The blood vessels of the sclera are largely confined to a superficial layer of tissue, and these, along with the conjunctival vessels, are responsible for the bright redness of the inflamed eye.
The danger posed by unseen underwater reefs led to an association of coral with death and interment that has figured in literature, poetry, music, and film, while the bright redness of precious Mediterranean coral was associated in European and Indian mythology with its origins in blood and gore.
Other males avoid violent conflict with individuals with brighter red faces than themselves, suggesting that this increased redness is a signal of social status between dominant and subordinate males [7].
Hyperemia was graded using a 5-point photographic bulbar conjunctival hyperemia grading scale: 0, none, normal; +0.5 trace, trace flush reddish pink; +1, mild, mild flush reddish color; +2, moderate, bright red color; +3, severe, deep, bright, diffuse redness.
The intensity of facial redness fluctuates in female mandrills, with faces being brightest red while fertile [7].
Now that they know the identity of the "redness gene", researchers can better understand the evolutionary phenomenon known as an "honest signal", where a particular trait, such as bright red feathers, is genuinely associated with higher-quality genes.
If you are prone to crying when you're upset, your eyes may also appear brighter as well, because the redness of your eyes that develops from crying contrasts with the color of your iris', making them appear more vibrant.
Eye redness and the difficulty of looking at bright light are also documented.
Urticaria features an area of central redness, on which is superimposed an irregular wheal, caused by local edema, and surrounded by a bright pink flare.
Eye drops like Visine helps eliminate redness and makes the whites of your eyes appear whiter, which will in turn make your eyes appear brighter.
