The cornea is the front ‘window’ of the eye and is responsible for
about two-thirds of the eye’s focusing power. Any abnormality in
the shape of the cornea will have an impact on the quality of
focusing in the eye. Topographical maps of the eye are critical
tools to analyze the shape of the cornea.
There are a few different ways of assessing the shape of the eye,
each method having advantages and disadvantages over the others.
As a result, BoydVision Centre chooses to use at least two
different methods of determining the topography of the cornea,
including the Humphrey ATLAS and the Oculus PENTACAM.
The
first considered best at measuring the front layer of the cornea
(useful for 'topography-based' laser treatment) and the latter is
state-of-the-art technology for measuring the back (posterior)
of the cornea.
When a scan is done of the cornea, it takes only a few seconds.
During this time you will experience no discomfort at all. The
only real challenge is to keep your eyes open and looking at the
appropriate target. The instruments notify us if there are any
imperfections in the scan, at which time we would repeat the scan
to ensure the best result.
Once the corneal topographical maps are printed, the examiner will
use the information to decide if there are certain types of
corneal pathology. The most commonly problems found using
corneal topograhy are keratoconus and pellucid marginal
degeneration. Both conditions are degenerative and are usually
considered contraindications to laser refractive eye surgery.
In addition to measuring the shape of the cornea, certain corneal
topography units are able to measure the thickness of the cornea.
When laser surgery is done to reduce or eliminate corrective
lenses, a certain amount of corneal tissue must be removed, making
it thinner. It is important to maintain a safe level of thickness
to keep the structural integrity of the eye intact. At BoydVision, we will also double check the thickness of the cornea
using ultrasound – you can never be too safe! |
