Why does a hypermetropic eye have its near point farther than 25 cm?
- The retina is too thick
- The eyeball is too long
- The eyeball is too short or the lens is too flat
- The pupil is too small in general usage
Show answer and solution
Correct answer: C. The eyeball is too short or the lens is too flat
1. In hypermetropia the eye's converging power is too weak.
2. This happens when the eyeball is too short relative to the lens.
3. Alternatively the lens may be too flat (low curvature).
4. Near rays converge behind the retina, giving a blurred image.
5. So the near point shifts farther than 25 cm.
6. A convex lens compensates by adding converging power.
_Source: syllabus Science Ch 11 'Human Eye and the Colourful World'_