Final answer:
In the word phakoanaphylaxis, 'phako' is the combining form that refers to the 'lens' of the eye, reflecting its Latin origin related to the shape of a lentil bean.
Step-by-step explanation:
In the term phakoanaphylaxis, the element that means lens is phako. This is a combining form that is used in medical terminology to refer to the lens of the eye. The word "lens" itself has interesting origins, deriving from the Latin word for a lentil bean, alluding to the similar convex shape. In optics, a lens such as a convex lens focuses light rays. For example, when parallel light rays enter a convex lens, they cross at a focal point on the opposite side due to the lens's shape and the law of refraction, which states that light bends toward the axis when transitioning into a medium with a higher index of refraction.