On Day 1 of the 36th Annual Meeting of the Asia-Pacific Association of Cataract and Refractive Surgeons (APACRS 2024), leading experts in cataract surgery delved into the profound impact and future prospects of femtosecond laser technology in advancing surgical techniques and outcomes.
Few advancements have sparked as much excitement and promise as the femtosecond laser. Often hailed as a game-changer in ophthalmic surgery, femtosecond laser-assisted cataract surgery (FLACS) represents a significant leap forward in precision, safety and patient outcomes.
The femtosecond edge
Leading the discussion (Editor’s Note: This symposium was conducted in Chinese, our writer obviously wrote this in English!) was Prof. Yao Ke (The Second Affiliated Hospital of Zhejiang University School of Medicine, China) who underscored the significance of FLACS since its approval by the China Food and Drug Administration (CFDA) in 2013. Presently, over 350 clinics across the country have integrated FLACS into their practice, with over 400,000 successful procedures conducted.
Prof. Yao emphasized FLACS’s role in reducing anterior capsular tears, irregularities and capsulorhexis decentration particularly in cases involving white cataracts. “Notably, FLACS proves advantageous in cases of high myopia combined with cataracts, enabling superior capsulorhexis, sizing, centering, precise capsulotomy and enhanced capsule-intraocular lens (IOL) overlap compared to conventional methods,” he said.
Furthermore, Prof. Yao noted that FLACS demonstrates superior outcomes in inducing lower internal aberrations, including higher-order aberrations, tilt, coma and spherical aberrations, particularly in monofocal and extended-depth-of-focus (EDoF) IOL procedures with a 5.0 mm pupil diameter, as compared to conventional phacoemulsification surgery (CPS). However, he cautioned about potential postoperative concerns such as fluorescein staining and dry eye symptoms associated with FLACS.
“Additionally, meta-analysis studies comparing FLACS and CPS found that FLACS is superior to CPS in terms of higher quality of circularity of capsulorhexis and the reduction of mean phase energy and effective phacoemulsification time (EPT). FLACS is also safe and more effective in reducing endothelial cell loss and postoperative central corneal thickening. In summary, FLACS shows advantages in achieving better and faster visual rehabilitation, visual quality and refractive outcomes,” explained Prof. Yao.
The numerous advantages that FLACS brings marked a significant advancement in ophthalmic surgery.
The rise of FLACS
Meanwhile, Dr. Zhang Guangbin (Xiamen Eye Center of Xiamen University, China) asserted that cataracts stand as the predominant cause of vision impairment among individuals over age 50, globally. The evolution of cataract surgery has profoundly impacted the lives of these patients, and the integration of the femtosecond laser has significantly enhanced precision and safety–further refining surgical outcomes.
Dr. Zhang highlighted that FLACS is anticipated to experience an 18.2% increase in compound annual growth rate (CAGR) in China from 2021 to 2026. Within his center, which had been performing FLACS over the past 11 years, the conversion rate for all departments to FLACS stands at 51.1%. This notable transition is attributed to the enhanced predictability and safety that FLACS offers, alongside a growing confidence in its efficacy.
He noted that there are different energy levels and frequencies for femtosecond lasers. “Low-energy, high-frequency femtosecond devices have a higher rate of complete anterior capsule incision and significantly reduce pupillary miosis,” he said, adding that both low- and high-energy femtosecond lasers have good safety profile.
Dr. Zhang emphasized FLACS’s advantages in anterior capsulotomy, lens fragmentation, corneal incision, and limbal relaxing incision. He said that FLACS confers several benefits, including the achievement of a more precise and uniform corneal incision. “In many instances, anterior capsule tears result from improper handling of the anterior capsule. Therefore, attaining a more flawless continuous curvilinear capsulorhexis (CCC) diminishes the risk of anterior capsule tear and enhances surgical success,” he elucidated.
Moreover, Dr. Zhang highlighted the femtosecond laser’s ability to achieve more accurate positioning for astigmatism correction. “Femtosecond-assisted astigmatic keratotomy, coupled with the use of multifocal IOLs, can yield favorable outcomes in correcting astigmatism ranging from 0.75 D to 1.5 D,” he elaborated.
Additionally, Dr. Zhang underscored that pre-splitting the nucleus with the femtosecond laser reduces energy consumption during surgery and safeguards the corneal endothelium.
Advancing IOL stability
Last but not least, Prof. Dang Guangfu (First Affiliated Hospital of Shandong First Medical University, China), discussed the relationship between the stability of the IOL and the capsular opening in cataract surgery.
“The centration of the IOL is an important factor affecting visual quality. IOL shape, axial length and the opening of the central anterior capsule all affect centration,” he said.
Prof. Dang noted that decentration of aspheric IOLs may increase aberration and astigmatism, and multifocal IOLs can decrease the value of modulation transfer function (MTF) in cases of decentration over 0.2 to 0.5 mm, and tilt over 2 to 5 degrees. Hence, a 5.5 mm diameter opening that covers the optic completely is the basis of IOL stability and posterior capsule opacification (PCO) prevention.
Comparing retrospective case series of manual capsulorhexis (Manual) and femtolaser-assisted capsulotomy (FLACS) involving cataract patients aged 55-75 who underwent these procedures between March 2021 and February 2022, Prof. Dang noted that FLACS resulted in 100% coverage of the anterior capsule opening versus 82% for Manual. Meanwhile, tilt was 4.7° for FLACS and 5.3° for Manual, while decentration was 0.23 mm for FLACS and 0.33 mm for Manual.
“IOL centering and tilt are closely related to the integrity of the capsular bag and the coverage of the capsular opening on the IOL. FLACS is an effective measure for continuous curvilinear capsulorhexis (CCC). Additionally, the femtosecond laser provides better protection for eyes with severe ligament relaxation and turbidity,” he concluded.
Editor’s Note: Reporting for this event took place during the 36th Annual Meeting of the Asia-Pacific Association of Cataract and Refractive Surgeons (APACRS 2024), held from May 30 to June 1, 2024 in Chengdu, China. The 36th APACRS annual meeting is jointly organized with the 24th CSCRS (Chinese Society of Cataract & Refractive Surgery) annual meeting.
