Understanding Hypermetropia

Hypermetropia, also known as farsightedness, is a vision defect where a person can see distant objects clearly but faces difficulty seeing near objects distinctly. This happens because the eye's optical system converges light rays to a focal point behind the retina, rather than directly on it.

Correcting Hypermetropia

To correct hypermetropia, a lens is needed that increases the overall converging power of the eye. This helps to bend the light rays more sharply so that the image is focused precisely on the retina.

• Convex Lens: A convex lens is a converging lens. When placed in front of the eye, it adds to the eye's refractive power, causing light rays to converge sooner and focus on the retina. This effectively corrects the defect of hypermetropia.
• Concave Lens: Concave lenses are diverging lenses and are used to correct myopia (nearsightedness), where the focal point is in front of the retina.
• Cylindrical Lens: These lenses are primarily used to correct astigmatism, a condition where the eye's refractive power is different in different meridians.
• Prism: Prisms are used to correct conditions involving eye alignment or double vision, not refractive errors like hypermetropia.

Therefore, a convex lens is the appropriate choice for correcting hypermetropia.