Investigation of progressive addition lens patient tolerance to dispensing anomalies.

Numerous reasons have been cited for patient non-tolerance to Progressive Addition Lenses (PALs). This paper considers two presbyopic subject populations - those who successfully wore PALs (n = 20), and those who were non-tolerant to them (n = 18). The dispensing accuracy of the PALs worn by subjects was assessed and the surface quality of those lenses worn by unsuccessful patients studied. These factors do not account for any significant differences between the two groups, suggesting that other causes must separate the subject populations.