Retinal detachment occurs when the light-sensitive photoreceptor layer begins to tear or pull away from the underlying choroidea. This can be caused by fluid from within the eye slipping through the opening and building up behind the retina. Fewer nutrients are supplied from the choroid to the retina. The longer this interruption lasts, the less reversible the retinal damage is. This results in dramatic vision loss and even complete blindness.
The first signs of retinal detachment include distorted vision (metamorphopsia), perceived flashes of light (photopsia), a sudden shower of little red/black dots across the field of vision or a kind of dark curtain moving up. Retinal detachment is considered a medical emergency due to its rapid, irreversible progression.