90 glaucoma cases (160 eyes) with field defects in at least one eye have been subjected to automatic perimetry on at least 5 occasions. The condition of the field defect is represented by the regression coefficient. The frequency distribution of the coefficients in groups based on references to age, sex, intraocular pressure, exfoliations, haemorrhages and therapy illustrates the possible importance or insignificance of these factors to the decay. The need for several consecutive examinations to establish with some significance a progression of field defects is demonstrated.