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

Find the following information:

1. what causes the defect
2. the symptoms displayed
3. propose what sort of lens may be used to correct each vision.

A1. For short-sightedness, the cause is usually because it runs in the family. It can also be an early symptom to show that someone may have type 2 diabetes. The scientific term for Short sightedness Is Myopia. The cause of this is that the light your eye takes in, has its focal point BEFORE the retina which gives a blurred image.

B1. The symptoms are that distant objects appear blurred while ones from short distance are still in focus.

C1. The type of lens that might be used to treat this is A concave lens because it gives a magnified view of a wide area. You can also get Laser eye surgery which is becoming increasingly popular.

A2. Long sightedness is also a condition that can be passed down from genes. Many babies are born with Hyperopia but it corrects itself as they get older.

B2. the symptom is that people cannot see things from a short distance because it is out of focus. This is why people need reading glasses.

C2. The lens that you may need to correct long sightedness is a convex lens because it creates a short focal point. You can also correct it with laser eye surgery