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Medeiros et al. (724) performed a novel analysis of data from the longitudinal Diagnostic Innovations in Glaucoma Study (DIGS) designed to evaluate structural and functional changes of the optic nerve in glaucoma. For this study, the authors selected 344 eyes of 204 patients who had been followed with serial GDx ECC scans over several years (mean: 3.5 visits) along with stereo disc photography and serial standard achromatic perimetry. A random coefficient model was developed to estimate the relationship between intraocular pressure and changes in RNFL thickness over time in those individuals who exhibited progression of the optic disc and visual field and those who did not. For the overall group, each additional mmHg increase in IOP was associated with an increased rate of loss in RNFL retardation of -0.25 microns per year. This relationship was highly significant. In patients who demonstrated progression by conventional testing, this relationship was much stronger with each mmHg increase in IOP associated with an additional loss of 0.13 microns per year. While several trials have demonstrated and association between field loss and disc progression with IOP, this is the first paper to examine the relationship between structural imaging of the RNFL and IOP, which is critical to further our understanding of the role of RNFL retardation in following glaucoma patients and suspects for progression. Similarly to prior studies, there was some disagreement between techniques used to define progression, which may represent false-positive classifications or temporal dissociation in testing results with patients followed within a limited time window.