Eye Care:
Hauser-Ross Eye Institute
How do your eyes work?
What keeps your eyes parallel?
About Cataract Surgery
Diabetes And Vision
Dry Eye Syndrome
Macular Degeneration
Flashes and Floaters
The Work of the Eyes. Have You Ever Wondered . . .
How do the eyes work? What keeps the eyes parallel, even when they move? How does the brain put images from both eyes together? These are questions people commonly ask about the work of the eyes. To understand these questions, it's important to think of the parts of the eyes as members of a "vision team" performing separate tasks while working together to create the images that we see every day.
How Do Your Eyes Work?
...much like a camera, by focusing light rays to for an image.
1. Cornea - The clear cover at the front that lets light in.
2. Iris - Colored ring that opens and closes to adjust amount of light entering the eye.
3. Pupil - Hole in iris, through which light enters the eye.
4. Lens - Transparent structure that focuses light rays on the retina.
5. Ciliary Muscles - Muscles inside the eye that change the lens's shape to focus images on the retina.
6. Retina - Lining at the back of the eyeball that receives the images focused by the lens.
7. Optic Nerve - Nerve at the back of the eye that transmits images from the retina to the brain.
What Keeps Your Eyes Parallel, Even When They Move?
Six muscles are attached to the outside of each eyeball. These muscles, with the help of the brain, maintain proper eye alignment. Each paired set of muscles is balanced, keeping eyes parallel. Each set works as a team: one pair pulls while another pair relaxes. The muscles turn the eyes in all directions and keep them parallel at the same time.
How Does The Brain Put The Images From Both Eyes Together
1. Each eye looks at the same object at the same time.
2. Each eye sees the object from a slightly different angle and sends a slightly different image to the brain.
3. The brain is able to blend the two very similar pictures into one -- a process called fusion.
Fusion Allows Us To . . .
1. Perceive one image from the two sent by the eyes
2. Perceive the image as having depth
3. Judge the relative distance between things
The Work Of The Eyes: A Study In Teamwork
The ability of the eyes to see well is the result of amazing coordination. In healthy eyes, muscles work in tandem to keep the eyes straight and balanced as well as to make them turn together in any direction. The pupil and the ciliary muscles attached to the lens control the entry and focusing of light rays. The retina registers the focused image, which passes via the optic nerve to the brain. The brain fuses, or blends, the images sent by each eye into on three-dimensional image.
All these members of the vision team work automatically, without our conscious effort. All of them are needed if we are to see as well as nature intended.
The YAG Laser Story
Can Cataracts Grow Back?
If you've had cataract surgery, you probably remember the excitement you felt as you steadily recovered your vision. Your world suddenly became more vivid and colorful. You probably started enjoying things that your poor vision had denied you.
But lately, have you noticed a steady decrease in your vision? You may have a secondary cataract. Cloudy vision as a result of a secondary cataract can easily be corrected with the YAG laser.
Cataract Surgery
To understand why your vision can become cloudy after surgery, you must first understand cataract surgery. A cataract is a clouding of the lens of the eye. Cataract surgery can best be explained when the lens of the eye is compared to a grape. The cataract has a front peel, a pulp and a back peel. During surgery the front peel and the pulp of the cataract are removed and the back peel is left in place. The lens implant is positioned in front of the back peel, which may be used to support it.
Cloudy Vision
Sometimes the back peel of the cataract becomes cloudy. This is called a secondary cataract. Many people who experience this describe it by saying, "My cataract grew back." What has really happened is that your vision has become blurry again because the back peel of the cataract has clouded. Making an opening or window in the center of this cloudy membrane allows you to see clearly again, the way you did after your cataract surgery. How is this achieved? The YAG laser is the answer.
Vision Restored
YAG laser light creates a hole in the membrane with no need for a knife. This laser surgery, known as a YAG laser posterior capsulotomy, requires no anesthesia other than eye drops.
We perform the procedure on an outpatient basis in our surgicenter. Bursts of YAG laser energy vaporize the center of the cloudy membrane and restore your vision within minutes. Since the laser energy enters the eye without cutting it from the outside there is no risk of infection.
