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YAG photoablation effective first-line treatment for vitreous opacities
Verify that the floaters are stable and ensure that the patient has realistic visual expectations.
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A 56-year-old certified ophthalmic technician presented for a comprehensive eye examination. He was complaining of persistent vitreous floaters in both eyes (left worse than right) for at least 10 years. Due to their large size, the floaters interfered with his visual acuity and caused obstruction of his central vision in the left eye; they were especially apparent when he read or used the computer. The patient said he could briefly improve his vision by making rapid head and eye movements in an attempt to cause the floaters to move away from his visual axis. He denied seeing flashes, a curtain over his vision or recent trauma.
The patient’s medical history was significant for osteoarthritis, fibromyalgia, hypertension, asthma, coronary artery disease, splenectomy and Raynaud’s syndrome. He was taking the following medications once daily in the morning: aspirin 81 mg, lisinopril 5 mg and meloxicam 7.5 mg.
Best corrected visual acuity measured 20/20 OD and OS. Pupils were equal, round, reactive to light and without afferent defect. Extraocular motility was full in all gazes in both eyes. Visual fields were full to finger counting in both eyes.
Intraocular pressure was 13 mm Hg OD and OS. Slit lamp examination was significant for mild meibomian gland disease, rare endothelial pigment and early nuclear sclerosis in both eyes. Dilated fundus examination was significant for moderate syneresis and vitreous floaters, posterior vitreous detachment (PVD) and a few macular drusen in both eyes. The arteriovenous ratio was mildly reduced in both eyes. The cup-to-disc ratio was 0.15 in both eyes. Both optic nerves were pink, distinct and healthy, with mild overlying fibrosis. The periphery of both eyes was flat and intact, with no holes, breaks or retinal detachments.
Digital retinal photographs were taken. A B-scan ultrasound showed dense central vitreous floaters. Vitreous floaters in the left eye cast a dense shadow over the macula, interfering with optical coherence tomography testing.
Diagnosis, management
Based on the exam findings, the patient was diagnosed with transient vision loss caused by both persistent vitreous floaters and PVD in both eyes. The left eye was significantly worse based on subjective complaint.
Management and treatment options for vitreous opacities were discussed with the patient, including continued observation, surgical vitrectomy and laser photoablation. Chemical vitreolysis for floaters is still in experimental stages and was not discussed.
Continued observation
Vitreous floaters alone do not threaten eye health. Once a serious condition such as a retinal tear or detachment is ruled out by dilated fundus examination, optometrists commonly take a “live with it” approach to management. In fact, many informational brochures routinely encountered in optometric practice suggest no treatment options and only advise having a comprehensive eye examination to rule out more serious eye conditions.
Surgical vitrectomy
In a large, retrospective study of 110 eyes, de Nie and colleagues reported the following complication rates after pars plana vitrectomy for primary vitreous floaters: cataracts, 38%; retinal detachment, 10.9%; spontaneously resolving vitreous hemorrhage, 10.9%; cystoid macular edema, 5.5%; epiretinal membrane, 3.6%; glaucoma (requiring subsequent iridectomy, trabeculectomy and Baerveldt tube), 0.9%; macular hole, 0.9%; postoperative scotoma, 0.9%. Endophthalmitis did not occur. Despite these complications, the authors reported that pars plana vitrectomy was a valuable method to manage bothersome vitreous floaters and noted a statistically significant improvement in average best-corrected visual acuity from 0.83 before treatment to 0.91 after treatment.
Images: Hyatt R
It should be noted that some patients who underwent cataract extraction in the months or years following vitrectomy had further complications of retinal detachment. In this study, these were considered a complication of the vitrectomy and not necessarily of having cataract surgery.
Laser photoablation
Laser photoablation (vitreolysis) works by vaporizing opacities into small gas bubbles that quickly dissolve. Once a laser pulse is emitted, treatment occurs by both ablation and lysis. Floaters are vaporized, and plasma forms.
In a study by Delaney and colleagues, Nd:YAG laser vitreolysis was found to be safe and without complication, but only about one-third of patients had moderate benefit. Pars plana vitrectomy, on the other hand, resulted in complete symptom resolution in more than 90% of patients. Other studies report a visual improvement without complication in nearly 100% of patients treated with laser, though sample sizes were small (Toczolowski et al., Tsai et al.).
