Optometry - Journal of the American Optometric Association
Volume 81, Issue 3 , Pages 157-161, March 2010

Current treatment for vitreous floaters

  • David P. Sendrowski, O.D.

      Affiliations

    • Southern California College of Optometry, Fullerton, California
    • Corresponding Author InformationCorresponding author: David P. Sendrowski, O.D., Southern California College of Optometry, Ocular Disease, 2575 Yorba Linda Blvd., Fullerton, California 92831.
    • ,
  • Mark A. Bronstein, M.D.

      Affiliations

    • UCI Medical School, lrvine, California

Article Outline

Abstract 

Vitreous floaters are a common complaint in the ophthalmic care setting. Patients seek explanation and advice regarding possible treatment options. Because the condition is considered benign, ophthalmic care practitioners have little to offer regarding treatment options. The majority of cases encountered are managed with patient education and reassurance. Although almost all patients accept the conservative management option, there is a small subset of patients who may desire a more aggressive treatment intervention for resolution of their visual symptoms. Information with regard to treatment options is readily available to patients through Internet searches and non–peer reviewed educational Web sites. The risks and benefits for these treatment options are not fully covered. Management of floaters should include education regarding “off-label” procedures as well as discussion about benefits and risks associated with such treatment options. It is vital that eye care practitioners advise and counsel patients with symptomatic floaters for optimum ocular health care. This article reviews the current conventional and “off-label” treatment options for symptomatic patients with vitreous floaters.

Keywords: Vitreous floaters, YAG laser, Vitreolysis, Vitrectomy

 

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Vitreous: structure and function 

To understand the symptomology of floaters one must become refamiliarized with the basic structure of the human vitreous. The vitreous is composed primarily of water. Collagen is an important structural protein in the vitreous.1 Many different types of collagen are found in the human vitreous; type II collagen, a homotrimer composed of 3 identical alpha chains, comprises 75% of the total collagen in the structure.1 The vitreous body is also composed of a group of noncollagenous structural proteins.2, 3 Collagen filaments and hyaluronic acid (HA) comprise the solid component of the vitreous gel.3 The ability of HA to retain water molecules is an important factor in maintaining the gel consistency of the vitreous.

One of the more common age-related events occurring in the vitreous is a posterior vitreous detachment (PVD). Complete PVD can be defined as a separation between the posterior vitreous cortex and the internal limiting lamina (ILL) of the retina.4, 5 The separation can be localized, partial, or total (complete) in nature. The optometric clinician should distinguish the complete PVD from other forms of vitreous separation, because the increased likelihood of ocular morbidity (retina breaks or tears) exists with partial or focal PVD.

Over the years, much has been learned about the epidemiology, pathogenesis, and the sequelae of a PVD. About half the patients with PVD are over age 50 with two thirds of patients having experienced the event by age 65.6 Several studies have found a higher incidence of PVD in women, a finding that suggests hormonal changes after menopause as a possible contributing factor to the PVD, affecting the biochemical components of the vitreous.7, 8 One study found that high estrogen levels were found to be protective against PVD and that lowered estrogen levels associated with menopause may lead to changes in the vitreous, predisposing an individual to a PVD. Higher levels of vitamin B6 were also associated with the development of PVD in premenopausal women, which may be attributed to an antiestrogen effect from that vitamin.8

The pathogenesis of a PVD results from9 liquid vitreous formation and destabilized collagen fibrils, both related to age. This destabilization, along with rotational eye movements, causes syneresis and collapse of the vitreous body. The volume displacement from the central vitreous to the subretinal space creates separation of the vitreous from the ILL, typically located at the posterior pole near or at the optic disc.10, 11, 12 HA depolymerizes with age and metabolic and environmental stress. This depolymerization causes HA to release water molecules and to ultimately form lacunae (pockets or localized areas of liquefied vitreous). Collagen filaments aggregate to form larger fibrils, which, in turn, cause further collapse of the vitreous structure. Collagen fibrils may float in these lacunae giving the patient the perception of floaters.

