The that obscures the orange reflection from the retina is the back surface of the vitreous. It has where it is normally adherent. The patient sees it as a large web or ring. Sometimes the vitreous detaches so vigorously that it yanks on the retinal photoreceptors. The patient sees a brief flurry of flashing lights.
Vitreous detachment is a normal phenomenon of aging. It usually occurs after age 60, or earlier in high myopia, intraocular inflammation, hemorrhage, trauma or surgery.
In youth, the vitreous has a uniform jelly-like consistency. In aging, pockets of fluid develop within the vitreous, notably the premacular bursa. The mixture of jelly and fluid components makes the vitreous unstable and it will eventually separate from the retina. When its circular attachment around the optic disc separates, an optically opaque ring is left on the back surface of the vitreous which the patient sees as a floating web. To observe this sequence, click here.
Rarely the separating vitreous tears a hole in the peripheral retina. To observe this sequence, click here.
Fluid within vitreous pockets may seep through the hole and detach the retina. To observe this sequence, click here.
What to do?
Refer urgently to an ophthalmologist because of the concern about retinal detachment. Because retinal detachment starts in peripheral retina, the vision loss may go unnoticed by the patient until the detachment spreads posteriorly.
Reattachment surgery is much more successful in restoring vision if the detachment is still peripheral at the time of surgery. Therefore, patients who report sudden new floaters or flashes should be examined promptly.
To learn more about vitreous and retinal detachment, go to Visual Disturbances: Floaters.