If your vision has completely blacked out in one eye and remains that way, seek emergency medical attention immediately. One major cause of sudden blindness in an eye is a central retinal artery occlusion. This is equivalent to a stroke in the eye. The emergency measures employed to treat an occlusion such as this are controversial, but if they are to have any effect, they must be begun as soon as possible.Without its blood supply, the retina can die very quickly. Vision that is only partially lost or that takes hours to days to be lost can be due to a number of conditions but should still be checked out on an urgent basis. The optic nerve may have lost its blood supply from a shutdown of small blood vessels. Retinal detachment can cause loss of vision, but it generally begins in the periphery and gradually works its way across the field of vision. If you lose your vision but it then returns within thirty to forty-five minutes, you may have suffered a transient ischemic attack (TIA), a warning sign that a stroke may occur in the near future.Usually the loss of vision occurs as a dimming of vision over a number of seconds, although occasionally it may appear as though a shade were slowly being drawn across the eye. A possible TIA requires urgent evaluation, because if you have a TIA you may need medication to reduce your tendency to form blood clots.
If your vision just becomes blurry but doesn’t black out, try blinking a few times or rinsing the eye with some water. Sometimes excess mucus from the glands in the eyelids may spread over your cornea and cloud your vision for a short while. If the blurring is accompanied by funny patterns in your vision and a headache begins after the blurring subsides, you may have suffered your first migraine, assuming you are a child or young adult. If the blurring does
not go away, have it checked out as soon as possible.