Posterior Vitreous Detachment

The vitreous gel is normally attached to the retina's internal limiting membrane, most firmly at the vitreous base, optic disc margin, and over retinal blood vessels. With age, the vitreous liquefies (syneresis) and separates from the retina, beginning posteriorly — posterior vitreous detachment (PVD). This is an extremely common, generally benign age-related process, but where vitreoretinal adhesion is abnormally strong, the separating vitreous can tear the retina, making PVD a common urgent same-day ophthalmology consultation despite usually being harmless.

As the liquefied vitreous separates from the internal limiting membrane, traction is exerted wherever adhesion remains abnormally strong — over retinal vessels, areas of lattice degeneration, or the vitreous base — and this traction can tear the retina, the mechanism underlying PVD-associated retinal tears and subsequent rhegmatogenous retinal detachment. Persistent, incomplete separation focally at the macula or disc (vitreomacular/vitreopapillary adhesion) can itself cause tractional pathology without a frank tear.

Classic presentation is acute new floaters (a "cobweb" or ring-shaped Weiss ring floater) and photopsias, usually unilateral. A "curtain" or shadow raises concern for an associated tear or detachment and warrants urgent, dilated exam.

Differentials include an associated retinal tear/detachment (the critical exclusion), vitreous hemorrhage from other causes (proliferative diabetic retinopathy, vein occlusion), migraine with visual aura (typically bilateral, scintillating scotoma with a characteristic march, unlike discrete peripheral PVD flashes), and vitritis/uveitis (inflammatory cells present, not just vitreous syneresis).

Every acute symptomatic PVD requires a prompt dilated fundus exam with scleral depression to search for a retinal tear. Vitreous pigment cells (Shafer's sign/"tobacco dust") on slit-lamp exam are a strong indicator of an associated tear. On OCT, posterior vitreous opacities predict retinal tears in acute symptomatic PVD, and a Weiss ring confirms complete separation from the disc.²

If a retinal tear is found, urgent laser photocoagulation or cryotherapy walls it off to prevent progression to detachment. If no tear is found initially, patients are counseled on warning symptoms and re-examined in several weeks, since traction can evolve and produce a delayed tear. A study of on-call resident triage found structured same-day dilated exam and appropriate follow-up protocols produced safe outcomes with low rates of missed tears.³ In patients with a retinal detachment history, fellow-eye posterior vitreous status on OCT helps stratify that eye's future detachment risk.¹

• New flashes/floaters require prompt dilated exam with scleral depression to find a tear before it becomes a detachment
• Vitreous pigment cells (Shafer's sign) strongly suggest an associated retinal tear
• A negative initial exam does not exclude a future tear — scheduled follow-up in several weeks is standard³
• OCT posterior vitreous opacities help predict which patients are at higher tear risk²
• Common pitfall: reassuring a patient without a scleral-depressed peripheral exam
• Common pitfall: missing a tear obscured by vitreous hemorrhage rather than treating hemorrhage as a red flag