What is Glaucoma?
Glaucoma is permanent damage to the main nerve of the eye. The damage is usually from excessive pressure inside the eyeball. The excess pressure is rarely felt by the patient. Vision is not noticeably affected until 75% of the nerve is dead, but it is important to begin treatment earlier. Lowering the pressure prevents additional damage. Additional permanent damage occurs every day that the pressure is too high. Vision is protected if treatment is begun before damage is severe, and if the pressure is consistently kept low enough. It is important to continue taking medication, so refill your glaucoma prescription before the medicine runs out!
What raises the pressure?
The inside of the eye is nourished by a clear fluid (not the tears) which is constantly being produced. If the drain for this fluid flows poorly, the pressure inside the eye will become excessive.
Why does the fluid drain poorly?
Like a sink, poor drainage can be due to a blocked opening (like a drain plug in sink) or clogged pipes (like grease and hair in sink). An anatomic abnormality can cause the iris to block the drain. Clogged pipes are often due to genetics or aging. High caffeine intake may aggravate pipe flow, but diet does not otherwise seem to affect glaucoma. Physical fitness tends to improve the pipe flow. High blood pressure aggravates glaucoma, but very low blood pressure can also worsen glaucoma.
What do open, closed, and narrow angle mean?
The drain opening of the eye is called the “angle”, so “closed angle glaucoma” means the opening is closed off; “open angle glaucoma” means the opening is clear but the pipes are clogged. “Narrow angle” mean the iris (the colored part around the pupil) is like a drain plug which is almost, but not quite, plugging the opening.
How is glaucoma diagnosed?
Specialists usually diagnose glaucoma by looking directly at the nerve for signs of damage. Visual field (side vision) tests help judge the amount of damage; these tests do not become abnormal until about 1/3 of the nerve is dead. Patients first notice reduced peripheral vision when the nerve is 3/4 dead. Glaucoma does not affect sharpness of vision until the nerve is mostly dead.
Glaucoma usually cannot be diagnosed just by measuring the pressure. Why? The nerve’s susceptibility to pressure damage depends on the structural strength of the nerve and the quality of its blood supply. So, a pressure that is too high for one person may be OK for another.
Pressure readings sometimes need adjustment. Pressure is measured from the force required to flatten a small part of the cornea. If the cornea is thin, the pressure will seem lower than it really is; if the cornea is thick, the pressure will read falsely high. The thickness must be measured by ultrasound to calibrate the reading.
How is glaucoma treated?
By lowering the pressure. For many patients, reduction to 15 is a good target. If the nerve damage is mild, 18 may be adequate; if damage is severe, 10 may be better. If pressure before treatment was teens, reduction by half is a good target. In some glaucoma patients who have normal eye pressure before treatment, improving blood flow to the nerve is as important as lowering eye pressure. Blood flow can be improved by opening constricted blood vessels (in patients with migraines or Raynaud’s syndrome) or by raising blood pressure if it is low.
How do we know if the pressure is low enough?
3-D photographs record the appearance and contours of the nerve. Increasing hollowness of the nerve indicates ongoing damage requiring lower pressure. Visual fields and nerve fiber layer measurements are repeated about yearly. If they worsen, greater pressure reduction is needed.
Do food and exercise affect eye pressure?
Caffeine can raise eye pressure, so don't drink more than 2 cups of coffee per day. Eye pressures tend to be higher in obese people who require treatment for high cholesterol and high blood sugar. So physical activity and healthy food are important. Eat mainly plants (fruits, vegetables) and whole grains. Avoid food that is processed or fried. If you eat animals, choose wild, free range and grass fed animals. (Animals that have been fed an unnatural diet of corn and other grains tend to have unhealthier fats: too much omega-6, not enough omega-3; too many unhealthy fats, and too little stearol. Free range chickens that eat grass and bugs lay eggs with healthier pigments (more orange yolk) -- those pigments reduce the risk of macular degeneration.
