Abstract
The effects of aging on retinal nerve fiber layer (RNFL) thickness should reflect the age-related losses in retinal ganglion cells (RGCs), but published data suggest that the relative rate of thinning of RNFL thickness with age is less than predicted by age-related losses of RGCs. Therefore, the present study was undertaken to reconcile the differences in age-dependency on measures of RGCs and axons that are incorporated in normative clinical data. Normative data for RNFL thickness and visual field sensitivities were obtained from the printouts of standard optical coherence tomography (OCT) and standard automated perimetry (SAP) for patients aged between 25 and 95 years, in decade steps. These data were used in models to estimate the number of RGCs underlying each measure. The age-related losses of RGCs derived from normative perimetry data agreed closely with published histologic data, without an age-dependent variable in the model. In contrast, the age-related losses of RGCs derived from normative total RNFL thickness data required an age-dependent decrease of 0.007 axons/microm(2)/year in axon density in the RNFL to account for the relatively slower rate of RNFL thinning than RGC loss. The analysis of normative data suggests a model of age-related thinning of RNFL in which the relationship between RNFL thickness and the density of RGC axons varies with the number of neurons that are lost through normal aging. This model posits that the OCT measurement of total RNFL thickness of a normal retina represents two components: 1) an age-dependent population of RNFL axons, and 2) a non-neural component that partially compensates for the age-related decrease in axons in the nerve fiber layer.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Graefe's Archive for Clinical and Experimental Ophthalmology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.