Top Five List for Toric Hydrogel Lenses
The other day yet another patient
told me that she wished she could see better with her contact lenses. Alas, she
had astigmatism, and several eyecare practitioners had told her that the vision
her spherical hydrogel lenses was the best she was going to get. No one had offered
her toric hydrogels (or GPs for that matter) to correct her astigmatism.
Her spectacle Rx was –3.00
–1.25 x180 OD and –2.75 –1.00 x175 OS. Acuity with her soft spheres
was 20/30 OD and 20/25 OS. It's difficult to imagine a patient whom you could more
easily satisfy with toric hydrogels, yet this scenario happens all the time with
patients who are new to me. Why do some practitioners resist fitting toric hydrogels
and worse, tell patients they have no other option besides spherical lenses?
Why Toric Hydrogels?
At the risk of preaching
to the choir, let me offer my top five list of what I think are great about modern
toric hydrogels that may persuade you to take the plunge.
Number 5: Acronyms.
Our profession uses many acronyms, but my favorite is LARS (left-add, right-subtract).
Of course, we use LARS to adjust the cylinder axis to compensate for any lens rotation
on the eye.
And if LARS doesn't work for you,
then you can use SCOR (spherocylinder over-refraction) and a cross-cylinder calculator
to determine your final prescription.
Number 4: Minimal Rotation.
Inconsistent lens rotation has always been the trouble with torics (hence Number
5), but the newest lens designs are very stable. I find most lenses consistently
rotate very little so that I have to compensate for lens rotation less and
Number 3: Plenty of Oxygen.
Prism ballasting of torics makes the bottom of the lens thicker than the top. This
results in less oxygen reaching the bottom of the cornea than elsewhere, increasing
the risk of neovascularization inferiorly.
The introduction of silicone hydrogels
in toric designs has minimized the risk of inferior corneal neovascularization,
resulting in eyes that are whiter and more comfortable.
Number 2: Frequent Replacement.
Long gone are the days of conventional replacement for most torics. Even in high-power
prescriptions, quarterly replacement is affordable; for common prescriptions, the
norm is now two-week replacement. Daily disposables are also available. In short,
we can offer our astigmatic patients healthy lens wear with clean, fresh lenses
just as we can for our spherical patients.
Number 1: Great Vision.
Patients come to us because they want to see well. If you aren't correcting their
astigmatism, they aren't seeing as well as they could and you aren't providing optimal
care. We fit our new patient described earlier in a two-week replacement silicone
hydrogel toric lens design. Her acuity improved to 20/15 in each eye. She was quite
pleased with the increased sharpness in her vision. She was also quite indignant
that no one had offered them to her before.
Lens fitting has never
been easier with modern toric hydrogels, and lens choices are almost limitless.
If you aren't prescribing them as often as you should, make the effort to start
using them on a more consistent basis. Better vision is within your patients' reach.
Dr. Jackson is
an assistant professor at Southern College of Optometry where he works in the
Advanced Contact Lens Service, teaches courses in contact lenses and performs clinical
Contact Lens Spectrum, Issue: February 2007