Hypermetropia

1. State that distant objects are clear and nearby objects are blurred. 2. Mention that the image forms behind the retina. 3. Give causes like short eyeball or weak converging power. 4. State that a convex lens is used. 5. Explain that it converges rays before they enter the eye.

Draw a hypermetropic eye with rays from a near object focusing behind the retina, then show a convex lens moving the image onto the retina.

A common wrong answer is to use a concave lens. That is wrong because a concave lens would diverge rays further and worsen near vision.

Hypermetropia is a defect in which a person sees distant objects clearly but nearby objects appear blurred.

Hypermetropia is a defect in which a person sees distant objects clearly but nearby objects appear blurred. Hypermetropia correction uses a convex lens of suitable focal length to increase the eye's converging power. An elder person may see the classroom board well but need to hold a newspaper farther away to read comfortably.

In hypermetropia, light from a nearby object is focused behind the retina instead of on it. This may happen because the eyeball is too short or the eye lens has too little converging power. A convex lens is used for correction because it helps the eye converge the rays earlier. Hypermetropia correction uses a convex lens of suitable focal length to increase the eye's converging power. If a person cannot read clearly at 25 cm but can read at 40 cm, the near point is too far. A convex lens is prescribed so the image of a near object forms on the retina. Explain the defect and its correction, or identify the lens in a case where nearby reading is difficult. A common wrong answer is to use a concave lens. That is wrong because a concave lens would diverge rays further and worsen near vision.