Published in Contact Lens

Low Astigmatism, Big Impact

This is editorially independent content
6 min read
Learn how correction with toric contact lenses for low astigmatism can lead to better vision and greater overall patient satisfaction.
Low Astigmatism, Big Impact
It’s 5pm at the end of a busy Wednesday. My student clinician checks in about our last scheduled patient of the day: A 30-something female seeing well with her current soft spherical daily disposable contact lenses. She says the lenses are “fine” and the student, eager to get home and study for tomorrow’s midterm, suggests we replicate her prescription this year and call it a day.
I look over the clinical data that has been collected and notice that the manifest refraction includes a diopter of with-the-rule astigmatism in both eyes. We’ve always included the full astigmatic correction in her spectacle prescriptions. Perhaps because everything was “fine,” however, we have never trialed a toric contact lens.
Should I extend what could be a quick appointment and refit this patient into a toric lens? If she thinks everything is “fine” will she even notice a difference? This is a question many clinicians might ask themselves but, according to prescribing patterns, their internal answer to both questions is often “no.”

Reasons to opt for toric contact lenses

If a patient has large amounts of astigmatism and their visual acuity would be significantly improved with a toric option, most would obviously reach for the astigmatic lens. But when a patient has small amounts of toricity, should we be utilizing toric contact lens options?
About half of all soft contact lens wearers have ≥0.75 diopters of astigmatism in at least one eye,1 but toric contact lenses are only fitted on about 25% of them.2 In fact, it’s been estimated that if astigmatism was always corrected in soft contact lens wearers, about 45% more would be wearing a toric design. If a near majority of our patients have refractive error that warrants a toric correction, why aren’t we prescribing appropriately?
The under-utilization of soft toric contact lenses by eyecare providers (ECP’s) is probably a result of misconceptions and outdated perspectives on soft toric contact lens performance. Some may assume a toric lens takes longer to fit (more visits, patient counseling, and overall chair time), but recent research has shown that there is no difference in the time required to fit soft spherical contact lenses compared to similar toric designs.3

Meet the modern soft toric contact lens

Modern soft toric lenses stabilize accurately and quickly on most patients, so ECP’s aren’t spending excessive time assessing and adjusting for rotation. As well, parameter availability has increased impressively in the last few years to include expanded cylinder power magnitudes, axis availability around the clock, and daily disposable options for most prescriptions.4
When we actually give patients with low amounts of astigmatism a chance to try soft toric lenses, they prefer the toric lens experience. In studies that have compared soft spherical designs to soft toric designs in patients with low (0.75 – 1.75 D) amounts of astigmatism, the toric lenses provided better high and low contrast visual acuity and less overall eyestrain.5 Importantly, compared to spherical options, toric soft lenses result in better subjective lens satisfaction, perception of vision clarity, and quality of life measures.3 Having all parts of refractive error corrected may also influence a patient’s perception of comfort.
In soft contact lens wearer with astigmatism, it has been reported that symptoms of discomfort can be more intense if the wearer has a poor subjective opinion of their vision.6 When a wearer is happy with their vision, they are more likely to be satisfied with comfort. Small amounts of astigmatic correction can play a major role in a wearer’s satisfaction with their contact lens experience.

In conclusion

We refit that end-of-the-day patient. That patient who was “fine” with her spherical daily disposables was unexpectedly delighted when we showed her the vision that could be achieved with the toric version of the same brand. At her follow-up appointment a week or so later, she remarked that she was so much happier with her contact lens experience. She noted that her “fine” response the previous week assumed that there were no other options or that, if there were, we would bring them up.
In this patient’s case, not offering the toric lens would have meant that we weren’t doing what our patient expected us to do: consider her unique clinical information and choose an option that addresses all of her visual needs. Next time you encounter a patient with low astigmatism who is “fine,” consider how you can enhance their whole experience with toric correction—a little bit goes a long way.

References

  1. Young G, Sulley A, Hunt C. Prevalence of Astigmatism in Relation to Soft Contact Lens Fitting. Eye Contact Lens 2011;37:20-5.
  2. Morgan PB, Efron N, Woods CA, International Contact Lens Prescribing Survey C. An International Survey of Toric Contact Lens Prescribing. Eye Contact Lens 2013;39:132-7.
  3. Cox SM, Berntsen DA, Bickle KM, et al. Efficacy of Toric Contact Lenses in Fitting and Patient-Reported Outcomes in Contact Lens Wearers. Eye Contact Lens 2018;44 Suppl 1:S296-S9.
  4. Lai N. Take a Turn with Soft Toric Lenses for Astigmatism. Contact Lens Spectrum 2019;34:25-8.
  5. Berntsen DA, Cox SM, Bickle KM, et al. A Randomized Trial to Evaluate the Effect of Toric Versus Spherical Contact Lenses on Vision and Eyestrain. Eye Contact Lens 2019;45:28-33.
  6. Maldonado-Codina C, Navascues Cornago M, Read ML, et al. The Association of Comfort and Vision in Soft Toric Contact Lens Wear. Cont Lens Anterior Eye 2021;44:101387.
Erin Rueff, OD, PhD, FAAO
About Erin Rueff, OD, PhD, FAAO

Dr. Erin Rueff received her Doctor of Optometry degree from The Ohio State University (OSU) College of Optometry. Upon graduation, she completed the Cornea and Contact Lens Advanced Practice Fellowship at OSU. After fellowship, she continued at OSU as a clinical instructor and completed a PhD in Vision Science. In 2018, she joined the faculty at the Southern California College of Optometry at Marshall B. Ketchum University. Dr. Rueff’s research interests include contact lens discomfort and compliance. She enjoys teaching students in the clinic and classroom on contact lens and general optometry topics. Her clinical interests include multifocals, gas permeable and scleral contact lenses, keratoconus, and dry eye.

Erin Rueff, OD, PhD, FAAO
💙 Our Sponsors
EssilorLuxottica LogoJohnson & Johnson Vision Logo