Actually, Ben's shown that higher pH is LESS irritating to eyes. 7.8 to 8 is supposed to be very, very gentle, but, unfortunately, it makes chlorine less effective. High levels of FREE chlorine don't tend to be irritating either. However Combined Chloramines tend to be very irritating to eyes as do other chemicals.

Adding chlorine should not raise pH, and, as it breaks down, it LOWERS it. This is why bleach, with a pH of 11, generally has zero effect on pH--it's alkaline enough to offset the acidic reaction of chlorine breakdown. It's also why di-chlor, which is virtually neutral, tends to lower pH.

Don't blame chlorine for these eye irritations. Something ELSE is clearly wrong with the water.