Question

The normal eye which can sufficiently refract light rays from an object \[20\]ft. ($6$mt.) away to focus clear object on retina is called as
A. Myopic
B. Emmetropic
C. Hypermetropic
D. No specific name

Answer 1

Hint: Light entering the eye is first bent, or refracted, by the cornea – the transparent window on the outer front surface of the eyeball. The cornea provides most of the optical power or the ability of the eye to incorporate light. Once light has passed through the cornea, it is again bent by the lens inside the eye into a more fine-tuned focus. The lens focuses light on the retina. To do this, the ciliary muscles of the eye change the shape of the lens, bending or flattening it to focus light rays on the retina.

Complete answer:
Option A Myopic: Myopia, also known as near-sightedness or short sightedness, is an eye disorder in which light is focused in front of, rather than at, the retina. This blurs distant subjects while near objects appear normal. Other symptoms may include headaches and eye strain. Since this is an eye disorder.
So, option A is not correct.
Option B Emmetropic: Emmetropia is a state of vision in which an infinitely distant object is brought into sharp focus with an eye lens in a neutral or relaxed state. This state of the normal eye is achieved when the refractive power of the cornea and the axial length of the eye are in balance, which helps to focus rays precisely on the retina, allowing perfect vision.
Hence option B is the correct answer.
Option C Hypermetropic: Hypermetropia, also known as farsightedness, hyperopia, or long-sightedness, is a condition in which the eyes clearly see distant objects but near objects are blurred. This blurring effect is caused by incident light focused behind, rather than on, the wall of the retina due to insufficient lens adaptation.
Since this is an eye disorder, option C is not correct.
Option D No specific name: Option D is wrong since emmetropic is the correct term used when a normal eye focuses a distant object on retina.
Option D is incorrect.

Hence, Option B. Emmetropic is the correct answer.

Note:
Light rays reflected from distant objects will focus on the retina after passing through the cornea, aqueous humor, the lens and finally vitreous humor. As light rays pass through these different mediums, they undergo a physical phenomenon called refraction. Refraction is the change of direction of light rays as they transition between different media.