SELC
Poll Shows Multifocal Preferences
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In our practice, four out of five
prefer Epi-Laser Monovision.
If you were a 55-year-old emmetrope,
which technology would you choose?
1. AMO Rezoom: 5%
2. Eyeonics Crystalens: 8%
3. Alcon Acrysof Restor: 15%
4. Visx Multifocal Ablation: 8%
5. Monovision Epi-Laser: 64%
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NearVision Conductive Keratoplasty was abandoned in 2007
because of unpredictability and lack of permanence for presbyopic
treatment.
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More Monovision Epi-Laser Information
We have a wealth of additional information on the
Monovision Epi-Laser procedure and what it can accomplish.
Contact Lens Trial
After a discussion of the pros and cons of
Monovision Epi-Laser with a prospective patient, we conduct a contact lens
trial. Not only does this trial allow us to ensure that patients can adapt
to monovision, it also allows us to determine each patient's ideal
monovision correction. Tailoring the correction to each patient's preference
is one of the keys to achieving a high level of success with Monovision Epi-Laser,
and a careful contact lens trial provides this opportunity.
During this process, we first determine the patient's
dominant eye and then test different corrections to determine two things;
first, to verify whether the dominant eye should be corrected for distance
(as is almost invariable the case), and second, how much add power to
provide for the near eye.
To determine the patient's dominant eye, we use a
rather nontraditional but infallibly simple instrument; a camera with a
viewfinder. If we hand a patient the camera and ask them to take a picture,
patients will automatically select their dominant eye to look through the
camera viewfinder, just as they would automatically use their dominant hand
if given a pen and told to write their name. While other tests can also be
used to assess ocular dominance, we've found this "camera test" to be both
simple and accurate.
Once we know the patient's dominant eye, we start the
contact lens trial by giving the patient the correction that most of our
Monovision Epi-Laser patients prefer: full distance correction in the
dominant eye and approximately -2.00D in the nondominant eye. Beginning with
that correction, we then adjust the add power based on the patient's
feedback. Depending on the patient's hobbies, he or she may prefer more or
less correction. For example, a musician may want less correction in order
to view music that is more than 0.5 meters away, while a patient who does a
lot of close work or is accustomed to reading at a distance of 10-12 inches
may prefer more near correction. Once the patient's optimum correction has
been determined, this correction can be permanently and reliable replicated
with Monovision Epi-Laser.
What about patients who are contact lens intolerant?
Fortunately, these patients are quite rare. Even if patients cannot tolerate
contact lenses on an ongoing basis, the vast majority can tolerated them at
least for the limited duration of the monovision trial. For those patients
who choose not to wear contact lenses because they feel uncomfortable
inserting and removing the lenses, extended wear lenses can provide the
necessary correction without requiring patients to handle the lenses.
For those rare patients who cannot tolerate a lens in
their eye for any length of time, a monovision correction can instead be
created using a pair of spectacles. This alternative typically involves
having the optical laboratory modify an existing pair of the patient's
glasses, making this option a bit more expensive and labor-intensive; but,
fortunately, it rarely needs to be done.
Conclusion
While properly educating patients and performing a careful contact lens
trial involves some additional work for the surgeon and the refractive
surgical team, the rewards make this effort worthwhile, both in terms of
patient satisfaction and in reducing the need to perform touch-ups or
monovision reversal. We have almost no patients who request monovision
reversal, and in most cases when patients need an enhancement, the problem
is simply a slight over- or under-correction in either eye, occurring for
the same reasons an eye ends up off target following normal binocular Epi-Laser.
Surgeons should be aware, however, that patients with Monovision Epi-Laser
tend to have less tolerance for slight residual refractive errors than
patients who undergo binocular Epi-Laser. Since monovision patients rely on
only one eye for distance and one eye for near, the accuracy of the
correction is paramount, especially in the distant eye.
The Bottom Line
Overall, we find Monovision Epi-Laser to be a win-win option for both
surgeons and patients. Patients appreciate having a permanent, hassle-free
solution to presbyopia, and the high level of patient satisfaction makes
Monovision Epi-Laser a valuable addition to our practice. To assure a high
level of patient satisfaction, however, surgeons need to select patients
carefully, educated them about the pros and cons of the procedure, and
conduct a careful contact lens trial to determine the patient's ability to
adapt to monovision and their ideal monovision correction.
Other Doctor's Have Opinions
"In monovision, if you have one eye set for distance
and the other eye at [near] and the separation is only up to 1.50 D, the
spatial frequencies are close enough together that the visual cortex can put
this information together and we get fusion at almost every distance."
J.M., M.D.
Neuroadaptation is the best surgeon overall, if one
eye looks at a lower contrast version of a picture and the other eye looks
at a higher contrast picture of the same image, then the picture is
presented to both eyes - it does not appear the same. It's a crapshoot to
see what the patients sees, and the patient either accepts it or he doesn't.
This is hard to understand by people who have eyes that are almost perfectly
matched.
J.H., M.D.
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