses, contact lenses or eye surgery for certain conditions. For example, do not expect to “throw away your glasses” after attending a few vision therapy sessions or practicing eye exercises at home. Vision therapy cannot “cure” refractive disorders or reverse nearsightedness. However, it may play an important role in addressing visual anomalies associated with vision development, perception and function.

Unlike other forms of exercise, the goal of vision therapy is not to strengthen the eye muscles. Instead, this progressive program of vision exercises is designed to help individuals develop or improve fundamental visual skills and abilities. Vision therapy helps individuals improve visual ease, efficiency and comfort while changing how they interpret or process information. Vision therapy can be beneficial for individuals of all ages, including children and older adults.

Treatment for glaucoma often begins with medicated eye drops. The goal of these medications is to lower the pressure in the eye (intraocular pressure) and prevent damage to the optic nerve.

To gain the most benefits of these medications, use them exactly as prescribed by your eye doctor. Sometimes your doctor may prescribe more than one type of eye drop. In this case, check with your doctor about how long to wait between using each kind.

Side Effects of Medicated Eye Drops

Although eye drops for glaucoma can help save your vision, all of these medications have some side effects. In addition, some of the medication may be absorbed into the bloodstream, which can cause side effects that affect body parts other than your eyes.

The most common side effects of medicated eye drops include:

• Redness of the eyes or skin around the eyes

• An itching or stinging sensation

• Blurred vision

• Changes in the color of your eyes, the skin around your eyes or the appearance of your eyelid

• Growth of your eyelashes

• Changes in your heartbeat or pulse

• Changes in your energy level

• Breathing changes, especially if you have asthma or other lung conditions

• Dry mouth
   

If you experience any of these side effects, tell your eye doctor. Do not stop taking your medicated eye drops unless you have spoken with your doctor. Using these eye drops as directed is the best way to help save your vision.

Types of Medicated Eye Drops

Your doctor may prescribe one or more type of eye drop. Some of the most common ones include:

• Prostaglandins. These help reduce the pressure in your eye and increase the flow of fluid out of the eye.

• Beta blockers. Beta blockers help decrease the pressure in the eye and how much fluid is made in the eye.

• Alpha-adrenergic agonists. With this type of eye drop, you can increase the flow of fluid out of the eye and reduce how much fluid is made in the eye.

• Carbonic anhydrase inhibitors. These are used to reduce how much fluid is made in the eye. These types of eye drops are not used very often.

• Miotic or cholinergic agents. Using this type of eye drop helps increase the flow of fluid out of the eye.
   

If you have a family history of glaucoma or are noticing problems with your vision, contact your ophthalmologist immediately for an appointment. He or she can help diagnose your vision problem and suggest appropriate treatment options.

The cognitive differences of special needs children and adults are well-documented, but vision issues often receive less attention. People with special needs have the same range of vision issues as their neurotypical counterparts; however, these vision problems occur at a much higher rate in special needs populations. Involving optometrists in your loved one’s care team allows their vision issues to be addressed alongside cognitive, behavioral, and other issues.

What Special Needs Populations May Have Additional Vision Issues?

Although many people with special needs have perfect eyesight, it is important to receive a comprehensive eye exam to rule out potential problems that may contribute to learning or behavioral difficulties. The following populations are at increased risk of vision problems requiring special treatment:

• Down Syndrome. More than half of kids and adults with Down Syndrome have some form of eye problems, including tear duct abnormalities, early age cataracts, accommodative dysfunction, or strabismus (eye misalignment).

• Autism spectrum disorder. A diagnosis ranging from Asperger’s syndrome to severe neurobehavioral problems, children with autism spectrum disorder display a range of cognitive and behavioral difficulties. Behaviors such as poor eye contact, sensitivity to light, atypical reactions to visual stimuli, or looking through or beyond objects are common. Some of these behaviors may be due to direct vision problems, such as problems with focusing or relaying visual messages to the brain.

• Fragile X. Individuals with Fragile X, a genetic disorder that more often impacts boys, may have difficulty with hand-eye coordination, spatial awareness, and visual sequencing. These vision issues often lead to learning difficulties.

• Premature birth. Children born prematurely may have difficulty with vision or visual processing. A thorough eye exam can diagnose subtle vision problems that impact typical development
   

Vision Therapy for Special Needs

After careful diagnosis of eye disorders, your optometrist can recommend a range of treatment options to correct vision problems. In some cases, simply using corrective lenses can improve visual acuity and attention. For other individuals, vision therapy may be needed.