Like any surgical procedure, however, there are possible side effects. The eye may develop a rise in pressure. There may be an increased chance of retinal detachment. Pre-existing retinal diseases such as macular degeneration may limit your vision after the treatment.
If your vision has decreased since you had cataract surgery, we recommend that you have a complete eye exam. The YAG laser may be your key to improved vision.
Remember . . .
If you have had cataract surgery and your vision becomes cloudy again, you may have a secondary cataract.
Secondary cataracts occur when the back peel of the lens, which is left in place after surgery, becomes cloudy.
With YAG laser surgery vision blurred by secondary cataracts can be restored in minutes with no needles, no stitches, and no healing time.
If your vision has decreased since your cataract surgery, we recommend you have a complete eye examination.
Diabetes And Vision
Diabetes is a disease, which, over time, affects many areas of the body, including the eyes. Diabetic retinopathy occurs when the damaging effects of diabetes have reached the retina of the eye. Most diabetics will develop some form of diabetic retinopathy, making this condition the leading cause of blindness in the world.
The retina is nourished by blood vessels. Diabetic retinopathy weakens these vessels, causing blood to leak into the retina, which swells and results in vision loss. The retina can also develop abnormal vessels and scar tissue, causing it to function improperly. These vessels are weak and often leak blood, which causes loss of vision.
Preventing Blindness
Diabetic retinopathy is a 'silent' disease, showing no symptoms in its early stage of progression. Vision loss occurs in later stages of this eye condition. Laser treatment is successful in slowing the progression of the disease by sealing or cauterizing sources of leakage.
The key to controlling diabetic retinopathy is by having yearly, dilated eye exams to look for and treat diabetic changes before they cause symptoms.
Dry Eye Syndrome
A disease that affects people of all ages, Dry Eye Syndrome is characterized by eyes that have a burning, itchy, gritty sensation.
Normally, tears keep the eye moist and comfortable. Sometimes, however, the eye stops producing tears, resulting in dryness and irritation.
When the eyes are dry they can become so uncomfortable that it may be painful to keep them open. But, for some people, the eyes become watery as other glands in the eye overproduce fluids to compensate for inadequate tears.
There are many causes of Dry Eye Syndrome, ranging from the aging process to the environment. Cigarette smoke, lack of humidity and certain medications can also cause or aggravate Dry Eye Syndrome.
An Inside Look At Dry Eye
Three very thin layers make up the healthy tear film that coats and protects the eye. They ensure that tears do not evaporate. When tears lack any of these components or when too few tears are produced, the tear film breaks down.
This breakdown results in dry spots in the cornea, causing the symptoms associated with Dry Eye Syndrome -- grittiness, burning, itchiness and general discomfort of the eye.
Treating The Syndrome
Various types of treatment are available to relieve the symptoms associated with Dry Eye. Artificial tear solutions are usually recommended for individuals with mild to moderate cases. Many different brands are available and can be purchased without a prescription.
More severe cases of Dry Eye Syndrome may warrant laser treatment. The laser can alleviate pain and dryness by sealing the tear drainage system in the eye. This causes natural tears to remain in the eye longer, reducing irritation and discomfort.
Before recommending laser treatment, we will perform a Punctual Occlusion Therapy Test. This simulates laser treatment to help you decide if it is appropriate for you.
Watch Out For These Conditions
Dry Eye Syndrome may be caused by any number of factors, including the natural aging process, allergies, vitamin A deficiency, or drugs and medications such as antihistamines, decongestants and diuretics.
Your environment can also affect the moisture of eyes. You can help your eyes by avoiding air-conditioned rooms, hot air vents, pollutants (cigarette smoke, oven cleaners and other harsh chemicals), and by using a humidifier. Protect your eyes from sun, wind and swirling debris.
If you are experiencing any of the symptoms associated with Dry Eye Syndrome, we recommend you have an eye examination.
Remember . . .