Balazs et al.13 found evidence of liquid vitreous occurring as early as age 4 and observed that by the time the human eye reaches its adult size (ages 14 to 18) up to 12.5% of the total vitreous volume consists of liquid vitreous. Thus, the speed at which vitreous liquefies can vary depending on the HA and collagen interaction, oxidative effects, and varying degrees of light exposure as the patient ages.14

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Formation of vitreous floaters 

In the younger patient, collagen aggregates into fibrils and mobilizes in lacunae and is associated with floater symptomology. These floaters tend to be fewer in number and more linear in form in comparison with older patients. Location along the visual axis produces the greatest visual discomfort. Thus, vitreous floaters can occur with or without the advent of a PVD. The onset of floaters in an eye with an attached vitreous suggests degenerative or pathologic changes associated with the vitreous body's ultrastructure or the result of cellular or acellular material introduced into the vitreous.9, 10, 13

Refractive etiologies, such as axial myopia, are associated typically with a liquefied vitreous observed among young patients with floater symptomology. Younger patients between the ages of 20 and 50 who have moderate myopia were found to manifest vitreous liquefaction and PVDs sooner than their age-matched counterparts who were emmetropic or hyperopic.13 Vitreous liquefaction has been found to be greater in myopes of 6 diopters or more.13

Other pathologic changes associated with vitreous liquefaction and structural integrity loss in a younger patient include Marfan's, Ehlers-Danlos, and Stickler's syndromes and diabetic vitreoretinopathy (secondary to elevated levels of glucose).

Floater symptomology in older patients usually presents with floaters that move with vitreous displacement during normal eye movement and scatter incident light,15 casting a shadow on the retina that is perceived by the patient as a grey, silhouettelike object(s) or a “spider web–like” image that moves across the visual plane. Patients typically convey that these floaters move rapidly in the visual plane when they attempt to focus on them.15 Uniform backgrounds such as a clear blue sky or white wall allow better perception of these vitreous floaters. Patients should be told to expect the floaters to become more prominent with these background conditions.

In addition, floater symptomology may be related to a newly formed PVD, which scatters light and casts varying degrees of shadows on the retina. This phenomenon is created by glial tissue of papillary origin that has adhered to the posterior vitreous cortex,16 known as a Weiss Ring (see Figure 1). A patient complaining of acute floaters with or without the presence of an associated Weiss Ring requires a dilated fundus examination to evaluate for possible retinal hemorrhage, retinal breaks, or detachment induced by the vitreous separation.17

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  • Figure 1 

    The appearance of a Weiss Ring usually indicates a fresh posterior vitreous detachment. This patient had a sudden onset of a floater in their vision with associated posterior vitreous detachment.

Because a sudden onset of vitreous floaters in either young or older patients may also be associated with several retinal conditions, such as a retinal detachment, retinal break(s), preretinal or vitreous hemorrhage, retinal vasculopathies (ie., proliferative diabetic retinopathy), and posterior uveitis, a comprehensive dilated fundus evaluation is a necessity in all cases.

Patients with benign symptomatic floaters do not usually complain about a dramatic loss of vision or visual acuity when the floater interrupts the visual axis. There are rare exceptions in which the floater is exceptionally large or is positioned on or near the patient's visual axis or line of sight. Figure 2 represents a large pigmented floater present in a patient who showed visual acuity loss when the vitreous floater obscured the visual axis. These types of vitreous floaters are rare but may require further management, which may include alternate treatment options.

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  • Figure 2 

    A large congenital vitreous floater located in the central visual axis of the patient's eye. Encapsulated primary vitreous that became dislodged later in life. Movement of the floater across the visual axis caused temporary loss of visual acuity and distortion.

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Conventional therapy 

Conventional management of most vitreous floaters typically requires only reassurance and education. Explanation of the visual phenomenon should be given to the patient along with the doctors' advice for follow-up care. In the presence of a symptomatic acute PVD, the patient should be re-evaluated with a dilated fundus examination periodically until the symptoms or vitreous traction has subsided. (2 weeks to 3 months depending on accompanying symptoms of photopsia).5

A complicated PVD associated with either Shafer's Sign (tobacco dust sign) or preretinal/vitreous hemorrhage warrants a more careful dilated fundus examination, because an increased risk of retinal break or detachment exists. If no retinal break or detachment is noted, a retinal consult or close follow-ups with dilated fundus examination should be considered. All patients should be advised of the signs and symptoms of an associated retinal detachment. These may include, but are not limited to, an increase in floaters or flashes or an appearance of a persistent curtain or shadow in the field of vision. Patients need to be told to return to the office immediately if any of these symptoms occur.

