Technological advances improve safety, precision of YAG vitreolysis for floaters

An upgrade in YAG laser technology may be a breakthrough in the management of vitreous floaters, offering a safe, effective and minimally invasive alternative that lies between “learn to live with it” and vitrectomy.

YAG laser vitreolysis has been around for some time, and a handful of surgeons worldwide embraced it long ago, have seen its potential and worked at further developments. The technique, however, has been surrounded by controversy due to justified safety concerns and lack of data. Difficulty in exactly targeting floaters, the risk of damaging the retina and lens, the potential consequences of the shockwave effect, and dispersion of energy inside the eye kept most eye specialists from considering it a feasible option.

“What has changed now, markedly improving the efficacy and safety of the procedure, is the advancement in the technology. Now we have YAG lasers, the Ultra Q Reflex and Tango Reflex by Ellex, that are specifically designed to precisely detect, target and vaporize floaters,” Inder Paul Singh, MD, said.

“The technique is booming now, and an increasing number of ophthalmologists are adopting it in Europe and the U.S. We have also founded the International Society of Vitreous Laser Surgery, open to ophthalmologists worldwide and aimed at promoting knowledge of this treatment, sharing experiences and protocols, and raising awareness,” Marie-José Tassignon, MD, PhD, said.

Underestimated condition

Doctors and eye specialists often underestimate how much floaters can affect the vision and life of patients, but they can be a bothersome, frustrating condition to live with.

Source: Marie-José Tassignon, MD, PhD

“We tended to minimize the impact of floaters because there was nothing we could offer that was safe and effective apart from the extreme solution of vitrectomy. Therefore, in most cases we dismissed these patients with a few tips on how to cope and learn to live with them. It was only when I started doing vitreolysis 4.5 years ago that I realized how many people are suffering from this condition, and it was shocking to me how much of an impact floaters have on patients’ quality of life,” Singh said.

When the only option was vitrectomy, most of his patients would go untreated, but now vitreolysis has lowered the threshold for intervention, he said.

Singh has treated about 3,000 cases using the Ellex Reflex technology. He recently presented the first 1,200 cases, of which 300 had a follow-up of 4 years. The overall adverse event profile was 0.8%, no case of retinal tear or retinal detachment occurred, and only a small peripheral retinal hemorrhage was reported in one of the first 20 cases.

Pioneer of vitreolysis

Tassignon was a pioneer of YAG laser vitreolysis, starting in the 1990s with the Frankhauser laser for treating the vitreous. Because there were few indications, this laser was abandoned in favor of the Aron-Rosa YAG laser, which was more specifically designed for the capsule.

“I published some papers on vitreolysis in the early 2000s and continued doing it until the Frankhauser laser broke down and there was no replacement for the parts. At that point, I stopped doing the procedure until the Ellex laser became available. The first models were not up to the standards of the Frankhauser laser, but the new one has an unprecedented quality and is gaining wide popularity. Now we have a very reliable and safe treatment option to offer. Patients always improve, and if they don’t, we can still do vitrectomy,” Tassignon said.

Evaluation of the vitreous classically starts with the slit lamp, using a magnifying lens. For more precise location of floaters, Tassignon uses ultrasonography with a 15 Hz to 20 Hz probe, which allows visualization of the collagen fibers in the vitreous and a good impression of the degree of liquefaction of floaters. If patients complain of dark floaters, OCT should be used to determine whether the bursa premacularis is still in place or if there is posterior hyaloid detachment.

“These are the parameters I use when I examine patients with symptoms of floaters. There are also questionnaires where patients are asked to classify their floaters in strands, membranes, dots and rings. Some years ago we used the endoscope, which allowed patients to objectivate their own floaters, but the technique was not precise. We need new devices, a dedicated technology for the diagnosis and precise evaluation of floaters,” Tassignon said.

Classification of floaters

Within the International Society of Vitreous Laser Surgery, of which she is president, Tassignon launched a project regarding the consensus-based classification of floaters along with a collection of images that will be available on the society’s website. Karl Brasse, MD, a retina specialist with a long-standing passion for images, is providing materials for this project and has proposed his own classification of floaters in relation to the anatomical structures involved (Figures 1 and 2).

