Comparing Laser Eye Surgery Results Is Not Easy – Here Are A Few Ways To Make It More Simple

The Snellen Chart is used to evaluate visual acuity (e.g. 20/20 vision)
The Snellen Chart is used to evaluate visual acuity (e.g. 20/20 vision)

Laser Eye Surgery results will usually be very good, almost wherever you go and have it done.

Whilst this is good news for patients, the challenge arises when a prospective patient tries to compare one clinic’s results with another. We have written about the need for standardised reporting in medical journals before, but we also think it would help patients make more informed decisions if they could more easily compare Laser Eye Surgery outcomes. For example, a broad review of the results shared by three chains shows that results vary:

  • Optical Express claims that “99% of all patients achieve 20/20 vision” (1)
  • Optimax claims that “97.15% have achieved 20/20 vision or better” (2)
  • Ultralase claims that “99% of people achieved 20:20 vision” (3)

Shouldn’t these claims be easy to compare? Unfortunately, they are not.

Questions To Ask When Comparing Laser Eye Surgery Results

Whenever one is comparing one group to another it is easier to arrive at conclusions about the groups if they are the same composition. In the claims above, that’s a challenge to do because it’s unclear who is in the sample. Here are some important questions that should arise for anyone scrutinizing the data (each of them can have an influence on reported outcomes):

  • How many patients are in the sample?
  • What treatment did the patients have?
  • When and at what stage of recovery were the post-operative measurements taken?
  • What prescriptions did the patients have before having Laser Eye Surgery?
  • Were the patients shortsighted or longsighted?
  • Did they have astigmatism?
  • Do they include people who had near and distance corrections?

Comparing Laser Eye Surgery Results – Some Principles To Keep In Mind

Usually, the more people there are in the sample, the more likely the results reflect you can have the results. Once at least 1000 people are included, you can have a high degree of confidence that the data represents real life. Sometimes, the following factors will depress results:

  • The inclusion of all types of laser eye surgery (including blade procedures, non-wavefront, LASEK / PRK)
  • Patient results at 1 day post-op may not represent their eventual outcomes
  • Including higher prescription patients (over – 6D or more than + 3D)
  • The inclusion of longsighted and astigmatic patients can depress outcomes
  • The inclusion of mono vision, partial treatments or PRESBYOND® Laser Blended Vision patients can depress outcomes
  • Are the results for binocular vision – the way most people see naturally (or are they measured per eye, with the other eye closed)

How easy is it to compare the chains Laser Eye Surgery results? It isn’t easy for us to compare them at all.

Here’s why: Optical Express’s results are based on “a study of 21,248 eyes” and “excludes mono vision and partial treatments”. We can’t really tell what treatment they had. When the results were measured is not specified. And, we can’t tell whether the outcomes are for shortsighted, longsighted or both, or whether they include astigmatism.

Optimax’s results are based on 2,668 patients who had LASIK between January 2007 and December 2009. It is important to note that these outcomes are only for shortsighted patients from -0.5 to -3.00 sphr with up to -0.75 cyl. We can’t tell at what stage of recovery the results were measured or if they included mono vision or partial treatments. It is likely that the results would be different if they included some of the factors we mention above (LASEK/PRK, higher prescriptions, longsightedness, or more astigmatism).

Ultralase’s results are based on 802 Ultra Elite laser eye treatments – their top of the line treatment – between 13th of July and 3rd of November 2009. Like the Optical Express, they exclude mono vision and partial treatments. Importantly, they mention that their outcomes are based on binocular vision, which the way most people see in day to day life. Again though, we can’t determine at what stage the results were measured, what prescriptions they included, whether the patients had astigmatism or not, or whether they were short or long sighted patients.

Therefore, we believe it’s difficult for people to compare Laser Eye Surgery outcomes, which is why we publish our Laser Eye Surgery results in such a way that every one of the above questions is answered. We, and we think most patients, would appreciate if all clinics did the same, so that patients could make more informed decisions by comparing like with like.

Contact a Patient Care Coordinator at 0207 224 1005 to discuss what results you can expect to achieve.