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macular degeneration

breakdown of cells in the macula lutea, resulting in a loss of central vision in the affected eye; peripheral vision is not affected. There are several varieties; most appear in persons 50 to 60 years of age (age-related macular degeneration), but one variety is congenital and is seen in younger people (stargardt's disease or Stargardt's macular degeneration). In about 75 per cent of cases the cause is not known, and nothing can be done to prevent, arrest, or reverse the process.
Patient Care. Since a large majority of cases of macular degeneration cannot be arrested or treated, care is aimed at making the most of the vision that the patient has. The condition does not progress to total blindness and usually is self-limiting. The inability to perceive detail can be compensated for in part by using large-type books and magazines and a magnifying lens for reading, and having adequate lighting whenever detail work is necessary.

Patients with macular degeneration are given a sheet of paper on which is printed a grid of horizontal and vertical lines. They are instructed to look at this grid daily and note whether there is any change in distortion of lines in the center of vision. This same technique can be used as a screening test to evaluate central vision. However, seeing distorted lines in the grid is not necessarily symptomatic of macular degeneration. Further examination by an ophthalmologist is necessary for a definitive diagnosis.
Grid for evaluating macular degeneration.
age-related macular degeneration (ARMD) a type having its onset between the ages of 50 and 60, the leading cause of blindness in persons over the age of 65. There are two main types, involutional and exudative age-related macular degeneration.

The involutional (dry or non-exudative) type accounts for 90 per cent of cases and is characterized by the gradual wearing out of the cells in the retinal pigment epithelium, resulting in a slow, progressive loss of central vision. Although visual acuity loss usually does not progress beyond the 20/200 level, this is a significant disability. Treatment is not generally available.

The exudative (neovascular or wet) type is characterized by the growth of a neovascular membrane within or very close to the macula, resulting in distorted and blurred vision. The vision loss from this type of macular degeneration may be only of hand movements. Laser photocoagulation of this form of macular degeneration is aimed at destroying the neovascular membrane; if diagnosed and treated very early when the membrane is small, significant loss of central vision may be avoided.
Patient Care. Health care providers can be of great help for early diagnosis of this devastating disease through ongoing patient education programs. After laser treatment, which is performed under a retrobulbar anesthetic, the patient should be instructed to leave the patch in place for at least six hours. Any increase in distortion or blurred vision should be immediately reported and followed up by an urgent outpatient exam. Low vision aids and services can improve quality of life for persons with this disorder.
Stargardt's macular degeneration Stargardt's disease.


Age-related macular degeneration, see there.

Age-related macular degeneration (ARMD)

Degeneration of the macula (the central part of the retina where the rods and cones are most dense) that leads to loss of central vision in people over 60.
Mentioned in: Cataract Surgery
References in periodicals archive ?
In other words, the mean increase in drusen number in patients with drusiform dry ARMD was 4.
In a recent study, Dutch scientist found that study participants that ate more fruits, vegetables and whole grains lowered this risk of ARMD by 35% compared to those that did not.
They found that study participants who ate the most fruits, vegetables and whole grains lowered their risk of ARMD by 35% compared to those who ate the least.
Age related macular degeneration according to age groups ARMD type Patients 40-49 yrs 50-59 yrs Dry ARMD 171 0 5 Wet ARMD 28 1 1 Totals 199 1 6 % 0.
For the first, we included variables for age, time before initial diagnosis, number of periods since initial diagnosis of DM (for diabetic retinopathy) or ARMD, and ocular comorbidities.
All other ARMD cases are the more severe "wet" form, where people tend to lose a significant portion of their vision.
RESULTS Patients with no ARMD (category 1) and mild or borderline ARMD (category 2) did not benefit from antioxidant and/or zinc supplementation.
The severity of wet ARMD is due to its neovascular nature, meaning that new blood vessels grow and invade the retina, distorting the cells that perceive images.
The groundbreaking Age-Related Eye Disease Study (AREDS) from the National Eye Institute (NEI) arm of the National Institutes of Health tested if high-dose antioxidant vitamins plus zinc could delay progression of ARMD.
Those who ate three or more servings of fruit daily had one-third less risk of developing severe ARMD compared to those who ate less than 1.