Title: Why Do My Eyes Blackout for a Second? - HubPages
Headings: Why Do My Eyes Blackout for a Second?
Why Do My Eyes Blackout for a Second?
Low Blood Pressure
Retinal Detachment
Vascular Problem
Other Possible Causes
Possible Causes of Visual Blackout

Content: Courtney Rhodes, Flickr. Some rights reserved. Vascular Problem
Some vascular problems can interfere with the structural pathways in the eye that affect vision. Diabetes, retinal artery or vein occlusion, hemorrhage and vasospasm can affect vision. There needs to be, as stated before, sufficient blood, for oxygen, going between brain and eyes for vision to function properly. Vascular problems can hinder this flow. A mini-stroke can also affect vision. Other Possible Causes
Other causes of a vision blackout include: High blood pressure
Visual migraine (painful headache)
Optic neuropathy
Giant cell arteritis
Increased intracranial pressure (in the skull)
Ocular ischemia (not enough blood flow in eye from carotid artery)
So, if your vision darkens, you might be having low blood pressure issues, other vascular problems, a retinal detachment or other issues with the structure of the eyes. It is important to see a doctor if you start to feel like you might faint or if you have other issues that might indicate something as serious as a stroke, like paralysis, confusion or speech impairment.