This early adopter learned the curve

A Georgia practice mastered femto-assisted cataract surgery by adopting its own evidence-based protocol.

By Johnny L. Gayton, MD, Riley Sanders, BS, & ReBecca Seabolt, RN, COT

The femtosecond laser, introduced in 2001 as a LASIK tool,¹ has become, since the arrival in 2012 of the Victus (Bausch + Lomb) a turn-to surgical necessity for many a corneal and cataract specialist. Its precision and safety are constantly compared with phacoemulsification; a February 2015 article found the overall complication rate for femto-assisted cataract surgery to be 1.8%; traditional phaco was 5.8%.² The study involved 273 femto-assisted eyes and 553 phaco-assisted eyes.² But any new technology has a learning curve, and the femto’s, while it has flattened,^2,3 still requires that you read the instruction manual.⁴

Figure 1. Pre-Omidria instillation.
ALL IMAGES COURTESY JOHNNY L. GAYTON, MD, RILEY SANDERS, BS & REBECCA SEABOLT, RN, COT

We found outcomes with a femto are optimized using an established protocol that: ascertains the psychological state of the patient; addresses the physical limitations of the equipment; efficiently couples laser and manual techniques; and achieves maximum mydriasis throughout the procedure.

We learned these techniques and made these observations — thus improving safety and outcomes — because our group was an early adopter of femtosecond-assisted cataract surgery (FACS). We are happy to share our discoveries made along the femto learning curve with you.

Before pre-op

Assess the patient’s mental and emotional state. A person who cannot comprehend what is being done with the laser could jerk his or her head, resulting in an incomplete capsulorhexis, extensive subconjunctival hemorrhage and/or a corneal abrasion. In the rare patient who has significant anxiety, we consider using either oral or IV sedation.

And even during the femtosecond procedure, I verbally reassure and even hold the patient’s hand, along with using topical drops. We explain every step of the procedure to the patient, especially what she will see and feel. We also have a second person present to make calm assurances, whether with words or touch. A patient who knows exactly what she will experience is less likely to jump or move during the procedure.

The pre-op eye exam

We look for corneal scars, opacities, vascularization, cataract density and zonular integrity. Any opacity or scar in the cornea can result in an incomplete capsulorhexis and/or an inadequate corneal wound. Patients should be assessed for zonular dehiscence risk factors. Surgeons should consider using capsular retractors or a capsular tension ring in selected patients when needed, and always should be prepared if a capsular complication arises.⁵

It is also important to evaluate how well the pupil dilates and whether the patient has floppy iris syndrome.⁶ (For patients who have a compromised corneal endothelium, we use extra viscoelastic during the phacoemulsification part of the procedure.) In patients who do not dilate well, we plan accordingly.

The next step is to see whether the patient can lie flat. Will her physique limit her ability to fit underneath the laser? Another issue: Does she have an exceptionally small palpebral fissure? For lasers that require the patient to be moved, evaluate the patient’s mobility and assess the difficulty involved in moving her to the laser bed and back.

The miosis issue

Obviously, the better dilated the patient’s pupil, the better the femtosecond treatment.

But, use of a femtosecond laser has been shown to immediately elevate prostaglandin concentrations in the aqueous fluid, contributing to intraoperative miosis.

In patients with significant miosis, we previously took them to the operating room for placement of a Malyugin ring prior to the femtosecond procedure.⁴ Several issues arose with that; ring placement required at least a 2.2-mm incision prior to the femtosecond procedure, and it also required significantly greater use of viscoelastic.

Some practices instill compounded Shugarcaine (lidocaine/epinephrine solution in BSS Plus) or epinephrine alone into patients prior to the femtosecond procedure.^4,7 While Shugarcaine allows for additional dilation, it is a compounded product.⁴ Recently, compounding has come under fire from the FDA and other governmental entities.⁸

Elevated prostaglandin concentrations can be mitigated by use of NSAIDs,⁹ but since intracameral epinephrine and Shugarcaine do not contain a NSAID, they would not prevent a prostaglandin increase.⁷

Figure 2. Post-Omidria instillation.

Figure 3. Post-femtosecond procedure.

Phenylephrine 1% and ketorolac 0.3% = mydriasis

My preference now is to inject BSS containing Omidria, which is a proprietary combination of phenylephrine 1% and ketorolac 0.3%, through a paracentesis incision made in the operating room prior to the femtosecond procedure.¹⁰ I do this on patients who have a 7-mm or smaller pupil. The wound is then sealed with the same BSS containing Omidria. The patient is then assisted to the laser suite for the femtosecond procedure. I have coined the term “Omidria and femtosecond assisted cataract surgery (OFACS)” to describe this technique.

