Will tissue-saving LASIK for high myopia cause permanent side effects such as halos and glares?

I fully appreciate your concerns about safety and long term complications when trying to make a decision on whether to proceed with LASIK, or for that matter any form of surgery. One of the greatest challenges for any refractive surgeon is deciding which is the best course of action in assisting a person with both high myopia and astigmatism.

With respect to laser-based options such as LASIK, ReLEx SMILE or PRK, the surgeon has to ensure that the patient has sufficient cornea thickness to achieve a stable outcome after surgery. An insufficient amount of corneal tissue remaining after LASIK might predispose a patient to an increased risk of corneal ectasia.

Implantable Collamer Lens (ICL) can be a good alternative in order to preserve corneal thickness and has the potential to have lower rates of developing dysphotopsia (haloes & glares). To be clear, dysphotopsia can occur in patients with ICL as well. Though the likelihood is potentially lesser than in LASIK for patients with very high levels of refractive errors. The main criteria here: Is there sufficient internal space for the eye to accommodate an ICL?

When I counsel patients on any surgery, I do try to give them a balanced perspective about benefits and risks. As with all forms of surgery, there are risks, results are often very good though not always perfect (e.g. residual 25 degrees) and vision remains stable for decades though not necessarily a lifetime. Risks of serious complications in LASIK are one of the lowest for any surgery (less than 1%) but it is still not risk-free.

Ultimately, many patients, and they run in the millions, make the decision to have refractive surgery based on careful weighing of the benefits of being independent of glasses and contact lenses versus the potential risks that have been widely known for the past 30 years. To be sure, the rates of complications have fallen over the years as technologies improve and our understanding of the potential risks of LASIK mature.

One final advice to help alleviate some of the information overload when researching on medical matters is to engage with a surgeon you trust. Let him guide you through the maze of information and identify key factors that are most relevant to your case. I wish you all the best in your efforts towards gaining spectacles independence.

Please see below for some recent articles on LASIK in high myopes & collagen cross-linking. You may find data there that might be useful.

LASIK in high myopia and astigmatism

https://www.ncbi.nlm.nih.gov/pubmed/27163613

https://www.ncbi.nlm.nih.gov/pubmed/25465210

Collagen Cross-linking & LASIK

https://www.ncbi.nlm.nih.gov/pubmed/27152484

https://www.ncbi.nlm.nih.gov/pubmed/25588591

Dr David Chan

Your predicament is understandable. High myopia and astigmatism may be more challenging to treat when cornea thickness is not adequate.

You may want to firstly find out why you are not suitable for ICL, as it is a better option for very high myopia and astig if you fulfill the anatomical requirements for ICL.

Tissue-saving LASIK is a treatment offered by some LASIK excimer lasers (the flying spot lasers). Depending on the excimer laser used, the cornea tissue thickness requirement may be a little different. So, checking with a clinic that uses a different laser system may not be a bad idea.

Regardless of this, side effects like dry eyes, glare, halos and poorer night vision tend to persist for longer for higher treatment degrees. However, generally speaking, it is very rare that these side effects would be so severe and disabling.

In my experience, so long as pre-op planning post-op care are done properly, high myopia and astig can still be successfully treated. Best wishes for your quest for visual freedom!

Dr Daphne Han

Hi Edmund

In an ideal world, we would have a way to show you what kind of visual side effects, glare and halos you would get after LASIK. These side effects are possible no matter what kind of laser refractive surgery you have e.g. LASIK (including tissue saving or non tissue saving LASIK), epiLASIK/PRK and SMILE.

[As an aside, 'Tissue Saving' LASIK was a 'Brand Name' for an ablation algorithm used on the Bausch and Lomb Technolas platform. This is now superseded by the Bausch and Lomb Teneo platform, and they have changed the name of the tissue saving mode to 'Eco mode'. In a way, the term 'tissue saving' is a holdover from people who have used the older machine.]

The main advice we can provide is that there is a higher risk you could notice visual side effects, the higher the spectacle power that is being treated. We do not know what your spectacle degree is, but in my practice I tend to explain more about these issues to people who have above about -8D or 800 degrees of shortsightedness/myopia.

Nowadays, I avoid LASIK for patients above about -10.50 to -11.00D. On the other hand, patients with low degrees eg -3D, or even -6D rarely have any issues with night time vision. These are just general guidelines and may vary from doctor to doctor.

As another reference, SIA allows prospective pilots to have LASIK if their myopia is -5D or below, and astigmatism -2D or below. These patients generally have good night time vision after LASIK.

Remember that 'higher risk' does not automatically mean you would get such problems. The actual severity depends on many factors such as pupil size in the dark, 'pupil offset' (from the corneal vertex), corneal thickness (since a thin cornea can only support a small optical zone), etc

Having said that, you need to consider your desire for refractive surgery versus the possible side effects. While I don't think working on a computer would be a problem, driving at night can sometimes be an issue if the side effects are bad enough. Personally, since I don't have a way to definitively demonstrate the side effects, I think it is advisable that you consider a worst case scenario.

If you are very worried, it is probably best that you stick with glasses or contact lenses, if you are not suitable for ICL surgery. If you are suitable, then ICL surgery would give you the least possibility of night time visual issues.

You might want to ask exactly why you are not suitable for ICL surgery. The most common reason would be that the anterior chamber (AC) depth is too shallow, in which case, ICL surgery is definitely not advisable.

If in the end, you decide to stick with optical aids rather than surgery, I find that many patients do well with contact lenses for high degrees of spectacle power.

This is especially true of 'hard' rigid gas permeable contact lenses, which allow comfortable wearing for the whole day, after an initial period of discomfort and getting used to it.