Oman Journal of Ophthalmology

EDITORIAL COMMENTARY
Year
: 2020  |  Volume : 13  |  Issue : 1  |  Page : 1--2

Femtosecond laser-assisted cataract surgery


Milind Prasannakumar Suryawanshi, Rashid Alsaidi 
 Ophthalmology Centre, MOD Hospital, Muscat, Oman

Correspondence Address:
Dr. Milind Prasannakumar Suryawanshi
Ophthalmology Centre, MOD Hospital, Muscat




How to cite this article:
Suryawanshi MP, Alsaidi R. Femtosecond laser-assisted cataract surgery.Oman J Ophthalmol 2020;13:1-2


How to cite this URL:
Suryawanshi MP, Alsaidi R. Femtosecond laser-assisted cataract surgery. Oman J Ophthalmol [serial online] 2020 [cited 2020 Jul 5 ];13:1-2
Available from: http://www.ojoonline.org/text.asp?2020/13/1/1/278554


Full Text



Femtosecond laser-assisted cataract surgery (FLACS), a new but less explored frontier of cataract surgery, was introduced by Nagy et al. in 2009.[1] In this technique, the laser energy is absorbed by the tissue to form a plasma of free electrons and ionized molecules, which expands rapidly as an acoustic shock wave. With time, the plasma cools and cavitation bubbles are formed. The force of the cavitation bubbles separates the tissue without heat generation or damage to the surrounding tissue.[2] The femtosecond laser is a solid, neodymium-doped glass laser, with a wavelength of 1053 nm, and it permits precise focusing of a 3-μm spot, accurate to within 5 μm inside the anterior chamber to achieve the desired effect.[3]

 Procedure



Docking

The first step is docking of patient interface. Depending on the manufacturer, the patient interface design could be contact (applanating) or noncontact (nonapplanating). With the patient in the supine position, the laser system is lowered while monitoring the descent on a videomicroscope until it touches the patient's cornea. On further lowering, the cornea is applanated and at this juncture, suction is applied to complete the docking. A rise in the intraocular pressure of about 15–20 mmHg occurs when suction is applied. Small conjunctival hemorrhage is common during the process of docking. There is a learning curve for docking even for an experienced cataract surgeon who is a novice to the femtosecond laser platform.[4]

Imaging

The different femtosecond laser platforms use either spectral-domain-optical coherence tomography (OCT) or ray-tracing reconstruction (three-dimensional confocal structural illumination) to image and map the treatment plan. While watching on a touch screen monitor, the limbal ring and main and side port incisions are adjusted. Decentration will result in improper placement of the main incision, side port incisions, and arcuate incisions to correct astigmatism. Centration of the capsulotomy ring is the next step. The size of capsulotomy and nucleotomy rings is adjusted next, and it depends on the size of the pupil. The latter is kept slightly larger than the former. Decentration and tilt can lead to complications. The pattern of lens fragmentation is based on the density of the nucleus and surgeon's preference. Initiating OCT scan, wave pattern of capsulotomy, lens offsets, lens fragmentation zone, corneal thickness, and wound tunnel length are adjusted and confirmed. A default clearance of 800 μ from the posterior capsule and 250 μ from the pupillary margin avoids complications. After pressing the footswitch, laser energy is delivered to perform in a sequence anterior capsulotomy; lens fragmentation; and main, side port, and astigmatic keratotomy corneal incisions.

Advantages of femtosecond laser-assisted cataract surgery

It is the accurate and predictable technique of cataract surgery. The capsulotomy is more precise in terms of its centration, shape, and size. In white intumescent cataract and subluxated cataract, FLACS is very helpful. It also reduces the risk of posterior capsule opacification, achieves better effective lens position, and reduces higher-order aberrations.[5] The initial concerns of “a uniform, imperfect capsulotomy” have dwindled off. Prior fragmentation by the laser reduces the risk of corneal endothelial loss and postoperative corneal edema.[6],[7] The cumulative dissipated energy used in FLACS is less compared to conventional phacoemulsification as the nucleus is already fragmented by laser. In challenging situations such as pseudoexfoliation, narrow anterior chamber, floppy iris syndrome, and hard cataracts,[8] FLACS reduces the potential risk of complications. Laser-assisted wound construction is good and iris tissue handling is less. The risk of endophthalmitis and postoperative anterior chamber inflammation is therefore less. Relaxing arcuate incisions is an added advantage in correcting astigmatism. Some machines have automated toric intraocular lens (IOL) planning which makes marks on capsulotomy, helping the surgeon to align the axis of toric IOL perfectly. The procedure is safe, and some researchers have even incorporated FLACS in surgical training of residents.[9]

Disadvantages

FLACS can be prohibitively expensive to the surgeon and patients. The procedure consumes more time. The scarred cornea is a contraindication for FLACS. Incomplete capsulotomy and incomplete incisions are common occurrences, and surgeon may have to complete them manually. In miotic pupil, performing capsulotomy and nucleotomy can injure the iris. Not being a portable instrument can be a handicap sometimes. Sometimes, laser delivery near the pupillary edge releases prostaglandins, making pupil very small, and rendering subsequent steps of phacoemulsification difficult.

The advent of FLACS has augmented the accuracy and predictability of cataract surgery, making it the refractive procedure, offering delight to the patient as well as the surgeon.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Nagy Z, Takacs A, Filkorn T, Sarayba M. Initial clinical evaluation of an intraocular femtosecond laser in cataract surgery. J Refract Surg 2009;25:1053-60.
2Sun H, Fritz A, Dröge G, Neuhann T, Bille JF. Femtosecond -Laser-Assisted Cataract Surgery (FLACS). In: Bille J, editor. High Resolution Imaging in Microscopy and Ophthalmology. Cham: Springer; 2019.
3Trikha S, Turnbull A, Morris R, Anderson DF, Hossain P. The journey to femtosecond laser-assisted cataract surgery: New beginnings or a false dawn? Eye2013;27:461-73.
4Christy JS, Nath M, Mouttapa F, Venkatesh R. Learning curve of femtosecond laser- assisted cataract surgery: Experience of surgeons new to femtosecond laser platform. Indian J Ophthalmol 2017;65:683-9.
5Nagy ZZ, Kránitz K, Takacs AI, Miháltz K, Kovács I, Knorz MC. Comparison of intraocular lens decentration parameters after femtosecond and manual capsulotomies. J Refract Surg 2011;27:564-9.
6Al-Mohtaseb Z, He X, Yesilirmak N, Waren D, Donaldson KE. Comparison of corneal endothelial cell loss between two femtosecond laser platforms and standard phacoemulsification. J Refract Surg 2017;33:708-12.
7Krarup T, Ejstrup R, Mortensen A, la Cour M, Holm LM. Comparison of refractive predictability and endothelial cell loss in femtosecond laser-assisted cataract surgery and conventional phaco surgery: Prospective randomised trial with 6 months of follow-up. BMJ Open Ophthalmo 2019;4.
8Chen X, Yu Y, Song X, Zhu Y, Wang W, Yao K. Clinical outcomes of femtosecond laser-assisted cataract surgery versus conventional phacoemulsification surgery for hard nuclear cataracts. J Cataract Refract Surg 2017;43:486-91.
9Cohen MN, Intili A, Ni N, Blecher MH. Femtosecond laser-assisted cataract surgery in residency training. Curr Opin Ophthalmol 2015;26:56-60.