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Alessandro A Jammal, Eduardo Bicalho Mariottoni, Atalie C. Thompson, Samuel Berchuck, Tais Estrela, Leonardo Shigueoka, Felipe A Medeiros; The Effect of Intraocular Pressure Control on Rates of Glaucomatous Structural Loss in a Large Clinical Population. Invest. Ophthalmol. Vis. Sci. 2020;61(7):5196.
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© ARVO (1962-2015); The Authors (2016-present)
Intraocular pressure (IOP) remains the only treatable risk factor for glaucoma. However, most investigations of the effect of IOP lowering on rates of glaucoma progression have focused on relatively small populations from clinical trials or cohort studies with restrictive criteria or treatment schemes. In this study, we investigate the effect of IOP on rates of change of retinal nerve fiber layer (RNFL) thickness in a real-world large clinical population.
Data were extracted from the Duke Glaucoma Registry, a large database of electronic medical records of patients with or suspected of glaucoma followed at the Duke Eye Center and satellite clinics. All records from patients with ≥6 months of follow-up and ≥2 good quality optical coherence tomography (OCT) RNFL scans and 2 clinical visits with applanation tonometry were included. Mean IOP was calculated as the average measurement during follow-up. Eyes were also categorized in 4 groups according to the frequency of IOP measurements <18mmHg over time: A: 100% of visits; B: 75%-100% of visits, C: 50%-75% of visits, D: <50% of visits. Eyes that underwent trabeculectomy or tube shunt were censored after the procedure. Rates of change for RNFL thickness were obtained using linear mixed models. Multivariable models were adjusted for age, gender, race, corneal thickness, follow-up time and baseline disease severity.
66,693 OCT tests of 18,222 eyes of 9,593 patients were included in the study with a mean follow-up of 3.4±1.9y. Average rate of change in RNFL thickness was -0.65±0.56µm/y. The proportion of eyes in the 4 categories A, B, C and D were 41%,15%,19% and 25%, with mean IOP values of 13.1±1.9, 15.9±1.5, 17.1±1.4, and 20.3±2.5mmHg, respectively. The corresponding mean rates of change for each group were -0.47±0.47, -0.60±0.54, -0.70±0.57, and -0.89±0.60µm/y, respectively. Each 1mmHg higher mean IOP was associated with 0.06µm/y faster RNFL loss (P<0.001), after adjustment for potentially confounding variables.
To the best of our knowledge, this is the largest study to evaluate the effect of IOP control on rates of RNFL loss in glaucoma. Our findings indicate that higher mean IOP is associated with RNFL thickness loss. In addition, they quantify the impact of different levels of IOP control on rates of RNFL change over time, which can be useful when establishing target pressures in clinical practice.
This is a 2020 ARVO Annual Meeting abstract.
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