P3 - Correcting Vision Flashcards
How do you correct short sight?
Using a diverging lens.
What is wrong with short sight?
The image focuses in front of the retina.
Who are more likely to be long sighted and why?
Young children - their lenses grow quicker than the eyeballs.
What is long sight caused by?
The eyeball being too short or the cornea and lens being too weak.
What lens is used to correct long sight?
Converging lens.
What is a laser?
A narrow, intense beam of light with waves of equal wavelength.
Lasers cauterise - what does this mean and how does it help? [1-2]
They burn and seal small blood vessels to reduce the amount of blood lost and protects against infection.
How can lasers be used to treat skin conditions?
They burn off the top scarred layer to reveal less-scarred lower layers.
How does laser eye surgery work?
The laser vaporises the cornea to alter its shape and focusing ability.
What is short sight caused by? [2]
The eyeball being too long or the cornea and lens system being too powerful.