Source: Karl Brasse, MD

“There are many different floaters, and if you want to develop a protocol to treat them, you have to classify them first. Different floaters have different prognoses and may or may not benefit from specific treatments. Not all of them can be taken care of by YAG,” Brasse said.

Group 1 in Brasse’s classification includes floaters that originate from the retina, often as a result of traction. The most typical is the operculum, visible as a whitish disc-shaped floater.

Group 2 floaters originate from the posterior hyaloid membrane and are embedded in this membrane. They include Weiss rings and fibrotic formations, and they have a good prognosis.

Group 3 floaters are located in the vitreous body, including the vitreous cortex and Cloquet’s canal. Condensation of vitreous fibrils leads to a wide variety of structures, such as strings, globuli, nets and clouds. They can be singular or multiple, localized or disseminated, small or large, difficult or easy to treat.

Group 4 floaters are, strictly speaking, not floaters but remnants of lens capsule after YAG capsulotomy. Specific techniques, such as can opener capsulotomy, are a frequent cause of this type of floater.

“There is little interest in what YAG capsulotomy might cause in the vitreous. People get premium lenses, but there is no premium YAG procedure for them. These floaters are man-made, and there are many out there,” Brasse said.

Group 5 floaters are secondary opacifications, not correlated to anatomical structures. They may be genetic, inflammatory, infectious or traumatic.

What to treat, what not to treat

“I almost always have success with vitreolysis in groups 1, 2 and 4. In group 3, most cases are treatable, but floaters quite often have the tendency to form again. Vitreous opacifications in group 5 are hardly ever treatable,” Brasse said.

According to Tassignon, when floaters are very dark or moving quickly, or when patients are 30 years or younger and there is no sign of vitreous detachment on OCT, vitreolysis should be avoided.

“Those floaters are located very close to the retina, and you cannot treat them with YAG. The only option you can offer these patients is vitrectomy. When I do a vitrectomy for this indication, I keep the anterior vitreous and never do a cataract surgery because cataract will not occur if you keep the anatomy of the anterior vitreous,” she said.

Other contraindications for vitreolysis, in her opinion, are floaters dispersed everywhere in the vitreous or big condensations of cloudy opacification.

Singh published data on 362 consecutive patients. Both Weiss rings and larger amorphous cloud were successfully treated.

“The difference is that amorphous clouds need a higher number of shots and sessions. We were able to achieve near 90% satisfaction in Weiss ring patients with only 1.3 sessions, while more than three sessions were needed for amorphous clouds because they are often denser and larger,” he said.

Singh does not treat asteroid hyalosis, nor thin lines or fine cobwebs, because they are difficult to target and vaporize, and would require innumerable shots. These are the cases in which he suggests vitrectomy if patients are symptomatic.

For patients with posterior vitreous detachment, his advice is to wait at least 6 months to neuroadapt. If they remain symptomatic and retinal conditions are favorable, he goes ahead with vitreolysis.

Keeping within safe limits

There are currently no protocols or guidelines concerning the number of shots per session or the number of sessions for each patient.

“I usually limit the number of shots to about 1,000 because both the patient and I get tired and to avoid the risk of pressure spikes. We have seen no vitritis, anterior chamber reaction or inflammation after the procedure, but we had 12 cases of significant pressure spikes in 3,000 patients. They were mostly people who had had YAG capsulotomy with floaters right behind the lens. The reason might be that we placed a significant number of shots, more than 700 or 800, and the gas bubbles or the debris of the floaters may have disrupted the outflow system of the eye, causing the pressure to go up. We do not know the exact mechanism, but we have seen less chance of IOP spikes when using a lower number of shots. In those specific patients, now I limit the shots to no more than 400 to 500,” Singh said.

In terms of safety for the retina, he found no complications in relation to the energy or number of shots. ERG and rod functionality testing (dark adaptation) regularly done in his patients showed that the procedure does not induce retinal toxicity, changes in rod functionality or other issues so far.

Published studies demonstrate YAG capsulotomy is known to lead to increased risk for retinal detachment, but this could be due to the direct transfer of energy from the capsule to the zonules and eventually to the vitreous base.

“We are firing directly into the vitreous, which is an entirely different anatomical structure,” Singh said.

In terms of number of sessions, he does not have specific limits. He reassesses after each treatment to determine if more sessions are warranted. He has done up to seven sessions in one patient. He only stops when patients are not improving.

