Editor,—Pigment dispersion syndrome is an autosomal dominant condition which leads to pigmentary glaucoma in up to 50% of cases. Campbell1 was the first to propose that posterior bowing of the peripheral iris with chaffing against the lens zonule was responsible for the liberation of iris pigment which recent developments in high resolution ultrasound biomicroscopy appear to bear out. Current theories suggest that the cause of this posterior iris bowing is “reverse pupil block”,2 in which the iris acts as a flap valve against the anterior surface of the lens allowing aqueous to pass from posterior to anterior chamber but not vice versa.

Pigment dispersion syndrome is a bilateral, symmetric …