Association Between 24-Hour Intraocular Pressure Fluctuation and Retinal Nerve Fiber Layer Thickness Measured by Optical Coherence Tomography.

PURPOSE: To evaluate the relationship between 24-hour fluctuation of intraocular pressure (IOPF) and RNFL thickness measured by spectral-domain optical coherence tomography (SD-OCT). MATERIAL AND METHODS: The study included 153 eyes of 80 patients. Seventy-five eyes (49%) were considered glaucoma suspects and 78 (51%) had a diagnosis of POAG. All eyes underwent peripapillary RNFL imaging with SD-OCT, standard automated perimetry (SAP), and 24-hour IOP measurements. Generalized linear mixed models were used to investigate the relationship between IOPF and RNFL thickness adjusting for potential confounding factors such as age, diagnosis of glaucoma, central corneal thickness, number of medications, mean IOP during the 24 hours, and disease severity. RESULTS: Mean age was 60.0±18.7 years for glaucoma suspects and 64.7±12.4 years for POAG patients. In univariable analyses, IOPF was associated with global RNFL thickness (P=0.012), but mean and peak IOP during the 24-hour were not (P=0.492 and P=0.229, respectively). When adjusted for confounding factors in the multivariable analysis, each 1 mmHg increase in IOPF was associated with a 2.30 µm thinner global RNFL (95% confidence interval: -4.25 to -0.36 µm, P=0.021). CONCLUSION: Higher IOPF was associated with thinner global RNFL thickness measured by SD-OCT. This finding corroborates a potential role for IOP fluctuation as a risk factor for structural loss in glaucoma. PRCIS: Abnormal short-term fluctuation of intraocular pressure is associated with thinner global retinal nerve fiber layer thickness in subjects with primary open angle glaucoma and glaucoma suspects.