Importance: Higher intraocular pressure variability may be associated with faster structural changes in patients with glaucoma.
Objectives: To investigate the association of mean intraocular pressure and intraocular pressure variability (defined as the SD of intraocular pressure and the intraocular pressure range) with the rate of retinal nerve fiber layer thinning over time in patients with glaucoma.
Design, setting, and participants: In this retrospective analysis of a longitudinal cohort, patients were enrolled from the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation study. A total of 815 eyes (564 with perimetric glaucoma and 251 with preperimetric glaucoma) from 508 patients with imaging follow-up for a mean of 6.3 years from December 2008 to October 2020 were studied. Data were analyzed from November 2021 to March 2022.
Main outcomes and measures: In this longitudinal study, eyes with at least 4 visits and 2 years of follow-up optical coherence tomography and intraocular pressure measurement were included. A linear mixed-effect model was used to investigate the association of intraocular pressure parameters with the rates of retinal nerve fiber layer thinning. Dominance analysis was performed to determine the relative importance of the intraocular pressure parameters.
Results: Of 508 included patients, 280 (55.1%) were female, 195 (38.4%) were African American, 24 (4.7%) were Asian, 281 (55.3%) were White, and 8 (1.6%) were another race or ethnicity; the mean (SD) age was 65.5 (11.0) years. The mean rate of retinal nerve fiber layer change was -0.67 (95% CI, -0.73 to -0.60) μm per year. In multivariable models adjusted for mean intraocular pressure and other confounding factors, faster annual rate of retinal nerve fiber layer thinning was associated with a higher SD of intraocular pressure (-0.20[ 95% CI, -0.26 to -0.15] μm per 1-mm Hg higher; P < .001) or higher intraocular pressure range (-0.05 [95% CI, -0.06 to -0.03] μm per 1-mm Hg higher; P < .001).
Conclusions and relevance: In this study, intraocular pressure variability was independently associated with structural change in patients with glaucoma, even after adjustment for mean intraocular pressure, supporting its potential value in clinical management.