I have not had russians long enough to know what happens to them in their senior years, but I would suggest you take him to a vet. Any change in the appearance of the eyes cannot be good. Possible infection, vitamin A deficiency, cataracts, etc.
A normal russian tortoise would be experiencing a slow down since around September (maybe August) if you live in the Northern Hemisphere. The onset of shorter days and cooler weather can trigger hibernation, even for tortoises that are kept warm and indoors all the time.
A russian can be kept awake for the winter. Check the care articles at www.russiantortoise.net Since your tortoise appears to have a potential health problem, I'd suggest you keep him warm and awake.
Good luck!