Is there anything positive about PVD floaters?

Vitreous opacities frequently appear with the onset of posterior vitreous detachment (PVD). Although floaters can be distressing and it may be hard to see anything positive in the experience, sufferers may find some peace of mind with the knowledge that PVD induced floaters can suggest a reduced likelihood of developing other, significantly more serious, eye conditions. Indeed, the detachment of the vitreous from the retina has been observed to be beneficial in some cases. The conditions described below serve as examples of the benefits that vitreous detachment may bring.

Retinal tears and detachments

As the vitreous humor ages, it liquefies, shrinks, and pulls away from the retina. If it separates uniformly and without complication it is referred to as a PVD. If a portion of the vitreous adheres to the peripheral retina, traction, or a pull on the retina may cause a tear and detachment. This is a serious condition which threatens permanent vision loss and must be treated immediately.

Exudative Age-Related Macular Degeneration (AMD)

Exudative AMD is also known as neovascular or “wet” AMD. This condition is characterized by abnormal blood vessel growth from the choroid (choroidal neovascularization) beneath the macula. These vessels can leak fluid and blood resulting in uneven, wavy, distorted vision, and even loss of vision. Exudative AMD is considered more severe than the non-exudative form of AMD. A 2007 study of 163 eyes by Krebs et al examined the incidence of PVD in a group of eyes with exudative AMD, non-exudative AMD, and a control group (no abnormalities of the macula). This study noted that eyes with no macular abnormalities or dry AMD had a significantly higher incidence of PVD than the eyes with exudative AMD. The authors of this study suggest a number of reasons for these observations, all related to the persistence of an attached posterior vitreous. Similar results were reported by Robison et al in 2009 when they concluded that “PVD may protect against exudative AMD, whereas vitreo-macular adhesion may promote exudative AMD.”

Proliferative Diabetic Retinopathy (PDR)

Proliferative diabetic retinopathy is a complication of diabetes which can lead to vision loss. This condition is characterized by the growth (i.e. proliferation) of new blood vessels along the retina and into the vitreous humor. A 1982 study of 163 eyes with diabetic retinopathy (see Jalkh et al) reported that the vitreo-retinal traction that results from an incomplete PVD is associated with an increased likelihood of PDR progression; whereas, the absence of vitreo-retinal traction (complete or no PVD) seemed to inhibit progression.

Thus, although a PVD can bring floaters into view, the same floaters may also serve as a reminder that the risks posed to the retina by an aging vitreous have diminished. This relationship has not escaped the notice of the medical community. In fact, the benefits of vitreous detachment have propelled research into the development of a pharmacologic substance(s) which would induce PVD as a prophylaxis against the conditions described above (Sebag, 1998 & 2010).

References

1. Mayo Clinic: Retinal Detachment Causes. http://www.mayoclinic.com/health/retinal-detachment/DS00254/DSECTION=causes (accessed June 6, 2011).
2. Krebs I, Brannath W, Glittenberg K, Zeiler F, Sebag J, Binder S: Posterior vitreo-macular adhesion: a potential risk factor for exudative age-related macular degeneration. Am J Ophthalmol 2007; 144:741-746.
3. Robison C, Krebs I, Binder S, Barbazetto IA, Kostolis AI, Yannuzzi LA, Sadun AA, Sebag J: Vitreo-macular adhesion in active and end-stage age-related macular degeneration. Am J Ophthalmol 2009; 148:79-82.
4. Sebag J, Glittenberg C, Krebs I, Binder S, Yannuzzi LA: Author reply. Am J Ophthalmol 2010; 149:172-73. [purchase]
5. Jalkh A, Takahashi M, Topilow H, et al: Prognostic value of vitreous findings in diabetic retinopathy. Arch Ophthalmol, 1982; 100:432-4.
6. Sebag J, Buzney SM, Belyea DA, et al: Posterior vitreous detachment following panretinal laser photocoagulation. Graefes Arch Clin Exp Ophthalmol, 1990; 228:5-8. [abstract]
7. Sebag J: Pharmacologic vitreolysis (Guest Editorial). Retina 18:1-3, 1998.
8. Sebag J: Pharmacologic vitreolysis – premise and promise of the first decade. (Guest Editorial) Retina 29:871-4, 2009.