Is LASIK a viable solution for presbyopia? Yes
Skepticism about LASIK for presbyopia is unfounded
Arguments against LASIK for presbyopia often stem from a poor understanding of the basic concept. In particular, people tend to think of multifocal optic sets that put distance and near into the same cornea – perhaps because this was, until recently, the only way of applying laser technology to the correction of presbyopia on the cornea. This technique is not perfectly safe; just like multifocal IOLs, it reduces the quality of vision. So, for historical reasons, some in the ophthalmic community have remained skeptical about LASIK for presbyopia. This is misguided: modern laser for presbyopia has nothing to do with such outdated approaches. Today, we use the laser blended vision approach, an option that was made commercially available by Carl Zeiss on their MEL80 and MEL90 platforms in 2009 as PRESBYOND®. It’s also referred to as “modified monovision,” but that’s a misnomer because PRESBYOND® is not a monovision approach; it’s a way of increasing the ocular depth of field and maintains binocular vision at both distance and near. If anything, it could be called “modified binocular vision.” The technique is based on continuous optics – we’re not constructing a bifocal cornea, we’re designing asphericity into the cornea to increase the depth of field in the eye. Furthermore, we achieve this spherical aberration without any reduction in contrast sensitivity or visual quality.
Using an excimer laser-based procedure is a tried and tested approach that has been used over 60 million times (and recently, on my own eyes). I can’t overstate how low-risk this operation is: the success rate approaches 100 percent. Patients undergo a 10-minute procedure, heal in a few hours, and are usually reading without glasses the same day. There’s just no comparison with previous approaches, such as refractive lens exchange or clear lens replacement; these procedures are less accurate, correlated with more side-effects, and are of higher risk (for example, they are associated with accelerated macular degeneration). Moreover, lens exchange methods are irreversible – once you’ve removed the natural lens you can’t put it back.
It’s also important to note that even youthful pure presbyopic patients are eligible for the LASIK approach to presbyopia; we can’t make the same claim for lens replacement techniques. In particular, intraocular surgery is associated with increased retinal detachment rates in younger patients: a 50-year-old has 20 times the chance of a retinal detachment after lens surgery as an 80-year-old. That is a very significant increase in risk – and, given the available alternative, an entirely unnecessary one. In fact, my view is that the current trend to replace lenses in patients as young as 50 or even 45 is at least flawed and possibly dangerous. I can understand why people have gone down this road – it’s because cataract surgery has become so much safer – but I suspect people will move away from it very soon, partly because of growing recognition that multifocal lenses are associated with degrading optics, safety issues, and that the LASIK option is safer and better.
The modern, LASIK-based approach to presbyopia is only just beginning, but I have no doubt of its potential to become the standard of care within the next 10 years. Perhaps it will become the norm for people to wear contact lenses from age 13 to 18, then receive LASIK for their 18th birthday so they can leave school with corrected vision. They might need another enhancement in their late 20s/early 30s, and then maybe some laser blended vision or PRESBYOND® in their mid-40s to avoid the need for reading glasses. That too might need a little adjusting after five or 10 years. And it’s no problem if they develop cataracts later – because then, thanks to the depth of field inserted into the cornea with the blended vision approach, we could choose an intraocular approach incorporating a monofocal, low PCO rate IOL with high-quality optics. That’s the optimal way of doing things, and that is how a lifetime of vision correction could work in the future.
I don’t accept that lens interventions are the best current answer. Patients always want maximum safety, and until invasive procedures are as safe as non-invasive procedures, in our practice there’s no realistic debate over the merits of LASIK versus lens exchange. It is simply not the case that a candidate for modern corneal presbyopic surgery – that is, depth of field control on the cornea with spherical aberration – should be offered lens surgery as an alternative to LASIK. Safety is the number one priority: that’s my feeling, and that of many of my colleagues.
The Royal College of Ophthalmologists refractive surgery guidelines published in April 2017 state in paragraph 21 of the informed consent section that “You must tell prospective patients if alternative interventions are available that could meet their needs with less risk, including from other practitioners.” I would find it hard to believe that full disclosure of the relative risks, accuracy, side effects, reversibility and adjustability of phacoemulsification with IOL implantation with corneal refractive surgery would lead to the patient opting for an intraocular option in the absence of cataract.