The symptomatic floater patient should be given time to generate questions of concern and, in rare cases, options for secondary treatment should be discussed. If secondary treatment is requested, advice should include the risks and benefits of each treatment option along with recommendations for a second opinion.

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“Off-label” treatment options for floaters 

Laser therapy 

The yttirum aluminum garnet (YAG) laser has become accepted as “the standard of care” for many ophthalmic surgeries. Yet, the use of the YAG for treatment of vitreous floaters has not been accepted widely by the ophthalmic profession and remains an “off label” treatment option for select cases. It is critical in these selected cases that the doctor and patient have an open and frank discussion regarding the off-label YAG treatment for floaters. Patients have access to vast amounts of information through the internet. With regard to vitreous floaters, many of these sites do offer patients an “option,” both laser and surgical, to remedy their visual symptoms. These remedies are not well described, and complications are rarely discussed. Thus, education is critical.

There is little clinical research utilizing a YAG for the treatment of vitreous floaters and its impact on patient's symptoms. One study performed by Tsai et al., reported the use of a YAG laser to treat vitreous floaters in one eye of patients with severe psychological reactions to the vitreous floaters.18 The Tsai group18 treated 15 patients who met the following criteria for laser treatment: floaters caused by localized vitreous opacities; symptoms persisted for at least 3 months without evidence of regression; patients suffered from fear, depression, or anxiety; and patients had a strong desire for a fast cure. None of the patients had a history of retinal detachment, diabetic retinopathy, or any retinal diseases.18 Each patient had a thorough preoperative ophthalmic examination, which included a binocular indirect ophthalmoscopic examination with scleral depression 360° to rule out retinal breaks or tears. The study concluded that all patients were satisfied with their YAG treatment during a 12-month follow-up, and no patients showed any significant visual deterioration or recurrence of their subjective floaters.18 This study included only 15 highly motivated patients, making it hard to draw sound clinical conclusions.

In a later study by Delaney et al., 42 eyes of 31 patients were enrolled in 2 treatment groups: a YAG laser group and a surgical (pars plana vitrectomy) group.19 Preoperative examination of the vitreous and retina was performed to confirm the presence of a complete PVD to determine the position of the vitreous opacity and to exclude any coexisting retinal disease. Laser treatment was not undertaken if the vitreous floater was located within 2 mm of the retina or the crystalline lens. At the end of their treatment, all laser vitreolysis (noninvasive photodisruption of vitreous strands, floaters, or adhesion bands) patients were given a questionnaire asking them to choose 1 of 4 postoperative assessments. Assessments included: failure, partial success, significant success, and complete success. In no eye was laser treatment 100% successful in eliminating symptoms. Results showed only 15 eyes benefited to some measure in that patients felt that the moderate benefit gained from laser vitreolysis of the vitreous floaters was adequate in relieving symptoms so as to alleviate the need for further surgery.19 Clinical improvement for most patients was only moderate in degree. None of the subjects reported a complete resolution of symptoms. In fact, 7.7% of the patients had a worsening of symptoms after their laser treatment. There were no ocular complications or adverse events from YAG treatment of vitreous floaters in this particular study. Based on these results, the authors concluded that laser vitreolysis for vitreous floaters was safe but led to only a moderate improvement of symptoms in only a third of the patients.19

A major deterrent in the utilization of the YAG laser for vitreous floaters is the lack of U.S. Food and Drug Administration approval for such use. It remains an “off-label” use of the procedure and requires greater patient education and documentation by the physician. In addition, most insurance companies will not reimburse physicians for this particular use of the laser, requiring the patient to self-finance the procedure.

Appropriate patient selection is vital for success in YAG vitreolysis treatment.18, 19 The size and location of the floaters, the amount of laser treatment necessary to obliterate the lesion, the number of treatment sessions, and the risk to adjacent ocular structures must be considered. Furthermore, current methods to assess functional impairment induced by vitreous floaters have not been established or standardized. Studies have found that some well-selected patients can expect some degree of resolution from their floaters, but patient satisfaction will vary greatly.18 Obviously, promoting realistic expectations will influence ultimate patient satisfaction and treatment decisions.

