Feature, Report

A laser treatment approach to floaters

Invasive surgery is often a step too far to eliminate vitreous floaters for many, but DR CON MOSHEGOV says an Australian-developed YAG laser therapy is proving to be an ideal first-line option for selected patients.

Patients troubled by vitreous floaters can be particularly motivated to seek treatment, but are frequently left disappointed when told they’ll need to learn to live with the irritating structures drifting through their field of vision.

The often-benign nature of symptomatic floaters can mean they’re underestimated by busy optometrists and ophthalmologists focused on more sight-threatening conditions.

Dr Con Moshegov.

But for many patients, floaters are frustrating and debilitating. In fact, a 2013 article in the International Journal of Ophthalmology found 76% of 603 people surveyed reported seeing floaters, with 33% saying they caused noticeable vision impairment. There is also a multitude of online forums teeming with aggravated sufferers.

One barrier to treatment is the perception that patients will require a vitrectomy to become floater-free, which may not be worthwhile for many due to its higher complication risk and likelihood of cataract formation. Less invasive vitreolysis, or laser floater treatment (LFT), with conventional YAG lasers have also been investigated but struggled because they weren’t optimised for the procedure.

This was the impetus for Adelaide company Ellex (now part of Quantel Medical, a subsidiary of Lumibird Medical) to focus its efforts on what it describes as the only holistic and CE mark approved [1] laser solution for floaters. The platform is called Reflex Technology available across both the Tango Reflex and Ultra Q Reflex laser systems. It features more efficient and safer energy profiles, while also enhancing visualisation of the anterior and posterior vitreous.

Ophthalmologist Dr Con Moshegov, of George Street Eye Centre in Sydney’s CBD, was among the first in Australia to introduce Ellex’s Reflex Technology into his practice in 2013. He was astonished by the response after listing the first-line, in-office procedure on his website.

“We had people come to our clinic for vitreolysis from all over, including a professional shooter from New Zealand who was heading to the [Glasgow] Commonwealth Games who complained of floaters getting in the way of his competitive ability,” he recalls.

“Floaters are common, but for many years people have been told they’ve got to learn to live with them, they’ll become less apparent over time, but the changes Ellex made to the YAG laser has made it a very attractive proposition to offer to these people.”

Ingenious design 

Moshegov is under no illusions that vitrectomy remains the definitive treatment due to its ability to essentially remove every floater. However, the risks of cataract formation, retinal detachment and endophthalmitis are important considerations.

“Laser cannot compete with an operation, but it is not an operation and that is its advantage; it doesn’t carry the risk of infection or the higher chance of complications,” he says.

“With vitrectomy, everyone eventually gets a cataract and if this happens before you become presbyopic in your 40s, that’s a very unfortunate scenario.”

According to Moshegov, the use of YAG lasers to eliminate floaters can be found in literature as far back as 1993. But for various reasons it never took off.

Part of the problem is the configuration of conventional YAG lasers that made it impossible for the practitioner to align their view with that of the laser beam. This meant the illumination and laser were delivered from a low, non- coaxial position with larger convergent zones, making it difficult to target and treat floaters.

Reflex Technology is available across both the Tango Reflex (pictured here) and Ultra Q Reflex laser systems.

Moshegov says the beauty of Ellex’s redesigned system means he can align his sight coaxially with the laser beam, greatly enhancing his visualisation of floaters often located in the mid and posterior vitreous. Having greater spatial context is also vital to ensure the laser is clear of ocular structures to avoid causing a cataract or retinal burn, for instance.

“Ellex have come up with a very simple, but very clever, twist on the design of the YAG laser,” he says. “It’s a solution in which a mirror bounces light off a chamber below, into the eye that allows the surgeon to see straight ahead and bounce the light off the red reflex.

“When the surgeon presses the button to allow the laser beam to go through, the mirror comes down, the laser goes through and then the mirror pops up again, and it all happens so quickly that the surgeon doesn’t even perceive that, for a split millisecond, they lost a view of the fundus.”

