The correct option is (c).
Explanation
The human eye functions as a natural optical instrument, utilizing a crystalline lens to refract light and form real, inverted images on a photosensitive screen known as the retina.Statement 1 is Correct: The crystalline lens of the human eye is a double convex lens made of a transparent, fibrous, jelly-like material. Like standard convex lenses, it is thicker in the center and thinner at the edges, allowing it to converge incoming light rays.
Statement 2 is Incorrect: The eye lens focuses light rays specifically on the retina, which contains light-sensitive cells (rods and cones). The optic nerve is responsible for transmitting electrical signals from the retina to the brain. The point where the optic nerve leaves the eye is known as the blind spot; no image is formed there because it lacks photoreceptor cells.
Statement 3 is Correct: A cataract is a common ocular condition, often associated with aging, where the crystalline lens becomes milky, cloudy, or opaque. This cloudiness obstructs the passage of light to the retina, leading to partial or complete loss of vision unless treated surgically.
Key Takeaway: The human eye utilizes a convex lens to focus light onto the retina, not the optic nerve. A cataract is a defect involving the opacification of this lens.