Macro of my gecko’s eye
Nocturnal geckos have to be able to block out the bright sun during the day while still retaining excellent night vision, which is why they have long zig-zagged pupils that can tightly constrict to let in only pinpoints of light. Interestingly, while humans cannot see colors in dim moonlight, these animals can discriminate between colors and their eyes are calculated to be almost 350 times stronger when it comes to seeing color.
Gharials are ancient creatures that are practically living fossils. Despite this, they have extremely well-evolved eyes that are located in such a way that they can keep almost their entire head underwater and leave their eyes out to look out for prey. Their eyes are also primed for night vision, as a thin, mirror-like structure at the back of their eye helps reflect light that was not already absorbed by the eye back into the eye a second time. When lights are shown on the creatures at night, their eyes will reflect the light so brightly that it looks like they are glowing.
Hippos can see under the water with excellent precision, but what is really fascinating about their eyes is the clear layer of membrane that protects them from debris found underwater. You can kind of see it in the picture.
Chameleons have some of the most unique eyes in the entire animal kingdom. They do not have an upper and lower eyelid, but instead just have a cone with a small opening just big enough for their pupils. Each cone can be separately rotated and the chameleon can actually look at two separate things in completely different directions at the same time. This visual advantage makes them exceptionally adept at hunting flying insects as they quickly buzz by.
Like most insects, butterflies have compound eyes, which are made of hundreds of microscopic, six-sided lenses that allow them to see in every direction simultaneously. While this type of vision prevents the bugs from seeing things in sharp focus, butterflies can see ultraviolet light, which is invisible to the human eye. This aspect of their vision helps to lead them to flowers filled with delicious nectar.
The square pupils of goats attract a lot of attention, but they aren’t just there to look pretty. The width of the pupils allows the animals to see at a 330 degree angle, as opposed to humans who generally see at around a 185 degree angle.
Frogs are well-known for their big eyes, but few people know why their eyes bulge out. They can protrude their eyes to help them see above the surface while they are underwater. When they close their eyes, they pull them back, where they are covered by a top opaque eyelid and two eyelids made of of thin, translucent membrane.
Some of the most evolved eyes in the entire animal kingdom belong to cuttlefish. Their strange, w-shaped pupils are unable to register color, but can see the polarization of light, which allows them to see contrasts, even in dim light. While humans reshape their eye lenses to see things in better focus, the cuttlefish reshapes its whole eye. Additionally, internal sensors in the eye allow the creatures to observe things in front of them and behind them at the same time.
Their cold, steely eyes are perfect for scoping out movement on the desolate steppes. Almond in shape, moderately spaced and set slightly obliquely, the eyes of a Siberian Husky are ice-blue, dark blue, amber, or brown. In some individual dogs, one eye may be brown and the other blue, or a compelling mixture of the two.