One of the most innovative features
of the ALLEGRETTO WAVE is the way it uses wavefront-optimized
technology to automatically compensate for the curvature of the
cornea. In earlier laser correction systems, the “optical
zone,” or area of correction, was centered on the front
of the cornea; the result was a flattened circular area that ended
with an abrupt edge, causing unwanted side effects like poor
night vision, glare,
and halos.
ALLEGRETTO WAVE changes all that. The ALLEGRETTO WAVE sends extra
pulses to the peripheral cornea area in order to compensate for
the angle of the laser beam. In this manner, the aspherical shape
of the cornea is preserved to a degree that older lasers simply
could not achieve. This compensation, combined with the incredibly
small, 1mm size of the laser, produces a smooth, effective optical
zone that results in what can only be described as high
performance vision.
Imagine a glass ball. If you took a flashlight and aimed it directly
at the top of the ball, the light would form a circular shape
on the surface of the ball. If you now aimed the flashlight towards
the side of the ball, the light would form an elliptical shape
and not seem as bright anymore. This is because the same amount
of light is suddenly distributed over a larger area and some of
the light is reflected away due to the angled surface of the glass
ball.
The illustration below demonstrates the need for additional pulses
to the corneal periphery, in order to compensate for the energy
lost through reflection. Therefore the natural cornea shape of
each patient can be maintained.

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