Why is the white's of my eyes turning brownish ?

Genetics/Aging: People of darker skin, asians, hispanics and especially blacks can sometime gain what we sometimes call 'racial melanosis, ' as we get older. Pinguecula, usually not described as brown, is a degeneration from sun exposure. Sometimes you can get nevus, a freckle. Rarely, one can get conjunctival melanoma. Best to let your eyemd examine you to get an accurate answer.

Grey spots: Sometimes I have patients worried after they notice small grey spot(s) on the white of the eyes which are a normal part of aging of the eye. These are light grey though and not brown like melanosis or nevi.