The Eye 👀
- The Cornea - Refracts light into the eye
- The Iris - controls how much light enters the pupil
- Rods - are more sensitive in dim light, but can't sense colour
- Cones - are sensitive to different colours but are not so good in dim light
Eye defects- you may be asked this in I/GCSE Biology 👓
Colour Blindness - when cones do not work properly in the retina
Cataracts - due to a cloudy patch on the lens, light is not able to enter the eye normally. People with a cataract commonly have blurred vision, struggle to see in bright light and colours look less vivid.
Myopia - when people are unable to focus on distant objects, because the lens is the wrong shape and either refracts light too much or the eyeball is too long. Light from distant objects is brought into focus before the retina.
Hyperopia - when people are unable to focus on near objects, because the lens is the wrong shape and either doesn't refract light enough or the eyeball is too short. Light from near objects is brought into focus behind the retina.
Eye defect Cures.😆
Hyperopia - cured by wearing glasses or contacts with a convex lens
Myopia - cured by wearing glasses or contacts with a concave lens
Cataract - cured by replacing the faulty lens with an artrificial one.
Drafted by Catrina (Biology)