Hyperopia and correction
Hyperopia means long-sighted – i.e, a person can see things clearly in the distance.
Sight long is great
A person who is long-sighted can focus clearly on far objects but cannot focus on near objects. Close objects are blurry.
This is caused by the eye being too short, the cornea being too flat or the power to focus being too weak.
Hyperopia – light rays focus too far behind the retina. The retina only receives a blurred image.
Hyperopia sight long is great
Here we can see the light is focused behind the retina and not on it which will make the image look blurry.
If it could, the lens would need to get rounder and therefore thicker so that light refracts more. So the problem is as follows:
The way to get the image to focus on the screen is to use a convex lens in front of our current convex lens.
The effect of using a convex lens in front of a convex lens is to move the image to the point where it focuses on the screen.
This has exactly the same effect as putting a convex lens in glasses in front of an eye that suffers from hyperopia when you need to see close objects.
Using a convex lens in a pair of glasses shortens `di` (image distance) to the point where it focuses on the retina.
SIGHT LONG Great
Use convex glasses (lens)