EyeWorld Asia-Pacific September 2018 Issue

A grid fragmentation pattern resulted in lower effective phacoemulsi cation time compared to a pie fragmentation pattern except where the lens density was more than 12%. Source: Mehdi Shajari, MD Optimizing femto fragmentation patterns based on lens density lowers phaco time Study finds lower effective phaco time with pie fragmentation pattern for denser lenses T he femtosecond laser has shown its ability to create a centered, perfectly round, reproducible capsulotomy. It also has the ability to make corneal, arcuate, and limbal relax- ing incisions and perform nuclear fragmentation. Several studies have shown femtosecond laser-assisted cataract surgery (FLACS) to be as safe and effective as conventional phaco- emulsification cataract surgery, but little difference is seen in the visual or refractive outcomes. 1 In terms of complications, intraoperative complications between FLACS and conventional cataract surgery have been shown to be similar, while postoperative complications in one study were lower in the traditional phaco group. 2 A review published in the Cochrane Database of Systemic Re- views in 2016, which included 16 randomized controlled trials that compared FLACS with traditional cataract surgery, “could not deter- mine the equivalence or superiority of laser-assisted cataract surgery compared to standard manual phacoemulsification.” 3 Mehdi Shajari, MD , Depart- ment of Ophthalmology, Goethe University Frankfurt, Germany, and coinvestigators decided to dig deeper as to why this might be, surprised at the lack of a significant difference. One of the points Dr. Shajari, along with principal investigator Thomas Kohnen, MD, PhD, chair- man, Department of Ophthalmol- ogy, Goethe University Frankfurt, and coinvestigators evaluated in a study published in the Journal of Cataract & Refractive Surgery was fragmentation patterns and their effect on effective phacoemulsifica- tion time (EPT). 4 Previous research had shown that FLACS could reduce ultrasound energy delivered to the eye with the potential to then reduce occurrence of corneal edema and endothelial cell loss. 5 In a retrospective case series of 150 eyes, Shajari et al. compared a femtosecond laser pie fragmen- tation pattern (75 eyes) to a grid fragmentation pattern (75 eyes). The average EPT was higher in the pie pattern compared to the grid pattern (6.63 ± 5.41 seconds com- pared to 4.26 ± 6.99 seconds), and the number of eyes that required no ultrasound energy to be used in the case was higher with the grid pattern. Further analysis showed, however, that lens density was a factor. Cataracts with a lens density of more than 12% (nine eyes in each group) had a lower EPT when the pie nuclear fragmentation pat- tern was used. Dr. Shajari said he thinks the lower EPT is significant enough to have a positive effect. As stated by Dr. Shajari and coauthors in the paper, lower EPT can lead to less corneal edema and endothelial cell loss. As such, Dr. Shajari thinks choosing a fragmentation pattern based on lens density is something by Liz Hillman EyeWorld Senior Staff Writer 28 EWAP CATARACT/IOL September 2018