turtle eye infection

Question
Well. this one day while i was cleaning out the turtle tank, i saw that my oldest turtle, Areoly keeps  her right eye close. the only time she opens her eye is when.... well.... once a while. Her eye is a color of dark green and red. She keeps scratching her right eye. I read that i should put on eye drops for her and put her in saltine water. what should i do. I had her for over 5-7 years now. Shes 9 or so years old. What should i do?

Answer
It can be that the eye is defective, been injured several possibillities  the best i can say is have a vet look at it to see.

what are you feeding?
what type lights, there is certain lights that are being researched as to if they can cause blindness

water temps?

please answer these for me