Eye Flashcards
1
Q
Retina
A
Where the rod and cone cells are located. Contains light receptor cells
2
Q
Rods
A
Detect light intensity
3
Q
Cones
A
Detect colour
4
Q
When there is a near object
A
- Ciliary muscle contracts
- suspensory ligaments loosen
- lens thickens
- so light is refracted STRONGLY
5
Q
When there is a far object
A
- Ciliary muscles relax
- susepnsory ligaments tighten
- lens becomes thinner
- so light refracts less
6
Q
Short sightedness
A
- Myopia
- rays of light focus in front of the retina
7
Q
Long sightedness
A
Hyperopia
- where rays of light focus behind the retina
8
Q
How can myopia be fixed
A
- using a concave lens to focus light on retina
9
Q
How can hyperopia be fixed
A
- using a convex lense to focus light on retina
10
Q
Treatments for myopia or hyperopia
A
- Hard and soft contact lenses (good for sport, comfortable)
- laser eye surgery (can change shape of cornea, which CHANGES HOW IT REFRACTS LIGHT ONTO THE RETINA)
- lens replacement surgery (replaces lens of eye with plastic artificial lens)
11
Q
Laser eye surgery for myopia
A
- cornea is slimmed down, reducing refractive power
12
Q
Laser eye surgery for hyperopia
A
Cornea shape is thickened so refractive power is increased
13
Q
Risks and positives of hard contact lenses
A
- can be more uncomfortable
- causes damage if broken
- requires cleaning
- far more durable
- less environmentally damaging
14
Q
Risks and positives of soft contact lenses
A
- more comfortable than hard contacts
- environmentally damaging
- higher risk of infection
15
Q
Pupil reflex in dim light
A
- radial muscles of iris contract
- circular muscles of iris relax
- dilated pupil (more light enters eye)
