Which pH could cause the least eye irritation?

The pH level that causes the least eye irritation is typically around neutral, which is a pH of 7. The reason a pH of 7.6 is considered here is that it is still relatively close to neutral and is within the range where many eyes can tolerate slight variations without significant irritation.

The pH scale ranges from 0 to 14, with 7 being neutral, values below 7 being acidic, and values above 7 being basic (alkaline). The human eye has a natural pH close to that of neutral, making it more comfortable for substances that are close to this pH.

When we consider a pH of 8.2, while it is just slightly above neutral, it is on the alkaline side and can cause some irritation, especially with prolonged exposure, as it deviates more from the natural conditions of the eye. A pH of 6.8, being slightly acidic, can also lead to irritation, particularly in sensitive individuals.

Therefore, a pH of 7.6 strikes a balance as it is still moderately close to neutral while being less likely to cause irritation than both the alkaline pH of 8.2 and the acidic pH of 6.8