What is the far point and near point of the human eye with normal vision?

The far point and near point of the human eye refer to the maximum and minimum distances, respectively, at which the eye can focus without using additional optical aids, such as glasses or contact lenses.

1. Far Point:

» The far point is the maximum distance at which the eye can see objects clearly without strain.
» For a normal human eye, the far point is considered to be at infinity. This means that the eye can focus on objects located at an infinite distance without any accommodation.

2. Near Point:

» The near point is the closest distance at which the eye can see objects clearly without strain.
» For a normal young adult with good vision, the near point is typically around 25 centimeters (about 10 inches). At this distance, the eye’s ciliary muscles are maximally contracted to increase the curvature of the lens and allow for clear focus on nearby objects.

It’s important to note that the near point tends to increase with age due to a condition known as presbyopia. Presbyopia is a natural aging process that results in a gradual loss of the eye’s ability to focus on close objects. As people age, the near point moves farther away, and they may need reading glasses or other corrective lenses for close-up tasks.

These values can vary among individuals, and factors such as age, genetics, and individual differences in eye anatomy can influence the far point and near point.