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Femtosecond laser cataract surgery and its place in 2022

At the completion of this CPD activity, optometrists will have developed their knowledge of femtosecond laser assisted cataract surgery (FLACS). Including:

  • Identify patients who would benefit from FLACS and write informed referrals
  • Learn the benefits and risks of FLACS
  • Understand the steps in the patient experience as they undergo FLACS
  • Understand post-operative complications and co-management

NOTE: Optomery Australia members can enter their details at the bottom of this article to have it automatically added to their Learning Plan. 

As the demand for cataract surgery increases, so does the need for authentic co-management of the condition. DR LEWIS LEVITZ delves into the clinical aspects of FLACS to help optometrists counsel patients and assist them in making informed choices about their surgery.

Dr Lewis Levitz
MBBCh, MMed, FCS(SA)Opht, FRCSEd, FRANZCO
Vision Eye Institute

Cataract surgery is the most commonly performed operation in Australia.1 It is a wonderful operation in that it restores both sight and functionality, and is often a life-changing event.

However, when I tell patients about the small chance of a complication, they sometimes nod their heads and think about some other poor chap that this might happen to. It is confronting for people to realise that if something does go wrong, it can go very wrong and have profound consequences.

A cataract operation is made up of a set of steps, each of which can lead to increasing safety with regards to the next step. If one step is incorrectly performed, it can lead to an escalating cascade resulting in a poor outcome.

It was to standardise and make some of these steps uniform that femtosecond laser assisted cataract surgery (FLACS) was introduced.2,3 This expensive technology both has, and has not, lived up to initial expectations.

The problem of assessing whether FLACS makes cataract surgery safer is made difficult by the fact that cataract surgery is already a very safe operation. Although there are inherent risks with any operation, the chances of having a safe operation, whether one uses conventional or laser assisted surgery, is above 97%.4

The Alcon LenSx Femtosecond Laser System. Image reproduced with permission of Alcon.

Some of the complications, such as cystoid macular oedema are usually self-limiting. Other complications, such as posterior capsular rupture, are more serious. This can lead to the surgeon being unable to use the selected toric or multifocal lens or having to use an anterior chamber lens.

Occasionally, the patient needs a second operation to remove pieces of the nucleus or cortex from the vitreous. A ruptured posterior capsule can also lead to decreased vision from chronic cystoid macular oedema and the risk of endophthalmitis increases. All of the above can lead to a disappointed patient with less-than- expected vision.

Capsulotomy 

The capsulotomy can be the most challenging part of the operation. There has been no dispute that laser capsulotomy position and shape is very precise.5 The capsulotomy should overlap the optic of the lens in each and every case. This decreases posterior capsular opacification and may be an important factor if the patient is offered a multifocal or extended depth of focus (EDOF) lens where exact placement and stability are paramount.

Having a laser with the ability to cut an exact capsulotomy regardless of the size of the eye certainly puts the patient at an advantage before the ophthalmologist proceeds to the next step. Most surgeons are able to perform a very good capsulorhexis in most cases, but only a laser will guarantee the same amount of circularity in every case. Laser capsulotomy has proved useful in complicated trauma cases, in cases of zonular weakness, and in white cataracts.5

Nucleus division 

It was initially thought that using a laser to divide the nucleus into quadrants or sections would reduce the ultrasound power needed to remove the cataract.62 This has been a contentious issue in the literature with studies both supporting this idea7 and studies showing that it made no difference.8,9 This is not at all surprising as each surgeon has a unique way of operating and having a nucleus divided into quadrants would be irrelevant for many surgeons.

Vision 

The latest randomised prospective studies show no long-term visual benefit in using FLACS with regard to long term vision.7,8,10

Posterior capsular complications

So, if the patients have no visual benefit from FLACS, why are people still offering this as an expensive technology?

In 2016, it was shown that all surgeons who changed from performing conventional cataract surgery (CCS) to performing FLACS had a reduction in their complication rate, regardless of their level of experience.11 A reduction in complication rate was also seen during registrar training12,13 and when operating on post-vitrectomized eyes.14

Two prospective randomised controlled trials were published in 2019 and 2020.10,8 It was noted that, using current software, there was a “significant reduction in posterior capsular rupture in the femtosecond laser assisted group”.8

Table 1: Posterior capsular complications reported in FLACS versus conventional cataract surgery. PRCT=prospective randomised controlled trial.

