Several colleagues have recently informed me how happy they and their
cataract patients have been with monovision. I credit Dr. Jay McDonald of
Fayetteville, Ark., for reintroducing me to this approach. Look for an upcoming
article in Premier Surgeon in which I interview Jay for his take
on this topic.
In a time when we have an expanding line of presbyopia-correcting
implants to offer, why would we consider such an old-fashioned approach?
Because it's simple and it works. Despite perceptions about this age-old
approach, monovision with an IOL:
- does not require a contact lens trial. In fact, a trial should
probably be avoided. Cataract patients who have never before worn contacts tend
to become more bothered by the experience of wearing contact lenses than the
monovision itself. They are more likely to reject the concept on the basis of
the unfamiliarity of the contact lens rather than the anisometropia.
- does not require significant anisometropia. Targeting plano in the
dominant eye and –1.25 D to –1.5 D in the nondominant eye will yield high-grade
intermediate and near vision. Some patients may need to increase their working
distance for some tasks such as needlepoint. Naturally, they can also resort to
readers that balance both eyes for very near.
- does not reduce stereopsis significantly. Patients who enjoy playing
tennis, for example, do not complain of inability to function on the court.
Postop patients typically can be measured to have high-grade stereo acuity.
- does not reduce contrast sensitivity significantly. While some
reduction in high spatial frequency contrast sensitivity occurs during distant
tasks in the nondominant eye, the patient can compensate. The brain "shifts"
its attention during these tasks to the dominant eye, which has perfect
contrast sensitivity. You won't find "perfect" contrast sensitivity in an eye
with a multifocal.
Additional advantages of monovision cataract surgery:
- Unlike multifocal implants, the very mild loss of contrast sensitivity
at distance is completely reversible. Many of my patients would much rather
spend their day without glasses, even if they have to put on a pair of specs to
drive at night.
- Monovision can be offered with a variety of implants. My personal
preference is to use a monofocal implant with either negative asphericity, such
as the Tecnis (Abbott Medical Optics) or the AcrySof IQ (Alcon), or a neutrally
aspheric lens, such as the SofPort AO (Bausch + Lomb).
- Monovision allows the surgeon to offer a refractive procedure without
the added cost of a multifocal or accommodating implant. This saves the patient
thousands of dollars. Note it is appropriate to bill for refractive services
incident to this procedure, including all non-covered services, such as
refractive evaluation, topography, pachymetry, limbal relaxing incisions and
refractive enhancements. The Corcoran Consulting Group (www.corcoranccg.com)
has developed audit-proof guidelines for the financial aspects of this
procedure, which are beyond the scope of this blog.
To be sure, there is a fair bit of work involved for the surgeon, just
as with a high-tech IOL. Getting the postop refraction to be perfectly
spherical and nailing emmetropia in the dominant eye are essential elements of
success; enhancements are occasionally necessary, and patients do have the same
demands as the higher-paying customers who have posterior chamber IOLs. But
there's something elegant about using nature's gift — the brain's plasticity —
to give patients spectacle freedom, and in the future I'm going to be doing more monovision.