Accomodation of the Lens
In this interactive animation, you can explore how the lens of the eye adjusts its thickness. This allows you to see an object in focus as it is moved to different distances from the lens. Drag the object to another position and observe how the lens changes. When you are looking at a very far away object, the lens of your eye is as thin as it can get, that means the ciliary muscle around your lens is relaxed. When you want to look at a closer object, your brain signals to the ciliary muscle to contract. This makes the lens thicker, which means its focal length becomes shorter. This way, the image is always located at the retina, and you see things in focus, no matter whether they are far or close. Keep playing with the animation and observe what happens! Try to answer the following questions: When you bring the object from far away closer, what happens to the size of the image? To the position of the image? To the shape of the lens? To the focal points of the lens?