PS-C12-3: OPEN-ANGLE GLAUCOMATOUS OPTIC DAMAGE IN RELATION TO SYSTEMIC AND OCULAR PERFUSION PRESSURE

Abstract

Objective: Glaucoma is the leading cause of irreversible blindness worldwide. One of the pivotal physiopathological mechanisms involved is reduced ocular perfusion pressure (OPP) at the optic nerve head, which depends on the mean arterial pressure (MAP) and intraocular pressure levels. The interplay association of variability and dips in the 24-h MAP with OPP in relation to glaucoma progression remains undocumented. Therefore, we conducted a retrospective longitudinal study to investigate variability and dips in the 24-h MAP and OPP in relation to the progression of open-angle glaucoma damage. Methods: A total of 265 patients with normal-tension glaucoma (NTG; n = 155) and primary open-angle glaucoma (POAG; n = 110) followed at the University Hospital Leuven with longitudinal visual field tests (n = 7000 measures, including both eyes) who underwent ambulatory blood pressure monitoring were studied. The main outcome was longitudinal changes in the mean deviation (MD), expressed in decibels (dB), which was retrieved from visual field tests. The intraocular pressure (IOP) was measured with applanation tonometry. MAP variability independent of the mean (VIMmap) was computed and the five lowest dips in MAP readings were further analyzed. OPP was the difference between 2/3 of the 24-h MAP minus 24-h intraocular pressure levels. Statistics methods included mixed models. Results: The mean age was 64.0y (53% were women). The IOP during eight years of follow-up was 11.3 mmHg. All IOP measures were higher in POAG than NTG (P < 0.046). POAG patients had lower OPP than NTG (P < 0.045). In adjusted mixed models, higher 24-h VIMmap was associated with longitudinal changes in MD in POAG (-2.07 dB changes, P < 0.001). The longitudinal changes in MD associated with dip measures ranged from -2.84 dB (95% confidence interval [CI], -4.12, -1.57; P < 0.001) to -2.16 dB (95% CI, -3.46,-0.85; P = 0.001) in POAG. Lower 24-h MAP combined with high variability and extreme dips in MAP resulted in worse progression of MD (P = 0.009). Reduced OPP was associated with -2.51 to -2.00 dB changes in the MD (P < 0.001) in POAG. Progression in MD was worse in patients experiencing reduced OPP along with high variability and dips in MAP. Conclusions: Progression of open-angle glaucoma damage is associated with high variability and dips in MAP, and reduced OPP. This progression exacerbates if the lower OPP occurs along with extreme dips in the MAP. 24-h ambulatory blood pressure and intraocular pressure should be implemented in the follow-up of glaucoma patients experiencing progression of the disease despite the intraocular pressure remaining normal.