The patient elected to initially treat his left eye. The laser used was an Ultra Q Reflex by Ellex, a YAG laser specifically designed and marketed to treat vitreous floaters and approved in the U.S., Europe and Canada for that specific purpose in 2013. It is able to vaporize dense Weiss rings and is also approved for posterior capsulotomy, iridotomy and posterior membranectomy.
The patient had a single treatment session and received 167 spots without complication. Intraocular pressure remained normal, and best corrected visual acuity was 20/20. The patient was satisfied with the resulting vision improvement and planned to have his fellow eye treated.
Composition of floaters
The vitreous is primarily composed of collagen, water, and hyaluronic acid. As the relationship between these components changes over time, floaters, strands, cobwebs or sheets may result, casting a shadow on the retina that is then seen in the visual field.
To better understand vitreous morphology changes with age, Sebag dissected vitreous from 59 human eyes ages 33 weeks gestation to 94 years. In samples younger than 29 years, he classified the vitreous as having a homogenous appearance. In samples between 30 and 69 years old, he found linear fibers that inserted into the vitreous base anteriorly, followed a symmetrical, parallel, horizontal course to the posterior vitreous, and oriented posteriorly at the macula.
In samples older than 70 years, the vitreous was significantly reduced and collapsed, and the fibers that were initially oriented parallel were now disorganized and tortuous. Furthermore, liquid vitreous was interspersed within the irregular spaces. It can be presumed that this shift in organization can be attributed to the translocation of hyaluronic acid from the vitreous gel into the liquid, further causing a structural change.
According to Ellex Medical Lasers Ltd., before treating, floaters should not be caused by any ocular pathology, should be stable and present for at least 2 months, and should not be accompanied by flashes of light. The flashes may indicate an incomplete PVD, which increases the risk of retinal detachment or retinal tear. Side effects of treatment with Ultra Q Reflex include cataract and IOP spike.
Health-related quality of life is significantly reduced by symptomatic vitreous floaters. Interestingly, Wagle and colleagues found that, on average, symptomatic patients were willing to trade 11% of their remaining life and take a 7% risk of blindness if they could get rid of their floaters.
First-line treatment
With its high safety profile, YAG vitreolysis is an excellent first-line treatment for symptomatic floaters in a patient whose quality of life is affected. If the result after vitreolysis is not satisfactory for the patient, vitrectomy is an obvious adjunct or follow-up procedure. Patient expectations are important.
This patient was considerably affected by his vitreous floaters. In addition to having to constantly shift his eyes to “look around” the floaters, he found them extremely distracting and was at times unable to read or use a computer. After the procedure, the patient reported immediate relief and estimated his quality of vision improved by 60%. He is looking forward to having his fellow eye treated in the near future.
In summary, first rule out retinal pathology. Verify that the vitreous floaters are stable and persistent and that a complete PVD has occurred. An in-depth discussion with the patient should take place to ensure realistic visual expectations. YAG vitreolysis is not just breaking big rocks into little rocks – it is actually stripping electrons and creating plasma, a mini nuclear reaction.
- References:
- Delaney YM, et al. Eye. 2002;16(1):21-26.
- de Nie KF, et al. Graefes Arch Clin Exp Ophthalmol. 2013;251:1373-1382.
- Sebag, J. Eye. 1987;1:254-262.
- Sebag, J. Graefes Arch Clin Exp Ophthalmol. 1987;225:89-83.
- Toczolowski J, et al. Klin Oczna. 1998;100(3):155-157.
- Tsai WF, et al. Br J Ophthalmol. 1993;77(8):485-488.
- Wagle AM, et al. Am J Ophthalmol. 2011;152(1):60-65.
- For more information:
- William Dunn, MD, FACS, is a specialist in vitreoretinal diseases and surgery at Florida Retina Institute in Daytona Beach, Fla.
- Darcy Eberle, OD, and Ruth Hyatt, OD, practice at the William V. Chappel Jr. Veteran’s Administration Outpatient Clinic in Daytona Beach, Fla.
- Dianne Kowing, OD, FAAO, is chief of the eye clinic at the William V. Chappel Jr. Veteran’s Administration Outpatient Clinic.
Disclosures: The authors report no financial disclosures.