The Human Eye Flashcards
(13 cards)
What does the cornea do?
Refracts light before it enters the eye
What does the iris do?
Controls the size of the pupil
What does the pupil do?
Lets light enter the eye
What is the retina made up of and what do they do?
Made up of cells that detect light
What does the optic nerve do?
Carries electrical signals to the brain
How does the eye focus on distant objects?
The lens becomes thin and flat, helping focus light from far away onto the retina.
How does the eye focus on near objects?
The lens becomes thicker and rounder to bend light more and focus it on the retina.
What is short-sightedness (myopia)?
The eye is too long or the cornea too curved, so light focuses in front of the retina.
Fix: Glasses with concave lenses spread out light.
What is long-sightedness (hyperopia)?
The eye is too short or the cornea too flat, so light focuses behind the retina.
Fix: Glasses with convex lenses bring light to a focus sooner.
How do we see an object?
- Light hits the object
- reflects off it
- enters the eye
- and is processed by the brain.
What happens to light when it hits an object?
Some light is absorbed, and some is reflected — we see the reflected light.
Why do coloured objects appear a certain colour?
Because they reflect only that colour and absorb the others.
Example: A red object absorbs blue and green light and reflects only red light.
What is ‘incident light’?
The light that hits an object — often white light, which contains all colours.
