Zeiss Topographer 
Carl Zeiss Meditec is an international giant in the field of manufacturing
and distributing high-end optics and optical products. The greatest
advantage of corneal topography is its ability to detect irregular conditions
of your cornea invisible to most conventional testing. And because the computer
can save
your exam information, Dr. Seibel can monitor any changes to your cornea
and/or your corneal stability over time. Corneal topography is
a computer assisted diagnostic
tool that creates a three-dimensional map of
the surface curvature of your cornea. The Zeiss Atlas 995 Topographer is the
most innovative tool of its kind. How does it work?
The cornea (the front window of the eye) is responsible for about
70 percent of the eye's focusing power. An eye with normal vision
has an evenly rounded cornea, but if the cornea is too flat, too steep,
or unevenly curved, less than perfect vision results. The Atlas 995 corneal
topographer consists of a computer linked to a lighted bowl that contains
a pattern of rings. During a diagnostic test, you would sit in front of
the bowl with your head pressed against a bar while a series of data points
are generated. Computer software digitizes these data points to produce
a printout of the corneal shape, using different colors to identify different
elevations, much like a topographic map of the earth displays changes in
the land surface. This is a painless and brief non-contact test. What do the colors mean?
Corneal mapping reveals patterns indicating conditions that may affect
the selection of the best type of vision correction or treatment
for you. These patterns are color-coded according to highs and lows
- red being the highest and purple being the lowest, in a continuous
rainbow order. A few examples of corneal color maps are shown below.
- This is a typical round cornea with a shape that changes uniformly from
the center to the edge
-
This is a typical astigmatism where the cornea is not round and has two balanced
but different focusing powers.
-
This is a asymmetric astigmatism where the cornea is not round and the focusing
powers are not balanced.
-
This is a keratoconus is a condition where an area of the cornea assumes a cone
like shape.
Corneal topography produces a detailed, visual description of the shape
and power of your cornea. This type of analysis provides Dr. Seibel with very
fine details regarding the condition of your corneal surface. These details are
used to diagnose, monitor, and treat various eye conditions. They are also used
in fitting contact lenses and for planning surgery, including LASIK. For LASIK
the corneal topography map is used in conjunction with other tests to determine
exactly how much corneal tissue will be removed to correct vision and with what
LASIK pattern.
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