Argument For Use of Laser Vitreolysis

Gustavo A. Corrales, MD

Symptomatic floaters is one of the most diagnosed conditions in adults. They cause significant disruption of vision and quality of life. Most patients complaining of floaters have been told to “learn to live with it” or “not to worry about it.” However, this is a very treatable condition that most often goes untreated.

Like most other medical conditions, the diagnosis of floaters represents a spectrum of severity with correlated symptoms. For the mild, asymptomatic floaters found incidentally, the best treatment remains observation. For the severe, diffuse, dense floaters, a vitrectomy is probably necessary (Figure 1). Between these 2 extremes lies the great majority of patients who present with a symptomatic Weiss ring or central symptomatic floaters from syneresis or consolidation. These patients complain of a persistent interference with their central vision. Very often, these patients have to pause for the floater to move in order to see something in detail, and some have even learned to move their heads and eyes a certain way to move the floater out of their central vision. Several studies have established how floaters affect quality of life and even decrease contrast sensitivity¹ and how floater treatment can improve these measures.² The vast majority of these patients can be helped by laser floater treatment.

From a technical standpoint, retina specialists have to be respectful of the tools used. If handled properly, these tools can bring about great benefits to the patient with minimal intervention. The pitfall is to be carried away by the elegance and results of the procedure. To avoid this, I usually stay under 200 shots at 5 mJ to 10 mJ per shot per session. The energy of the shot depends on the position and density of the floater. I prefer to do multiple sessions rather than deliver a large load of energy at once. That way, you can watch for intraocular pressure (IOP) spikes that hint at a risk of a permanent increase in IOP. The safety of the procedure has been established by studies performed by Karickhoff³ and others.^4,5

Young patients with floaters are often caught in the controversy of whether to treat or observe. These patients tend to have dense floaters without a posterior vitreous detachment (PVD). I have found that a vitreous still attached to the retina can be advantageous to the treating retina specialist. Dense floaters that may not be amenable to treatment with laser or may require significant energy can be safely treated by severing the fibrillar attachments that keep them in the center. By releasing these central attachments, the floaters tend to be pulled toward the peripheral retina and away from the center. This may be enough to provide the patient with immediate, significant symptomatic relief.

Our goal in the treatment of symptomatic floaters is to achieve improvement in quality of vision and life with the least intervention and risk possible. Laser floater treatment and pars plana vitrectomy (PPV) are both tools that are at our disposal to help our patients toward this end.

Argument Against Laser Vitreolysis

Christopher R. Henry, MD, and Harry W. Flynn Jr., MD

Symptomatic vitreous floaters can arise from a number of different etiologies, including PVD, vitreous syneresis, myopic vitreopathy, asteroid hyalosis, vitreoretinal lymphoma, and uveitis. Vitreous opacities can affect quality of life and may be particularly bothersome to individuals who have high levels of psychosocial stress.⁶

Many opacities associated with a PVD will diminish in size over time, move out of the central axis of vision, or migrate anteriorly where they are no longer in focus. Additionally, some patients will demonstrate central adaptation where they are no longer aware of the presence of the floaters. A large percentage of patients with a symptomatic PVD will thus be accepting of observation, but what should we do for those patients who are not willing to coexist with their symptomatic vitreous floaters? Should YAG vitreolysis be considered as a first-line treatment option?

The published results for YAG vitreolysis demonstrate this to be a mediocre procedure in terms of efficacy. A randomized clinical trial by Shah and Heier evaluated 52 patients who had symptomatic PVD with complete Weiss ring, of which 36 patients were randomized to YAG vitreolysis and 16 were randomized to a sham YAG laser procedure.² In this trial, 53% of patients in the treatment arm reported a significant or complete resolution of symptoms compared to 0% of patients in the sham arm at 6 months follow-up (P<.001). No significant differences in visual acuity were found between the groups. While no differences in adverse events were found in the initial study, an extended follow-up study beyond 6 months did demonstrate that 3/35 (8.6%) patients in the treatment arm later went on to develop a retinal tear.⁷ The primary author of this study and colleagues have since published an opinion article stating that YAG laser vitreolysis is not ready for widespread adoption because of limited comparative data, lack of FDA approval or CPT code, and a 50% success rate not being acceptable in a cash-payment model.⁸

Reported side effects of YAG vitreolysis include increased symptomatic floaters, intraocular pressure elevation, cataract, direct iatrogenic damage to posterior capsule in phakic patients, retinal hemorrhage, and retinal detachment.^9-11 Furthermore, YAG vitreolysis sessions can be time-consuming, with a mean number of 218 to 564 laser shots (and a mean total power of 366.7 mJ to 3,384 mJ) being required in single laser sessions, as reported from published series.^2,12,13 Are 400 shots and 2,000 mJ to the vitreous cavity really a good idea? Finally, there should be some concern that YAG vitreolysis is not performed only by retinal specialists, as general ophthalmologists and optometrists (in the 4 states where it is allowed) market the procedure to the general public. There is a wide-variety in experience amongst the practitioners performing YAG vitreolysis, and outcomes following this procedure may be unpredictable.

