Question

The decreased accommodative ability of the eye causes

• A. Farsightedness
• B. Presbyopia
• C. Nearsightedness
• D. Colourblindness

Hint:

Associate "Presbyopia" with "old age". It's the reason why many older people need reading glasses. While its effect is similar to farsightedness, its cause (loss of accommodation) is distinct.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Accommodation is the ability of the eye lens to change its focal length to focus on objects at varying distances. This ability naturally decreases with age. The question asks for the name of the condition caused by this decrease.

Step 2: Detailed Explanation:
\[\begin{array}{rl} \bullet & \text{Presbyopia: This is an age-related vision defect. As a person ages, the ciliary muscles weaken, and the eye lens gradually loses its flexibility. This reduces the eye's power of accommodation. As a result, the near point of the eye recedes, making it difficult to see nearby objects clearly. This is the direct result of decreased accommodative ability. } \\ \bullet & \text{Farsightedness (Hypermetropia): This can occur at any age and is typically caused by the eyeball being too short or the lens system having too little refractive power, causing the image of a nearby object to form behind the retina. } \\ \bullet & \text{Nearsightedness (Myopia): This can occur at any age and is typically caused by the eyeball being too long or the lens system having too much refractive power, causing the image of a distant object to form in front of the retina. } \\ \bullet & \text{Colourblindness: This is a genetic condition where the person is unable to distinguish between certain colors due to a defect in the cone cells of the retina. It is not related to accommodation. } \\ \end{array}\]

Step 3: Final Answer:
The decreased accommodative ability of the eye, typically due to aging, causes Presbyopia.