Andrew A. Dahl, MD, is a board-certified ophthalmologist. Dr. Dahl's educational background includes a BA with Honors and Distinction from Wesleyan University, Middletown, CT, and an MD from Cornell University, where he was selected for Alpha Omega Alpha, the national medical honor society. He had an internal medical internship at the New York Hospital/Cornell Medical Center.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
Glaucoma is the term applied to a group of eye diseases that gradually result
in loss of vision by permanently damaging the optic nerve, the nerve that
transmits visual images to the brain. The leading cause of irreversible
blindness, glaucoma often produces no symptoms until it is too late and vision
loss has begun.
An elevation in the pressure within the eye (the intraocular pressure, or IOP) is
generally, but not always, associated with the development of glaucoma, although
additional factors are also likely to play a role in its development. The optic
nerve fibers inside the eye are damaged, resulting in vision loss that
begins in the peripheral fields of vision. Glaucoma usually affects both eyes,
but one eye may be more severely affected than the other.
Glaucoma is a disease of the major nerve of vision, called the optic nerve. The optic nerve receives light-generated nerve impulses from the retina and transmits these to the brain, where we recognize those electrical signals as vision. Glaucoma is characterized by a particular pattern of progressive damage to the optic nerve that generally begins with a subtle loss of side vision (peripheral vision). If glaucoma is not diagnosed and treated, it can progress to loss of central vision and blindness.
Glaucoma is usually, but not always, associated with elevated pressure in the eye (intraocular pressure). Generally, it is this elevated eye pressure that leads to damage of the eye (optic) nerve. In some cases, glaucoma may occur in the presence of normal eye pressure. This form of glaucoma is believed to be caused by poor regulation of blood flow to the optic nerve.
How common is glaucoma?
Worldwide, glaucoma is the leading cause of irreversible blindness. In fact, as many as 6 million individuals are blind in both eyes from this disease. In the United States alone, according to one estimate, over 3 million people have glaucoma. As many as half of the individuals with glaucoma, however, may not know that they have the disease. The reason they are unaware is that glaucoma initially causes no symptoms, and the subsequent loss of side vision (peripheral vision) is usually not recognized.
What causes glaucoma?
Elevated pressure in the eye is the main factor leading to glaucomatous damage to the eye (optic) nerve. Glaucoma with normal intraocular pressure is discussed below in the section on the different types of glaucoma. The optic nerve, which is located in back of the eye, is the main visual nerve for the eye. This nerve transmits the images we see back to the brain for interpretation. The eye is firm and round, like a basketball. Its tone and shape are maintained by a pressure within the eye (the intraocular pressure), which normally ranges between 8
mm and 22 mm (millimeters) of mercury. When the pressure is too low, the eye becomes softer, while an elevated pressure causes the eye to become harder. The optic nerve is the most susceptible part of the eye to high pressure because the delicate fibers in this nerve are easily damaged.
The front of the eye is filled with a clear fluid called the aqueous humor, which provides nourishment to the structures in the front of the eye. This fluid is produced constantly by the ciliary body, which surrounds the lens of the eye. The aqueous humor then flows through the pupil and leaves the eye through tiny channels called the trabecular meshwork. These channels are located at what is called the drainage angle of the eye. This angle is where the clear cornea, which covers the front of the eye, attaches to the base (root or periphery) of the iris, which is the colored part of the eye. The cornea covers the iris and the pupil, which are in front of the lens. The pupil is the small, round, black-appearing opening in the center of the iris. Light passes through the pupil, on through the lens, and to the retina at the back of the eye. Please see the figure, which is a diagram that shows the drainage angle of the eye.
Legend for figure: This diagram of the front part of the eye is in cross section to show the filtering, or drainage, angle. This angle is between the cornea and the iris, which join each other right where the drainage channels (trabecular meshwork) are located. The arrow shows the flow of the aqueous fluid from the ciliary
body, through the pupil, and into the drainage channels. This figure is
recreated from Understanding and Treating Glaucoma, a human anatomy board
book by Tim Peters and Company Inc., Gladstone N.J.
In most people, the drainage angles are wide open, although in some individuals, they can be narrow. For example, the usual angle is about 45 degrees, whereas a narrow angle is about 25 degrees or less. After exiting through the trabecular meshwork in the drainage angle, the aqueous fluid then drains into tiny blood vessels (capillaries) into the main bloodstream. The aqueous humor should not be confused with tears, which are produced by a gland outside of the eyeball itself.
This process of producing and removing the fluid from the eye is similar to that of a sink with the faucet always turned on, producing and draining the water. If the sink's drain becomes clogged, the water may overflow. If this sink were a closed system, as is the eye, and unable to overflow, the pressure in the sink would rise. Likewise, if the eye's trabecular meshwork becomes clogged or blocked, the intraocular pressure may become elevated. Also, if the sink's faucet is on too high, the water may overflow. Again, if this sink were a closed system, the pressure within the sink would increase. Likewise, if too much fluid is being produced within the eye, the intraocular pressure may become too high. In either event, since the eye is a closed system, if it cannot remove the increased fluid, the pressure builds up and optic-nerve damage may result.
Headaches can be divided into two categories: primary headaches and secondary headaches. Migraine headaches, tension headaches, and cluster headaches are considered primary headaches. Secondary headaches are caused by disease. Headache symptoms vary with the headache type. Over-the-counter pain relievers provide short-term relief for most headaches.
Diabetes mellitus is a chronic condition characterized by high levels of sugar (glucose) in the blood. The two types of diabetes are referred to as type 1 (insulin dependent) and type 2 (non-insulin dependent). Symptoms of diabetes include increased urine output, thirst, hunger, and fatigue. Treatment of diabetes depends on the type.
