Laser Approach Advantageous for Cataract Surgery
ORLANDO, Fla., Oct. 25, 2011 — Two new studies on the use of femtosecond laser procedures in cataract surgery back the argument that the technology may be safer and more efficient than the standard procedures used today.
According to data presented at the annual meeting of the American Academy of Ophthalmology (AAO), being held this week in Orlando, using a femtosecond laser to fragment the existing lens in patients’ eyes has several advantages.
In a study by Dr. William Culbertson of the University of Miami School of Medicine, pretreating cataracts with the femtosecond laser affected the level of ultrasound energy needed to soften the cataracts. This emulsification is performed so that the cataracts can be easily suctioned out. Surgeons want to use the lowest possible level of ultrasound energy because, in a small percentage of patients, it is associated with slower recovery of good vision after surgery and/or problems with the cornea, which is the clear outer layer of the eye. Ideally, in appropriate cases, ultrasound would be eliminated altogether.
In Culbertson’s study, 29 patients had laser cataract surgery with a femtosecond laser in one eye and the standard cataract procedure, called phacoemulsification, in the other. The laser surgery element comprised a capsulotomy step, where a circular incision is made in the lens capsule, followed by laser lens fragmentation — where the laser splits the lens into sections and softens it by etching cross-hatch patterns on its surface.
Standard surgery included a manual incision, followed by ultrasound emulsification and aspiration. After cataract removal by either method, intraocular lenses were inserted into eyes to replace the natural lens and provide appropriate vision correction for each patient.
The use of ultrasound energy was reduced by 45 percent in the laser pretreated eyes, compared with the eyes that received the standard cataract surgery procedure. Also, surgical manipulation of the eye was reduced by 45 percent in eyes that received laser pretreatment as compared with manual standard surgery. This study involved the most common types of cataracts, those graded 1-4. Culbertson noted that these findings may not apply to higher-grade cataracts.
“In clinical practice, surgeons would expect safer, faster cataract surgery when laser pretreatment is performed before cataract removal,” Culbertson said. “The combination of precision and simplification that is possible with the femtosecond laser represents a major advance for this surgery.”
In the second study, by Dr. Mark Packer of Oregon Health and Sciences University in Portland, the safety of laser cataract surgery was assessed in terms of loss of corneal endothelial cells, as measured after cataract surgery. Measuring endothelial cell loss is one of the most important ways to assess the safety of new cataract surgery techniques and technology. These cells preserve the cornea’s clarity, and because they don’t regenerate, they must last a lifetime. Packer’s study found that, when laser lens fragmentation was used in 225 eyes, there was no loss of endothelial cells, while the 63 eyes that received standard treatment had cell loss of 1 to 7 percent.
“Our finding, that laser lens fragmentation appears to protect corneal endothelial cells, represents a significant benefit of this new surgery,” Packer said. “This procedure is safer than standard cataract treatment and is likely to mean better vision and fewer eye health concerns for cataract patients, over the long term.”
The two studies further validate the value of femtosecond laser surgery, the AAO said. Although ultrafast lasers have been used in refractive surgery for many years to reshape a patient’s cornea, the key challenge with cataracts has been that the lens sits much deeper within the eye. It wasn't until 2009 that a new femtosecond laser source capable of reaching that deep was approved by the US Food & Drug Administration.
For more information, visit: www.aao.org
- femtosecond laser
- A type of ultrafast laser that creates a minimal amount of heat-affected zones by having a pulse duration below the picosecond level, making the technology ideal for micromachining, medical device fabrication, scientific research, eye surgery and bioimaging.
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