|
| | |
Macular degeneration
Macular degeneration Damage or breakdown of the macula, which is an area in the back of the eye that controls central vision. It may be caused by injury or aging; and while it does not progress to total blindness, patients with macular degeneration require special optical aids to enlarge distant and near objects.
RELATED TERMS--------------------------------------
Macula
A specialized part of the retina containing mostly cones. The macula is used for all detailed visual tasks. The center of the macula is called the fovea. If a disease process harms or destroys the macula, vision is usually reduced to 20/200 (legal blindness).
Central
In anatomy and medicine (as elsewhere), central is the opposite of "peripheral" which means away from the center.
Vision
The sense of sight.
Injury
Injury is damage or harm caused to the structure or function of the body caused by an outside agent or force, which may be physical or chemical.
Aging
The process of becoming older, a process that is genetically determined and environmentally modulated.
Blindness
Legal blindness is defined as: 1) visual acuity of 20/200 (only being able to see the big E on the eye chart) or less in the best eye even with the eyes corrected by glasses or contact lenses; or, 2) The peripheral visual field is reduced to 20 degrees of visual angle or less. Twenty degrees of visual angle is about the size of a one foot ruler held at arms length.
Optical
Having to do with vision.
Aids
A medical condition where the immune system cannot function properly and protect the body from disease. As a result, the body cannot defend itself against infections (like pneumonia). Aids is caused by the Human Immunodifiency Virus (HIV). This virus is spread through direct contact with the blood and body fluids of an infected individual. High-risk activities include unprotected sexual intercourse and intravenous drug use (sharing needles). There is no cure for AIDS; however, research efforts are on going to develop a vaccine.
SIMILAR TERMS--------------------------------------
Macugen
Macugen is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): pegaptanib sodium.
Macula
A specialized part of the retina containing mostly cones. The macula is used for all detailed visual tasks. The center of the macula is called the fovea. If a disease process harms or destroys the macula, vision is usually reduced to 20/200 (legal blindness).
Macula lutea
The cone rich area of the human eye that contains the fovea.
Macular Edema
A swelling (edema) in the macula, an area near the center of the retina of the eye that is responsible for fine or reading vision. Macular edema is a common complication associated with diabetic retinopathy.|See also: Diabetic retinopathy; retina.
Macule
A discolored, flat spot of skin.
PREVIOUS AND NEXT TERMS--------------------------------------
Mumps
Mumps is a viral disease characterised by fever, headache, and inflammation of the salivary glands. It may lead to complications such as meningitis.
Meningitis
An infectious disease that strikes membranes covering the brain and spinal cord (meninges). It can be caused by bacteria, viruses, or fungi. It can follow another infection somewhere else in the body, often ears or sinuses. If bacterial meningitis is not treated within hours, it can lead to death or permanent brain injury.
Meninges
Membranes which surround and protect the brain and spinal cord; anatomically there are 3 meninges: the pia mater, which adheres to the brain and the spinal cord, the dura mater, which adheres to the bone and the arachnoid between these two membranes.
Menopause
Is a stage of the human female reproductive cycle that occurs as the ovaries stop producing estrogen, causing the reproductive system to gradually shut down. As the body adapts to the changing levels of natural hormones, vasomotor symptoms such as hot flashes and palpitations, psychological symptoms such as increased depression, anxiety, irritability, mood swings and lack of concentration, and atrophic symptoms such as vaginal drynes.
Migraine
A vascular headache associated with changes in the size of the arteries within and outside of the brain. A migraine begins when hyperactive nerve cells send out impulses to the blood vessels, causing constriction, followed by the dilation of these vessels and the release of prostaglandins, serotonin, and other inflammatory substances that cause the pulsation to be painful. Migraine is a genetic disorder that is inherited. A migraine causes mild to severe pain and lasts from 4 hours up to a week. Migraines usually occur 2 to 4 times per month.
Macular degeneration
Monocular vision
A condition in which one eye is blind, or in which one eye refuses to register images in co-ordination with the better eye.
Multiple sclerosis
An auto-immune disease of the central nervous system, mainly affecting young adults, whose origin is unknown. It damages nerve fiber insulation (myelin) in a random and patchy manner, causing a wide range of neurological defects. It is characterized clinically by symptoms that typically abate spontaneously in the early years of the disease but often get gradually worse in later years.
Muscular dystrophy
An inherited condition that is due to a gene on the X chromosome. It is therefore called a sex-linked gene. It results in the inability to produce a vital muscle chemical resulting in muscle wastage, stumbling, then inability to walk and death by the age of about 20.
Myasthenia gravis (MG)
Myasthenia gravis is a neuromuscular disease in which there is a failure of the nerves' ability to stimulate and control the actions of certain muscles, especially those of the eye, face, lips, tongue, throat, and neck.
Myopia
Also known as nearsightedness, myopia is a refractive error caused by an eyeball that is too long to focus light on the retina or a cornea which is too steeply curved. In these cases light focuses instead in front of the retina. People with myopia are usually able to see close objects well, but objects in the distance—such as highway signs or writing on a chalkboard—appear blurred.
We thank you for using the Health Dictionary to search for Macular degeneration. If you have a better definition for Macular degeneration than the one presented here, please let us know by making use of the suggest a term option. This definition of Macular degeneration may be disputed by other professionals. Our attempt is to provide easy definitions on Macular degeneration and any other medical topic for the public at large.This dictionary contains 25007 terms. |
|
|
