Glass Eyeballs

Switch on the light, change the water content in the eye lens and thus its curvature. On the projection screen, which represents the retina, you can watch the reversed image from the lantern. Automatic focusing of the optical system of the eye on a given object is called accommodation. This is the ability of the eye lens to change its shape and with it the refractive angle depending on the distance of the observed object. The eye lens is attached by zonular fibres to the ciliary body which keep it flat when focusing on a distant object. However, when focusing on a nearby object they will relax and the walls of the lens will curve. The nearer the observed object the greater the need for accommodation. Accommodation disorders include nearsightedness, farsightedness and astigmatism.