Diabetes - as a complication of vascular growth within the eye. Macular degeneration - with a severe hemorrhage under the macula breaking through the retina, and bleeding into the vitreous. Valsalva related vitreous hemorrhage - severe straining can raise the venous pressure around the eye high enough to cause a vitreous hemorrhage. This can also occur with trauma. Cataract - a severe cataract can cause more than just blurred vision.
Some cataracts cause a loss of vision under glare circumstances.
Corneal abrasion - A centrally located abrasion can cause a loss of vision. Others symptoms are pain, tearing, redness, and a sensation that something is in eye. Corneal ulcer - an infected cornea can sometimes cause a loss of vision along with pain and redness. Severe chronic glaucoma can also cause a loss of vision over time. Iritis - pain, sensitivity to light, blurred vision or a loss of vision.