Tassignon prefers, even in the best indications, to stop after three sessions.

“If it does not work the first time, you can try a second time, but if it does not work after two or three sessions, it is not worth going further. At that point I propose to leave it as it is or do vitrectomy,” she said.

Brasse does, on average, one or two treatments per patient. He does his diagnosis and evaluation on the first day and treatment on the second day.

“I like to have a night between diagnosis and treatment, so that patients can think about it,” he said.

He has 4 years of experience with the Ellex laser, and it was only with this laser that he started doing the procedure.

“I have invested a lot of time, energy and enthusiasm in this procedure. I have done 1,100 cases and have a waiting list of 6 months. It is a time-consuming procedure if you want to do it really well,” he said.

New features

The main feature that differentiates the Ellex Reflex laser from its predecessors is the proprietary coaxial illumination technology that makes the surgeon’s eye and the slit lamp illumination converge on the same optical path and focuses them at the same optical plane as the treatment beam. In previous YAG lasers, the illumination was off axis, coming from a different angle with respect to the axis of vision and the laser.

This is an important aspect, according to Singh: “With the new illumination system, we have the ability to identify and, in real time, judge if we are safe enough to fire since we are able to see the floater and the retina at the same time.”

One fear to dispel is the risk for overheating, he said. The Ellex laser has a fast firing rate of up to three shots per second, but the heat is quickly dissipated in between shots.

“You cannot fire fast enough and long enough to have the heat build up,” Singh said.

Finally, there is concern that breaking a floater might create smaller floaters.

“This is the reason why YAG vitreolysis needs more shots than YAG capsulotomy because we are not just breaking but vaporizing. This is also why in a number of patients, depending on how dense and how big the floater is, we might need multiple sessions,” Singh said.

Randomized controlled study

A randomized controlled study including 36 patients undergoing vitreolysis for Weiss rings and 16 controls was recently published in JAMA Ophthalmology by Chirag P. Shah, MD, MPH, and Jeffrey S. Heier, MD.

“There are a handful of doctors around the world who are performing YAG vitreolysis, but there was no randomized controlled study prior to our study. That was the motivation for starting this trial, to get some data and possibly pave the way to further trials,” Shah said.

The study was designed to treat patients with symptomatic Weiss rings in a single session. An average symptomatic improvement of 53% was reported, with a broad range from 0% to 100%.

“These results showed us that patient selection was very important to maximize success. Seven of the eight people who reported no subjective improvement of symptoms had significant objective resolution of their floaters by a masked grader. We must determine why they were not good candidates for YAG vitreolysis. Were their expectations unrealistic? Was there some persisting microscopic floater that bothered them? This cohort of dissatisfied patients was significant, representing 22% of treated patients,” Shah said.

Personally, Shah treated patients with YAG vitreolysis only within the study and is not continuing to do it now. He believes that further evidence is necessary to validate the procedure.

“YAG vitreolysis for symptomatic floaters is not FDA approved. We need at least one large, multicentered clinical trial to better understand the risks and benefits of the procedure across all floater types. This would also help the procedure gain acceptance within the ophthalmic community,” he said.

Safety concerns

Soon after the paper by Shah and Heier, JAMA published a report from the American Society of Retina Specialists. The ASRS Research and Safety in Therapeutics Committee conducted a retrospective assessment of cases of vitreolysis complications voluntarily reported by practitioners in the U.S. over a period of 6 months. Sixteen complications in 15 patients were reported by seven specialists, including elevated IOP leading to glaucoma, cataract, retinal tear, retinal detachment, retinal hemorrhages, scotomas and an increased number of floaters.

Jennifer I. Lim, MD, committee member, also published a commentary to Shah and Heier’s paper in which she pointed out that the study was based on too small a sample size to prove that YAG vitreolysis is a safe procedure.

“I think the jury is still out, and I would not recommend YAG laser routinely for floaters,” she said.

She also noted that the study included only Weiss rings and that conclusions cannot be extended to floaters in general.

“More research is needed before we generalize,” she said.

Lim expressed concern for complications, especially in the retina, such as tears, hemorrhages and detachment.

“Many of the patients who have floaters are moderately to very nearsighted and are already at risk for retinal detachment. I would definitely avoid vitreolysis in these patients,” she said.