Phenylephrine promotes dilation of the pupil while the ketorolac blocks COX-1 and COX-2 enzymes.¹⁰ This drug combination has been shown in FDA trials to work more effectively to prevent miosis than either ingredient separately.¹⁰ Instilling the ketorolac at the beginning of the procedure effectively shuts down prostaglandin synthesis.¹⁰ We have found that by the time the patient is underneath the laser, the pupil is larger, but more importantly the patient no longer experiences miosis following the femtosecond procedure. By maintaining pupillary dilation, the ensuing removal of the cataractous material and insertion of the intraocular lens is much easier and safer.¹¹

We also perform an anterior segment OCT. We look for capsular defects and the position of the posterior capsule — is it easily recognizable? In extremely dense lenses, the posterior capsule may not be adequately recognized. If so, we move the treatment more anteriorly to make posterior capsule injury less likely. If a patient has a dense lens or Fuchs’ dystrophy, we perform a more aggressive nuclear fracture to minimize the later use of ultrasonic energy.^12,13

Laser on

As you are bringing the patient into position, it is important to have his or her neck as comfortable as possible. For patients with a large nose, you might need to turn the head slightly away from the treatment eye to help with laser positioning. Also, the patient’s head should be in a position whereby she is less likely to move. We also like to have the patient look straight ahead at a fixation target with the contralateral eye, as any movement can result in a less than optimal femtosecond procedure. Proper docking of the laser should minimize lens tilt.⁴

Figure 4. Pre-intraocular lens implantation.

Some patients simply will not allow the interface to be perfectly centered. In those cases, we have found that it is best to center the laser treatment on the pupil rather than the lens capsule. During the actual femtosecond procedure, we watch closely and encourage the patient not to move. If any untoward event or excessive patient movement occurs, I take my foot off the laser pedal. It is better to have an incomplete laser treatment than to have the laser treatment delivered incorrectly.

Also, if the patient has to be moved after the procedure, help her into a wheelchair or stretcher. Patients have decreased vision following the femtosecond procedure. This decreased vision could increase the patient’s anxiety level and make it more difficult to move her. Reassure the patient that this decreased vision is normal and temporary. Be aware that some patients are predisposed to a vasovagal response when having procedures.¹⁴

Lens implantation

We then move the patient to the operating room where the eye is prepped and draped. I insert viscoelastic through the sideport incision prior to making the primary incision, because in the event of a rare, incomplete anterior capsule collapse, a radial extension of the capsule could occur. As the viscoelastic is instilled, I use Dr. Lisa Arbisser’s technique of depressing the anterior capsule to be sure there are clear margins all the way around; it is a good way to check the integrity of the capsulorhexis.¹⁵ If the capsulorhexis is not complete, make it so with capsulorhexis forceps. Because of the excellent nuclear laser fragmentation, the nucleus can be divided earlier during the phacoemulsification, helping to protect the capsule. I have found that the pneumodissection that occurs during the femtosecond procedure keeps me from having to do any hydrodissection until the nucleus is removed. (In a recent lecture, Dr. Robert Osher said this further reduces the likelihood of a posterior capsule injury.)

After removing the nucleus, I use a J cannula on a syringe containing BSS, or subincisional hydrodissection, to allow easier and safer removal of epinuclear and cortical material. I have also found that frequent hydrodissection following removal of the nucleus allows for a much easier removal of cortex and cleaner capsules. I also inject BSS under the capsule following lens implantation; this helps remove any retained bits of cortex and viscoelastic.

New roles

FACS has the potential to offer excellent results and its utilization is expanding. Intracameral injections of phenylephrine/ketorolac show promise in helping dilate the pupil wider and counteracting intraoperative miosis from femtosecond-induced prostaglandin synthesis in the anterior chamber.

I hope these techniques help make femtosecond laser surgery safer and more effective for you as they have for me. I believe femtosecond- assisted cataract surgery is a significant advance in the field of cataract surgery leading to safer surgery with improved outcomes. OM

REFERENCES

About the Authors

Johnny L. Gayton, MD, is in private group practice at Eyesight Associates in Warner Robins, Ga. Disclosures: Dr. Gayton disclosed that he is a consultant to Optimedica and Bausch + Lomb, and is a speaker for Optimedica. Riley Sanders is a senior at Mercer University School of Medicine. His passion for ophthalmology began when he worked as an ophthalmic technician. His academic interests include study of the visual system and the impact of various ophthalmic therapies. He can be reached at rileysanders88@gmail.com. ReBecca Seabolt, RN, COT, CCRC, a longtime employee of Gayton Eyesight Associates, is Dr. Gayton’s clinical supervisor.