There are hundreds of different eye diseases and vision problems. Some have no cure, but many others are treatable. You can assist in your own eye health by following a healthy lifestyle and seeing your eye care professional on a regular basis and any time your vision changes.
The four most common eye conditions leading to loss of vision or blindness are:

Diabetic retinopathy.
Age-related macular degeneration.

Eye conditions commonly seen in children include:

Amblyopia: Amblyopia (also called “lazy eye”) happens when your child’s brain and one eye aren’t working together properly and the brain favors the other better-seeing eye. They’ll have reduced vision in the non-favored eye. This is the most common cause of vision impairment in children.
Strabismus: Strabismus is a lack of coordination between your child’s eyes, which causes the eyes to cross or turn out. Your child’s eyes don’t focus together on a single image at the same time. This can cause reduced 3D vision and/or the brain may favor one eye over the other, which can cause loss of vision in the non-favored eye (amblyopia, see above).
Conjunctivitis: Conjunctivitis, also known as pink eye, is an inflammation of the clear tissue that lines the inside surface of your eyelid and the outer coating of your eye. This tissue is called conjunctiva. It helps keep your eyelid and eyeball moist. Pink eye can be highly contagious, especially among children. Although it doesn’t damage vision, it causes itchy, red, blurry, tearing and discharge.