THE EYE & COMMON PROBLEMS [B10.5 & 10.6] Flashcards
B10.5 & 10.6
The coloured part of the eye? (around pupil)
Iris
Transparent area of sclera at the front of the eyeball
Cornea
Hole where light enters the eye
Pupil
Clear disc behind the pupil
Lens
Both ends of the lens
Suspensory Ligament
Both ends of Supensory Ligament
Ciliary Muscle
White outer layer of the eye
Sclera
Back of the eye (inside)
Retina
Back of the eye (leading out the eye)
Optic Nerve
Function of the Iris
Controls light that enters the pupil by contracting or relaxing to change the size of the pupil.
Function of Ciliary Muscle
Contracts + relaxes to accommodate for seeing near + far.
Function of Retina
Where light is focused on the light-sensitive cells of retina.
Myopia
Short-sightedness
Hyperopia
Long-sightedness
CAUSES for Myopia
Lens too curved OR long eyeball SO light in focused front of the retina (falls short) SO images are blurry
CAUSES for Hyperopia
Lens too flat/thin OR short eyeball SO light is focused BEHIND the retina or the lens can’t refract strongly enough SO images are out of focus
ACCOMMODATION for Myopia
Glasses with CONCAVE lens to SPREAD OUT the light before it reaches the eye so that it is in perfect focus on the retina
ACCOMMODATION for Hyperopia
Glasses with CONVEX lens to bring light rays together before they reach the eyeball so that they will be brought in perfect focus of the retina.
ACCOMMODATION for seeing FAR
ciliary muscle RELAXES, pulmonary ligament CONTRACTS, lens becomes THINS —-> LESS light refraction
ACCOMMODATION for seeing NEAR
ciliary muscle CONTRACTS, pulmonary ligament RELAXES, lens becomes THICK —-> MORE light refraction