According to Ellex, the Reflex Technology being described includes True Coaxial Illumination (TCI) that generates a titratable red reflex as a contrast comparison and a precise aiming beam. This is incorporated within a unique slit lamp illumination tower that converges the user’s sight line, target illumination and treatment beam into one optical path.

The company says the technology also features a superior energy beam profile. An issue with conventional YAG laser is the required high energy levels, which can damage surrounding ocular tissue or cause an intraocular pressure (IOP) spike.

“They shaped the beam to concentrate on a miniscule target, generating significant plasma to vaporise the floater,” Moshegov says.

“With older lasers you had to use more energy to achieve the same result and because it wasn’t so concentrated, you had the danger of causing the emanated shockwave to damage surrounding tissues.”

Moshegov says, while this is still possible with the Ellex platform, the system has another key feature to minimise risk. It allows the ophthalmologist to ‘off-set’ where the most intense portion of the beam will be located – either in front of or behind the target.

“Preferably you off-set behind because that way you can focus on to the floater and have a safety margin, because the actual beam is going to concentrate behind it.”

Selecting the right candidates

Floaters are opacities in the vitreous cavities that cast shadows on the retina. Patient selection is a vital part of vitreolysis, with the size, location and density of floaters usually determining eligibility.

Moshegov says the best candidates have Weiss ring floaters, which are solitary, well circumscribed and located in the middle of the vitreous cavity. These are commonly caused by a posterior vitreous detachment.

He also uses Reflex Technology to treat diffuse, cloud-like floaters (amorphous), which can be harder to eliminate.

“With these it can take two, three, four sessions before making it translucent enough for the patient to be happy,” he says.

“The worst type of floaters aren’t even highlighted or outlined, it’s like a curtain or veil of opacification, something called a thickened posterior hyaloid face; it’s the interface between the detached vitreous and what’s behind it. I avoid using vitreolysis for that type of floater.”

Ellex’s Reflex Technology emits a four- nanosecond burst of energy at a potent power density to vaporise and covert floater collagen and hyaluronic molecules into a gas, which is then resorbed into the eye.

Patient selection is a vital part of vitreolysis, with the size, location and density of floaters usually determining eligibility.

Moshegov says it has been a challenge to convince his colleagues about this process due to a common belief floaters are merely broken into smaller fragments.

He believes this misconception has come about due to the way YAG lasers are applied to the posterior capsule, which does create fragments, that will eventually sink out of view. Larger floaters will require some dissection as part of the vaporisation process.

Although it isn’t a contraindication, Moshegov believes it is also easier to treat pseudophakic eyes than phakic eyes. This is because the optical clarity is better in a pseudophakic eye than one with an ageing natural lens, and there is no risk of inducing a cataract. At worst, a pit or two can be seen on an IOL, but multifocal IOLs make focusing the laser beam more challenging.

Business case 

In terms of the business case for adopting such technology, Moshegov says it has been a solid revenue earner for his practice, alongside his main areas of focus – cataract and refractive surgery.

Many people irritated by floaters are highly motivated to seek treatment. Most have found their way to Moshegov’s clinic through a description of the procedure on his website.

However, the versatility of the Tango Reflex laser also makes it a viable proposition. It features two types of laser; YAG for vitreolysis and frequency doubled N:dYAG for selective laser trabeculoplasty for glaucoma. Ellex says that Red Reflex technology improves YAG overall, achieving high-definition capsulotomies, enabling excellent visualisation and elimination of broken fragments, preventing a common patient complaint of sudden floater development after this treatment.

“So, if a surgeon needs a new YAG laser for posterior capsulotomies, why wouldn’t you spend a bit extra on the instrument that can do the whole lot,” Moshegov says.

“Even if you don’t take up vitreolysis, you will still be recouping the capital expenditure on the laser by doing those other things like capsulotomy and SLT.”

NOTE: Dr Con Moshegov has no financial disclosures and didn’t receive benefits from Ellex.

References 

1. Tango Reflex has a CE Mark (Conformité Européenne) for the indication of laser vitreolysis. Tango Reflex is currently not approved for the indication of laser vitreolysis in the USA. 

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