Black eyes

Question
Hello.

I own a 13 year old mare who moved from England to America exactly one year ago.  She has had no problems with the heat so far but recently the area around her eyes has gone really dark /black.  I noticed a few weeks ago she wasn't drinking any water in the stall, only in the pasture.  One day she will drink nothing and then the next day she will drink a lot.  I put electrolytes in her food.  
Her diet has not changed so I just wanted to know if I should do anything with her to give her more energy and get rid of the darkness around her eyes.

Answer
Hi Laura, I don't understand if your talking about the actual eye ball going black or the skin around the eyes.  If it's just the skin it's nothing to worry about, it's only because she sweats and makes that dark skin look more prominent.  If it's her actual eye ball or any part of her eye ball, I would contact a vet.  I can't answer that question if it's her eye ball seeing how I'm not a vet.  Horses don't get dark "circles" around their eyes like people when they're tired so unless she's acting too lazy for your liking I wouldn't change her diet.  If she is lethargic then you could still contact a vet and get some blood work done to see if she's anemic or dehydrated causing her to be lethargic.  If she is then you may alter her diet, but until you know I wouldn't change anything.  But, you wouldn't see dark around her eyes just because she's tired.  If you have any doubt, contact a vet.  Good luck, Jessica