Posture-Induced Intraocular Pressure Changes at Different Times of Day in Primary Open-Angle Glaucoma: Associated Factors and Exploratory Analyses of Antiglaucoma Medication Regimens.

PURPOSE: To compare posture-induced intraocular pressure (IOP) differences at two measurement times in eyes with primary open-angle glaucoma (POAG) and to identify associated factors.

METHODS

In this retrospective observational study, 108 eyes of 61 POAG participants receiving antiglaucoma medications were included. Sitting and supine IOP were measured at 9 a.m. and 9 p.m. using the iCare IC200 rebound tonometer. Ocular parameters, including subfoveal choroidal thickness, corneal hysteresis, and systemic parameters, including body mass index and blood pressure, were assessed. Mixed-effects models were used to analyze factors related to posture-induced IOP differences (supine minus sitting IOP).

RESULTS

Posture-induced IOP differences were significantly greater at 9 a.m. (3.5 ± 2.0 mmHg) than at 9 p.m. (2.7 ± 1.7 mmHg; P < 0.001). At 9 a.m. higher sitting IOP (P = 0.010) and greater subfoveal choroidal thickness (P = 0.003) were associated with larger IOP differences. At 9 p.m. lower body mass index (P = 0.005), higher blood pressure (P = 0.004), greater supine blood pressure elevation (P = 0.036), and higher corneal hysteresis (P = 0.017) were associated with larger IOP differences. The presence of any individual antiglaucoma medication class within the topical regimen was not significantly associated with posture-induced IOP differences. However, in exploratory analyses, combination therapy with an α2-adrenergic agonist and a Rho kinase inhibitor was associated with smaller IOP differences, particularly at 9 a.m. (P = 0.031).

CONCLUSION

Posture-induced IOP elevation was greater in the morning in POAG eyes. Multiple ocular and systemic factors, including blood pressure-related parameters, contributed to these differences, which varied by measurement time. Analyses of antiglaucoma medication regimens were exploratory, and findings should be interpreted with caution.