The lens is a transparent, flexible structure that changes shape to focus light on the retina.

The cornea is the clear, front part of the eye that protects the eye from injury and infection.

The retina is a thin layer of tissue at the back of the eye that contains light-sensitive cells called photoreceptors.

The iris is the colored part of the eye that controls the size of the pupil.

The pupil is the black hole in the center of the iris that allows light to enter the eye.

The macula is a small area in the center of the retina that is responsible for sharp central vision.

The optic nerve is a bundle of nerve fibers that carries signals from the retina to the brain.

Cataracts are a clouding of the lens that can lead to blindness if left untreated.

Cataracts are also the most common cause of blindness in children.

Age-related macular degeneration is the most common cause of blindness in adults over the age of 50.

Diabetic retinopathy is the most common cause of blindness in people with diabetes.

Open-angle glaucoma is the most common type of glaucoma.

Blurred vision is the most common symptom of glaucoma.

Eye drops are the most common treatment for glaucoma.

Phacoemulsification is the most common treatment for cataracts.