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no it is same
It's in the centre of a round segment!
It is because the central portion of the lens i.e. optical centre can be considered similar to a parallel sided glass slab.
If you are talking convex and concave, they both have an optical lens. Sorry if that doesn't help, but what do I know.
Optical Energy, better known as Optical Power, is the converging strength of a lens. As an example a lens with a high Optical Power will have a wider range of view but less focal distance. A lens with low Optical Power will have a longer focal distance but less range of view.
no it is same
If you look through the lens at a distant point, the point image will not move when the lens is rotated slightly about a vertical or horizontal axis the goes through the nodal point. This is called the optical center. With a thin lens this is close to the geometric center, with a longer complex lens the optical center is buried somewhere inside. The optcial center of a complex lens may or may not be inside an element.
axis or optical center
The optical center of the lens is a point on the axis of a lens is the point where any ray passing through this point, the incident part and the emergent part are parallel. It is important for the proper refraction of light.
Benjamin Franklin
It's in the centre of a round segment!
Benjamin Franklin did.
No, you cannot change the bifocal prescription on glasses without changing the lens. The lens is what is prescribed by your eye doctor. The frame, however, can be changed.
bifocals are glass lens that you place upon your nose & push up. they help you see better & / read
Optical axis. There ya go!
The term "bifocal" refers to eyeglasses with two distinct optical powers, typically used to correct both nearsightedness and farsightedness in a single lens.
optic centre is the geometrical centre of the lens the rays of light passing through this point emerges in the same direction without bending.