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How are
Macular Degenerations diagnosed?
The early
signs of Macular Degeneration are usually detectable in a thorough eye exam
even before the disease begins affecting vision. The doctor will examine the
eye with special lenses, which help to show the interior of the eyeball
through the pupil, the opening in the centre of the iris through which light
rays enter the eye. Tests for Macular Degeneration include:
- Acuity tests which measure the accuracy of
your reading and perception vision at specific distances in specific
lighting situations. This is the test that people are most familiar with
and typically involves a standard eye chart.
- The Amsler grid test which is used to check for
the extent of sight loss spots. Usually the patient is asked to look
directly at a spot on a test page that is lined like graph paper, to see
if any of the surrounding lines look blurred or wavy and if the central
spot can be seen looking straight at it.
- Colour testing which can help to determine the
status of your cone cells. Since cone cells are the retinal cells that
interpret colour, your doctor will be better able to determine the
health of these cells through your performance on these tests. There are
several types of colour tests which measure various aspects of vision.
- A dark adaptation test which will measure how
well your eyes adjust to changes in lighting. Information from this test
can help the doctor to better understand the current function of your
rod cells, which are the retinal cells responsible for night vision.
- A fluorescein angiogram which allows inner eye
structures to be visualised. A non-toxic dye is injected into the
patient's arm and it moves through the bloodstream, including the blood
vessels in the eyes. Photos are then taken of the retina and macula,
which will identify new blood vessel growth and leakage from blood
vessels. New blood vessel growth is a feature of wet age-related Macular
Degeneration, which is explained in detail in the section of this website
describing the different forms of Macular Degeneration.
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