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.
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.
Cataracts are extremely
common, and most cataracts are a result of the aging process.
Although many
cataracts are not significant enough to require treatment, surgical removal of
cataracts is usually safe and effective, resulting in improvement of vision.
Cataract surgery should be performed when the visual loss from the cataract
significantly impacts the lifestyle of the individual patient.
What is a cataract?
A cataract is an eye disease in which the clear lens of the eye becomes
cloudy opaque, causing decrease in vision. Although the word cataract to
describe this condition has been part of the English language only since the
middle of the 16th century, the eye disease has been recognized and
surgically treated since ancient times.
The lens is a portion of the eye that is normally clear. It assists in
focusing rays of light entering the eye onto the retina, the light-sensitive
tissue at the back of the eye. In order to get a clear image onto the retina,
the portions of the eye in front of the retina, including the lens, must be
clear and transparent. Once light reaches the retina, the light initiates a
chemical reaction within the retina. The chemical reaction, in turn, initiates
an electrical response which is carried to the brain through the optic nerve.
The brain then interprets what the eye sees.
In a normal eye, light passes through the transparent lens to the retina. The
lens must be clear for the retina to receive a sharp image. If the lens is
cloudy from a cataract, the image striking the retina will be blurry and the
vision will be blurry. The extent of the visual disturbance is dependent upon
the degree of cloudiness of the lens.
Most cataracts are related to aging. Cataracts are very common in older
people. By age 80, more than half of all Americans either have some degree of
cataract or have already undergone cataract surgery in one or both eyes. By age
95, this percentage increases to almost 100%. A cataract can occur in either
or both eyes. Individuals with a cataract in one eye usually go on to develop a
cataract in the other eye as well. A cataract is not contagious and cannot
spread from one eye to the other or from person to person. Cataracts do not cause the eye to tear abnormally.
They are neither painful nor make the eye itchy
or red.
Although vision can be restored in most people with cataracts, age-related
cataracts are still the most common cause of blindness in the world, primarily
because many third-world nations lack appropriate surgical services.
As life span increases in the developed world due to modern technology and
new methods of treatment of acute and chronic disease, the incidence of
age-related cataracts will continue to increase.
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.
Alcoholism is a disease that includes alcohol craving and continued drinking despite repeated alcohol-related problems, such as losing a job or getting into trouble with the law.
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.
Glaucoma is a common eye condition in which the fluid pressure inside the eye rises because of slowed fluid drainage from the eye. If untreated, glaucoma may damage the optic nerve and other parts of the eye, causing the loss of vision or even blindness.
Eye floaters are deposits or condensation that forms in the eye's vitreous humor. These deposits cast shadows on the retina, and as the eye moves, the deposits shift position, making it appear as though the shadows are moving or floating.
Smoking is an addiction. More than 430,000 deaths occur each year in the U.S. from smoking related illnesses. Secondhand smoke or "passive smoke" also harm family members, coworkers, and others around smokers. There are a number of techniques available to assist people who want to quit smoking.
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.
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.
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.
Retinitis pigmentosa (RP) is a genetic condition that causes retinal degeneration and eventual vision loss. Symptoms include night blindness and tunnel vision. Visual field testing and electrophysiological testing are essential in diagnosing RP. Though there is no cure for RP, vitamin A therapy and an omega-3-rich diet may be recommended for patients to slow disease progression.
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.
Sunburn is caused by overexposure to UV radiation from the sun. UV rays can also damage the eyes. Repeated overexposure to UV rays also increases the risk for scarring, freckles, wrinkles, and dry skin. Symptoms of sunburn include painful, red, tender, and hot skin. The skin may blister, swell, and peel. Sun poisoning (severe sunburn) include nausea, fever, chills, rapid pulse, dizziness and more. Treatment for sunburn depends upon the severity. Sun protection and sunscreen for an individual's skin type is recommended to decrease the chance of sunburn.
Age-related macular degeneration (AMD) is a disease that gradually destroys the central vision. In people over 60, AMD is a leading cause of vision loss. Wet AMD occurs when abnormal blood vessels behind the retina start to grow under the macula, leaking blood and fluid and causing rapid vision loss. In dry AMD, light-sensitive cells slowly break down in the macula, resulting in gradual vision loss. Pain is not associated with either form of AMD.
Double vision (diplopia) is a symptom that my indicate Graves' disease, myasthenia gravis, stroke, multiple sclerosis, Guillain-Barre syndrome, diabetes, cataracts, aneurysm, brain tumor, or migraine. Symptoms and signs include eye pain, droopy eyelids, nausea, headache, and a cross-eyed appearance. Treatment of double vision depends upon the underlying cause.
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.
Nonprescription eyeglasses are available over the counter (OTC) and are typically used by people who can no longer read fine print. OTC trifocals are helpful for those who require multiple distances or focal lengths for near and intermediate tasks. OTC sunglasses should offer 100% protection from the sun's UVA and UVB rays. OTC magnifying glasses are useful for viewing tiny objects or fine print.
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.