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 with normal vision refer to the maximum and minimum distances at which the eye can focus clearly without the need for accommodation (adjustment of the lens shape).
Far Point: The far point is the distance at which the eye can see distant objects clearly without any strain or accommodation. For a person with normal vision, the far point is considered to be infinity (∞) since the eye can focus parallel rays of light coming from distant objects onto the retina without any effort.
Near Point: The near point is the closest distance at which the eye can focus on an object clearly without any strain or accommodation. In individuals with normal vision, the near point is typically around 25 centimeters (cm) or 10 inches from the eye. At this distance, the ciliary muscles in the eye contract to increase the curvature of the lens, allowing for proper focusing on nearby objects.
It's important to note that the near point can vary slightly among individuals depending on factors such as age and eye health. As people age, the flexibility of the lens decreases, and the near point gradually moves farther away from the eye. This is why many individuals may require reading glasses or corrective lenses as they get older to assist with near vision tasks.
Overall, the far point and near point of the human eye play a crucial role in our ability to see objects clearly at different distances, allowing us to have a range of clear vision from distant objects to those close to us.
