Eye Problem?!

Eye Problem?

When I read late at night, I use a lamp and my surroundings are pretty dark. So if I read for about 10 minutes or so, then turn off the light, my left vision gets this dark film covering it, and it doesn't go away even when I turn back on the light.
Does anyone know anything about this?
Thanks!

2 months ago
I should add that only one eye does this. The other one is fine. Thanks!

This is called dark-light adaptation. The same thing occurs when you're going from a brightly lit room to a dark room such as a theater. However, there is a normal span of time for your eyes to recover. Dark to light and light to dark adaptation should take place within 3 to 5 minutes. If there is a delay in the amount of time for dark-light adaptation (which is by the way a function of the retina) it could be indicative of a number of disease entities.

Please have yourself evaluated by a retina specialist or at the very least a general ophthalmologist.