The OM femto round table
Glenn N. Pomerance, MD; Keith A. Walter, MD; and Johnny L. Gayton, MD discuss the benefits.
Dr. Gayton: When did you adopt femtosecond laser cataract surgery and why?
Dr. Pomerance: After learning that some of my colleagues had adopted laser cataract technology and with patients asking me if I did the procedure, I felt like the proverbial guy left on the platform as the train left the station! I felt as if I was letting my patients down and not keeping up. I felt it was my duty to my patients to at least investigate further.
My good friend Johnny Gayton invited me to his facility to see two femto cataract systems, LenSx from Alcon and Catalys from Abbott, in action side by side. I was at once impressed with flow of care, how undisruptive it was, what a difference it made to the patient and staff, and how it made potentially difficult surgeries easier. The outcomes on day one were impressive.
However, I still was not convinced that a practice of my size could afford the technology, as my surgical volume was not sufficient to support a purchase. It was about this time I discovered that both manufacturers were permitting mobilization. I contacted ForTec and found that accessing the technology would not require a large capital outlay or large maintenance cost and would deal with my concerns about obsolescence.
The learning curve was extremely short for me, largely due to the excellent training and ease of use. Because I am experienced in IntraLASIK, the docking was easy for me, but might cause a surgeon not familiar with laser vision correction to have a slightly longer learning curve.
After just over a year and 150 procedures (more than I thought I would have), the controversy over whether the procedure increases safety, accuracy and outcomes is also settled. It makes sense that micromanipulations inside the eye would be more precise than manual, but the dramatic reduction in ultrasound energy cannot be overstated. The entire procedure, including the three to four minutes for the laser portion, takes just slightly longer than a standard phaco, largely because of the shorter time with instruments in the eye.
In my experience, no surgeon can match the precision of the laser, no matter how experienced the surgeon is.
Dr. Walter: We were interested because we are academic and wanted to be on the cutting edge. We got in a little late. We heard some adverse things about original femtos — that they weren’t as solid and caused some complications we weren’t interested in seeing in our patients. When we did due diligence, we wanted the best laser. You don’t have to get that complicated explaining femto to patients. They know technology has changed: The telephone is now a PC, a bank account. ‘Laser or scalpel?’ Most patients say, ‘Give me laser, Doc.’ Even routine cases.
Dr. Gayton: One reason I got involved with femto surgery is like Dr. Pomerance, I like to be up to date. I like the ability to offer our patients first-class quality cataract surgery. Also, we deal with numerous patients with dense, hypermature cataracts. Some are so dense that (before femto) I occasionally had to eliminate phaco as an option, and, even with capsular dye, performing the capsulectomy was sometimes difficult. So I was very interested in a better way to address the hypermature cataract patient.
When we brought the Catalys laser (AMO) on board, we found it enabled us to do hypermature cataracts more efficiently with better outcomes, akin to those of our usual cataract surgery patients. We then discovered that our patients with compromised corneal endothelium also benefited significantly from the advantages of femto. The procedure is more precise: It fragments the nucleus so we don’t have to use as much ultrasonic power, and that’s kinder to the corneal endothelium.
A significant number of patients in our area have short eyes with a smaller anterior segment, and thus have a very shallow anterior chamber. When doing traditional surgery on small eyes, we are more apt to lose control of the capsulectomy. It is also sometimes difficult to obtain working space inside the anterior chamber. If you can control your capsulorhexis and fragment the nucleus before entering the eye, the procedure becomes safer and easier.
Recently we had a very interesting case. During the OCT part of the procedure, we noted a significant zonular defect prior to using the femto. The femto let us do a perfect capsulorhexis and nuclear fracture even with a significant loss of zonules. Since we knew where the defect was ahead of time, we were able to safely control removal of the cataract. The procedure was uncomplicated without extension of the zonular defect.
Dr. Gayton: Dr. Pomerance, do you have any unique ways of explaining differences between traditional and laser surgery?
