Posterior vitreous detachment (PVD) is the separation of the posterior vitreous cortex from the inner surface of the retina. It usually occurs at the base of vitreous liquefaction. Similar to vitreous liquefaction, posterior vitreous detachment can be caused by a variety of states other than age, such as aphakic eyes, intraocular inflammation, vitreous blood accumulation, trauma, myopia, and long eye axis. As the liquefied cavity in the central part of the vitreous expands, the posterior vitreous cortical layer thins and fissures appear, and the liquefied vitreous enters the posterior vitreous space through the fissures, causing rapid separation of the posterior cortex from the retina. Due to the tight adhesion of the vitreous to the edge of the optic disc, an annular clouding (Weiss ring) the size of the optic disc appears in front of the retina after separation.
When PVD occurs, the patient will notice floating objects in front of the eye, such as dots, filaments, flies, and rings, which are caused by the floating of the concentrated gel into the visual field. If the detached vitreous body tracts on the retina, the patient may experience a “lightning” or “flashing” sensation. Traction can also cause blood vessels to rupture, creating a pooling of blood in the vitreous, and the patient may experience a “red smoke” appearance. When excessive traction leads to retinal fissure formation and retinal detachment, the visual field becomes deficient and the patient has an obscured sense of vision.
In PVD formation, although the vitreous has separated from the retina in most areas, the adhesions remain attached and produce traction at the site. As the eye moves, the floating vitreous cortex exerts a pulling force on the retina in the anterior-posterior or tangential direction; because the peripheral retina is thin and prone to degeneration, the macula is also prone to degeneration in highly myopic eyes, and this pulling can cause peripheral retinal fissures or macular fissures. This pull can cause a retinal fissure or macular fissure in the periphery. When the liquefied vitreous passes through the retinal fissure into the retinal sensory layer, a rhegmatogenous retinal detachment (RRD) occurs. It can be seen that vitreoretinal detachment from vitreous liquefaction and posterior detachment is an important mechanism in the pathogenesis of RRD. Therefore, detailed fundus examination should be performed when PVD symptoms appear, and no specific treatment is necessary after excluding retinal fissures and retinal detachment.