This article is more than 5 years old. Information may no longer be current.
Femtosecond laser offers advantages in challenging cataract cases
Laser technology helps surgeons perform steps that would normally be more difficult with traditional manual approaches.
Click Here to Manage Email Alerts
In cataract surgery, the femtosecond laser can assist us in making a capsulorrhexis, creating corneal incisions and even softening and dividing the lens nucleus. In routine cases, these steps can aid the surgeon in minimizing phaco energy and reducing corneal astigmatism with relaxing incisions.
For challenging cases, such as those with loose zonules, lens subluxation and intumescent cataracts, the femtosecond laser can accomplish steps that are difficult or nearly impossible with traditional manual methods.
Capsulorrhexis creation
Patients with an intumescent white cataract are at risk for radialization of the capsulorrhexis due to the increased intralenticular pressure from liquefied lens material. With the manual technique, care must be taken to control the capsulorrhexis by pressurizing the anterior chamber and depressurizing the capsular bag contents to avoid rapid run-out of the capsular tear. In our surgery center, we are fortunate to have two different femtosecond laser platforms, the OptiMedica Catalys and the Alcon LenSx, both of which can be used in a wide variety of cataract cases.
For a recent case involving an intumescent white cataract, I was able to use the Catalys, which can create a complete, perfectly round capsulorrhexis in less than 2 seconds, to simplify the surgery. This efficiency allowed for release of the intumescent lens fluid and lowering of the intralenticular pressure immediately with the capsulorrhexis creation.
Figure 1. Top frame: The Catalys laser’s imaging system alerts the user to a pre-existing posterior capsule defect (yellow arrow) with a warning sign (red box). Bottom frame: The grid pattern was used to soften and divide the lens nucleus at a 6.5-mm zone, while the capsulorrhexis was created with a 5-mm diameter.
Images: Devgan U
Figure 2. Inset frame: Viscoelastic is injected with the left hand while the phaco probe is used to remove the last nuclear fragments. The viscoelastic prevents vitreous from prolapsing through the posterior capsule defect (yellow arrow). Main frame: Because the Catalys laser created a centered 5-mm capsulorrhexis, the optic of the three-piece IOL was button-holed through and captured behind the anterior capsular rim, which then stretched to the rhomboid configuration seen here (blue dashed line). The posterior polar opacity is seen (yellow arrow), as well as the edge of the posterior capsule defect (yellow dashed line), which has extended after IOL insertion. The anterior hyaloid face remained intact, and there was no vitreous prolapse.
Another challenging situation in which femtosecond lasers excel is creation of a capsulorrhexis in an eye with weakened zonular support or subluxation of the cataractous lens. In manual techniques, it becomes difficult to tear the capsulorrhexis by hand when the zonular laxity prevents the surgeon from achieving adequate tension of the capsule surface. Techniques using one hand to stabilize the capsule edge while the other hand tears the capsulorrhexis have been described, but using the femtosecond laser makes this surgical step easy. The surgeon simply centers the laser guidance over the desired area and, with no tension on the zonules, a perfectly round capsulorrhexis is instantly created.
Real-time imaging
The laser aspect of the technology is only half of the story, however. The real-time optical coherence tomography imaging incorporated into this technology is a benefit before entering the eye with instruments.
Recently, I was referred an 88-year-old patient with a brunescent cataract that precluded a view of the retina. His other eye had a sulcus-fixated IOL, open posterior capsule and mild pseudophakic bullous keratopathy. Upon slit lamp examination, the nucleus was opaque, dense and brown. I planned on using the Catalys’ nucleus grid program to soften the lens nucleus and divide it into quadrants. This would allow me to use less ultrasonic phaco energy during surgery and preserve more of the patient’s corneal endothelial cells.
When I placed the patient under the laser, I received a warning message from the laser telling me that the contour of the posterior capsule was abnormal. When I examined the OCT image, I was surprised to see a posterior polar opacity with a pre-existing defect of the posterior capsule. This changed my entire game plan for the surgery, and I now understood why the first surgeon encountered difficulties with cataract surgery in the patient’s fellow eye.
Hydrodissection would have caused the posterior capsule defect to extend dramatically and would likely have resulted in displacement of the entire lens nucleus into the vitreous. Instead, gentle viscodissection was performed to create a barrier between the posterior capsule and the cataract and to preserve the anterior hyaloid face and prevent vitreous prolapse. Additionally, dispersive viscoelastic was used to recoat the corneal endothelium periodically during surgery for maximum protection.
When the nuclear pieces were removed, more viscoelastic was used to tamponade the posterior capsule defect during cortex removal. For the lens implant, a three-piece monofocal aspheric lens with a 6-mm diameter optic was selected. It was initially placed in the ciliary sulcus, and then the optic was button-holed through the laser-created 5-mm capsulorrhexis. It was a perfect fit with the anterior capsular rim overlapping the optic from haptic to haptic, and it was beautifully centered because the laser had created the capsular opening precisely in the central zone. The anterior hyaloid face remained intact, and there was no vitreous prolapse. A small aliquot of triamcinolone was used to confirm this and aid in postoperative inflammation control.
The next day the patient’s eye looked great, and he was seeing well. His challenging case was aided by the femtosecond laser in many ways, including creation of a perfectly centered and sized capsulorrhexis, softening and division of a truly brunescent cataract, and preoperative real-time imaging that alerted me to his pre-existing ocular conditions.