A Must for Improved Quality of Life
I. Paul Singh, MD
Resolving symptomatic vitreous floaters has been a passion of mine for the past 6 years. To date, I have performed more than 4,000 laser treatments to address this condition. Based on my experience, I can confirm that floaters, whether small or large, can have a tremendous impact on patient satisfaction and quality of life.
In the past, ophthalmologists tended to minimize the impact that floaters have on patients because we lacked a viable option to treat them. Today, some skepticism surrounding laser floater treatment (LFT) remains, mostly stemming from the fear of potential complications. However, as is common in ophthalmology, the technology for laser vitreolysis has improved, as have the indications and safety profile.
Historically, the only treatment offered for vitreous floaters was pars plana vitrectomy (PPV). Unfortunately, not all patients are good candidates for PPV; for these patients, the only option was to observe many of the common types of floaters, such as a Weiss ring or other solitary vitreous opacities. However, these floaters can still negatively affect a patient's quality of life.
Now, with advances in laser technology, the definition of clinically significant vitreous opacity has changed: Symptomology does not have to be as severe as that for vitrectomy. Smaller floaters that were often considered to be not clinically significant enough to warrant surgery (Weiss rings, amorphous clouds and strings) are now potential candidates for treatment. So, patients who were historically ignored can now be treated earlier in the disease process. It is important to note that LFT is not intended to replace or compete with vitrectomy. The ideal patient for LFT is different from that for vitrectomy.
Visualization is one of the key differentiating factors between a standard Nd:YAG laser and the laser technology now available for vitreolysis. With a standard Nd:YAG laser, the illumination tower comes from below (noncoaxial position) and the aiming beam comes from a different optical pathway, meeting at the posterior capsule. This is great for capsulotomies, but, if a floater is more posterior, the surgeon cannot see it because the aiming beam, the illumination tower, and the laser criss-cross, and the view is lost just a few millimeters behind the lens. It is also impossible to obtain any spatial context to determine the location of the floater in relation to the retina with traditional Nd:YAG lasers.
With the laser I use to perform vitreolysis (YAG Reflex Laser Systems, Ellex), I can visualize not only behind the capsule but all the way to the retina. The illumination tower and treatment beam are on the same optical pathway, which provides true and titratable coaxial illumination and maximizes spatial context. The laser can fire at any position of the slit lamp. With this laser, we have the ability to titrate the illumination to provide best contrast with the floater while providing enough spatial awareness with the lens and the retina.
The energy delivered differs with current technology to improve efficacy and efficiency. These lasers use a truncated energy beam, which allows for less dispersion of energy. Using even 5 or 6 mJ, we can break up a floater and cause vaporization in a very small area. A smaller Weiss ring typically requires about 200 to 300 shots per session, and the treatment is complete when resolution is observed. Larger floaters—the amorphous clouds and strings—respond well to laser vitreolysis but may require multiple sessions for resolution of symptoms.
One of the fears cited by those skeptical of LFT relates to the amount of laser energy required. However, the relationship between laser energy and dispersion in the eye is not linear. One mJ equates to about 110 µm of convergence zone (shock wave), but when if you up to 10 mJ, that only increases to 200 µm. We are not linearly increasing how much energy is in the eye. Also, unlike with vitrectomy, we are severing or vaporizing the vitreous strands rather than pulling or tugging directly on the vitreous.
From a safety standpoint, adverse events can happen if one is not familiar with the laser and the nuances of maximizing visualization. It is possible to hit the lens if focused too close to the lens or hit the retina if focused on the retina. These adverse events can be avoided by not firing when too close to those structures. Some skeptics point to studies observing the risk of retinal detachment and cystoid macular edema (CME); it is important to remember that those studies used older lasers, and many of the patient populations studied had a history of retinal detachment before LFT. Shah et al1 conducted the first placebo-controlled, randomized, masked trial using the newer lasers. At 1 year, there were no adverse events seen in the treatment arm, and, incidentally, a retinal defect was seen in the placebo arm.
My colleagues and I conducted a retrospective analysis of 1,272 procedures performed in 680 patients with amorphous and Weiss ring floaters.2 Ten adverse events were recorded, comprising seven cases of IOP spikes, two cases of hitting the lens, and one retinal hemorrhage. The retinal hemorrhage resolved in 3 months with no long-term effects. There were no inflammatory issues, no observations of anterior chamber or vitreous cell flare, no exacerbation of diabetic retinopathy, and no progression of epiretinal membrane or CME.
