Posterior Vitreous Detachment

Posterior vitreous detachment (PVD) is separation of the posterior vitreous cortex from the internal limiting membrane of the retina, due to age related liquefaction (syneresis) and weakened vitreoretinal adhesion.

• Occurs in about 25 percent of people over 50 and 65 percent over 65; earlier in myopia, after cataract surgery, trauma, inflammation and vitreous haemorrhage.
• Acute symptomatic PVD develops over days to weeks; complete detachment typically completes within weeks.
• Complications from vitreoretinal traction: retinal tears (about 10 to 15 percent of acute symptomatic PVD), vitreous haemorrhage, and retinal detachment.
• Anomalous PVD (incomplete separation) contributes to macular hole, epiretinal membrane, and vitreomacular traction.

• Sudden onset of floaters (a ring or "cobweb" Weiss ring, spots, flies), photopsia (flashes of light in the temporal periphery, more noticeable in dim light with eye movement).
• Painless; central vision usually normal. A shadow or curtain implies retinal detachment.
• Signs: Weiss ring (glial ring from the optic nerve edge), vitreous collapse, retrovitreous space, pigment granules in the anterior vitreous (Shafer sign or tobacco dust, suggests a retinal tear), vitreous haemorrhage.
• Red flags: new large shower of floaters, field loss, a veil, haemorrhage.

• Dilated fundus examination with scleral indentation by an ophthalmologist at presentation (within 24 to 48 hours of new floaters and flashes) to search carefully for retinal tears and detachment.
• B-scan ultrasound when the view is obscured by haemorrhage.
• Optical coherence tomography for the macula (vitreomacular traction, macular hole, epiretinal membrane).
• Repeat examination at 2 to 6 weeks (earlier if haemorrhage, pigment in the vitreous, or symptoms change), because new tears develop in about 2 to 5 percent.

• Uncomplicated PVD without tear: reassurance and no treatment. Floaters often fade over weeks to months by neuroadaptation.
• Advise urgent re-presentation within 24 hours for new floaters, increased flashes, a shadow or curtain, or a drop in vision.
• If a symptomatic retinal tear is found: laser retinopexy (2 to 3 rows of confluent burns around the tear, 200 to 500 micrometres, 0.1 to 0.2 seconds) or transconjunctival cryopexy, within 24 to 48 hours.
• Vitreous haemorrhage with no view: head elevation, B-scan, and early review (a retinal tear is found in a high proportion).
• Persistent debilitating floaters: Nd:YAG laser vitreolysis for selected well defined (Weiss ring) floaters, or pars plana vitrectomy (risk of cataract, retinal tear, detachment, endophthalmitis) after a long observation period and full counselling.
• Vitreomacular traction with symptoms: observation (about 10 to 30 percent release spontaneously), or vitrectomy.
• Avoid heavy physical strain and contact sport for a few days if symptoms are acute.