When a minus lens is moved away from the eye, what happens to its perceived power?

When a minus lens is moved away from the eye, the perceived power of the lens decreases. This is due to the optics of how lenses work. A minus lens, which is concave in shape, diverges light rays that pass through it, creating a virtual image that appears closer than the actual object.

As the distance between the lens and the eye increases, the effective focal length of the lens also increases, which leads to a decrease in the lens's perceived optical power. In simpler terms, the farther the lens is positioned from the eye, the less effective it becomes at diverging the light rays, and thus, the image appears less magnified or pronounced.

This principle is crucial for understanding lens behavior in various optical settings, particularly in fitting patients with corrective lenses. Understanding how positioning affects perceived lens power helps in making more accurate adjustments during refraction assessments.