Dr. Pomerance: I make analogies the patient grasps about the ways the laser can be beneficial, by minimizing manual manipulations in the eye. I use the analogy of an autopilot in an airplane, which does the work under the watchful eye of the pilot. Since so much other surgery is done with lasers, patients easily comprehend the potential benefits of similar technology for eye surgery. I point out that the laser often reduces the potential negatives of conventional surgery.
Dr. Gayton: One way that I explain the difference between pure ultrasound and femto laser assistance is by shining a light at the patient and asking, “Who am I shining the light at?” They easily get the answer. I repeat this once or twice with different people in the room with them continuing to answer correctly. I then clap three times and ask, “Who was I clapping at?” They can’t tell. I then say that is one of the main differences between light and sound energy. Light is more focused and directional as opposed to sound, which is more dispersed. That is a prime reason why laser is kinder and gentler to the eye.
For those with hypermature cataracts or corneal dystrophy, I use another analogy. I ask those patients, “Have you ever had your power go off, resulting in ice melting and refreezing inside the freezer? The resulting block of ice is then difficult to remove as opposed to removing little ice cubes.” Patients with dense cataracts typically understand that analogy.
Dr. Gayton: Have you found any patients for whom femto offers significant advantages?
Dr. Walter: I think the laser is better at removing soft cataracts, these cases are easier with femto than by manual elimination. Manually they are more difficult to rotate — difficult to crack and divide and chop. But with femto, you get a bubble layer around the lens, and it buoys the lens up, and you can prolapse; the epinucleus is typically fused to the nucleus and it comes out in one piece. Routine soft cases are even easier than by manual.
Dr. Pomerance: Many of my patients have small to moderate amounts of astigmatism that would remain without the use of laser-assisted technology. The femtosecond laser is extremely precise and effective in reducing this astigmatism. I did a study of how better to approach astigmatism with the Catalys. I have used several astigmatism nomograms such as the one presented by Dr. Julian Stevens and others but have adapted the Donnenfeld nomogram as presented in the LRI calculator by Abbott for my own use.
Although some surgeons appreciate the ability to adjust standard astigmatism incisions by opening them selectively postoperatively, I appreciate not having to do so. I make all astigmatism correction using intrastromal incisions. I have never been able to approach the accuracy of the laser when a manual approach is used.
Dr. Gayton: Any patients in whom the laser is contraindicated, or in whom it can be a more risky option?
Dr. Walter: If the patient has a head tremor, or hydropic neck, there might be trouble getting them to stay stable. But those cases are rare. Small pupil as well.
Dr. Pomerance: With deep-set eyes and prominent brows, even the small LOI [liquid optic interface] tends to be difficult because the brow often gets in the way when attempting to position properly. With obese patients, it may be tough to get the patient’s body to fit under the Catalys laser. Also, if the patient has a really big abdomen, the head may pulse up and down when the heart beats. Large patients may also have problems breathing evenly and shallowly if the neck is as hyperextended as it needs to be for proper positioning.
Dr. Gayton: Tell patients who move significantly when they breathe to hold their breath for the less than two seconds that it takes to do capsulorhexis and take shallow breaths during the rest of the procedure. One group of patients you need to be cautious with are those with corneal scars. Since they can get uneven distribution of the laser, always check the capsulorhexis well when doing these eyes.
Dr. Gayton: How about femto laser-assisted cataract surgery in patients with glaucoma?
Dr. Walter: I haven’t done any with a bleb, but those with mild glaucoma or pressure I don’t feel bad at all, the pressure doesn’t go up, when I put suction on. Patients can still see, they don’t lose profusion to retina, they enjoy the light show. I have no qualms with that.
Dr. Gayton: I have done a couple of patients with blebs and had no issue. I’ve leaned towards using the smaller interface in those patients. One of the things I have appreciated regarding using the Catalys laser is that after suction is applied, I never had a patient who had no light perception. They can always see the light, giving conclusive proof that the intraocular pressure was not raised to an inordinately high level, whereby you had to worry about some optic nerve insult.
