A: A sudden increase in number and size of floaters is a warning that small amounts of blood and debris have appeared in the vitreous. The flashes are sensations from the retina as it is pulled or torn, or is rubbed by the loosened vitreous. If a tear breaks a larger retinal blood vessel, the blood spilling into the vitreous can cause a massive increase in floaters or even total loss of vision in that eye. The floaters will usually decrease in a few weeks or months and vision will improve, as long as the retina is not detached.

Most retinal tears do not cause problems and are not especially dangerous. However, if fluid starts to leak through them, the retina will start to peel (like wallpaper) and the detachment process begins. At first, you may have no symptoms, especially if the detachment is off to the side. Later, a "curtain" of darkness will start moving in and block out vision from one direction (the position depends on the location of the detachment). When the peeling process reaches the central zone of the retina (the macula), vision will suddenly and dramatically blur. As time goes on (which could be hours, days, or weeks), the curtain will continue to darken more and more of your vision, until you are left only able to see bright light. If you experience any of these symptoms, contact your ophthalmologist as soon as possible for a thorough evaluation.