An Eye for Alkaline Exposure

To confirm that I have sufficiently irrigated an eye that has been exposed to an alkaline substance, I use nitrazine paper strips to test the pH of the conjunctival fluid. These are the same strips used by obstetricians to test for amniotic fluid leakage; they identify pH values between 4.5 and 7.5. Until the strips register a pH well within this range, I need to continue irrigating.