What's the Problem with Short Sighted People, and what can Correct it?

-The Eye naturally has a Convex Lens to Focus the Light onto the Back of the Eye to make an Image -If the Eyeball is too Long, or the Lens is too Powerful, then Distant Objects will be Focused in Front of the Retina, making it Blurry -Correcting it requires a Concave Lens, as it can Diverge the Light before it Enters the Eyes which then it can Focus on the Retina