Science (086) — AI-generated practice question

Hypermetropia (far-sightedness) is a defect in which the near point of the eye is farther than the normal 25 cm. The person cannot see nearby objects clearly.

Cause: In a hypermetropic eye, either the focal length of the eye lens is too long or the eyeball is too small. As a result, light rays from a nearby object are focused at a point behind the retina instead of on it, forming a blurred image.

Role of accommodation: When the ciliary muscles contract fully, the eye lens becomes maximally thick, giving its shortest possible focal length. However, even at maximum accommodation, the focal length of a hypermetropic lens is still not short enough to focus nearby objects (within 25 cm) onto the retina. The minimum focal length limit is never crossed, so nearby objects always appear blurred.

Correction: A convex (converging) lens of appropriate power is used to provide the extra converging power, bringing the image onto the retina.

Source: Chapter 10 — Defects of Vision and Their Correction, Section 10.2(b); Section 10.1.1

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• Examiners expect: definition of hypermetropia, the structural cause (long focal length / small eyeball), explanation of image forming behind retina, and why full accommodation still fails.
• Mentioning the minimum focal length limit of the eye lens is the key conceptual point that directly answers "even when fully accommodated."
• Always end with the correction method — it is usually part of the expected answer even if not explicitly asked.
• Avoid lengthy diagrams unless asked; a brief description suffices for 5 marks.