Cornea- The clear covering at the front of the eye that lets light rays into the
eye
Pupil- A round opening that controls the amount of light entering the inner eye
Iris- The colored circle in the eye that surrounds the pupil and controls its size
Lens- A curved, inner part of the eye; it focuses light on the retina
Retina- The light sensitive tissue that lines the inner eye
Optic Nerve-Nerve that takes impulses to the brain
Rod- A receptor that is very sensitive to light but can only distinguish black from white
Cone- A receptor that can distinguish colors but is not very sensitive to light
Nerve Impulse- Electrical signal transmitted along nerves
Vitreous Humor- Jelly like fluid in the eyeball
Nearsightedness- (Myopia) A condition in which the retina is too far from the lens; A person sees only close objects clearly
Farsightedness- (Hyperopia) A condition in which the retina is too close to the lens; a person can see only distance objects clearly
Presbyopia- Lens becomes less flexible. Common after the age of 40.
Sclera- The white part of the eye. Composed of tough fibrous tissues that protects the inner layers of the eye.
Astigmatism- A condition in which the cornea or the lens is irregularly shaped, causing blurred vision
Color Blindness- A hereditary disorder in which a person can not distinguish certain colors
Glaucoma- A gradual increase of fluid pressure within the eye; it can damage the retina and lead to blindness
Cataract- A condition in which the lens of the eye becomes cloudy. More common among older people
Sty- An infection at the base of the eye lash
Conjunctivitis- Caused by a bacterial, virus, or allergic reaction. Primarily because of poor hygiene. Spread by direct contact. (Pink eye)
Detached Retina- Occurs when the retina tears away from the inner eyeball, this produces a blind spot around the tear.
Ophthalmologist- eye surgeon
Optometrist- eye doctor
Optician- lens maker