Femtosecond Laser-Assisted Cataract Surgery Pearls
The femtosecond laser brings a new level of precision to portions of cataract surgery and has the potential to increase the already high safety profile of cataract surgery.
There are currently several femtosecond lasers cleared by the FDA for use in cataract surgery in the United States. This includes the LenSx (Alcon), the Catalys (Optimedica), the LensAR (LensAR Inc.), and the Victus (Technolas/Bausch & Lomb).
Each company's trainers will provide thorough advice on how to perform the femtosecond laser portions of the surgery. However, techniques and best practces are still evolving. In the video attached, eight pearls for early adoption of the LenSx Laser are shared. Likewise, the pearls below are geared towards the LenSx laser, although similar techniques may be helpful with other laser platforms.
Practice Verbal Anesthesia
Verbally counsel your patient to look into the laser. It is critical with the first- and second-generation suction rings to obtain good centration when the suction ring is docked onto the globe. Therefore, the patient needs to be reminded to look straight into the laser, not up at the surgeon. I also remind my patients to remain relaxed. It is important to avoid Bell phenomenon; sometimes, 1 mg midazolam with 25 mg of fentanyl administered by the anesthesiologist is helpful.
Achieve Centration and Suction
Similar to the IntraLase femtosecond laser (Abbott Medical Optics Inc.), head tilt and eyelid exposure are important to achieve good centration on the eye and good suction. Move the patient’s eyelashes out of the way and tape the extra dermatochalasis from the upper or lower eyelids if necessary.
Measure the Pupil’s Size Before the Case
When suction occurs, patient’s pupil size will decrease. The smallest capsulorhexis that can be generated with the LenSx Laser has a circumference treatment of 4.3 mm; the laser will only treat 0.5 mm smaller than the pupil. My preference is a capsulorhexis of 5.1 mm for standard, toric, and multifocal IOLs and 6.0 mm for accommodating IOLs. By measuring the pupil size before starting a case, I have not had to cancel a surgery because of poor dilation. I counsel patients with intraoperative floppy iris syndrome ahead of time.
Be Aware of the Three-Plane Corneal Incision
The patient is set up in the OR in the same fashion as for cataract surgery. I typically make my incisions around 30º to 45º away from the flat plane. The femtosecond laser designs such precise three-plane incisions that the incisions at a steeper angle are around 80º to 90º. If using a Slade spatula or the Sinskey hook, aim downward to open the incisions, as this maneuver avoids generating article planes in the corneal stroma.
Double-Check the Capsulotomy
A laser-generated capsulorhexis will do a better job than a manually created one at obtaining the effective lens position. Sometimes, however, the laser can generate adhesions. I recommend using a cystotome or Utrata forceps to confirm that the capsulotomy is free of tags and adhesions.
Scrape the Cortical Material Before I/A
A capsulorhexis created by the LenSx laser will be generous and aim superior and posterior to the capsule and into the cortical material. There are no adverse side effects of this treatment. The capsulorhexis, however, is cleaved so cleanly that purchasing the cortex with the I/A port can be challenging. Before I perform I/A, I use the Shepherd Capsule Polishing Curette or a cortex club (Epsilon USA) invented by Peter J. Cornell, MD, and scrape around the cortical material before the nucleus is removed. Roughing the cortical material allows greater cortical purchase with the I/A tips, making removal easier.
Release Built-Up Gas Bubbles
Capsular rupture during hydrodissection and hydrodelination has been a concern.The laser generates gas that can become trapped behind the lens. This is a similar phenomenon to the opaque bubble layer experienced time to time due to gas expansion during the flap’s creation with the Intralase femtosecond laser. It is not uncommon for gas bubbles to become trapped in and behind the lens fragments with the LenSx Laser. I recommended a careful hydrodissection of the fragments or completely cracking the nucleus to release the buildup of gas bubbles.
Confirm Residual Astigmatism
I usually open the limbal relaxing incisions with a Slade spatula or a Sinskey hook in the operating room if the astigmatism is 0.5D or greater. I confirm the residual astigmatism via the Optiwave Refractive Analysis (WaveTec Vision) before I open incisions. If I feel the astigmatism management is not required at the time of surgery sometimes I wait till the following day. If the patient still presents with residual astigmatism I may choose to open them the next day in the office.
This material first appeared in CRS Today: http://bmctoday.net/crstoday/2013/01/article.asp?f=from-slipknots-to-lasers
- Roberts RV, Sutton G, Lawless MA, et al. Capsular block syndrome associated with femtosecond laser assisted cataract surgery. J Cataract Refract Surg. 2011;37:2068-2070.