Myopia (near-sightedness)
- CBSE · NCERT Class 10, Ch 10 The Human Eye and the Colourful World
- ICSE Class 10, Unit 3 Human Anatomy and Physiology
Myopia, also called near-sightedness or short sight, is an eye defect in which near objects look clear but distant objects look blurred.
In a myopic eye, light from a distant object meets in front of the retina, not on it. So the far point is nearer than infinity. There are two causes. The eyeball may be too long, or the eye lens may curve too much.
The fix is a concave lens of suitable power, one that is thinner in the middle. It spreads the rays slightly, so the eye focuses them on the retina.
A small example
A student cannot see clearly beyond 2 m. The concave lens must make a distant object appear to be 2 m away. So its focal length is f = -2 m. Its power is P = 1/f = 1/(-2 m) = -0.5 D. The minus sign confirms a concave lens.
Where marks go
In CBSE, Question 39 of the 2026-27 Science sample paper gives 1 mark for naming the lens. The 2026-27 Science marking scheme answers: a diverging (concave) lens. A diagram of how that lens helps carries 2 marks. So the drawing is worth more than the name.
In ICSE, the 2024 Biology paper told a story like the one above, for 3 marks. It asked for the defect, where the image forms, and the lens. CISCE's 2024 Biology report names an error on each part. Some wrote "hyperopia". Some wrote "beyond the retina" instead of "before the retina", and lost a mark. Some wrote convex instead of concave.
Myopia, image in front, concave lens: the three go together. Compare it with hypermetropia.
Sources
Facts last checked against these sources on 30 September 2026.
- Science, Class X (2026-27), Chapter 10: The Human Eye and the Colourful World · NCERT
- Science (086) Marking Scheme, Class X 2026-27 - Question 39 · CBSE Academic Unit
- ICSE Biology syllabus, Examination Year 2028 (January 2026) - Class X, Unit 3 · CISCE
- ICSE 2024 Analysis of Pupil Performance: Biology - Question 7(v) · CISCE
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