1. If your eyes are burning, itching, irritated or feel gritty, you may have Dry Eye Syndrome.
2. Dry Eye Syndrome affects all ages and its causes are varied - such as environment, medications and age.
3. There are many effective treatments today. If you suspect you have Dry Eye Syndrome, we recommend you have an eye examination.
Macular Degeneration
The macula is the fine vision center of the retina in the back of the eye. Providing central vision, the macula is essential for many daily activities such as driving, reading and sewing. As we age, the macula can begin to break down or degenerate, resulting in blurred or distorted central vision. Macular degeneration is one of the most common causes of legal blindness in adults over age 60.
Types of Macular Degeneration: Wet Vs. Dry
Sometimes tiny blood vessels begin to grow under the macula. If these vessels leak, blood can drain into the fine vision center of the macula and impair vision. Laser treatment can halt vision loss by sealing the leaking blood vessels. Photodynamic therapy (PDT) is a new technique used to treat "wet" macular degeneration. Combining laser treatment with light-sensitive drugs can stabilize or improve vision.
The "dry" form of macular degeneration is usually evident as a loss of pigment from the macula, resulting in gradual central vision loss. The progression of this form of macular degeneration is often slowed when patients take multivitamins rich in vitamin E, zinc and copper.
Protecting Your Vision
Early warning signs of macular degeneration can be best detected with an Amsler grid. Look for changes in the lines of the grid (distorted, blurry, missing pieces) and contact your eye care provider immediately when changes occur.
Flashes and Floaters
Floaters are common eye symptoms that occur as the eye ages. If you've ever seen "bugs", specks, faint strings or flashes of light in your field of vision, you've experienced floaters and flashes.
Generally these phenomena are harmless. Floaters, however, that appears suddenly as a cloud of dark spots or a spider web, especially when accompanied by flashes of light, may signal a torn or detached retina. This is a serious eye problem and can lead to vision loss. If you experience these symptoms, it is important to see an ophthalmologist as soon as possible.
How Floaters Occur
Floaters are actually tiny particles that float around within the eye. Usually they are the result of changes in the vitreous gel, which fills the large middle portion of the eye.
The vitreous is a clear, jelly-like material, which changes with age. During childhood it is solid like gelatin. As we age, the vitreous begins to liquefy.
Sometimes when the vitreous ages and becomes more liquid, a sudden collapse of the gel occurs. This collapse or vitreous separation causes microscopic particles to "float" within the eye, casting tiny shadows on the retina. We see these as specks or webs depending on their shape.
Floaters Can Signal Retinal Problems
Occasionally floaters signal a more serious eye problem, such as a retinal tear. The retina is a very fragile membrane that lines the inside of the eye, coming in direct contact with the vitreous. The vitreous and retina attach to each other in places. As the vitreous separates, it can pull on the retina at these attachments and cause it to break or tear, especially if the retina has weak spots.
When a tear is present, fluid from the vitreous leaks under the retina and separates it from the underlying layer in the eye. When this happens, the retina ceases to work, resulting in loss of vision.
What about harmless flashes and floaters? Will they ever go away?
Flashes may persist for several months and may occasionally last close to a year. They are caused by the movement of the collapsed vitreous within the eye and are most apparent in the dark.
Floaters may gradually diminish as time goes by, but they will not go away completely. They are most apparent against a light background. Lowering the lights while reading can help.
If you experience flashes or floaters, we recommend you have an eye examination.
An Eye Exam Is Your Best Assurance
Not everyone who has floaters develops a retinal tear. About 1 in 10 who experience a shower of floaters and flashes of light will have a tear. The sudden appearance of a cobweb type floater by itself is only rarely associated with a torn retina, but still needs to be evaluated. Early detection and treatment of retinal tears can prevent vision loss.
Watch Out For These Conditions
1. Floaters are the specks, "bugs", and threads that dart in and out of your field of vision.
2. Floaters occur as the eye ages, and while annoying, are usually harmless.
3. Floaters that appear suddenly or are accompanied by flashes of light can signal a retinal tear or detachment.
4. Early diagnosis of retinal tears and detachments can lead to early treatment and may prevent vision loss.