A large meta-analysis of all current randomised controlled studies stated in 2020 that “in our subgroup of randomised controlled trials, posterior rupture seemed less with FLACS , which was of clinical significance…”.7 The most recent meta-analysis of randomised controlled trials once again showed the benefit of FLACS with regard to posterior capsular complications.15 Again, this validates the fact that the capsular rupture rate is less than 1% in almost all series of FLACS where more than 1000 patients were enrolled.16

This does not mean that all surgeons who use conventional surgery are less safe or should change to FLACS. One has to take into account that complications are very rare with regards to cataract surgery and that for some surgeons, the decrease in complications would be hard to measure.17 Table 1 (above) shows posterior capsular complications reported in FLACS versus conventional cataract surgery.

What will your patient experience?

As the patient’s primary eyecare provider, the optometrist is in a unique position to prepare their cataract patients for the next phase of their treatment. Your patient will have questions and will want to know what to expect. They will want to be reassured. If they chose to have FLACS, you might want to explain the following steps:

The patient would expect to be wheeled into a laser suite on a trolley. They would expect to be in the laser suite for five to seven minutes.

The patient would have a drop of local anaesthetic applied to the eye. A speculum, which is a small medical device that looks like a large paper clip, would be placed in the fornix. This keeps the eye open and allays the patient’s often expressed fear of ‘what happens if I close my eye during the procedure’. There is minimal if any discomfort.

The laser machine would be connected to the patient’s eye by either a plastic device that looks like a plastic cup, or a columnar device that looks like a small tube. This is called the patient interphase (PI).

Figure 2: Patient interphase, from the patient’s perspective.

The PI in certain machines holds a small contact lens that is almost identical to a slightly thickened contact lens used in your practices. It allows the PI to attach to the cornea with suction. The patient would be asked to look at a target surrounded by light. Many years ago, a more solid contact lens was used. However, a softer material with a better fit is now used (Figures 1 and 2).

The machine would then apply suction to stabilise the eye and the surgeon initiates the laser with a foot pedal. The actual laser procedure may take less than 40 seconds.

It is silent and the patient is often still waiting for ‘their laser’ when the suction is released and they are reassured that all went well. The patient would then either be taken to theatre where they would have their cataract removed under topical anaesthetic or to the anaesthetic bay to have a local subtenons anaesthetic given by the anaesthetist.

Once in theatre, the corneal incision, if made by the laser, would be opened manually or the surgeon would make a new incision. This is the first time the eye is ‘open’ as the laser has cut the capsulotomy and divided the nucleus into quadrants or segments without exposing the intra-ocular contents to the outside environment.

How do you know who might benefit?

Optometrists are ideally placed to see which patients would benefit from being offered FLACS.

The optometrist is usually the first person to notice if a patient has pseudo-capsular exfoliation, which is associated with capsular weakness. These patients would be ideal for FLACS as no forces would be applied to the capsular bag during capsulotomy.5

In a similar vein, the referring optometrist would know if they had an elderly patient with corneal endothelial disease who might also benefit from FLACS.7

I also suggest to all my patients who have chosen EDOF or multifocal lenses that they should consider having FLACS. That way, there is a greater chance that their intraocular lens will be well placed with a 360-degree capsular optic overlap holding the lens stable in the capsular bag.18 (Having part of a multifocal lens slip through an eccentric or irregularly capsulorhexis and lie in a tilted position could change the optics of the visual system).

If you are co-managing a patient who has had FLACS, then you might mention beforehand that they may have a small sub-conjunctival haemorrhage around the limbus after the operation. This sometimes occurs if the suction causes a tiny subconjunctival vessel to bleed. This is totally innocuous and of no importance.

The place for FLACS

Femtosecond assisted laser cataract surgery does not give better final vision than conventional cataract surgery. However, recent high-level evidence has demonstrated that FLACS decreases the risk of having a complication which could lead to a poor visual outcome.

The process itself is quick and pain-free and is sometimes over before the patient realises it has begun. It definitely has a place for certain ocular conditions and when high precision with regards to capsular size and position is needed.

