B1D Part 1 The Eye Flashcards
Blind spot
Where the optic nerve attaches to the retina
Ciliary muscle
Change the shape of the lens(accommodation)
Cornea
Refracts(bends) light
Iris
Controls the amount of light entering the eye
Optic nerve
Takes nerve impulses to the brain
Pupil
Let’s light into the eye
Suspensary ligament
Attaches ciliary muscle to lens
Retina
Contains light sensitive cells
Where light is focused at back of eye
Structure of eye
Cornea Pupil Iris Lens Retina Optic nerve
Far away objects
Lens must be thinner
Ciliary muscles relax
Suspensary muscles stretch
High muscle tension on lens
Near objects
Lens must be fatter (more refractive power )
Ciliary muscles contract
Suspensary ligaments slacken
Muscle tension on lens is low
Accommodation
The process of focusing light onto the retina
Binocular vision
Two eyes facing forward
Judge distances
Comparing images from both eyes
More similar images=further away the object
Short sighted
Can’t see things far away
Long sited
Can’t see close things
Red green colour blindess
Inherited
Genetic
Lack of specialised cells in the retina
Convex
Long sited
Concave
Short sighted
Corneal surgery
Changes curvature Of cornea to correct focusing problems
No more glasses
But can damage eyes
Stigmatism
Wrong shaped eyeball can cause eyesight problems
