Patients with glaucoma who are undergoing cataract surgery are no different than other patients: they want and expect the best. Cataract surgery delivers very high-quality outcomes, and a variety of options are available that incorporate new technologies to achieve tailored results. Most recently, laser cataract surgery has evolved, and we should consider its application for our patients with glaucoma. With an appropriate understanding of the technology, we can offer patients the benefits of greater precision, improved refractive outcomes, and reduced ultrasound energy that laser cataract surgery can provide. Future developments in the area of femtosecond laser technology will undoubtedly add to our capabilities. Because my experience is with the Catalys Precision Laser System (OptiMedica Corporation), I will mostly focus on my and other users' experience with this platform. To my knowledge, the Catalys System is the only femtosecond laser indicated for cataract surgery that is not contraindicated for use in patients with glaucoma.

BENEFITS

Consistent performance of the capsulotomy is a hallmark of laser cataract surgery. Many different femtosecond laser platforms are able to consistently produce a complete and circular capsulotomy based on the surgeon's specified diameter and location. My experience is that these capsular openings are at least as robust as a manually created capsulorhexis.1 The advantages of a consistent opening with 360ยบ overlap on the IOL's optic include reduced posterior capsular opacification, stable IOL placement with less tilt, better centration, and more predictable effective lens position, and the ability to capture the IOL's optic if needed. The added benefit for the patient and surgeon is the reliability of executing this sized and shaped capsular opening (Figure) by creating this capsulotomy with the laser.

Additionally, lens fragmentation and softening reduce intraocular manipulations, and ultrasound energy can be reduced or even eliminated.2 The surgeon's desired patterns of lens fragmentation are readily employed, which facilitate the separation of lenticular segments.3 Softening of the cataract additionally reduces ultrasound use and can therefore limit injury to tissue from phacoemulsification. In an analysis of my first 100 cases, the average cataract grade based on the Lens Opacities Classification System III was 2.4, and the average cumulative dissipated energy with the Infiniti Vision System (Alcon Laboratories, Inc.) was 2.34. At minimum, I feel treatment of the nucleus with a femtosecond laser can make a fairly dense cataract behave more like a softer-grade cataract for easier extraction. If the lens is not overly dense to begin with, then ultrasound is usually eliminated.

Corneal arcuate incisions can be placed with exquisite accuracy to reduce postoperative astigmatism. With femtosecond laser platforms, the surgeon can program the arc's length and depth. Adding to the accuracy of relaxing incisions created with the femtosecond laser, the surgeon can specify the angle of penetration as well as the orientation of the cuts. With the Catalys, single, paired symmetric and paired asymmetric arc incisions are possible, and I have used them successfully. This element of refractive tailoring can be brought to our glaucoma patients as well and, in my experience, is simply not possible with manual techniques.

CONCERNS

Currently, all laser cataract surgery platforms need to stabilize the eye for data acquisition and treatment, and different vacuum-based interfaces are used. Given that glaucoma patients have issues concerning IOP elevation and consequent optic nerve damage, it is imperative that IOP rise and the duration of time under the dock be minimized. The Liquid Optics Interface that the Catalys uses has been shown to induce a rise in IOP of approximately 10 mm Hg.4 This appears to be a fairly minimal elevation, but any pressure rise still should be judged for its tolerability given the degree of optic nerve damage present in an individual patient.

Additionally, the interface should keep conjunctival trauma and subconjunctival hemorrhage to a minimum. This concern is heightened in patients with a bleb. Successful use of the Catalys in patients with a trabeculectomy bleb has been undertaken (personal communication, Burkhard Dick, MD, PhD, November, 2012). These eyes were carefully docked, laser treatment and cataract surgery were completed, and the blebs maintained their function. My own experience indicates a low-level incidence of subconjunctival hemorrhage.

The pupil's dilation is often compromised in glaucoma patients. Having the ability to enlarge the pupil with intracameral pharmacology, viscoelastic instillation, or a pupil expansion ring or iris hooks and still safely apply the interface and treat the patient are a key element to delivering the benefits of laser cataract surgery in these challenging situations. Many Catalys users have reported the ability to create incisions, manipulate the pupil, and still perform a normal docking of the eye to the laser.

TAILORED OUTCOMES

Femtosecond laser cataract surgery ushers in a new level of precision to an already successful surgical procedure. Refractive outcomes are more tailored, and ultrasound use can be minimized. Patients with glaucoma and the associated issues such as a small pupil, a compromised optic nerve, or dense nuclear sclerosis can and should be able to take advantage of this new technology.

  1. Auffarth GU, Reddy KP, Ritter R, et al. Comparison of the maximum applicable stretch force after femtosecond laser-assisted and manual anterior capsulotomy. J Cataract Refract Surg. 2013;39(1):105-109.
  2. Conrad-Hengerer I, Hengerer FH, Schultz T, Dick HB. Effect of femtosecond laser fragmentation on effective phacoemulsification time in cataract surgery. J Refract Surg. 2012;28(12):879-884.
  3. Conrad-Hengerer I, Hengerer FH, Schultz T, Dick HB. Effect of femtosecond laser fragmentation of the nucleus with different softening grid sizes on effective phaco time in cataract surgery. J Cataract Refract Surg. 2012;38(11):1888-1894.
  4. Schultz T, Conrad-Hengerer I, Hengerer FH, Dick HB. Intraocular pressure variation during femtosecond laserassisted cataract surgery using a fluid-filled interface. J Cataract Refract Surg. 2013;39(1):22-27.