There are many reason that can causes sudden vision loss. First, ischemia, or a reduction of the amount of oxygen and nutrients to the tissues of the eyes will cause sudden loss of eyesight. It is just like a stroke of the eyes that can cause temporary or permanent damage to the retina.
Besides, an ocular migraine can also cause sudden loss of eyesight, resulting from transient wavy vision or a blind spot in one or both eyes. And your vision will be recover after 10 to 50 minutes.
In addition, the increasing of intracranial pressure can also cause sudden loss of eyesight.
Is there any other symptoms accompanied by sudden loss of eyesight? Was there an pain? Was it like turning on/off a switch or kinda slow like a dimmer? Sudden vision loss is usually caused by ischemia, or a reduction of the amount of oxygen and nutrients to the tissues of the eyes, resulting in temporary or permanent damage to the retina. It is more common in adults 50 years of age and older.
There are a number of reasons can cause sudden vision loss, and most of them are painless. One reason is caused by the retinal artery occlusion, which are the blood clot blocks the artery supplying blood to the retina of the eye. It would make permanent vision loss if the retinal artery occlusion doesn't treat well.
Another reason would be the retinal detachment. However, it would occur slowly, maybe a few days. And the eye hemorrhages would damage the structure of the eye so that cause retinal tears, macular diabetes to make sudden vision loss.
There are quite a few factors that can cause sudden loss of eyesight. For example, if you overuse your eyes for a period of time or even just several nights, your eyes may experience sudden loss of sights. Then, some bad reading and watching habits and gestures are also among the factors that cause sudden eyesight loss. Some like to read books or check cell-phones at night. Some like to lie on the sofa while watching TV. Others keep playing games or surfing on the internet for several or whole day without giving their eyes some rest. These bad behaviors will make our eyes very dry and tired and thus cause sudden loss of eyesight. Therefore, we really need to get rid of these bad habits and learn to protect our eyes carefully.