Which term describes the condition in which parallel incident rays of light come to a point focus on the retina?

The term that accurately describes the condition in which parallel incident rays of light focus precisely on the retina is emmetropia. In emmetropia, the eye’s optical system is perfectly balanced, meaning that the focal point of the light rays entering the eye coincides with the surface of the retina when the eye is at rest (i.e., without accommodation). This results in clear vision at all distances for an individual who is emmetropic.

In contrast, hyperopia (farsightedness) occurs when light rays focus behind the retina, leading to difficulty seeing nearby objects clearly. Myopia (nearsightedness) is the condition where light rays focus in front of the retina, making distant objects appear blurry. Astigmatism is a refractive error due to an irregularly shaped cornea or lens, which causes distorted or blurred vision at all distances.

Understanding these definitions clarifies why emmetropia is the correct answer, as it reflects the optimal focusing condition of the eye for clear vision.