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New method of laser capsule polishing might prevent PCO
Shockwaves remove lens epithelial cells from the anterior and posterior capsule as well as the capsule equator.
 Pavel Stodùlka |
A new technique for complete cleaning of the inner capsule by laser-generated pulses may reduce capsular opacity after cataract surgery, according to a surgeon speaking at the winter meeting of the European Society of Cataract and Refractive Surgeons in Istanbul.
Capsule opacity is the most common late complication of cataract surgery, resulting in decreased quality of vision and necessitating YAG capsulotomy. It is also a major impediment to technological advancements such as fully functional accommodating IOLs and lens refilling. Attempts to remove residual cells by aspiration proved to be ineffective because of the limited possibility of cleaning the equator of the bag.
“We are now proposing an innovative laser method, the laser capsule opacity prevention (LCOP) procedure, that allows us to reach and clean every corner of the capsular bag,” Pavel Stodùlka, MD, PhD, said.
The laser, manufactured by ARC Laser, is an Nd:YAG laser set at a wavelength of 1,064 nm and a pulse duration of 8 ns. A dedicated disposable probe with a 300-µm diameter optic fiber is used to reach the inner side of the capsular bag.
How it works
Laser pulses hit the titanium target at the tip of the laser probe at a frequency of 2 Hz to 10 Hz and generate shockwaves that remove the lens epithelial cells (LECs) and make them available for aspiration.
“The initial pulses may be facing toward the posterior capsule to clean minor remnants of the cortex just after nucleus and cortex removal. Then the IOL is implanted and serves as a shield for the posterior capsule during the following stages of the treatment. New shockwaves are directed toward the anterior capsule, 360° all around the lens equator. Germinating LECs are detached and aspirated, leaving the anterior capsule perfectly clean and transparent,” Dr. Stodùlka said.
Study results
In a study on cadaver eyes, Mamalis and colleagues demonstrated that shockwave laser pulses remove not only the germinating LECs but also the binding proteins laminin and fibronectin from the lens capsule. These proteins serve as a scaffold for proliferating cells.
“Without these proteins, lens epithelial cells are not able to migrate on the capsule,” Dr. Stodùlka said.
In a study, an intra-individual comparison between eyes operated with and without LCOP after cataract surgery was carried out. Both eyes were implanted with the Crystalens HD (Bausch + Lomb) by Dr. Stodùlka, using the same phacoemulsification unit.
“Three-month results showed a much clearer capsule in the eyes where LCOP was performed,” Dr. Stodùlka said. Also, BCVA and contrast sensitivity were better.
A multicenter study with longer follow-up will be organized to evaluate the efficacy of this method.
LCOP is a safe, easy and promising method for the prevention of capsule opacification, Dr. Stodùlka said. If cleaning the lens material as thoroughly as possible is a goal of cataract surgery, LCOP might be the logical third step after nucleus and cortex removal.
“Certainly this procedure does make the capsule clean. Whether it prevents [posterior capsular opacification], we don’t know yet, but we hope to be able to demonstrate it,” he said. – by Michela Cimberle
Reference:
- Mamalis N, Grossniklaus HE, Waring GO 3rd, et al. Ablation of lens epithelial cells with a laser photolysis system: histopathology, ultrastructure, and immunochemistry. J Cataract Refract Surg. 2010;36(6):1003-1010.
- Pavel Stodùlka, MD, PhD, can be reached at stodulka@lasik.cz.
- Disclosure: Dr. Stodùlka is a consultant for Bausch + Lomb.
 Oliver Findl |
This technique of using the laser pulse “shockwave” for killing lens epithelial cells after irrigation and aspiration is interesting. I was among the first to perform this procedure in a couple of eyes more than 5 years ago. We had problems of iris pigment dispersion and iris hemorrhages at the time. These problems seem to be resolved now. Potentially, this technique could help to eradicate LECs and therefore hinder anterior and posterior capsule opacification. Obviously, a follow-up of 3 months is much too short and eight eyes are too few for any deductions to be made. A properly designed randomized controlled trial with a standard open-loop IOL and a validated PCO documentation and quantification technique are needed to assess the potential of this interesting approach.
— Oliver Findl, MD
Head of the Department
of Ophthalmology, Hanusch Hospital, Vienna, Austria
Disclosure: No products
or companies are mentioned that would require financial disclosure.