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Friday, November 4, 2011

POSTERIOR VITREOUS DETACHMENT

SIGNS AND SYMPTOMS
The patient, usually over the age of 50, will present with a sudden onset of floaters. There is usually one floating spot that is especially large and troublesome to the patient and serves as the impetus to seek immediate care. There may also be associated photopsia if the patient is experiencing vitreoretinal traction. If the patient presents with multiple floaters, there may be an associated vitreous hemorrhage, especially if there is an associated reduction in visual acuity. Patients who report diffuse floaters during routine examination usually are suffering from benign vitreous syneresis and not posterior vitreous detachment.

PATHOPHYSIOLOGY
The vitreous is comprised of collagen fibrils and glycoaminoglycans, supported by hyaluronic acid molecules. With aging, reduction in hyaluronic acid causes loss of support to the collagen. The vitreous may collapse, with detachment of the posterior hyaloid face from the optic disc. This usually is observable ophthalmoscopically as an annulus floating in the vitreous over the posterior pole. As the vitreous detaches peripherally, areas of vitreoretinal adhesion may result in a tear in the sensory retina with the ensuing possibility of a rhegmatogenous retinal detachment. If the tear bridges a blood vessel, a vitreous hemorrhage ensues.

MANAGEMENT
A PVD found asymptomatically on routine examination is benign, but requires monitoring yearly. A patient who presents with a sudden onset PVD without retinal breaks or hemorrhage requires repeat peripheral examination in six weeks, as the risk of retinal complications is highest within the six weeks following vitreous detachment. If no retinal breaks are seen at that point, routine yearly examination is all that is needed. Prophylactically treat any fresh breaks associated with a new PVD immediately with photocoagulation or cryoretinopexy.

CLINICAL PEARLS

Occasionally, a new PVD will present with a small amount of pre-retinal or vitreous hemorrhage without an observable retinal break. This patient needs a detailed peripheral exam using scleral indentation as well as Goldmann and/or Volk lens evaluation.
If no retinal breaks are initially detected, the patient needs a repeat evaluation every two weeks for six weeks to look for an occult break not originally found. If you do not observe any breaks after six weeks, the blood resulted from torn retinal or disc capillaries, and the patient is out of immediate danger.

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