She tells her patients with floaters that they can learn to live with them, although it is not the perfect situation.

“The second option is surgery. You can do a vitrectomy, but I don’t advocate it unless patients are so bothered that they are almost psychologically impaired. Often these are patients who do a lot of computer work, for example graphic designers, who need clarity and are severely impaired in their work by the coming and going of floaters in their visual field,” she said. “Vitrectomy also has potential severe complications, but there is better data and evidence available about the safety of vitrectomy for floaters than there is for YAG vitreolysis, so I’d rather do vitrectomy than YAG.”

Safety pearls

“When something is new in medicine, people are naturally skeptical until a large body of evidence proves that it is safe and it works. This is often not achieved until big companies enter the scene and invest in trials. I am now setting up a study on my results in collaboration with three German university clinics, and I also do a lot of training courses,” Brasse said.

One pearl he gives is to start with easy cases, such as patients who are pseudophakic and have a lens with no glistening that would reflect the light back.

“Key advice is to start with 100 pseudophakic patients, take time, do it out of regular sessions and have an assistant holding the head of the patient firmly against the head rest,” he said.

A pearl Singh uses for his training sessions is “if the floater is in focus and the retina is out of focus, you have enough distance to fire safely. If the retina is in focus at the same time, then you are too close and do not fire.”

Without the new illumination system, this simple tip would not be possible, he said.

“No. 2 is how to keep a safe distance from the crystalline lens; 3 mm is safe, but there is a learning curve to understand how far back behind the lens you can fire. What’s important is that this laser can fire anywhere along the slit lamp position, and you can titrate the illumination to give yourself the spatial context of anterior floaters from the lens,” Singh said. – by Michela Cimberle

• References:
• Cohen MN, et al. Ophthalmic Surg Lasers Imaging Retina. 2015;doi:10.3928/23258160-20150909-11.
• Hahn P, et al. JAMA Ophthalmol. 2017;doi:10.1001/jamaophthalmol.2017.2477.
• Ivanova T, et al. Eye (Lond). 2016;doi:10.1038/eye.2016.30.
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• Koo EH, et al. Br J Ophthalmol. 2017;doi:10.1136/bjophthalmol-2016-309005.
• Lim JI. JAMA Ophthalmol. 2017;doi:10.1001/jamaophthalmol.2017.1683.
• Lin Z, et al. Case Rep Ophthalmol. 2017;doi:10.1159/000453332.
• Milston R, et al. Surv Ophthalmol. 2016;doi:10.1016/j.survophthal.2015.11.008.
• Shah CP, Heier JS. JAMA Ophthalmol. 2017;doi:10.1001/jamaophthalmol.2017.2388.
• Sharma P, et al. Prim Care. 2015;doi:10.1016/j.pop.2015.05.011.
• Sun IT, et al. Case Rep Ophthalmol. 2017;doi:10.1159/000477159.
• Stringer CEA, et al. CJEM. 2017;doi:10.1017/cem.2016.358.
• Tassignon MJ, et al. Asia Pac J Ophthalmol (Phila). 2016;doi:10.1097/APO.0000000000000189.
• Vandorselaer T, et al. Bull Soc Belge Ophtalmol. 2001;280(2):15-19.

• For more information:
• Karl Brasse, MD, can be reached at Butenwall 22, 48691 Vreden, Germany; email: karl.brasse@t-online.de.
• Jennifer I. Lim, MD, can be reached at 1855 W. Taylor Street, Suite 250, Chicago, IL 60612; email: jennylim@uic.edu.
• Chirag P. Shah, MD, MPH, can be reached at 50 Staniford St., Suite 600, Boston, MA 02114; email: cpshah@eyeboston.com.
• Inder Paul Singh, MD, can be reached at 3805b Spring St., Suite 140, Racine, WI 53405-1641; email: inderspeak@gmail.com.
• Marie-José Tassignon, MD, PhD, can be reached at Department of Ophthalmology, Antwerp University Hospital, Wilrijkstrtaat 10, 2650 Edegen, Belgium; email: marie-jose.tassignon@uza.be.

Disclosures: Singh reports he is a consultant for Ellex. Brasse, Lim, Shah and Tassignon report no relevant financial disclosures.

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