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BLOG: Five reasons why astigmatism should be corrected during cataract surgery
Does astigmatism matter? Do patients undergoing cataract surgery really care whether you reduce their cylinder? About a third of U.S. cataract surgeons don’t routinely address astigmatism in patients undergoing this procedure. Here are five reasons why I would encourage this group to reconsider their approach:
1. Most patients’ refractive astigmatism increases after cataract surgery. That’s because preoperative corneal astigmatism is greater than manifest astigmatism in most eyes. Nearly 70% of corneas have 0.75 D or more of preoperative corneal astigmatism — enough to affect their vision meaningfully. Performing cataract surgery alone actually worsens the astigmatic state of most of our patients.
2. With a multifocal lens, residual astigmatism is especially bothersome. Multifocal lenses reduce contrast to a degree that does not bother the vast majority of patients, unless there are other comorbidities that reduce contrast. Of these comorbidities — such as optic nerve disease, macular pathology and dry eye — astigmatism is the easiest to address with a simple, simultaneous procedure or toric lens to greatly reduce or eliminate it.
3. Development of future disease years after cataract surgery can degrade vision, so correcting astigmatism now only improves patients’ long-term outlook. How many of our patients will eventually develop dry eye or maculopathy that reduces visual acuity? How much easier would their lives be if they did not have to contend with astigmatism as well, requiring challenging refractions and prescription spectacles for distance vision? Shouldn’t we try to make life easier for our patients as they get older?
4. Patients genuinely appreciate the procedure, and it works. A recent survey of 200 of patients in my practice, Harvard Eye Associates in Laguna Hills, Calif., showed that 51% of patients undergoing astigmatic keratotomy (with a blade, before our femtosecond laser arrived) were within 0.25 D of their target spherical refraction, 70% were within 0.5 D, and 86% were within 0.75 D. In other words, astigmatic keratotomy can be highly accurate. And what effect does a little residual astigmatism have on satisfaction? A survey we conducted on the same 200 patients showed 80% of patients with less than 0.5 D of astigmatism reported they were extremely satisfied with surgery vs. only 56% with more than 0.5 D. So what it takes to raise the bar on your surgical quality — as it’s viewed by the patient — is addressing astigmatism.
5. It’s easy to get started. This video shows the steps and equipment (less than $2,000) required to perform limbal relaxing incisions. Of course, a femtosecond laser is a more elegant, if more expensive, way to accomplish the same thing.
As surgeons, we all seek to improve our results over the course of our careers, and one of the large steps forward I took long ago was addressing astigmatism. I hope many of my colleagues will do the same.