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Eye Image

Every morning, we open our eyes and become immersed in a wealth of visual information. The eyes and related brain structures are a complex system that allows us to experience visual information from the surrounding world. It is easy to take clear vision for granted, but even subtle changes in the structure or functioning of the eyes can disrupt our sight. An eye care provider conducts a thorough eye exam to ensure that these components are functioning together well.

Basic Eye Anatomy
The eyeball is not a single, spherical structure as is commonly thought. It consists of a smaller, curved portion called the cornea that attaches to a larger, roughly spherical structure called the sclera (the white of the eye). The eyeball is filled with a jelly-like substance called the vitreous fluid.
Toward the front of the eye are three essential structures: the iris, pupil, and lens. The iris is the colored part of your eye. It can open and close to determine how much light to let in through the pupil, the black hole in the center of your eye. Finally, the lens is a flexible, convex structure that changes shape to direct light rays in different directions within the eye.
At the back of the eyeball is a layer of tissue called the retina. The retina consists of millions of photosensitive cells that react to certain types of light. Cone cells are clustered toward the center of the retina, and react to colors and details in bright light. Rod cells, which are spread toward the periphery of the retina, react to dim lighting conditions.

How the Eyes Facilitate Vision
When light enters the eye through the pupil, it passes through the lens, which changes shape to ensure that the light rays hit the retina. When the light rays reach the back of the eye, it stimulates the rod and cone cells to fire. Cone cells detect fine details and color in the center of your visual field. Rod cells detect edges in peripheral vision and allow us to perceive shapes in dim light.
The rods and cones in your retina convert light energy into electrical signals, which exit the eye through the optic nerve, located just below the center of the retina. The optic nerve carries visual information to the occipital cortex in the very back of your brain, where it is processed to result in a rich visual experience.
If any part of this complex arrangement functions improperly, vision is impaired. Thus, it is essential to receive regular optometry exams to have your eye structures and visual abilities checked.
Sun Image

Optometry warnings about the damaging effects of ultraviolet radiation on our eyes have not yet reached the degree of public awareness of that of skin damage. Yet, the sun can be just as damaging upon our eyes with unprotected exposure. Short-term exposure to very bright sunlight can result in a type of sunburn to our eyes regardless of the season. Photokeratitis -- also known as "snow blindness" and "flash burns" -- is a sunburn to the eye's cornea and conjunctiva, the membranes lining the eyelids and the outermost lining of the eye. Like a skin sunburn, the initial inflammation, pain and redness can last up to 48 hours before subsiding. Treatment such as cold cloths over the eyes and an over-the-counter anti-inflammatory medication can help relieve some of the painful symptoms, but the best treatment is prevention best obtained by wearing sunglasses and a hat with a brim.

The Damage Adds Up
One day on the beach and a couple of days of sore eyes doesn't seem like much, but eye care providers warn that the effect is cumulative and the damage increases with every day of unprotected overexposure. Long-term damage goes beyond crow's feet from squinting in the bright sunlight. Years of unprotected exposure to the sun can result in increased chances of cataracts, damage to the retina, macular degeneration, cancer of the eye itself and cancer of the eyelid. Pterygium, a recurring condition where the conjunctiva grows over the cornea to restrict vision, requires repeated surgeries to keep in check is also common.

Not All Sunglasses Are Equal
Any pair of sunglasses is better than wearing none at all, but not all sunglasses provide the same degree of protection to the eye. Ask your eye care provider for recommendations to fit your lifestyle and your budget.
Protection Image

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.
Eye Conditions Image

The human visual system is an amazing network of anatomical structures. Even minor changes in the structure or function of a component of the eye can significantly affect visual acuity. Because we rely so heavily on our visual system to receive and process information, it is essential to keep the eyes functioning properly. Visit your eye care provider regularly for a vision check-up to ensure any of these common eye conditions are diagnosed and treated properly.

