Its a misconcept that Power of a lens is actually equal to inverse of focal length. Infact power of a lens depends on the refractive index of the medium. Power in a medium = (refrative index of medium) / (Focal length of lens in that medium). The front and rear focal lengths obey the relation you give.

The maximum focal length of eye lens is 2.5 cm. The distance between lens and retina is 2.5cm. Minimum focal length occur when you focus on images at your nearpoint The minimum focal length of eye lens is 2.27 cm. Was this answer helpful?

Since from lens makers formula we can observe that focal length of lens is inversely proportional to refractive index of medium of lens . Hence net refractive index of lens decreases when it is dipped in a denser medium than air, hence focal length increases.

The power of a lens is a measure of the degree of convergence or divergence of the light rays falling on it. The power of a lens depends on its focal length. The smaller the focal length of a lens, the greater is its power.

The increased curvature of the lens increases its refractive power. This process is called accommodation. Accommodation usually also involves convergence, when both eyes turn toward the midline to focus on close objects. The increased refractive power allows us to see near objects.

Higher angles of curvature lead to shorter focal lengths due to the fact that light waves are refracted at a greater angle with respect to the optical axis of the lens.

As the refractive index is increased, the focal points (blue spheres) move closer to the lens, and vice versa. These parameters are the fundamental elements defining the geometrical optics of a simple lens and can be used to calculate important properties of the lens, including focal length and magnification factor.