April 2016

 

EW CATARACT

 

Is femtosecond laser-assisted cataract surgery safer than conventional cataract surgery?


by Ellen Stodola EyeWorld Senior Staff Writer

 
   

Dr. Miller delved into this question at the 2016 Hawaiian Eye meeting

There has been much debate about whether using a femtosecond laser improves outcomes in cataract surgery. In a session at the 2016 Hawaiian Eye meeting, Kevin M. Miller, MD, Los Angeles, presented on whether femtosecond laser- assisted cataract surgery is safer than conventional cataract surgery. In the early days, it seemed that it was not safer, he said, but it has since improved. Femtosecond laser- assisted cataract surgery (FLACS) turns mediocre surgeons into good surgeons, he said. It takes several critical steps of the surgery out of the surgeons hands; all that needs to be done is to position the patient, dock the laser to the eye, assure the tilt is minimal, and fire the laser. FLACS produces consistent and reproducible results, Dr. Miller said. However, there are still pros and cons to using this new technology. One disadvantage in his opinion is that using a femtosecond laser will stunt the growth of surgeons in training. Eventually, most simple cases will be done with a laser, Dr. Miller said, but most likely, difficult cases will still need to be done conventionally. Because surgeons will not be refining their surgical skills on easy cases, this could adversely impact their ability to handle the complicated cases. There are many cases that cannot be handled with a FLACS approach, Dr. Miller said, including those with small pupils, deep set eyes, nystagmus, extreme kyphosis, tremors, corneal opacities, narrow lid fissures, previous corneal surgery, peripheral corneal vascularization, dementia, posterior synechiae, and overhanging blebs.

On the positive side, relaxing incisions with a femtosecond laser are more predictable. There is a consistent optical zone, Dr. Miller said, and there is a consistent arc length and incision depth with less chance of inadvertent perforation. This helps remove the surgeon variable from the equation, he said.

The capsulorhexis is rounder and more predictable with a femtosecond laser, Dr. Miller said. This reduces the likelihood of a tear out or radialization with a beginner surgeon. An incomplete capsulorhexis or one that is too small can have negative implications in surgery, so this helps to reduce the risk of these issues.

Again on the negative side, Dr. Miller said that radial tears in the anterior capsule will still occur. Posterior corneal folds from rigid interface devices, interface bubbles, and corneal opacities can produce small untreated zones in the capsulorhexis. Suction loss can produce large untreated zones, and these untreated zones may tear out if the capsule is grasped abruptly or taken out with a phaco probe. If a radial tear occurs, Dr. Miller said that other complications could follow. Another negative is that FLACS is associated with a transient rise in IOP, which in turn is associated with the development of subconjunctival hemorrhages. This could be harmful in eyes with advanced glaucoma.

A positive feature of using the femtosecond laser is that the nucleus is prefragmented and softened before the application of ultrasound energy. This reduces the time needed to remove the densest part of the cataract and results in reduced cumulative dissipated energy or effective phaco time, Dr. Miller said. It also helps with faster visual recovery.

The safety of FLACS is gradually increasing, Dr. Miller said. IOP rises are now lower, and the patient interface devices are gentler on the external ocular surface. Many of the steps have been automated, including detection of the limbus, placement of the incisions, and placement of the capsulorhexis. External incision architecture is improving, he said, and trapped gas within the capsular bag is less of a problem as techniques have evolved. Cortex removal is also less of a problem, and docking time has improved, Dr. Miller added. Improvements have helped posterior capsule concerns. Better imaging has made detection of the posterior capsule easier, and there are fewer cases of posterior capsule rupture and dropped nucleus. Results using the femtosecond laser continue to improve with experience, Dr. Miller said.

Editors note: Dr. Miller has no financial interests related to his comments.

Contact information
Miller: kmiller@ucla.edu

Femto laser cataract surgery: safe or no Femto laser cataract surgery: safe or no
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