They have 24 eyes arranged in four clusters; 16 are simply light-sensitive pits, but one pair in each cluster is complex, with a sophisticated lens, retina, iris and cornea. Trilobites went down a ...

The uvea is made up of a layer of blood vessels, a muscular ring that surrounds your pupil, and the iris, the colored part of your eye. Together, they help your eyes focus so you can clearly see ...

Neovascularization of the retina, iris and angle is responsible for some of the most serious diabetic ocular complications including vitreal hemorrhage, traction retinal detachment and angle closure.

That coloured circle is called the iris and the black spot in the middle is the pupil. This is the part of the eye that lets the light in. Lights out please! When it’s dark, muscles in the iris ...