Why doesn’t this happen anywhere else? Cut your finger? Both hands get infected. Ingrown toe tail? Both feet hurt.
They have greatly restricted blood flow due to their structure, and very close proximity to the most important organ in the human body. And I wanna take a minute to appreciate how much of an evolutionary novelty sight must have been. Producing photo transferring chemicals and seeing your mate for the first time.
While sight is great, if you think of it as a electromagnetic wave sensors, natured has evolved that feature in several ways.
For example, you skin can feel infra red radiation in the form of heat. Our ancestors evolved specialised cells that detected visible-light radiation and those cells became increasingly sophisticated organs. But the ability to detect light intensity has existed for a lonnnng time. Even in the primordial puddle, it was useful to know where the sun was shining.
Another comparison I saw was that eyes are electromagnetic sensors and touch is a nuclear force sensor. Smell is just a special kind of sense of touch that only reacts to certain molecules.
there are actually a few other cases of this in the body and it’s because your eyes aren’t actually a part of your bloodstream so the eyes are treated as foreign objects along withthe others I mentioned being thyroid follicles ovarian follicles and sperm inside testicular ducts the last 2 being they only have one set of chromosomes so are biologically different to you
