Relationship between structure of optic nerve/nerve fiber layer and functional measurements in glaucoma

Glaucoma is a progressive optic neuropathy characterized by structural changes of the optic nerve and retina that are associated with the development of visual functional defects. The temporal relation between structural signs of the disease with psychophysical measures such as visual field tests is important to clarify to determine the best methods to detect glaucoma and progressive glaucomatous damage in the clinical setting. This paper reviews recent advancement in the perception of this structure-function relation.

Quantitative measurement of optic disc and nerve fiber layer integrity have shown initial promise in early longitudinal studies in detecting progressive glaucoma before the development of progression using standard perimetry. Additionally, selective measures of visual function may be able to detect glaucoma before conventional methods as well; however, the relation between these newer specialized functional tests and optic disc analyzers in detecting progression awaits further study.

Defining the clinical relation between structure and function cannot be done outside of the context of the instrumentation used to assess these parameters. Unfortunately, longitudinal studies that compare newer clinical instruments that measure the structural and functional characteristics of the optic nerve to current conventional testing are lacking, but are required to validate these emerging technologies.