How is pressure reduced?
By drops, laser or surgery. Eye drops are usually taken once or twice daily. If the drops are discontinued, the pressure will return to a higher level, so it is important to refill medication before the bottle is empty. Two or three separate bottles may need to be taken each day to reduce pressure sufficiently. If more than one bottle is being used, it helps to wait at least 5-10 minutes between different medications; otherwise, one medication will wash away the other. Also, doses of medication prescribed twice daily should be taken roughly 12 hours apart. To prevent bacterial contamination, avoid touching the bottle tip to the lashes, lids, eye or anything else. One good way to instill drops is to lie down flat; look straight up at ceiling; bring the bottle directly above your eye; squeeze, and drop will fall straight down into your eye.
The two common glaucoma laser treatments (trabeculoplasty and iridectomy) are very safe. Laser trabeculoplasty lowers pressure by improving flow through the drain channels for patients with clogged pipes (open angle glaucoma). The effect usually lasts for years; the treatment can be repeated. Laser trabeculoplasty usually lowers the pressure about as much as one bottle of drops. Often, laser trabeculoplasty is combined with long term use of medications for best pressure control.
Laser iridectomy is a preventive treatment for patients with narrow angles. It does not lower the pressure, but prevents the pressure from rising in the future. The iris is permanently shifted away from the drain, so that the iris will not block the opening.
If medications and laser are insufficient, surgery will usually lower the pressure.
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. A cataract can occur in either or both eyes. It cannot spread from one eye to the other.
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 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 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. 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 should I do if I have a red eye?
If you had glaucoma surgery and develop a red eye, call the office immediately. This may mean you have a serious eye infection that needs emergent attention. If the white part of your eye is bright red without any trauma to it, pain or change in vision, then you probably have subconjunctival hemorrhage. It can happen after you cough, sneeze or strain. A small capillary blood vessel broke and caused a small hemorrhage. It will resolve without any intervention. If the white part of your eye appears pink with discharge, you may have an infection and require antibiotic treatment. Call the office and arrange for an appointment if you are uncertain.
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.
Dry eye symptoms may include any of the following:
stinging or burning of the eye;
a sandy or gritty feeling as if something is in the eye;
episodes of excess tears following very dry eye periods;
a stringy discharge from the eye;
pain and redness of the eye;
episodes of blurred vision;
inability to cry when emotionally stressed;
uncomfortable contact lenses;
decreased tolerance of reading, working on the computer, or any activity that requires sustained visual attention;
Following are suggestions to avoid dry eye symptoms:
Use artificial tears, gels, gel inserts, and ointments - available over the counter - as the first line of therapy. They offer temporary relief and provide an important replacement of naturally produced tears in patients with aqueous tear deficiency. Avoid artificial tears with preservatives if you need to apply them more than four times a day or preparations with chemicals that cause blood vessels to constrict.
Wearing glasses or sunglasses that fit close to the face (wrap around shades) or that have side shields can help slow tear evaporation from the eye surfaces.
Indoors, an air cleaner to filter dust and other particles helps prevent dry eyes.
A humidifier also may help by adding moisture to the air.
Avoid dry conditions and allow your eyes to rest when performing activities that require you to use your eyes for long periods of time. Instill lubricating eye drops while performing these tasks.
What are the different types of eye pain?
There are many different kinds of eye pain. It may feel like something is stuck in the eye (foreign body sensation) or sharp pain that lasts for a very short time. You may have dry eye or blepharitis, which is an inflammation of the eyelids. You can try using a few drops of artificial tears to rinse and moisturize the eye. If it is blepharitis, you can use warm compress to clean the eyelids followed by light scrubbing. If the eye pain feels like burning, it may also be dry eye. If it burns and your eye is pink, with discharge, you may have conjunctivitis and that will require medical attention. If the eye is sensitive to light, redness and aches, you may have iritis or endophthalmitis. Endophthalmitis is a medical emergency and requires treatment by the doctor.