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age-related macular degeneration (ARMD) A
progressive condition that results in the gradual
deterioration of the macula, the portion of the
RETINAthat provides the ability to see fine detail,
and loss of vision from the center of the field of
vision. ARMD is the leading cause of VISION IMPAIR-
MENT, resulting in functional limitations and legal
blindness in people over the age of 50. ARMD
develops when the retina’s BLOODsupply dimin-
ishes. The macula’s high concentration of cones,
the cells responsible for color and fine detail
vision, makes it especially vulnerable to damage
and its cells begin to die. The death of the cells
result in diminished vision. ARMD may affect one
eye at first, though nearly always affects both eyes
as it progresses.
There are two forms of ARMD, atrophic (com-
monly known as dry) and neovascular (commonly
known as wet). All ARMD begins as the atrophic
form, in which the nourishing outer layer of the
retina withers, or atrophies. Approximately 90
percent of ARMD remains in this form and pro-
gresses slowly. In the remaining 10 percent, new
blood vessels begin to grow erratically within the
choroid, the blood-rich membrane that nourishes
the retina. These blood vessels are thin and fragile,
and bleed easily. The resulting hemorrhages cause
the retina to swell, distorting the macula and
accelerating the loss of cells.

Symptoms and Diagnostic Path

ARMD begins insidiously and people tend to
attribute early symptoms to the normal changes of
aging. Early symptoms include

• blurring of words when reading
  
  
  • “missing pieces” in the field of vision, such as
    parts of words or gaps in the appearance of
    lines or objects
  
  
  • the need for increased light to perform tasks
    that require close vision
  
  
  • faded colors
  
  
  • tendency to look slightly to the side of objects
    to see them clearly
  
  
  • distorted or wavy lines on linear objects such as
    signs, doorways, and railings (suggests wet
    ARMD)
  
  
  
  

As the macular degeneration progresses, a blind

spot in the center of vision becomes apparent and

enlarges. Wet ARMD progresses far more rapidly

than dry ARMD. A simple screening test called the

AMSLER GRID can show the gaps in vision that

occur with either form of ARMD. The ophthal-

mologist uses further procedures, such as OPHTHAL-

MOSCOPYand SLIT LAMP EXAMINATION, to visualize the

retina and macula and determine which form of

ARMD is present and how extensive the damage.

The ophthalmologist looks for signs of exudation

(swelling of the tissue that oozes fluid) that sug-

gests wet ARMD, and for drusen (spots of depig-

mentation on the macula that signal the loss of

retinal cells). For wet ARMD, the ophthalmologist

may perform a diagnostic procedure called fluo-

rescein angiography, in which the ophthalmologist

injects fluorescein dye into a VEINand then takes

photographs of the retina as the dye flows

through its blood vessels.

Treatment Options

Treatment options for ARMD are limited, and at

this time there really are no treatments for dry

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