References 

1. What Are The Most Common Surgeries In Australia? – Surgery.com.au. Accessed October 31, 2021. https://www.surgery.com.au/common-surgeries-in-australia/

2. Abell RG, Kerr NM, Vote BJ. Toward zero effective phacoemulsification time using femtosecond laser pretreatment. Ophthalmology. 2013;120(5):942-948. doi:10.1016/j.ophtha.2012.11.045

3. Roberts T V., Lawless M, Bali SJ, Hodge C, Sutton G. Surgical outcomes and safety of femtosecond laser cataract surgery: A prospective study of 1500 consecutive cases. Ophthalmology. Published online 2013. doi:10.1016/j. ophtha.2012.10.026

4. AbellRG,Darian-SmithE,KanJB,AllenPL,EweSYP,Vote BJ. Femtosecond laser-assisted cataract surgery versus standard phacoemulsification cataract surgery: Outcomes and safety in more than 4000 cases at a single center. J Cataract Refract Surg. Published online 2015. doi:10.1016/j. jcrs.2014.06.025

5. Bala C. Femtosecond laser capsulotomy. J Cataract Refract Surg. Published online 2021. doi:10.1097/j. jcrs.0000000000000728

6. Hatch KM, Schultz T, Talamo JH, Dick HB. Femtosecond laser-assisted compared with standard cataract surgery for removal of advanced cataracts. J Cataract Refract Surg. Published online 2015. doi:10.1016/j.jcrs.2015.10.040

7. Kolb CM, Shajari M, Mathys L, et al. Comparison of femtosecond laser–assisted cataract surgery and conventional cataract surgery: a meta-analysis and systematic review. J Cataract Refract Surg. Published online 2020. doi:10.1097/j.jcrs.0000000000000228

8. Roberts HW, Wagh VK, Sullivan DL, et al. A randomized controlled trial comparing femtosecond laser–assisted cataract surgery versus conventional phacoemulsification surgery. J Cataract Refract Surg. Published online 2019. doi:10.1016/j.jcrs.2018.08.033

9. Schweitzer C, Brezin A, Cochener B, et al. Femtosecond laser-assisted versus phacoemulsification cataract surgery (FEMCAT): a multicentre participant-masked randomised superiority and cost-effectiveness trial. Lancet. Published online 2020. doi:10.1016/S0140-6736(19)32481-X

10. Day AC, Burr JM, Bennett K, et al. Femtosecond Laser-Assisted Cataract Surgery Versus Phacoemulsification Cataract Surgery (FACT): A Randomized Noninferiority Trial. Ophthalmology. Published online 2020. doi:10.1016/j. ophtha.2020.02.028

11. Scott WJ, Tauber S, Gessler JA, Ohly JG, Owsiak RR, Eck CD. Comparison of vitreous loss rates between manual phacoemulsification and femtosecond laser–assisted cataract surgery. J Cataract Refract Surg. 2016;42(7):1003- 1008. doi:10.1016/j.jcrs.2016.04.027

12. Brunin G, Khan K, Biggerstaff KS, Wang L, Koch DD, Khandelwal SS. Outcomes of femtosecond laser-assisted cataract surgery performed by surgeons-in-training. Graefe’s Arch Clin Exp Ophthalmol. 2017;255(4):805-809. doi:10.1007/s00417-016-3581-x

13. Hou JH, Prickett AL, Cortina MS, Jain S, De La Cruz J. Safety of femtosecond laser-assisted cataract surgery performed by surgeons in training. J Refract Surg. Published online 2015. doi:10.3928/1081597X-20141218-07

14. Wang EF, Worsley A, Polkinghorne PJ. Comparative study of femtosecond laser-assisted cataract surgery and conventional phacoemulsification in vitrectomized eyes. Clin Exp Ophthalmol. Published online 2018. doi:10.1111/ ceo.13133

15. Chen L, Hu C, Lin X, et al. Clinical outcomes and complications between FLACS and conventional phacoemulsification cataract surgery: a PRISMA-compliant Meta-analysis of 25 randomized controlled trials. Int J Ophthalmol. Published online 2021. doi:10.18240/ijo.2021.07.18

16. Levitz LM, Dick HB, Scott W, Hodge C, Reich JA. The latest evidence with regards to femtosecond laser-assisted cataract surgery and its use post 2020. Clin Ophthalmol. Published online 2021. doi:10.2147/OPTH.S306550

17. Levitz L, Reich J, Hodge C. Posterior capsular complication rates with femtosecond laser-assisted cataract surgery: a consecutive comparative cohort and literature review. Clin Ophthalmol. Published online 2018. doi:10.2147/OPTH. S173089

18. Levitz, L M, Scott, W; Lawless, M; Dick, B; Nagy Z. Comment on : Comparison of femtosecondlaser-assisted cataract surgergery and conventional cataract surgery:a meta-analysis and sydtemic review. J Cart Refract Surg. 2021;47(2):278.

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