Explain myopia and hypermetropia, with their causes and correction. Draw diagrams.

1. 1 · Open in one line. A normal eye focuses images on the retina by accommodation; defects occur when the image forms in front of or behind it.
2. 2 · Myopia: meaning and cause. Far objects look blurred. The eyeball is too long or the lens's focal length too short, so the image forms in front of the retina.
3. 3 · Myopia: correction. A concave lens of suitable focal length moves the image back on to the retina.
4. 4 · Hypermetropia: meaning and cause. Near objects look blurred. The eyeball is too short or the lens's focal length too long, so the image forms behind the retina.
5. 5 · Hypermetropia: correction. A convex lens of suitable focal length brings the image forward on to the retina.
6. 6 · Draw four diagrams. [Diagrams: myopic eye and corrected eye with a concave lens; hypermetropic eye and corrected eye with a convex lens; label retina, image and lens]
7. 7 · Real-life link. Students who cannot read the board from the back bench often have myopia; school eye tests catch it early.
8. 8 · Close in one line. Myopia needs a minus (concave) lens and hypermetropia needs a plus (convex) lens.

Scoring tip: Diagrams carry many marks here. Show clearly where the rays meet: in front of the retina, behind it, and on it after correction.