Eyes Main (10.2) Flashcards
(25 cards)
In bright light and dim light, what does the pupil do?
Becomes smaller or becomes larger to increase/decrease the amount of light entering the eye.
What’s the use of eyebrows?
Prevents sweat from getting into the eyes.
What’s the use of eyelashes?
Prevents small particles from getting into the eyes.
How does light enter our eyes?
Through cornea.
What’s the special feature of the image formed on retina?
It’s sharp and inverted.
What parts of the eye helps focus light onto the retina?
Cornea, lens, jelly-like fluid.
When looking at a near object, what happens to the focusing muscles and the lens?
The focusing muscles contract and the lens become thicker.
When looking at a distant object, what happens to the focusing muscles and the lens?
The focusing muscles relaxes and the lens become thinner.
What are the two kinds of light-sensitive cells on the retina?
Cone cells and rod cells.
What’s the characteristics of cone cells?
Sensitive to bright light and color.
What’s the characteristics of rod cells?
Sensitive to dim light and cannot detect colour.
Why can’t we see images formed on the blind spot?
Because there are no light-sensitive cells on it.
How is short sight caused?
The lens being too thick or the eyeball being too long, or both.
How can short sight be corrected?
By wearing glasses with concave lenses.
How is long sight caused?
The lens being too thin or the eyeball being too short, or both.
How can long sight be corrected?
By wearing glasses with convex lenses.
What’s the problem with astigmatism?
Blurred vision.
How is astigmatism caused?
The cornea or the lens (or both) is unevenly curved.
How can astigmatism be corrected?
Wearing lenses with different curvatures at different points.
What’s the cause of cataract?
The lens becomes cloudy.
How to cure cataract?
Replace the lens with artificial lens.
How is colour-blindness caused?
One or more types of cone cells not working properly.
How can colour-blindness be corrected.
Cannot be corrected.
Draw the cure to short sight.
