The natural lens inside your eye is clear and flexible when you are born. Light should pass through the lens without scatter, glare, faded colour or blurry vision. It’s flexibility also allows it to change shape to focus on near, intermediate and far objects. The lens slowly looses its clarity and flexibility.
As yet there are no lens implants that are as good as the natural healthy human lens in a young person. The key to cataract surgery is that one should wait long enough that the vision after surgery will be better than before. If spectacle independence suits your lifestyle better and you choose multifocal lenses you can expect better quality vision after surgery than with a mono-focal lens. This means that surgery can be done sooner, even while the lens is still relatively clear with great visual outcomes.