Sarcoidosis, a disease resulting from chronic inflammation, causes small lumps (granulomas) to develop in a great range of body tissues and can appear in almost any body organ. However, sarcoidosis most often starts in the lungs or lymph nodes.
Retinal detachment is the separation of the retina from its attachments to the underlying eye tissue. Symptoms of retinal detachment include flashing lights and floaters. Highly nearsighted young adults and those who've had cataract surgery are at higher risk for retinal detachment.
Marfan syndrome is hereditary condition affecting connective tissue. A person with Marfan syndrome may exhibit the following symptoms and characteristics: dislocation of one or both lenses of the eye; a protruding or indented breastbone; scoliosis; flat feet; aortic dilatation; dural ectasia; stretch marks; hernia; and lung collapse. Though there is no cure for Marfan syndrome, there are treatments that can minimize and sometimes prevent some complications.
Optic neuritis is inflammation of the optic nerve, the structure that connects the eye to the brain. The precise cause of optic neuritis is unknown, but it is thought to be a type of autoimmune disorder. Optic neuritis most commonly develops due to an autoimmune disorder that may be triggered by a viral infection.
A cataract is an eye disease that causes the eye's lens to become cloudy and opaque with decreased vision. Causes of cataracts include diabetes, hypothyroidism, certain genetic illnesses, hyperparathyroidism, atopic dermatitis, and certain medications. Symptoms and signs include a decrease in vision and a whitish color to the affected eye. Treatment depends upon the patient's specific visual needs and may involve cataract surgery.
Many common eye disorders resolve without treatment and some may be managed with over-the-counter (OTC) products. It's important to visit a physician or ophthalmologist is the problem involves the eyeball itself or the condition hasn't improved after 72 hours of use of an eye-care OTC product.
Birthmarks and other abnormal skin pigmentation is caused by the body's inability to produce enough melanin. Abnormal skin pigmentation can cause conditions such as vitiligo, pigmentation loss, melasma, albinism, port wine stains, macular stains and hemangioma.
Uveitis is inflammation of the eye. Symptoms include blurred vision, eye pain, eye redness, and floating spots before the eyes. Treatment may involve prescription eyedrops, antibiotics, and wearing dark glasses.
The most common cause of a black eye is due to an injury to the face or head. Most black eye injuries are minor and heal on their own, however, some may lead to significant injury. In addition to trauma to the face, cosmetic surgery can cause a black eye(s) as a side effect. People should be aware of the situations in which medical care should be sought immediately for a black eye.
Blindness is the state of being sightless. Causes of blindness include macular degeneration, stroke, cataract, glaucoma, infection and trauma. Symptoms and signs may include eye pain, eye discharge, or the cornea or pupil turning white. Treatment of blindness depends upon the cause of the blindness.
Iritis is inflammation of the iris, the colored portion of the eye. Symptoms include a red, painful eye, blurry vision, and light sensitivity. Treatment usually involves cortisone eyedrops.
Becoming infected with chickenpox during pregnancy could cause birth defects in your unborn child. Likewise, shingles could also cause problems for your unborn child. If you are pregnant and haven't had chickenpox, avoid exposure to infected people. Zostavax, the shingles vaccine, can reduce the incidence of shingles by half. Women should wait at least three months after receiving the vaccine before trying to get pregnant.
Diabetes and eye problems are generally caused by high blood sugar levels over an extended period of time. Types of eye problems in a person with diabetes include glaucoma, cataracts, and retinopathy. Examples of symptoms include blurred vision, headaches, eye aches, pain, halos around lights, loss of vision, watering eyes. Treatment for eye problems in people with diabetes depend on the type of eye problem. Prevention of eye problems include reducing blood pressure, cholesterol levels, quitting smoking, and maintaining proper blood glucose levels.
eye. Read about symptoms, signs, diagnosis, treatment, and prognosis.
Coats' disease is a rare eye condition that typically progresses to vision loss or blindness in one eye. Gradual vision loss is usually the first symptom, followed by a cloudy white or yellow pupil due to the presence of a cataract. Treatment focuses on limiting the blood vessel progression and may involve cryotherapy or laser photocoagulation.
Klippel-Trènaunay-Weber (KTW) syndrome is a condition characterized by port-wine stains or birthmark malformations in the skin, soft tissue and bony growths (generally involving a limb), and vascular anomalies (varicose veins). The cause of Klippel-Trènaunay-Weber syndrome is not known, however, recently, there have been some cases that run in families. There is no significant treatment for Klippel-Trènaunay-Weber syndrome.
Disease prevention in men includes routine screening tests that are part of basic prevention medicine. Take an active role in your own health care and discuss screening tests with your doctor early in life. Age of screening and timing of screening depends upon the condition being assessed.
Disease prevention in women includes screening tests that are a basic part of prevention medicine. All screening tests
are commonly available through your general doctor. Some specialized tests may be available elsewhere.
In 1912, Dr. George Coats described one sharply outlined form of exudative retinitis,
clinically characterized as follows:
Occurrence in infantile or juvenile male patients
Unilaterality
Absence of systemic diseases
Exudates below the retinal vessels
Retinal hemorrhages
Slow progression to retinal detachment,
cataract, atrophy, or glaucoma
Today little has been added. This rare condition is not inherited and may be
successfully treated if caught early. However, since is not usually diagnosed
early, it usually progresses to cause a marked
loss of vision or blindness in
one eye.
What are causes and risk factors for Coats' disease?
No causes or risk
factors are known.
At this point, although there is no known hereditary
component or any other cause, there may be some evidence to suggest that Coats'
disease is caus...
Glaucoma is the term applied to a group of eye diseases that gradually result
in loss of vision by permanently damaging the optic nerve, the nerve that
transmits visual images to the brain. The leading cause of irreversible
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