Andrew A. Dahl, MD, FACS
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.
William C. Shiel Jr., MD, FACP, FACR
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.
In this Article
- Blindness facts
- What is blindness?
- What are the different types of blindness?
- What causes blindness?
- What are symptoms and signs of blindness?
- How is blindness diagnosed?
- What are treatments for blindness?
- What is the prognosis for blindness?
- When is someone considered legally blind?
- Is blindness preventable?
- Find a local Eye Doctor in your town
What are treatments for blindness?
The treatment of visual impairment or blindness depends on the cause. In third-world nations where many people have poor vision as a result of a refractive error, merely prescribing and giving glasses will alleviate the problem. Nutritional causes of blindness can be addressed by dietary changes. There are hundreds of thousands of people who are blind from cataracts. In these patients, cataract surgery would, in most cases, restore their sight. Inflammatory and infectious causes of blindness can be treated with medication in the form of drops or pills.
What is the prognosis for blindness?
The prognosis for blindness, again, is dependent on its cause. In patients with blindness due to optic-nerve damage or a stroke, visual acuity can usually not be restored. Patients with long-standing retinal detachment in general cannot be improved with surgical repair of their detachment. Patients who have corneal scarring or cataract have a good prognosis if they are able to access surgical care of their condition.
When is someone considered legally blind?
Legal blindness is not a medical term. It is defined by lawmakers in nations or states in order to either limit allowable activities, such as driving, by individuals who are "legally blind" or to provide preferential governmental benefits to those people in the form of educational, service, or monetary assistance. Under the Aid to the Blind program in the Social Security Act passed in 1935, the United States Congress defined legal blindness as either central visual acuity of 20/200 or less in the better eye with corrective glasses or central visual acuity of more than 20/200 if there is a visual field defect in which the peripheral field is contracted to such an extent that the widest diameter of the visual field subtends an angular distance no greater than 20 degrees in the better eye.
It is estimated more than a million people in the United States meet the legal definition of blindness.
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