The relationship between structural and functional alterations in glaucoma: a review

Abstract

This article reviews the relationships between structural changes and visual function losses produced by glaucomatous damage. Structural characteristics of the optic nerve head and retinal nerve fiber layer include both qualitative and semi-quantitative clinical assessment methods as well as quantitative imaging techniques. Visual function properties include standard (white-on-white) automated perimetry and new techniques such as short wavelength automated perimetry and motion displacement threshold perimetry. Previous investigations consistently report a significant relationship between structural and functional deficits in glaucoma, with structural changes usually being reported to occur earlier than functional losses. In cases of focal damage, there appears to be a good topographic relationship between structural and functional losses. Several optic nerve head and retinal nerve fiber layer measures are reported to be good predictors of glaucomatous visual field loss. However, previous investigations of structure-function relationships in glaucoma are limited by the small number of patients evaluated in most studies, the lack of well-defined inclusion/exclusion criteria as well as detailed descriptions of the patient population, and the paucity of prospective longitudinal studies that have been performed.