the Time for Monovision Over?
CRAIG W. NORMAN, FCLSA
For quite some time I've been contemplating
exactly what place monovision has in presbyopic contact lens patient management.
Our practice, like most, has many monovision wearers, and while
we don't necessarily like the idea of not providing patients with maximum vision
out of both eyes at all distances, we have learned to live with it when employing monovision. It seems like we don't offer alternatives to monovision wearers if they
don't have visual symptoms or complaints, but maybe we should.
So why do we make use of monovision so often? Is it because of
a lack of designs? Probably not, as we have a significant number of excellent multifocal
and bifocal hydrogel, silicone hydrogel and GP lenses for us to offer to this patient
segment. A hybrid lens will also soon be available.
Does ease of fit play a role? Historically that might have been
true, but most of the aforementioned designs are relatively simple to fit today.
Is it patient response in that they prefer monocular vision over
binocular vision? I doubt it. In fact, Dr. Kathryn Richdale and others from The
Ohio State University College of Optometry published a wonderful study in May 2006
called "Comparison of Multifocal and Monovision Soft Contact Lens Corrections in
Low-Astigmatic Presbyopic Patients." Richdale et al assessed visual performance
and patient satisfaction in a crossover study of 38 presbyopic patients. They randomized
the study patients first into either multifocals (Bausch & Lomb SofLens Multi-Focal)
or monovision (B&L SofLens 59) for one month. The researchers measured visual
performance with high- and low-contrast visual acuity at distance and near as well
as near stereoacuity. They measured patient satisfaction using the National Eye
Institute Refractive Error Quality of Life Instrument (NEI-RQL) questionnaire and
by recording the patients' final lens preference.
Among the many interesting findings in this study:
Patients lost less than one line of vision from the best-spectacle
correction with either multifocal or monovision lenses.
The average stereoacuity decreased by 79 seconds of arc
with monovision vs. multifocals.
On the NEI-RQL, 76 percent of patients reported that they
preferred multifocal contact lenses over monovision.
The authors state that the reason why patients prefer the multifocal
contact lens correction to monovision by more than a 3:1 ratio is most likely because
the multifocal provided comparable visual acuity without compromising stereoacuity
to the same degree as monovision.
Time for a Change
Why do we still use monovision so often? The reasons are multifaceted,
but for many it may be nothing more than a habit of taking the path of least resistance
and suggesting monovision because it's what we've always done.
Instead, I think we all should consider multifocal and bifocal
contact lenses as the first option more often. And when we do, we might be surprised
at how positively patients respond. CLS
For references, please visit www.clspectrum.com/references.asp
and click on document #134.
Craig Norman is director
of the Contact Lens Section at the South Bend Clinic in South Bend, Indiana. He
is a fellow of the Contact Lens
Society of America and is an advisor to the
GP Lens Institute. He is also a consultant to B&L.
Contact Lens Spectrum, Issue: January 2007