What acidity (minimum pH) will most patients tolerate when using ophthalmic salines? After sone decades of trying to answer that question (and many continue to try), it is becoming increasingly evident that the question rather then the answer may be flawed. It is now evident that both patient and saline are variables within the problem; the patient through inherent (genetically based) differences, and gradual physiological change (i.e. aging and environmental history); and the solutions through physical and chemical shifts over time. It is with those changes asociated with the ophthalmic salines that his study was concerned
