Quantifying retinal nerve fiber layer loss in glaucoma using a model of unilateral hypertensive pseudoexfoliation syndrome

Purpose: To correlate the amount of glaucomatous field loss with amount of retinal nerve fiber layer (RNFL) loss using a novel model consisting of eyes of subjects with pseudoexfoliation syndrome (PXS) in 1 eye only with elevated intraocular pressure, using the fellow eye as a marker of baseline healthy anatomy, allowing precise correlation by elimination of intersubject anatomic variation. Methods: In each eye with PXS we recorded standard automated perimetry mean deviation and the percentage loss of Stratus optical coherence tomography - RNFL thickness relative to the fellow non-PXS eye, and correlated these 2 measurements. Results: Twenty-six subjects with unilateral hypertensive PXS were enrolled. Twelve of 26 eyes had glaucomatous visual field loss. In eyes without field defect there was a broad range of RNFL thickness loss from almost none to nearly 50%. In some of these eyes whereas RNFL thickness was within normal limits it was clearly reduced compared with the fellow eye. All eyes with field defect except one had lost greater than 50% RNFL thickness. Conclusions: This model of unilateral hypertensive PXS allows correlation of functional and structural loss in glaucoma while eliminating interindividual anatomic variability. It suggests that optical coherence tomography can have an important role in the diagnosis and management of early glaucoma before visual field loss is detected.