Amplitude of accommodation

Have you ever seen a camera lens? It opens and closes to let in different amounts of light, right? Our eyes work kind of like that too. But instead of opening and closing, they change their shape to let in more or less light.

The part of our eye that does this is called the lens. Just like with a camera lens, the amount of light that can come into our eye depends on how much the lens can change shape.

When we're young, our lenses can change shape a lot. That means we can see things that are far away, like a bird in a tree, and things that are close up, like the letters on this page.

As we get older, though, our lenses can't change shape as well. That means we might need glasses to see things that are far away or close up.

That ability to change shape is called the "amplitude of accommodation." It's like how far our lens can "stretch" to focus on different things. The stronger our amplitude of accommodation, the easier it is for us to see things at different distances without needing glasses.

So, amplitude of accommodation is a fancy way of talking about how well our eyes can change shape to let in different amounts of light and focus on things at different distances.