|Year : 2019 | Volume
| Issue : 1 | Page : 1-4
One-year follow-up of patients after yttrium aluminum garnet laser vitreolysis for vitreous floaters
Amr Saad Bessa
Department of Ophthalmology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
|Date of Web Publication||14-Aug-2019|
Prof. Amr Saad Bessa
Ismail Serry Street, Sidi Gaber, Alexandria
Source of Support: None, Conflict of Interest: None
Background: This study was performed to evaluate the efficacy, complications, and patient satisfaction and follow-up for 1 year after neodymium yttrium aluminum garnet (Nd:YAG) laser vitreolysis for visually disturbing vitreous floaters. Aims: To evaluate the role of Nd:YAG laser vitreolysis in visually disturbing vitreous floaters. Settings and Design: This was an institutional, observational, cross-sectional retrospective study. Subjects and Methods: A retrospective observational study was conducted on 86 eyes of 71 patients suffering from persistent vitreous floaters with complete posterior vitreous detachment who underwent laser vitreolysis with the Ultra Q Reflex™ (Ellex Medical Lasers, Adelaide, Australia), in the first half of 2015. Follow-up was done for 1 year. Patient satisfaction was graded from 0% to 100%. Laser settings and complications were recorded. Results: Average subjective symptomatic improvement was 66.23%; 44.2% of patients reported excellent satisfaction (75%–100%) and 32.6% reported good satisfaction (50%–74%). 45.3% of patients required 3–4 sessions. Average power setting was 5.3 mJ. One case of iatrogenic cataract treated by phacoemulsification and intraocular lens implantation occurred. Another case suffered limited vitreous hemorrhage which completely resolved. Conclusions: Laser vitreolysis is a safe, effective method for the treatment of symptomatic visually disturbing floaters.
Keywords: Detachment, posterior vitreous, retinectomy, vitreous floaters, Weiss ring, yttrium aluminum garnet laser vitreolysis
|How to cite this article:|
Bessa AS. One-year follow-up of patients after yttrium aluminum garnet laser vitreolysis for vitreous floaters. Egypt Retina J 2019;6:1-4
| Introduction|| |
In the young, vitreous is a clear, solid gel filling the vitreous cavity. Despite appearing homogeneous, the vitreous is composed of at least 98% water, and only 0.1% is made up of macromolecules which include collagens, glycosaminoglycans, proteoglycans, and noncollagenous glycoproteins. With age, an aggregation of Type II collagen fibers in the vitreous occurs due to a loss of Type IX collagen, resulting in an increase in fluid-filled spaces (synchysis) and optically dense structures (syneresis) which may form vitreous floaters.
A subset of patients are persistently annoyed by floaters and therefore seek intervention , especially myopes and those who suffer posterior vitreous detachment (PVD), where these floaters interfere with the visual axis.
Floaters may appear in various forms; the first type occurs in young myopes with gel liquefaction, leaving clear spaces interspersed with string-like protein strands. Syneresis may form a different morphology where the gel protein fibers may coagulate to form cotton ball-like clumps or clouds. The Weiss ring which occurs after PVD due to separation of the condensed ring of collagen fibrils around the optic nerve is a characteristic type, producing a visually significant floater, particularly in patients whose visual demands involve near activities., It may occur as a complete or an incomplete ring. Cobwebs or vitreous strands could also annoy patients; these floaters can be treated with vitreolysis. Opercula from retinal tears may also produce dense floaters, such as intraocular inflammation, asteroid hyalosis, or chronic vitreous hemorrhage, which may need vitrectomy.
The severity of the symptoms is determined by the size, centrality, anteroposterior location of the floaters, which vary due to their mobility, and the patient's anxiety level. These factors may theoretically predict the number of symptoms produced by a floater and the satisfaction level after treatment.,, Most practitioners do not consider vitreous floaters a significant clinical problem; however, floaters may cause a negative impact on quality of life, causing reading and driving difficulty, giving rise to treatment options including laser vitreolysis and pars plana vitrectomy.
