Zero energy phaco possible without a laser

Surgeons describe a high vacuum manual chop cataract surgery technique with little or no phaco energy.

Issue: November 10, 2015

ByCourtney E. Bovee, MD

ByDavid L. Nash, MD

ByFredric J. Gross, MD

ByDebora E. Garcia-Zalisnak, MD

Cataract surgeons have an addiction. We are ever in the pursuit of better outcomes for our patients with faster recovery times. With each technological leap in phaco machines and platforms, instruments and now laser-assisted cataract surgery, cataract surgeons are getting closer to zero energy phaco.

Some have proposed femtosecond laser-assisted cataract surgery is a step toward zero energy phaco. Impressively, in 2013, Dick and Shultz shared their steps to obtaining zero energy phaco in 91% to 97% of their patients with the addition of not only the femtosecond laser, but also larger diameter irrigation and phaco tips and increasing the vacuum settings. We have been able to achieve similar results by manually fracturing the lens using a modification of the pop-and-chop technique described by Pandit and Oetting in 2003. This technique could be a valuable solution for many patients. Especially when considering the time and cost to both surgeons and patients, femtosecond adds to both categories.

Cumulative dissipated energy

Cumulative dissipated energy (CDE) is a built-in measurement of the Infiniti and Centurion vision systems (Alcon) and was designed to allow surgeons to monitor the energy delivered during phacoemulsification. Lower CDEs translate into less phaco energy being used, which is associated with better corneal recovery after cataract surgery and more rapid visual rehabilitation. Lower CDEs have been demonstrated using chopping techniques vs. traditional divide-and-conquer techniques. Supranuclear techniques also offer the potential of lower CDEs given the lens disassembly is done without using phaco energy.

In our clinic, we use a supranuclear dividing technique (pop-and-chop: https://www.youtube.com/watch?v=3tFWlA0vxmI) with high vacuum settings using the Centurion and have observed extremely low CDEs (typically less than 10 in both attending and resident cases with mild to moderate nuclear sclerosis). In addition, we have observed several patients with mild to moderate nuclear sclerosis who had a CDE of 0 (zero CDE cataract surgery: https://www.youtube.com/watch?v=U3QVvmv_fiE).

Pop-and-chop technique

In our cases we use the new Intrepid infusion sleeve and balanced tip (Alcon) with a linear phaco energy of 50%, a vacuum of 550 mm Hg and an aspiration rate of 40 mL/min. The pop-and-chop technique involves prolapsing the lens out of the bag during hydrodissection. During this process, the lens “pops” out of the bag with a standard size capsulorrhexis. Viscoelastic can be placed behind the lens for protection of the posterior capsule, but it is not necessary. A second instrument of the surgeon’s choice (straight or curved) is then introduced behind the posterior lens surface. The phaco handpiece is placed through the main wound onto the anterior surface of the lens. The two instruments are brought together, manually disassembling the lens into fragments that can then be removed with minimal or no phaco energy. The lens remains at the level of the iris plane or slightly anterior to protect the endothelium and prevent injury to the capsular bag.

In our practice, this technique was readily teachable to residents and found to be as equally safe as the standard divide-and-conquer technique. Visual outcomes and adverse events were equal with both techniques. This technique has several advantages in both a private practice with high volumes and educational settings with novice surgeons. Pop-and-chop was shown to be faster than the standard divide-and-conquer, offered a good alternative for soft nuclei that are challenging to sculpt and allowed for less stress on the zonules in patients with pseudoexfoliation or prior trauma.

Of course, “zero energy” is a bit of a misnomer. Every action takes energy. Some actions just use less than others. What is an important concept to recognize is that laser-assisted cataract surgery is not the only way to achieve zero energy phaco during cataract surgery, and it certainly is not the cheapest or most time-efficient. Abolishing the need for phaco power in the eye is a reality and it is attainable, but you do not need a laser to do it.

References:
Bovee C, et al. Pop & chop phacoemulsification reduces resident surgical case time. Presented at: Virginia Society of Eye Physicians and Surgeons annual meeting; June 19-20, 2015.
Chen X, et al. Sci Rep. 2015;doi:10.1038/srep13123.
Conrad-Hengerer I, et al. J Cataract Refract Surg. 2013;doi:10.1016/j.jcrs.2013.05.033.
Dick HB, et al. J Cataract Refract Surg. 2013;doi:10.1016/j.jcrs.2013.07.002.
Pandit RT, et al. J Cataract Refract Surg. 2003;doi:10.1016/S0886-3350(03)00339-0.

For more information:
Fredric J. Gross, MD, is a glaucoma specialist at Mid-Atlantic Eyecare, Chesapeake, Va., and an associate professor at the Eastern Virginia Medical School, Norfolk, Va. He can be reached at 109 Wimbledon Square, Suite E, Chesapeake, VA 23320; email: heye5@aol.com.
Courtney E. Bovee, MD, is a fellow in glaucoma at the Massachusetts Eye and Ear Infirmary. She can be reached at 101 Canal St., Suite 514, Boston, MA 02114; email: courtneybovee@gmail.com.
David L. Nash, MD, is a fellow in pediatric ophthalmology and strabismus at the Mayo Clinic. He can be reached at 615 8th St. SW, Rochester, MN 55902; email: david.loring.nash@gmail.com.
Debora E. Garcia-Zalisnak, MD, is an ophthalmology resident at the Eastern Virginia Medical School, Norfolk, Va. She can be reached at 205 Westover Ave., Norfolk, VA 23507; email: debora.e.garcia@gmail.com.

Disclosures: The authors report no relevant financial disclosures.