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WASCA (Wavefront Aberration Supported Cornea
Ablation) is a method for wavefront-guided ablation.
This new method records all existing eye aberrations
with the Asclepion Wavefront Aberrometer and
calculates the customized pattern for laser
correction. We measured the low and high order
aberrations of eyes before and after Lasik and
Epilasik, as well as before and after flap creation.
Natural examples of aberrations are the way car and
street lights can seem to have a halo, starburst or
surrounding fringe around them at night. Aberrations
are related to quality of the light which is focused
on to the retina and subsequently the quality of
vision you experience. Once measured, the aberration
profile is incorporated into the programming of the
Excimer laser to deliver you a more precise result
and, ultimately, better vision. Improved night
vision and reduced glare, in particular.
Refractive Errors and Treatment
- Zeiss Mel-80
- Visumax
- Zeiss Topography
- Aberrometer
- Visante OCT
- Pachymetery
- ORA
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What is Refractive Error?
The function of the eye is to see clearly the objects around
us. The inability of the eye to accurately focus the rays of
light coming from distance on the retina is called
refractive error. This condition may be either because the
eye is too short or long in length, or because the cornea or
lens does not have the required refractive power. There are
three types of refractive errors:
 Myopia (near-sight):
this is the condition in which the eye is too long and the
light is focused in front of the retina. Distant objects are
blurred but the near objects are seen clearly. The eye has
too much optical power and to correct it the optical power
is reduced by either minus glasses or contact lenses, or by
surgery.
 Hypermetropia (long-sight):
this is the condition in which the eye is too short and the
light is focused behind the retina. The eye has less optical
power than is needed. When young the eye can use the lens
within the eye to compensate, but reading glasses are needed
at a relatively early age. Later, distance glasses (plus)
are needed as well, such that glasses for distance and near
are required.
 Astigmatism:
this is the condition where the eye does not focus the light
evenly, usually due to the cornea of the eye being more
curved in one direction than the other. It may occur on its
own or may be associated with myopia or hypermetropia.
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What is Presbyopia?
Presbyopia is the normal aging process, where the lens
progressively loses its capacity to increase its power for
near vision (loss of accommodation). The distance vision may
be normal, but the near vision becomes blurred with age
greater than about 45 years. This is corrected by wearing
reading glasses (plus) for the near work. This condition may
occur in itself or may be present alongwith pre-existing
myopia, hypermetropia or astigmatism.
What are the ways of treating refractive errors?
The refractive errors may be treated by either of the
following ways:
- Glasses : this is the simplest and most popular way
of correcting refractive errors
Contact lens: this option is cosmetically much better
though the maintenance and cleaning of contact lenses
may be cumbersome. There is also a slight risk of
infection to the cornea, if the contact lenses are not
cleaned properly before use.
Refractive surgeries: these are increasingly becoming
popular with the advent of more predictable laser
treatments.
- Monovision : An alternative way to deal with presbyopia
is called monovision. In monovision, your dominant eye
is given a distance prescription, while your other eye
is given a near prescription. Contact lens practitioners
have used
monovision for years. Refractive surgeons use
it as well. While monovision can decrease your need for
reading glasses, it can take some getting used to.
Monovision can hinder depth perception, and you may not
feel comfortable driving or reading for extended periods
without glasses to bring both your eyes into optimal
focus. If you've never experienced monovision, try it
with contact lenses first to make sure you're
comfortable with it. If you are, your eye surgeon can
give you permanent
monovision LASIK or other refractive
surgery.
- Phakic IOL (ICL) : Putting an additional artificial lens
within the eye on top of the existing natural lens is
called Phakic IOLThe ICL (Implantable Collamer Lens) is
one of the latest technological advancements in vision
correction. The ICL is a long lasting solution for
refractive error. Through its myopia treatment, the ICL
offers excellent quality of vision.
- Removing the natural lens : Removing the natural lens
and replacing it with an artificial lens of adequate
power: it is similar to a routine phacoemulsification
surgery, except that it is done in a clear lens and not
a lens with cataract.
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