One minute, you're able to see clearly. The next minute, your vision is blurry — or maybe you can't even see at all! Sudden vision loss of any severity can be scary. It's important to understand the possible cause of this symptom.
1. Detached Retina
The retina is a piece of tissue at the back of the eye that gathers light and sends messages to the optic nerve. If it detaches from the back of the eye, your vision will become blurry — often in just one part of your visual field. You may also see flashes of light and black specks.
This ailment is the reason why, in all cases of sudden vision loss, you should seek emergency medical care. If you do have a detached retina, then you'll need surgery ASAP to repair it and prevent the vision loss from being permanent. If you wait too long to seek treatment, the retinal tissue will die, and there will be no way to repair it.
Usually, glaucoma is a condition that comes on slowly. However, there is a sub-type of glaucoma, called angle-closure glaucoma, that can appear suddenly. It causes vision loss, usually along with eye irritation and redness. Most patients also feel nauseous at the onset of angle-closure glaucoma.
This condition is caused by an increase in pressure in the eye due to a buildup of fluid. Your eye doctor can administer specialized eye drops that bring the pressure down. You may also need surgery to more permanently open up the tissues that drain your eye and prevent another attack. Usually, most of the vision is recovered with treatment, but you may have some level of lasting vision loss.
If you have an autoimmune disease like lupus or rheumatoid arthritis, this is one possibility to consider. The iris of the eye, which is the colored tissue you can see, becomes inflamed because the body's own immune system starts attacking it. Usually, sudden vision loss caused by iritis is accompanied by eye pain and extreme sensitivity to light. Anti-inflammatory medications and immune suppressants can bring the inflammation back under control and restore your vision. This may be a sign that you need to adjust your doses of any medications you're already taking for your autoimmune disorder.
Note that these are just three of the more common causes of sudden vision loss. It can also come on due to a stroke, a migraine, or an eye infection. The moral of the story is to seek medical care ASAP when this occurs. Regardless of the cause, you will need professional care to recover your vision or prevent additional vision loss.