Q-switched neodymium yttrium aluminum garnet (Nd:YAG) laser is the only“Food and Drug Administration-”approved laser used for vitreolysis. Early publications by Tassignon et al. and Little and Jack  reported using Nd:YAG laser in vitreolysis, keeping at least a 2-mm distance between the targeted floater and the crystalline lens. Adaptation of a proper contact lens and optimal strength of energy with accurate focusing are vital to increased vitreolysis efficacy and avoidance of retinal injury.,
Laser vitreolysis works by floater photovaporization using a very short pulse width (nanoseconds) and a small spot size measured in microns which produces optical breakdown at low energy levels with ionization, disruption and floater disintegration without heat effects as collagen shrinkage or burning, causing floater vaporization and conversion into gas bubbles. If treatment is delivered below the level of optical breakdown, floaters are fragmented rather than vaporized with moderate relief of symptoms.
The maximum energy used per pulse should be 2.0–8.0 mJ, with a maximum number of points administered of 500 points per session, ranging from 1 to 5 sessions. Furthermore, no laser should be applied if the floaters were located within 2 mm of the retina or crystalline lens. By applying these criteria, the risk of retinal damage should be reduced if not eliminated. Patients selected for vitreolysis must not have an active retinal pathology or active inflammation. Floaters should be present and stable for 2–3 months with complete PVD, which is more likely to be present in older patients (more than 45 years) with sudden onset of PVD symptoms. Synchysis scintillans, asteroid hyalosis, and vitreous opacities after vitritis and long-standing vitreous hemorrhage are contraindicated for vitreolysis and necessitate vitrectomy.
Pars plana vitrectomy
Pars plana vitrectomy (PPV) achieved higher success rates in removing floaters, but with more complications including retinal breaks (7%) retinal detachment (0%–6.8%), and secondary cataract (23%).,
| Subjects and Methods|| |
We reviewed the files of 71 patients (86 eyes) treated by Nd:YAG laser floater-lysis in the first half of 2015 using the Ultra Q Reflex™ (Ellex Medical Lasers, Adelaide, Australia). All data were reviewed concerning patient epidemiology, history, ocular examination, floater characteristics, treatment parameters, number of sessions, patient satisfaction, and complications.
All patients were 40 years old or older, with stable visually significant floaters for 3 months after complete PVD using binocular ophthalmoscopy, ultrasonography, and optical coherence tomography, with no active retinal pathology. The number and density of their seen floaters, their activity, their degree of discomfort were documented, and their satisfaction rate after laser vitreolysis was enquired upon in a percentage from 0% to 100%.
Full history-taking and ocular examination with pupillary dilatation were conducted. The patient was always asked to draw the bothersome shadow on a paper sheet. Consequently, patients were counseled on the procedure and signed an informed consent.
Neodymium yttrium aluminum garnet laser vitreolysis
After topical anesthesia, special contact lenses were used for the procedure with a coupling agent as Ocular Karickhoff 21-mm Vitreous Lens™ for posterior floaters, Ocular Payman 18-mm Wide Field Vitreous Lens™ for anterior floaters, or Ocular Karickhoff 25-mm Off-Axis Vitreous Lens™ for off-axis floaters; all lenses were manufactured by Ocular Instruments, Washington Seattle, USA. Anterior or posterior off-set of laser aiming beam was used according to the location of the opacity.
The Ultra Q Reflex™ (Ellex Medical Lasers, Adelaide, Australia) contains a flipping reflex illumination mirror which provided a co-axial view with the aiming beam. The laser was fired in shots at the targeted floater, staying 3 mm away from the lens and the retina.
The procedure (20–40 min) was initiated with a single pulse to produce floater optical breakdown (typically 2.5 mJ); hence, the energy was titrated.
