eye stuff i didnt need for y10 mocks

• Long sighted people are unable to focus on objects near them
• short sighted people are unable to focus on objects far away from them
• being short sighted means light rays converge before the retina, this is known as myopia, it can be caused by the eyeball being too long or the lens being too short and fat
• being long sighted means that light rays converge behind the retina, this condition is known as hyperopia, it can be caused by the eyeball being too short or the lens being too long and thin
• myopia can be corrected using a concave lens which causes the light to refract out,
• hyperopia can be corrected using a convex lens which refracts light inwards
• concave lenses are lenses that have a thicker rim and a thinner middle. it refracts light outwards for people who rays converge before the retina
• convex lenses are lenses that have a thicker middle and a thinner rim. They refract light inwards for people who light converges after the retina
• contact lenses are a way to correct vision without surgery, they are placed on the eye. and compensate for the fault in focusing. However they can get infected and cause discomfort. They are good because they are almost invisible and are more convenient than glasses.
• laser eye surgery is a way to correct myopia and hyperopia. It uses a laser to change the shape of the cornea. Its good because the surgeons can see exactly what they are doing and it is very precise. It can completely correct vision. However there are risks of complications such as infection
• replacement eye surgery is a way to treat hyperopia. The natural lens is removed and plastic lens is inserted in its place. However it carries higher risk as it involves working inside the eye. Can cause damage to the retina, could lead to loss of sight.