This symptom is called dark curtains because of the sensation that happens in the eye. It has been described as if a dark curtain has settled across your vision. This kind of thing can be from a retinal detachment. A retinal detachment occurs when the retina of the eye separates from the existing, underlying layer of blood vessels or choroid. The aging process can cause this, or if there is significant stress out on the eye. Either way, if the retina is not reattached within a few hours, there can be permanent damage to the patient's vision.
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