What is the transparent structure behind the pupil that changes shape to help focus images?

The lens is the transparent structure located just behind the pupil in the eye that adjusts its shape to help focus light onto the retina, allowing us to see clearly at various distances. When we look at objects that are far away, the lens flattens out, and when we look at nearby objects, it becomes more rounded. This process, known as accommodation, is crucial for providing a sharp image to the retina, where photoreceptors convert light into neural signals for the brain to interpret.

Other structures mentioned, such as the retina, iris, and cornea, serve different functions. The retina is responsible for capturing light and converting it into neural signals, the iris controls the size of the pupil and regulates the amount of light entering the eye, and the cornea is the outermost layer that helps to focus light but does not change shape like the lens. Thus, the lens is uniquely equipped to perform the critical task of adjusting focus.