The image distance from the eye lens in the normal eye when we increase the distance of an object from the eye

In a normal human eye, the distance between the eye lens and the retina (where the image is formed) is fixed and is approximately equal to the diameter of the eyeball (about $2.3\text{ cm}$). When we increase the distance of an object from the eye, the ciliary muscles relax, making the eye lens thinner. This increases its focal length ($f$) so that the incoming parallel or less-diverging rays are still focused precisely on the retina. Thus, the image distance ($v$) remains constant and unchanged.

• Option A is incorrect because if the image distance increased, the image would form behind the retina, resulting in blurred vision.
• Option B is incorrect because if the image distance decreased, the image would form in front of the retina.
• Option D is incorrect because while the absolute image distance is determined by the eyeball's size, for any given normal eye, changing the object distance does not change the image distance; the eye lens adjusts its focal length instead.