The relationship of structure-function in glaucoma

Glaucoma is a progressive optic neuropathy and functional visual loss characterized by an acquired atrophy of the optic nerve due to the loss of retinal ganglion cells and their axons in the retina.Measurement of visual function is usually based on white-on-white standard automated perimetry (SAP).Glaucomatous defect in visual field typically manifested as nerve fiber bundle defect.Examination of the optic nerve head topography can be conducted using a variety of imaging techniques such as the retina tomography or similar instruments.Although either structural or functional damage can occur without the other developing,it is generally thought that structural damage is detectable before functional loss with the tools currently available and the location of visual field defect was corresponding with specific retinal nerve fiber layer (RNFL) damage.Many studies suggest that RNFL thickness measurements with OCT may provide a better cross-sectional representation of visual function than with HRT Ⅱ and GDx VCC measurements.The relationship between glaucomatous structure damage and functional changes plays a central role in the diagnosis,classification and visual function evaluation of glaucoma.This article provides a review of the structure-function relationship in glaucoma. Key words: glaucoma;  visual function;  visual field;  retinal nerve fiber layer