There are several inherent problems and potential risks that are not apparent with other ocular uses of the YAG laser. Unlike YAG capsulotomies and iridotomies, the ophthalmic tissue being treated is in motion. Vitreous floaters make both aiming and utilization of the treatment energy more difficult than with other YAG laser procedures. Second, location of symptomatic vitreous floaters is near the posterior pole of the eye, more specifically the optic nerve head and retinal vascular regions.20, 21 Miscalculations with applied laser energy or treatment site could result in potentially sight-threatening complications. Serious ocular side effects could include retinal tears, vitreo-retinal hemorrhages, or retinal detachments.22 Certainly, better targeting computerization and alignment would be helpful with future laser vitreolysis. These options are not currently available on current instrumentation, which relies more on surgical skill and experience with the laser.22, 23 Research is limited with regard to information about the effects and safety of such treatment options on floater symptomology.

Surgical intervention 

Combined cataract surgery with anterior vitrectomy has been described as a treatment option for patients with both cataracts and symptomatic vitreous floaters.23 This technique has been reserved for older patients with early or advancing lens opacification.

New surgical techniques, such as microincision vitrectomy, may offer a more complete cure from symptomatic vitreous floaters than laser vitreolysis. It might be a better option for treatment of patients who demand resolution from their symptomatic vitreous floaters (see Figure 3). Although no clinical studies have been done to show its effectiveness, this “off-label” use of microincisional vitrectomy has been used to treat patients with symptomatic vitreous floaters.

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  • Figure 3 

    Before and after 23-gauge microincisional vitrectomy. Patient had asteroid hyalosis, which made the evaluation of the wet age-related macular degeneration difficult and required vitrectomy to better monitor the condition.

Currently, some common indications for microincisional vitrectomy use are macular pucker, macular holes, diabetic retinopathy without extensive membrane dissection, vitreous hemorrhage, and tractional retinal detachment.24, 25 There remains a general reluctance in the ophthalmologic community to perform this ocular surgery on eyes with corrected acuity of 20/20. Some of the reluctance may be related to the natural history of vitreous floaters and PVD and the resolution of both conditions with a combination of time and conservative treatment. Additionally there are potential risks (i.e., endophthalmitis, retinal tears, bleeds, or detachments) associated with vitrectomy surgery.24 These risks might be unacceptable for patients and surgeons with benign symptomatic vitreous floaters.24 Patient selection and education is absolutely vital for this treatment option for symptomatic vitreous floaters when considering “off-label” microincisional vitrectomy. As with YAG vitreolysis, surgical experience and ocular risks must all be well understood by the patient. Future studies are needed to determine both the risk and benefits of these treatment options for patients with floaters symptomology.

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Conclusions 

Today the best treatment options for symptomatic vitreous floaters remain conservative ones, with close follow-up and education. Time and patient reassurance will, for the most part, result in reduction or resolution of initial symptoms and has, over time, shown to be a sound treatment option.

In terms of “off-label” treatment, laser and surgical options for vitreous floaters have not been adequately defined. The primary purpose of “off-label” laser and surgical options are the alleviation of symptoms associated with vitreous floaters.25 A secondary benefit may be the reduction of the patient's mental stress created by the floaters. Alternately, the primary risks of “off-label” use of laser and surgical options are the unwanted ocular complications of retinal tears, vitreoretinal hemorrhages, endophthalmitis, and retinal detachments. Currently, there are no clinical studies that provide adequate information about the ocular benefits or complications associated with such treatment options. Although patient symptomology from vitreous floaters can be reduced or in some cases alleviated by laser or surgical intervention, the patient benefit may not offset the potential risk from the procedure. The decision for treatment of symptomatic vitreous floaters should be done on a case-by-case basis. Patient annoyance, stress, and anxiety created by the vitreous floaters is an important factor in that decision-making process.

Regardless of the treatment option agreed upon by the patient and doctor, it is important to educate patients by becoming familiar with “off-label” treatment options, on the risks and benefits of all treatment procedures, and to allow time for the patient and doctor to consider what is best for the visual health of the patient.

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References 

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PII: S1529-1839(09)00524-7

doi:10.1016/j.optm.2009.09.018

Optometry - Journal of the American Optometric Association
Volume 81, Issue 3 , Pages 157-161, March 2010

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