Horses eyes

Question
My friends mares eyes are not smooth, they look like there are rods coming out of the iris? (the black part) and a ball as well, I've been trying to find information on this, and haven't been able to. We are wondering if it is normal or not, and if its leading to blindness? Could you please help me get some answers

Answer
Sally:

great question. If these are what i think you are describing, in fact, these do occur in a number of horse normally and are called "copora nigra" (black bodies). they may reduce sunlight induced glare and to help induce visual clarity during daylight. I hope this helps some. Let me know if you have any other questions.