This article follows on from my recent Zoom seminar which I recently posted, in which I presented current studies that have impact on the day to day management of glaucoma and cataract surgery.
In this seminar, which had over 200 registered attendees I looked at 4 studies, each of which will become the subject of an article
In this first instalment I discuss how I have changed my approach to cataract surgery following the recent FEMCAT study
Femtosecond, laser assisted cataract surgery (FLACS)
I first wrote about femtosecond Laser Assisted Cataract Surgery (FLACS) in May of 2013. In that article and many others that followed, I made the statement that I thought the FLACS was possibly the beginning of a new area in cataract surgery and would ultimately evolve to the point that it would be the new norm. The beginning of new era in cataract surgery with more and better to come.
I was so convinced that this was the way forward that I was even prepared to outrightly purchase a machine of my own. At over half a million dollars, that is no mean feat. In fact some did purchase their own, even sole practitioners. Thankfully I didn’t have to as a number of other ophthalmologists thought the same as me and so Victoria Parade Surgical Centre (VPSC) came to the party and bought one. They felt that they wanted to be an centre of excellence and therefore should have the latest technology. Since then, I have performed thousands of cases and in fact became the main surgeon, at VPSC performing FLACS.
Since then, there have been a multitude of peer review articles published, the latest of which is an article published in the April edition of the Journal of Cataract and Refractive surgery (JCRS): https://journals.lww.com/jcrs/Fulltext/2020/08000/Comparison_of_femtosecond_laser_assisted_cataract.3.aspx?context=FeaturedArticles&collectionId=1
Also, an earlier article published in the Lancet in January 2020: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(19)32481-X/fulltext
In essence, these articles confirm what I was beginning to suspect and which many others were also beginning to suspect.
Findings of the Lancet article
The Lancet article is a Femtosecond laser-assisted versus phacoemulsification cataract surgery study (FEMCAT)
In this study there were total of 1476 patients, 704 had FLACS and 685 had conventional cataract surgery.
The study authors hypothesised that FLACS should provide superior outcomes over conventional cataract surgery because of its greater degree of precision and its superior ability to perform lens fragmentation, although at a greater cost.
The study looked at a number of endpoints:
1.Wether FLACS had more or less complications to conventional surgery
2.Wether visual outcomes were better or worse
3.Wether the ability to achieve the desired refraction was any different to conventional surgery
4. Wether astigmatism was correctable to a better degree
5.The incremental cost of the treatment (over a patient who did not have FLACS) and who has a good, non FLACS result
Their conclusion was that, to quote from the article, “Despite its advanced technology, femtosecond laser was not superior to phacoemulsification in cataract surgery and, with higher costs, did not provide and additional benefit over phacoemulsificaction for patients or healthcare systems.
So lets examine these points
Does FLACS have any serious complications
One of the main questions was wether FLACS resulted in a reduction in complications over standard cataract surgery. This question is probably the most frequently asked by patients. One of the findings about FLACS is that due to the lens fragmentation provided by the laser, less phaco energy Is required and so theoretically, this should lead to less endothelial cell loss and thus better outcomes. In practice, and from study findings, this has not really been borne out. My own impression is that softening a dense lens does not seem to make it easier to remove and I still find myself using phaco energy to break up the lens. Further, most lenses can be successfully pre-chopped, meaning that no sculpting is required. This is equivalent to the laser breaking up the lens, also requiring no sculpting
The study concluded that FLACS was as safe as conventional surgery but no safer. Further, there did seem to be an increased tendency for anterior capsular tears, which has also been my experience.
Are Visual outcomes better with FLACS
By this, the question is wether the best corrected vision (with or without glasses) was any different to standard surgery
The findings were that FLACS was not inferior but also no superior. This means that patients having FLACS were just as likely to achieve their best corrected vision as those patients having conventional surgery.
Does FLACS achieve desired refraction any better
One of the problems with standard cataract surgery is achieving the desired refractive outcome unaided. That is to say, that if the goal is emmetropia then post operatively, patients ideally should be within 0.5 Diopters (and ideally within 0.25) of Plano to enable good distance vision without glasses.
In practice, most surgeons can only achieve this 85% of the time. This leaves a 15% group that will still require distance correction or in need of a further procedure to achieve that goal.
With FLACS, the hope was that with greater precision, would come greater refractive predictability. In reality, this has not been the case.
It would seem that although a capsulorhexis performed with a laser is perfectly round and perfectly sized compared to a manual rhexis, this has not resulted in any great benefit. Theoretically a rhexis that is too large will allow forward vaulting of the intraocular lens and therefore a myopic outcome and conversely, a rhexis that is too small will result in a more posterior position of the lens and therefore, potentially a hyperopic outcome.
Refractive outcomes with FLACS have not been found to be any better than with standard surgery.
Similarly, patients with astigmatism are no better of with FLACS
Cost of laser assisted cataract surgery
Laser cataract surgery is unquestionably expensive and the conclusion of the study is that it is not cost effective
So who should have FLACS?
The one area where laser assisted surgery is potentially better is in patients who have an advanced, intumescent cataract where the risk of an anterior scapular tear is high (Argentinian flag sign)
As the laser performs the capsulorhexis in under one second, the risk of a tear is greatly reduced although not entirely eliminated.
Patients with loose zonules such as those with PXF may also benefit as the rhexis is created without further zonular stress.
A manual capsulorhexis with result in further dehiscence of the lens due to zonular tearing increasing the risk of a dropped lens or lens dislocation
Patients with endothelial dystrophy such as as Fuch’s may also be better of as there may be less endothelial cell loss but even here, with pre-chopping there may be little benefit.
How I have changed my approach to cataract surgery
I no longer routinely offer FLACS as it is not cost effective.
I now offer it to patients who have significant PXF and who appear to have loose zonules
If a patient has an advanced, intumescent cataract I recommend it as a means of minimising the risk of a capsular tear.
Lastly, if a patient has obvious, significant zonular laxity for example after trauma or in patients with Marfan’s, I also offer it.
If the cost of FLACS comes down with time, which I do not believe will happen then I will offer more widely but at present, the cost is prohibitive and not justified