The Eye

Dim Light

Pupil dilates - the iris muscles relax and the radial muscles contract

Bright light

Pupil narrows- Iris muscles contact to prevent damage to the retina

Cornea

Protects and focuses on light rays

Suspensionry ligaments

Hold lens in place

Lens

Focuses light on retina

Iris

Regulates amount of light entering the eye

Retina

Senses light

Ciliary Muscles

Changes shape of lens

Accommodation

Changing the shape of the lens to focus on a near/ distant object

Close object

Ciliary muscles contract (smaller diameter)

Suspensory ligaments loosen

Lens thicker- converge light rays more strongly

Image is focused on retina

Distant object

Ciliary muscles relax (larger diameter)

Suspensory ligaments loosen

Lens thinner- Converge light rays less

Image focused on retina

Myopia

Shortsightedness

Eyeball shortened

Concave lens- light refracted outwards

Light rays can then be focused on the retina

Hyperopia

Longsightedness

Eyeball elongated

Convex lens- light refracted inwards

Light rays focused on retina