Myopia: Those who suffer from myopia can see near objects clearly, but not the far away objects. This defect of vision occurs when the eyeball slightly elongates from front to back.

Below, we can see how images are focused on the retina of someone with myopia. It is also called as Short sightedness.

Myopia is corrected with a concave lens, which curves inward like the inside of a bowl. The lens changes the focus, so images fall on the retina as they should.

Figure below shows the defected and the corrected eye.

Hypermetropia: Hypermetropia is also known as hyperopia or farsightedness. Those who deal with hyperopia have difficulty seeing things that are near to them but have better vision for objects that are far away.

This defect of vision arises when the lens or cornea is out of place or insufficiently curved, leading to reduced vision quality.

Depending on by how much the focal length has been altered due to the effects of hyperopia, powered convex lenses can be used for the remedy of this defect. Figure below shows the defected and the corrected eye.

Defected Eye

Corrected Eye