Investigate the two types of sight defect- long-sightedness and short sightedness.

Find the following information:

A) What causes the defect

The things that could cause defect for short sightedness are certain diseases and certain Drugs (type 2 diabetes). It also may run into families.

The things that could cause defect for long sightedness are less curved corneas – the main optical component of the eye. There may also be a hereditary component, as the children of long-sighted parents can be long-sighted. 

B) The symptoms displayed

The symptoms displayed for short sightedness are:

·         Blurry vision, particularly at night

·         Problems seeing objects up close

·         Eyestrain, Aching eyes, headaches

A child with this problem may have no symptoms, but a child with more severe and serious farsightedness may:

·         Have headaches

·         Problems reading

·         Rub his/her eyes often

C) Propose what sort of lens may be used to correct each vision.

The correct lens for a person which has long sightedness would be a convex lens, and the suitable lens for a person which has short sightedness would be a concave lens.