Question

Arrange the following parts of the human eye in the order that light passes through them :
1. Cornea
2. Retina
3. Pupil
4. Crystalline lens

• A. 1 \(\to\) 3 \(\to\) 4 \(\to\) 2
• B. 3 \(\to\) 1 \(\to\) 4 \(\to\) 2
• C. 1 \(\to\) 4 \(\to\) 3 \(\to\) 2
• D. 4 \(\to\) 3 \(\to\) 1 \(\to\) 2

Hint:

Think of the eye as a camera:
- Cornea = Protective lens cover.
- Pupil = Aperture opening.
- Crystalline lens = Camera focusing lens.
- Retina = Digital sensor / film.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks for the correct anatomical sequence of structures in the human eye through which incoming light travels before forming an image.

Step 2: Key Formula or Approach:
We trace the path of light from outside the eye to the light-sensitive surface inside the eye.

Step 3: Detailed Explanation:

• 1. Cornea: This is the thin, transparent, dome-like outer membrane at the front of the eye. Light first enters the eye through the cornea, which performs most of the initial refraction.

• 2. Pupil: After passing through the cornea (and the aqueous humor), light travels through an opening called the pupil. The size of the pupil is adjusted by the iris to control the amount of light entering the eye.

• 3. Crystalline Lens: Light then passes through the flexible crystalline lens. The lens adjusts its shape (focal length) to focus light precisely onto the back of the eye.

• 4. Retina: Finally, the focused light reaches the retina, which is the light-sensitive screen containing photoreceptors (rods and cones) at the back of the eye. The retina converts the light into electrical signals sent to the brain.

• Thus, the correct sequence is: Cornea (1) \(\to\) Pupil (3) \(\to\) Crystalline lens (4) \(\to\) Retina (2).


Step 4: Final Answer:
The correct order is 1 \(\to\) 3 \(\to\) 4 \(\to\) 2.