If a patient remains symptomatic from vitreous floaters, after an acceptable period of observation, we would argue that small-gauge PPV remains a superior option for appropriate patients, at least in terms of efficacy and predictability. With small-gauge PPV, clinical results appear favorable. In a study of 143 consecutive patients (168 eyes), Mason et al reported a high surgical success rate, with 94% of patients reporting their experience as a complete success and 92% of patients reporting either no symptoms or very mild symptoms following PPV for symptomatic vitreous floaters.¹⁴ Complications included 12 eyes (7.1%) with iatrogenic retinal breaks, 2 eyes with vitreous hemorrhage, 1 eye with cystoid macular edema, and no eyes with postoperative retinal detachment or endophthalmitis at a mean follow-up of 18 months. The authors demonstrated a significant improvement in visual acuity, with a mean Snellen-equivalent vision of 20/40 preoperatively vs 20/25 postoperatively.

Similarly, Sebag et al reported on 76 eyes with vitreous floaters undergoing PPV.¹⁵ They prospectively evaluated contrast sensitivity in 16 patients. Complete resolution of symptoms was seen in 15/16 (93.8%) patients in this group. Complication rates were retrospectively assessed in 60 patients and included 1 eye (1.7%) developing an epiretinal membrane and no eyes experiencing iatrogenic retinal breaks, retinal detachment, or endophthalmitis at a mean follow-up of 17.5 months. While it is true that a small percentage of patients undergoing PPV for vitreous floaters could become blind from secondary retinal complications, endophthalmitis, or anesthesia complications, it appears that PPV is a more efficacious procedure to address symptomatic vitreous floaters. It is also notable that PPV are performed by vitreoretinal surgeons, with a high level of specialized training, and the results of this procedure are more predictable.

The fact of the matter is that most patients who have vitreous floaters associated with a PVD will improve on their own and will not require intervention. Among those patients who remain symptomatic, the best available data suggest that PPV has higher success rates compared to YAG vitreolysis and is a more predictable procedure. Future trials are likely forthcoming to evaluate safety comparisons between YAG vitreolysis and small-gauge PPV. At the current time, we believe that the role for laser vitreolysis of vitreous floaters should remain limited.

References

1. Yuan Y, Shi P. Degradation of contrast sensitivity function following posterior vitreous detachment. Am J Ophthalmol. 2017;177:225.
2. Shah CP, Heier JS. YAG laser vitreolysis vs sham YAG vitreolysis for symptomatic vitreous floaters: a randomized clinical trial. JAMA Ophthalmol. 2017;135(9):918-923.
3. Karickhoff JR. Laser Treatment of Eye Floaters. Washington Medical Publishing, LLC; 2017.
4. 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.
5. Katsanos A, Tsaldari N, Gorgoli K, Lalos F, Stefaniotou M, Asproudis I. Safety and efficacy of YAG laser vitreolysis for the treatment of vitreous floaters: an overview. Adv Ther. 2020;37(4):1319-1327.
6. Kim YK, Moon SY, Yim KM, Seong SJ, Hwang JY, Park SP. Psychological distress in patients with symptomatic vitreous floaters. J Ophthalmol. 2017;3191576.
7. Shah CP. The art and science of YAG vitreolysis. Paper presented at: The American Academy of Ophthalmology Annual Meeting; October 2018. Chicago, IL.
8. Su D, Shah CP, Hsu J. Laser vitreolysis for symptomatic floaters is not yet ready for widespread adoption. Surv Ophthalmol. 2020;65:589-591.
9. Hahn P, Schneider EW, Tabandeh H, Wong RW, Emerson GC. American Society of Retina Specialists Research and Safety in Therapeutics (ASRS ReST) Committee. Reported complications following laser vitreolysis. JAMA Ophthalmol. 2017;135:973-976.
10. O’Day R, Cugley D, Chen C, Fabinyi. Bilateral posterior capsule injury after Nd:YAG laser vitreolysis: unintended consequence of floaters treatment. Clin Exp Ophthalmol. 2018;46:956-957.
11. Liu X, Wang Q, Zhao J. Acute retinal detachment after Nd:YAG treatment for vitreous floaters and posterior capsule opacification: a case report. BMC Ophthalmol. 2020;20:157.
12. Souza CE, Lima LH, Nascimento H, Zett C, Belfort Jr. R. Objective assessment of YAG laser vitreolysis in patients with symptomatic vitreous floaters. Int J Retin Vit. 2020;6:1.
13. Singh IP. Modern vitreolysis - YAG laser treatment now a real solution for the treatment of symptomatic floaters. Surv Ophthalmol. 2020;65:581-588.
14. Mason JO, Neimkin MG, Mason JO, et al. Safety, efficacy, and quality of life following sutureless vitrectomy for symptomatic vitreous floaters. Retina. 2014;34:1055-1061.
15. Sebag J, Yee KMP, Wa CA, Huang LC, Sadun AA. Vitrectomy for floaters - prospective efficacy analysis and retrospective safety profile. Retina. 2014;34:1062-1068.