Grid FLACS reduces corneal endothelial cell count loss in dense cataracts
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In patients with dense cataracts, a grid-based femtosecond laser helped reduce corneal endothelial cell count loss during phacoemulsification, according to a study published in the American Journal of Ophthalmology.
Soon-Phaik Chee, MBBS, of the Singapore National Eye Center, and colleagues wrote that previous studies have shown the benefit of femtosecond laser-assisted cataract surgery over manual phacoemulsification (PE). However, they were non-randomized studies and used the “stop and chop” method.
“When dealing with brunescent lenses, the most energy efficient technique for managing the tough nucleus is using a technique which minimizes sculpting,” Chee and colleagues wrote. “Thus, the comparison between FLACS and the manual PE in these studies was perhaps not as well matched as when an in-situ phaco chop technique is used.”
Researchers compared the 600-µm grid femtosecond laser-assisted cataract surgery (FLACSg) with a 16-segment FLACS (FLACS16) and PE in patients with nuclear opacity (NO) of at least 5 (LOCS III). Researchers used the Victus laser platform (Bausch + Lomb) for the procedures and performed the in-situ chop technique in all cases.
Investigators collected data on patient demographics, best corrected visual activity at baseline and at 1 month after operation, endothelial cell count (ECC), effective phacoemulsification time (EPT) and perioperative complications. The outcome measures of the study were loss of ECC at 1 month after surgery and EPT.
Chee and colleagues randomly assigned 93 patients (93.5% Chinese, mean age 74.3 years) to undergo FLACSg (22 patients), FLACS16 (23 patients) or PE (48 patients). In the study population, the most common NO for cataract grading was 5 or 6.
Although they observed a trend, Chee and colleagues found that EPT was not different among the treatment arms. However, EPT was higher for patients with NO greater than 6 compared with NO 6 or less (P < .001). There was also no difference in mean duration of surgery among the treatment groups (PE, 16.38 minutes; FLACS16, 15.26 minutes; FLACSg, 15.29 minutes).
One month after surgery, patients treated with FLACSg had less ECC loss than those treated with PE (P = .018). The difference in ECC loss between the PE and FLACS16 groups was not significant.
Chee told Healio/OSN that initially, their findings may seem surprising.
“However, using a laser to fragment the nucleus into 16 segments and manual PE are not that different in their effect on EPT when a direct phaco chop technique is used,” she said.
“They are similar in essence, as phaco energy is not used to chop through the dense nucleus nor laterally separate the tough fibers that bind the pre-fragmented segments.”
Perspective
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This study looks at truly advanced cataracts which have a LOCS III grading of nuclear opalescence grade 6 or higher, which equates to our dense, brunescent cataracts.
These cataract types are more challenging because of the amount of ultrasonic energy needed to break up and emulsify these cataracts, with high amounts of ultrasound being associated with more endothelial cell loss. If we can soften or divide these cataracts into smaller segments using mechanical methods or laser energy, then we may be able to aspirate them with less phaco power.
Can FLACS, femtosecond laser-assisted cataract surgery, be employed to be of benefit in these eyes? To answer this, the authors compared three arms: phaco chop by expert surgeon Soon Phaik Chee, MBBS, FLACS with a 16-segmentation pattern, and FLACS with a grid pattern. Results were the same across the board, including a fairly long 15- to-16-minute total surgery time, except for postop endothelial cell loss. In the phaco chop cases, the endothelial cell loss was 12%, for FLACS with segments it was about 10%, and for FLACS with grid treatment it was almost 7%. A statistical benefit was found for FLACS with grid treatment over phaco chop and FLACS segmentation, which makes sense because this grid laser energy pattern is given to specifically soften a dense nucleus.
While it is nice to have access to very expensive technologies such as femtosecond lasers, which can have a modest benefit in some cases, an experienced surgeon can perform phaco chop and produce the same results for all metrics other than endothelial cell loss. And it should be noted that all groups studied had a final postop endothelial cell count of more than 2,200 cells/mm2 for patients who averaged 72 to 76 years old, which is plenty to ensure a clear cornea for the rest of their lives.
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