Tear ph range 6.5 to 7.6 with a median of 7.0. Tears act as a buffer for the eye and will vary dependant on enviroment.The eye surface tissue is at 7.2 to 7.5. The salenity of tears is around 9000 ppm dependant on body hydration. Body ph is 7.35 to 7.45 and isotonic at 0.9 % or 9000 ppm.
Hope this helps.
Later
Steve