Eye Anatomy 6 4 Anatomy The eye is

Eye Anatomy 6. 4 Anatomy

The eye is made of 3 tunics (layers) 1. Sclera: Outer, protective fibrous covering. (White of eye) Cornea: “Window” in front of the eye that covers the pupil & iris

The eye is made of 3 tunics (layers) 2. Choroid: Middle layer made of blood vessels that supply nutrients to the inner eye. Iris: Colored, circular muscle that contracts to control how much light enters the eye. Pupil: Black opening in the center of the iris that allows light to enter Lens: Focus light onto the retina

The eye is made of 3 tunics (layers) 3. Retina: Light sensitive tissue that lines the inner eye. Photoreceptors Rods: smaller, B&W vision, & low levels of light Cones: larger; color vision Macula: Central part of retina (clearest vision); Reading Fovea Centralis: Center of the macula; all cones no rods; Sharpest vision. Blind Spot: Where optic nerve meets retina: No rods or cones

Chambers of the Eye Aqueous Humor Vitreous Humor ● Water cushion ● Gelatinous cushion ● Anterior chamber (btw ● Between lens & retina cornea & iris) ● Posterior chamber (btw iris & lens)

Diseases of the Eye Myopia: Nearsighted - Can’t see distance. Eyeball is too long → light focuses before the retina. PRK/Lasik: Shave cornea

Diseases of the Eye Hyperopia: Farsighted - Can’t focus close. Eyeball is too short → light focuses after the retina. Lasik/CK: Tighten/steepen cornea

Diseases of the Eye Glaucoma: Pressure from the aqueous humor damages the optic nerve = blindness

Diseases of the Eye Conjunctivitis: Pink Eye; inflammation of the conjunctiva. • Contagious: Bacterial or Viral • Noncontagious: Irritant (dust, dirt, debris)