Dry Eye
Dry eye is a highly common -- and vexing -- eye condition. Dry eye develops when your eye no longer produces an appropriate tear layer. Tears lubricate the surface of the eye, protect against infection, and ensure clear vision. Dry eye can be associated with age, environmental irritants, certain medications, and medical conditions such as diabetes, thyroid problems, and rheumatoid arthritis. An eye care provider may recommend medications, dietary changes, or surgery to rectify the problems associated with dry eye.

Astigmatism
If the cornea, the front part of the eyeball, is shaped incorrectly, light does not focus properly on the retina. This leads to blurred vision regardless of the distance you are from an object. Although most people have a slight amount of astigmatism, it becomes problematic when it causes visual distortions, blurred vision, headaches, or eye discomfort. Fortunately, astigmatism is easily corrected by prescription glasses or contacts.

Low Vision

Many people do not have perfect 20/20 vision. When their visual deficits cannot be improved with the best possible glasses, individuals are considered to have low vision. Low vision may be associated with severe medical conditions or trauma to the eye. An optometry exam can identify cases of non-correctable low vision and options for low vision care.

Cataracts
As your eyes get older, the lens of your eye may become cloudy. By age 80, nearly half of individuals develop some lens clouding, referred to as cataracts. Cataracts can also form through genetic disorders or other medical conditions. Symptoms include blurred vision, changes in colored vision, poor night vision, or double vision. The early symptoms of cataracts can be reduced by changes in lenses or lighting conditions. In later stages, surgical removal of the cataract may be warranted.

Glaucoma
Glaucoma does not refer to damage to the eyeball itself, but rather to the optic nerve that carries visual information to the brain. Changes in eye pressure may constrict the nerve, causing glaucoma. Medicated eye drops are a common treatment, but surgery may be necessary in severe cases.
If you experience any change in vision, visit an eye care provider immediately. An eye exam is essential to monitoring eye health, preserving your vision for life.
Intricate and complex, the eyes take in and process light and communicate information to the brain through electronic impulses. Several diseases and conditions - viral, bacterial, and genetic - affect the eyes and their ability to function properly. Any sign of unusual eye symptoms should prompt a visit with an eye care professional.

Cytomegalovirus (CMV) Retinitis
Associated with acquired immunodeficiency syndrome (AIDS), this disease also affects people whose immune systems have been compromised for other reasons like chemotherapy or bone marrow transplant. The virus invades the retina and damages photoreceptor cells, causing floaters, blurry vision, flashes, and/or decreased peripheral vision. Left untreated, CMV retinitis leads to detached retina and blindness.

Keratoconus
An eye condition in which the cornea thins, weakens, and loses its normal round shape, keratoconus causes astigmatism and nearsightedness. Though the exact cause is not yet known, research has shown that an imbalance in enzymes within the cornea might cause keratoconus. No cure exists for keratoconus, but effective methods of treatment which slow its progression and reduce symptoms have been developed.

Fuchs' Corneal Dystrophy
An inherited disease, Fuchs' corneal dystrophy causes endothelial cells which regulate fluid in the cornea to die. This leads to corneal edema (swelling). Symptoms include glare, blurred or distorted vision, painful blisters on the cornea, a cloudy or hazy cornea, corneal swelling, and corneal thickening.

Macular Dystrophy
A genetic eye disorder, macular dystrophy damages the photoreceptor cells located on the macula (the center of the retina), leading to a loss of central vision. Central vision is used to look straight ahead and is necessary for activities such as reading, driving, and recognizing faces. There are two types of macular dystrophy: Best disease, which affects children, and adult onset macular dystrophy, which occurs in adulthood.

Retinitis Pigmentosa (RP)
A rare, inherited disease, RP causes the photoreceptor cells in the retina to progressively degenerate. This degeneration first narrows the field of vision and leads to decreased night vision. Eventually, photoreceptors deteriorate so extensively that the disease causes near blindness with only slight peripheral and a small area of central vision remaining.

Stargardt Disease
A form of inherited macular dystrophy which affects children and young adults, Stargardt disease is characterized by the death of photoreceptor cells on the macula (the center of the retina). Sufferers usually lose central vision while peripheral vision remains intact.