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Sphero-toric Lenses
A new option in refractive surgery, offered for the correction of severe
refractive errors with astigmatic components.
Until recently, one of the limitations of implanted contact lens was the
fact that the ICL could only be produced as a spherical lens based on
the ideal ball-shaped eye. This meant that patients with a higher grade
of astigmatism (the eye is asymmetrically curved, not ball-shaped) would
have to undergo a second procedure, usually LASIK, to have their astigmatism
corrected (see bioptics procedure). Two surgical procedures - both associated
with risks - result in significantly higher costs and a longer recovery
period for the patient.
Today, patients with astigmatism can receive the sphero-toric, or simply
toric ICLs. External toric contact lenses have two powers in them, created
with curvatures at different angles (one for astigmatism, the other for
either myopia or hyperopia). There's also a mechanism to keep the contact
lens relatively stable on the eye when you blink or look around. Despite
what opthamologists know about toric contact lenses, it was very difficult
apply this design to ICLs. Production of sphero-toric ICLs started just
a few years ago and they have been used at the ALZ clinic since November
of 2001.
The surgery requires special preparations and additional measurements.
In addition to the diopter values to correct for myopia or hyperopia,
exact measurement of the axis is important for astigmatism. Care must
be taken to prevent the implanted lens from rotating inside the eye so
that it stays in the correct position for the long-term.
The ALZ clinic works very closely with the ICL manufacturer. Each of the
lenses is custom manufactured for each patient and delivered with an implant
scheme for the exact positioning of the lens.
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