Vision therapy retrains the eyes and brain to react differently to visual stimuli. For example, someone with hand-eye coordination difficulty might practice reaching, grasping, and following objects visually. Vision therapy typically includes in-office sessions to master key skills, followed by at-home practice exercises. Successful vision therapy may significantly improve visual attention and positively impact overall learning ability in those with special needs.

Accurate vision involves much more than good eye health. The brain integrates signals from the eyes with information from the motor, balance, and auditory systems to create an accurate view of the world. Following traumatic injury, one or more components of this complex system may be damaged. Receiving a thorough vision assessment following a traumatic injury can speed treatment of visual deficits as well as overall recovery.

Anatomy of the Visual System

Vision begins when light enters each eye, stimulating cells on the back of the eyeball. These signals are summed and sent through the optic nerve extending from the back of each eye. The optic nerves cross over to the opposite side of the brain before relaying visual information to the occipital lobe, found in the very back of the head. Here, visual information undergoes more complex processing to identify objects, see movement, and visualize color. Damage to any part of this pathway -- from direct trauma to the eyes themselves to head injury -- may disrupt accurate visual processing.

Potential Vision Problems Following Traumatic Injury

Depending on the part of the head affected, a variety of vision problems may arise following a traumatic injury. Some common issues include:

• Visual acuity. Some individuals may experience nearsightedness (poor distance vision), farsightedness (poor close vision), or other issues with visual acuity following injury. These are most often treated using corrective lenses.

• Loss of visual field. Sometimes, a person may lose ability to see out of an entire quadrant or half of the visual field.

• Double vision (diplopia). Double vision often occurs after injury, affecting almost all everyday activities.

• Visual alignment. When the eyes turn inward, outward, up, or down, you may have difficulty fixating on an object, smoothly tracking moving objects, or scanning.

• Visual-motor integration. Loss of eye-hand or eye-body coordination often leads to difficulty performing everyday tasks.

• Visual-auditory integration. The visual and auditory systems communicate constantly. Injuring this system impairs ability to associate what is seen with what is being heard at the same time.
   

Treatment Options

While certain vision problems can be easily treated with corrective lenses, others may require vision therapy. A vision therapist will work with you to practice skills to improve coordination of eye signals with behavioral responses. Although some visual skills take months or even years to fully recover, practicing daily improves the likelihood of a full recovery.

The name conjures up pain, but ocular migraines are less about headaches and more about a vision problem. Ocular migraines are temporary visual disturbances that can last up to 30 minutes. This condition can affect one eye or both eyes simultaneously. An ocular migraine does not typically cause pain unless accompanied by a migraine headache.
 

Ocular Migraine Symptoms

Multiple visual symptoms can signal an ocular migraine attack. Ocular migraines can appear suddenly and distort your field of vision like a cracked mirror or window. It is frightening, but the symptoms usually disappear within a half-hour.

A small blind spot will appear, often surrounded with flickering lights and wavy lines surrounding the perimeter of the spot. The blind spot will enlarge and sometimes moves across your field of vision during the ocular migraine attack.

Ocular migraine sufferers can also experience prodromes that develop days or weeks before an attack. Prodromes can cause mood swings, food cravings, and sluggishness.
 

Ocular Migraine Causes

Many things that trigger migraine headaches are also root causes behind ocular migraines. If you have a family history of suffering from migraine headaches, your chances are much higher for struggling with ocular migraines.

Changes in blood flow to the brain occur while suffering from an ocular migraine. These migraines are triggered by a build-up of inflammation around the nerves and blood vessels in the brain and the rest of the head.

Middle-aged adults are the most common migraine sufferers. Women are three times more likely than men to suffer from migraines.

Common migraine triggers include cigarette smoke, perfume, bright or flickering lights, sleep deprivation, and stress. Certain foods can also be a problem including cheese, caffeinated drinks, red wine, chocolate, smoked meat, and artificial sweeteners.
 

Ocular Migraine Treatments

Since ocular migraines cause no pain and typically disappear within a half-hour, there is no specific treatment required for this eye condition.

If you are driving, reading or performing a task that requires good vision, stop the activity and relax during an ocular migraine attack. Resume your activity once your vision returns to normal. If it is accompanied by a migraine headache, visit your eye care professional to get an eye exam and discuss some treatment options.

Keep a log of your diet and activities to help you identify ocular migraine triggers. This will help you know what foods to avoid consuming and activities to avoid doing in the future.

