Vision loss is the abnormal decline in the quality of normal vision. It can be partial or complete. Some kinds of vision loss may be at least partially preventable or correctable. Others may not. The two main types of vision loss are central, meaning the central part of the visual field; and peripheral, or the side visual fields. Symptoms of vision loss can include blurry vision, seeing flashes of light, floaters, sensitivity to light and seeing halos around lights.
Here are the five main causes of vision loss:

1. Wet age-related macular degeneration
AMD stands for age-related macular degeneration. It occurs mainly in people over the age of 50. Wet macular degeneration vision is like looking through the hole of a doughnut, with the hole part either very blurry or missing entirely. This condition occurs when abnormal blood vessels form underneath the eye’s macula, which is the central part of the retina. The macula is responsible for clear, sharp central vision. These abnormal blood vessels break open and bleed, causing inflammation and damage to the macula. Symptoms of wet AMD include blurry vision, straight lines appearing to be wavy and difficulty with seeing details in low light conditions. Treatment includes biologic medications and laser therapy.

2. Cataract
A cataract occurs when the eye’s lens, which is normally crystal clear, becomes clouded with proteins. This can result in symptoms like colors seeming to be less vivid, seeing halos around lights, needing brighter light to see and multiple changes in eyeglass prescription over a short time. Causes include aging, injury to the eye, certain kinds of eye surgery and possibly a history of alcoholism. This condition is typically treated by surgery.

3. Diabetic retinopathy
This condition occurs when high blood glucose levels from poorly controlled diabetes cause damage to the blood vessels in the eye. These blood vessels carry oxygen and vital nutrients to the delicate tissues of the retina. The retina is the part of the eye that receives and transmits visual information to the optic nerve, which in turn sends those signals to the brain. This condition is serious and can result in total blindness. Symptoms include worsening vision quality, patchy or blurry vision, sudden vision loss and floaters in the visual field. Treatment includes laser therapy and the injection of medications directly into the eye.

4. Glaucoma
This is a serious condition in which there is a buildup of fluid within the eye, increasing the pressure of these fluids. The most common type, open-angle, often has no symptoms. This is why eye doctors check for fluid pressure in the interior of the eye as part of a routine eye exam. Glaucoma is serious and can result in complete blindness if left untreated. Treatment is usually with special medicated eye drops, which help to reduce and control interior eye fluid pressure. Laser therapy, surgery and oral medications are also sometimes used to treat this condition. Another type of this condition, acute angle-closure, may result in symptoms like nausea and vomiting, blurry vision, eye pain, eye redness and severe headache.

5. Amblyopia
This is also called lazy eye. It occurs when the brain ignores signals from one of the eyes. Over time, this can cause vision loss in the affected eye, even though it appears to be normal. It typically begins in childhood. Untreated, it can result in severe vision loss over time. It’s sometimes caused by another eye condition called strabismus, or crossed eyes. Treatment of amblyopia includes glasses and patching the good eye to try to force the other eye to function normally.