Dr. Pomerance: I have done only one patient with the Express Mini-shunt, using a standard LOI interface. Careful patient selection is required but normally the Express doesn’t intrude far enough to be of concern. Such might be a concern for an aqueous shunt, although I have no experience to date.
Dr. Gayton: Have you ever had to do a canthotomy to be able to apply an interface?
Dr. Walter: Not since the LOI-12 [liquid optics interface] came out.
Dr. Gayton: Until two weeks ago I had never had to do one. I had a patient with the smallest palpebral opening I have seen. Even the 12-mm interface was too large.
Dr. Gayton: Any tips to share regarding making the procedure easier and safer?
Dr. Walter: I’m a fan of LOI-12, I am only using the 12 interface. It fits tighter around the limbus, there is less chance for any little eye movement. One downside: maybe the main incision is not peripheral enough. But I look at the OCT to decide if I want to do an incision. I suppress maybe one out of 100. Incisions open easier with an LOI-12. If the surgeon is new to them, use the 14. I take 12 and center properly to have a better case.
Dr. Gayton: I use the 14 most of the time, but I will use the 12 several times a day. I have not thought about exclusively using the 12.
Dr. Walter: It evolved over time. We started measuring white to white. We were strict at first: If it’s 12 or less use 12; if over, use 14. But then we noticed maybe they weren’t that accurate, so I went to 12.5 until we were able to use the 12. I haven’t had a problem using it even on a really big eye.
Dr. Gayton: One more tip: Whatever femto system you’re using, make sure the patient looks straight ahead with the contralateral eye. If they move it enough, even with the suction applied, you could get movement with the operative eye.
Dr. Gayton: Do you know anyone who has abandoned femto?
Dr. Walter: It depends on your comfort zone, with a more refractive-type surgeon. When trying to treat astigmatism I embrace laser for that reason. Others may shy away (great vision first day), and some laser platforms are easier to use than others. Some laser platforms are more comfortable for some patients.
Dr. Pomerance: No one near me has abandoned the laser, but economic factors are always an issue and affect volumes sporadically.
Dr. Gayton: At our practice, we were enjoying a high conversion rate until the ACA entered the picture, resulting in patients paying higher copays, deductibles and premiums. It had a significant depressing effect. It was pure economics. Thankfully we’ve seen a resurgence of late.
With patients with hypermature cataracts who cannot afford upgraded surgery, I tend to give them a complimentary interface and do the procedure. By the way, this helps prove to CMS that we are charging for premium services and not the femto, since we use the femto on some of our traditional procedures.
Dr. Walter: Regarding the conversion rate, we are successful with sending out material ahead of the patient’s appointment. We break the ice with, “This is not your father’s or grandfather’s cataract surgery, we have premium lenses and lasers.” It is one brief letter with a pamphlet.
When patients come in, they know about the femto option and they see a video about it at the practice. We have a 70% conversion rate. We went from a 20% conversion rate to 70%.
If you barrage patients at the front door, they will say, just give me standard surgery. They should be educated on the options. It’s easier to convert patients when they are educated.
Dr. Gayton: One pearl that I picked up from Dr. Walter is using a video to demonstrate the difference between a capsulectomy performed with the laser and one performed manually. I also agree with sending educational materials out ahead of time.
With the MIGS procedures, we can now offer many of our patients with glaucoma improved pressure control and refractive cataract outcomes. It is clearly a new paradigm. It’s also quite striking on OCT to notice how narrow some of these anterior chamber angles are, because of angle anatomy or inordinately large cataracts. Cataract surgery in patients with narrow angles is more safely done with femtosecond laser assistance, and it frequently results in a significant decrease in pressure. OM
Johnny L. Gayton, MD, is in private group practice at Eyesight Associates in Warner Robins, Ga.
Glenn N. Pomerance, MD, is the founder, medical director and chief surgeon of Pomerance Eye Center, P.C., in Chattanooga, Tenn.
Keith A. Walter, MD, is a professor of ophthalmology at Wake Forest Baptist Medical Center, Winston-Salem, N.C.