Of our five senses, humans rely on vision most strongly. Our everyday experience of the world is colored by our ability to see, our memory draws heavily upon visual information, and many activities of daily living are challenging without sight. As a result, it is essential to protect your eyes from damage. Regular visits to an eye care provider allow you to receive a professional eye exam that checks for damage due to inadequate eye protection.
 

Eye Strain

Americans are spending more time than ever in front of screens. From checking email on smartphones to staring at a computer screen in your office to watching TV in the evenings, too much screen use can cause eye strain. Experts recommend taking at least five minutes per hour to relax your eyes and alleviate strain. Go for a brief walk or focus on distant objects to reduce eye strain before returning to the task at hand.
 

Dust, Wind, and other Environmental Stressors

It is easy for eyes to become damaged by windy conditions, blowing dust, air pollutants, and other small particles in the air. When facing dusty or windy conditions, eye drops or safety glasses can protect your eyes from damage. Contact wearers should opt for glasses to prevent particles from irritating the surface of your eyes. Whenever possible, stay indoors on very windy or dusty days to prevent eye damage. If your eyes become very irritated, visit the eye doctor for a thorough optometry exam and treatment recommendations.
 

Sun Protection

Everyone knows that UV rays cause sunburns, but did you know that UV exposure damages your eye tissue as well? Lengthy, intense exposure to UV rays may increase your risk of macular degeneration, cataracts, and other eye conditions that affect your vision. To stay safe, find a pair of sunglasses that block 100% of UVA and UVB rays. Darker lenses or more expensive styles do not always translate to better UV protection. When possible, choose wrap-around styles that do not let light in from the side. Sunglasses are not just for summertime or bright days -- UV damage can occur year-round and can be especially bad during the wintertime when sunlight reflects off of ice and snow.

In general, the best policy is to avoid taking chances with your eye health. Wear proper protection when heading outside, playing sports, and working with dangerous tools or chemicals. Your eyes are designed to last a lifetime; treat them well, and you can avoid major vision problems that affect everyday life.

Macular degeneration represents one of the most significant causes of vision loss in older adults. According to the Centers for Disease Control and Prevention, an estimated 1.8 million people currently suffer from macular degeneration, with an additional 7.3 million people at risk of developing this condition. Understanding the causes of and treatments for macular degeneration allow you to receive the optometry care needed to curb the incidence and progression of this disease.
 

What Is Macular Degeneration?

Dry macular degeneration is a chronic eye disease in which the macula, a portion of the retina, deteriorates. When light enters the eye, it hits the retina, which lies on the back of the eyeball. Neural signaling from cells in the retina allows us to see clearly. If the macula degenerates, it cannot transmit visual signals to the brain, leading to blurred vision or a blind spot in the central portion of the visual field. A less common form of the disease, called wet macular degeneration, occurs when blood vessels behind the retina leak fluid, causing changes in central vision.
 

Curbing Macular Degeneration

Certain characteristics put individuals at a higher risk of developing macular degeneration. Being Caucasian, growing older, and having a family history of macular degeneration are strong risk factors outside of your control. Other risk factors, such as obesity, smoking, poor diet, cardiovascular disease, and high cholesterol can be modified through lifestyle change.

To prevent macular degeneration, optometrists recommend incorporating healthy fruits and vegetables into your diet, reducing caloric intake to manage your weight, quitting smoking, increasing physical activity, and reducing your consumption of saturated and trans fats to lower your cholesterol. Your doctor can help you construct a healthy diet and lifestyle plan to reduce your risk.

Currently, dry macular degeneration is irreversible. However, it often progresses slowly and certain treatments may reduce the rate of progression. Annual visits to the optometrist to receive an eye exam are essential to monitoring the condition. Your eye doctor may recommend taking supplements, as high levels of vitamins A, C, and E as well as zinc and copper may reduce the progression of macular degeneration. Increasing your intake of omega-3 fatty acids and lutein may also help, although more research is needed to confirm the efficacy of these treatments.

Treatment for wet macular degeneration may include injection of prescription medications, photodynamic therapy, or laser treatment to destroy abnormal blood vessels and prevent new vessel growth. In very advanced cases of macular degeneration, an optometrist may recommend surgery to implant a telescopic lens in one eye.

Sources:

American Health Assistance Foundation (2012). Macular degeneration research: About macular degeneration.
Mayo Clinic (2012): Macular degeneration.