The eye Flashcards
What is the cornea?
A transparent window with a convex shape and high refractive index
What does the corns do?
Most of the eyes focusing
What is the iris?
The coloured part of the eye
What does the iris do?
Made up of muscles that control the size of the pupil
What is the pupil and it’s function?
A hole in the middle of the iris that controls the light intensity entering the eye
What does the lens do?
Changed shape to focus light from objects at various distances
What is the lens connected to and how?
The ciliary muscle via the suspensory ligaments
What happens when the ciliary muscles contract?
Tension is released and the the lens takes on a fat more spherical shape
What happens when the ciliary muscles relax?
The suspensory ligaments pull the lens into a thinner flatter shape
What is the retina covered by and what do they do?
Light sensitive cells that detect light and send signals to the brain to be interpreted
What is the far point?
The furthest distance the eye can comfortably focus for normal sighted people this is infinity
What is the near point?
The closest distance the eye can focus on for adults it’s approximately 25cm
What happens as the eye focuses on closer objects?
The power increases
The lens changes shape (fatter)
The focal length decreases
How is the eye similar to a camera?
1) a real inverted image forms of the retina and our Brain flips it (like film on a camera)
2) the film or ccd in a camera are equivalent to the retina in the eye- they detect light focused on them and record it
What happens when the eye is focussing on far away objects?
Power decreases
Lens changes shape (thinner)
Focal length increases
