Purpose: This study was performed to differentiate glaucomatous changes of the optic disk that may be caused by increased intraocular pressure from those that may be pressure independent.
Methods: For 357 patients with primary open-angle glaucoma, the optic disk was morphometrically analyzed, and the intraocular pressure was measured in 24-hour profiles.
Results: By performing an intraindividual bilateral comparison, the differences in the maximal intraocular pressure values of the right eye minus the left eye of the same individual were significantly correlated with the differences in neuroretinal rim area and mean perimetric defect of the right eye minus the left eye. No significant correlations were found for the parapapillary atrophy.
Conclusions: The results indicate that the eye with the higher pressure compared with the fellow eye with the lower pressure showed neither a significantly larger nor smaller parapapillary atrophy, which suggests that the papapapillary atrophy, compared with the neuroretinal rim area and the visual field defect, is less dependent or almost independent of an increased intraocular pressure.