I think of LFT to PPV as selective laser trabeculoplasty to filtering surgery in glaucoma. We do not necessarily want to assume the risk of even the postoperative down-time with traditional glaucoma surgery, so we opt for SLT as first-line or earlier therapy for mild to moderate patients. In the same vein, I offer LFT to patients who are not good candidates for PPV or who have been told by a vitreoretinal surgeon that PPV is not warranted for their type of floater, such as a Weiss ring. Our success rate for patients with Weiss ring floaters is more than 93% patient satisfaction.2 Bottom line, it is possible to truly ease patients' suffering and greatly improve their quality of life with LFT.
1. Shah CP, Heier JS. YAG laser vitreolysis vs sham YAG vitreolysis for symptomatic vitreous floaters. JAMA Ophthalmol. 2017;135(9):918-923.
2. Singh IP. Treating vitreous floaters: patient satisfaction and complications of modern YAG vitreolysis. Paper presented at: ASCRS/ASOA Annual Meeting; May 6-10, 2016; New Orleans, LA.
Proceed With Caution
Chirag Jhaveri, MD
As a retina specialist, I recognize that vitreous floaters are a real problem. I do not belong to the old school of thought that suggests we simply tell patients with floaters not to worry and send them home. In this day and age, we have the technology needed to address this condition. Although most patients can tolerate floaters, there are certainly patients who will inevitably be bothered by this condition, whether due to the floaters themselves or to their personality type.
With laser vitreolysis, more energy enters the eye than with any other Nd:YAG laser procedure. The treatment typically requires 6 to 8 mJ of laser energy and 200 to 300 laser shots per session. Most patients require more than one session. Delivering this amount of energy into the eye is not without potential complications. I have had patients referred to me with posterior capsular ruptures requiring cataract surgery and vitrectomy within 1 or 2 weeks. I have also treated patients with increased IOP that would not decrease on maximum drops; instead of filtering surgery, we performed vitrectomy, which then lowered the IOP. Retinal tears, retinal detachments, retinal hemorrhages, optic nerve damage, and CME have also been reported after laser vitreolysis.1
In a prospective study,2 investigators randomly assigned 52 patients to laser vitreolysis or sham laser vitreolysis. They found that 54% of patients in the laser vitreolysis group noted symptomatic improvement, compared with 9% in the sham group. Although it is positive that half of the patients experienced an improvement, nearly half did not. That is potentially problematic for a procedure that comes at an out-of-pocket cost to patients and sometimes requires multiple treatment sessions. Further, the investigators used photography and OCT to visualize the vitreous floaters pre- and postoperatively. They noted a 95% resolution of floaters on examination. But, as noted above, only 54% of the patients experienced an improvement in their symptoms. This may imply that, although effective, laser vitreolysis may not necessarily address patients’ underlying problem.
In an earlier study of 39 patients,3 38% reported moderate or significant benefit from laser vitreolysis, whereas 61.5% found no improvement. Of patients who required subsequent PPV, 93.3% experienced a resolution of symptoms. In my opinion, we cannot go wrong with PPV, and the PPV we perform today is not your dad’s vitrectomy; these are small-incision vitrectomies with a very good safety profile. Further, PPV is a covered procedure.
Vitreous opacities are a complex change in the vitreous gel. Careful assessment is required to identify the ideal candidates for laser vitreolysis. It is important that the surgeon evaluating patients for vitreous floaters be capable of providing alternative options for those who are not ideal candidates for laser vitreolysis.
1. Hahn P, Schneider EW, Tabandeh H, Wong RW, Emerson GG. Reported complications following laser vitreolysis. JAMA Ophthalmol. 2017;135(9):973-976.
2. Shah CP, Heier JS. YAG laser vitreolysis vs sham YAG vitreolysis for symptomatic vitreous floaters. JAMA Ophthalmol. 2017;135(9):918-923.
3. Delaney YM, Oyinloye A, Benjamin L. Nd:YAG vitreolysis and pars plana vitrectomy: surgical treatment for vitreous floaters. Eye (Lond). 2002;16(1):21-26.