Can someone tell me if I’ve gone wrong somewhere in the following line of reasoning? It’s a line of reasoning which leads me to believe that, when we look at an object underwater, it’s image is actually formed upright (instead of inverted) on our retina. The reason I assert that the image formed is upright is because the aqueous humour-air interface (which is responsible for the refraction which causes the image to be inverted in most cases) is replaced with an aqueous humour-water interface. Water and the aqueous humour both have a refractive index of approx. 1.34, so little or no refraction will occur when light passes from one to the other. The reason I am paying no attention to the refractive index of the cornea (approx. 1.38) is because the opposite sides of the cornea can be considered as parallel for the purposes of this experiment. Because the refraction occuring between the two mediums (water and the aqueous humour) in this instance is effectively negligible, rays which are parallel at the cornea can be considered to be still parallel at the lens, as demonstrated in the attached picture. Values I’ve been able to gather for the refractive power of the lens are: 20 diopters when relaxed, and 30-33 during accommodation. Therefore, parallel rays striking the lens will be focused approx. 3-5 cm behind the lens. The distance from the lens to the retina, however, is only 1.4-1.7 cm. The image of the object in the water, therefore, is upright on the retina. Have I gone wrong somewhere? P.S. To make the scenario easier to cope with, assume that the object in question is small enough for the light rays reflected off its top and bottom sides in to the eye to be parallel.