Time was always allowed for the mobile floater to settle into its new position before firing again. For multiple floaters, treatment was commenced from front backward to improve the surgeons' view, and from top downward as gas bubbles may impede vision for higher floaters. [Figure 1] demonstrates the Weiss ring before vitreolysis, [Figure 2] shows the Weiss ring partially fragmented during the procedure, and [Figure 3] shows the final outcome after laser vitreolysis.
|Figure 2: Shows the Weiss ring partially fragmented during the procedure|
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No postvitreolysis eye drops were required. A 3rd day follow-up for visual acuity and intraocular pressure (IOP) testing was performed. Patients were asked about improvement after 2–3 weeks; other treatment sessions were performed if symptoms persisted, for a maximum of five sessions per eye. Follow-up extended for 1 year.
| Results|| |
Eighty-six eyes were treated by Nd:YAG laser vitreolysis. The mean age was 57 years (38–76 years) [Table 1].
|Table 1: Demonstrates previous ocular conditions/ co-morbidities in the treated eyes|
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The mean refraction was −1.2 Diopters (+3.0 D–−15.5 D), whereas the mean corrected visual acuity was 0.8 (0.4–1.2). The mean IOP was 14 mmHg (10–21 mmHg). Targeted floaters were classified into premacular (4.6%), midvitreal (52.3%), or Weiss ring floaters (43%). The number of sessions ranged from 1 to 5 [Table 2].
The mean energy used per session was 5.3 mJ (3.2–7 mJ), and the total shots administered per session ranged from 65 to 553 points with a mean of 377. The pulse rate was 1 in all procedures.
Regarding patient satisfaction, the mean patient satisfaction was 66.23%, with the majority of patients (44.2%) reporting excellent satisfaction (more than 75% improvement of symptoms) [Table 3].
|Table 3: Patient satisfaction after yttrium aluminum garnet - laser vitreolysis|
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Regarding complications, one case of iatrogenic cataract, which was managed by cataract extraction and intraocular lens implantation, occurred. Another case suffered vitreous hemorrhage due to a retinal vessel injury, which was immediately treated by argon laser, and the vitreous hemorrhage resolved completely within 2 weeks, and a patient satisfaction of 85%, for this patient, at the end of the vitreolysis sessions. Follow-up for all patients for 1 year was uneventful.
| Discussion|| |
PVD is the most common cause of symptomatic floaters which may annoy patients altering their life quality. Floaters may exist as Weiss rings, cobwebs, and midvitreous strands, and most can be vaporized by Nd:YAG laser if the proper approach was adopted concerning diagnosis of a complete PVD, determination of floater morphology, distribution and distance from the retina and crystalline lens, and using adequate treatment parameters.
The safety, efficacy, and ease of any procedure determine its success. Floaters are treated by either laser vitreolysis or PPV. Treatable adverse events may occur with vitreolysis. Geller  reported a transient increase in IOP in five eyes which was controlled medically and resolved spontaneously. In addition, Koo et al. reported occurrence of iatrogenic cataract after tackling floaters close to the lens capsule. In our hands, a case of iatrogenic cataract occurred during the early cases of the learning curve, especially when the 18-mm Karickhoff lens was used.
Patient satisfaction rates ranged from 38% to 90% in several studies;,, this may be attributed to different patient selection criteria and the variability of targeted floater morphology, in addition to different parameters used. We believe that targeting Weiss rings yield better results with higher patient satisfaction rates, more than other floaters.
When comparing laser vitreolysis to PPV, Delaney et al. concluded that vitrectomy is more efficient regarding the elimination of floaters, but with more complications as retinal detachment. They used lower energy values (1.2 mJ), achieving less than desired improvement of symptoms, but there were no vitreolysis complications, which may be due to the smaller number of cases.
de Nie et al. reported retinal detachment (23%), cystoid macular edema (5.5%), and epiretinal membrane formation (3.6%), a case of resistant glaucoma and a macular hole after PPV for floaters. However, Navarro et al. reported excellent patient satisfaction after PPV for floaters with no reported complications, although their study was conducted on 16 eyes only.
To conclude, laser vitreolysis is a noninvasive procedure to treat indicated symptomatic vitreous floaters via nano-pulse technology with good patient satisfaction. However, it needs an alert and experienced operator for proper patient selection, awareness of the complications, and safe performance of the procedure.
| Conclusion|| |
Yag vitrolyis is an effective method for treatment of symptomatic floaters. In large floaters, it could be helpful in reducing its size.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]