Purpose: To investigate the relationship between clinical factors including 24-hour mean ocular perfusion pressure (MOPP, (2/3) x mean arterial pressure [MAP] - intraocular pressure [IOP]) and visual field (VF) progression in eyes with medically treated normal-tension glaucoma (NTG).
Methods: One hundred one eyes of 101 NTG patients followed up for more than 4 years (mean follow-up, 6.2 years +/- 12.1 months) were included after retrospective chart review. Several clinical factors including demographic, systemic, ocular risk factors, and 24-hour MOPP were explored for associations with decreasing VF. Kaplan-Meier analyses were performed to compare outcomes with reference to four risk factors (age, myopia, and elevated MAP and MOPP fluctuation) for VF deterioration. Hazard ratios (HRs) for the association between potential risk factors and glaucoma progression were obtained using Cox proportional hazards models.
Results: Overall VF progression was detected in 29 (28.7%) eyes. There were significant differences between progressors and nonprogressors in nocturnal MAP and MOPP fluctuations (both P < 0.0001), 24-hour MAP, and MOPP fluctuations (both P < 0.0001), initial mean deviation (P = 0.0034), and pattern standard deviation (PSD) score (P < 0.0001). Both elevated 24-hour MAP and MOPP fluctuations were associated with greater VF progression probabilities based on Kaplan-Meier analyses. Among all risk factors investigated, the Cox proportional hazards model indicated that VF progression was significantly associated with 24-hour MOPP fluctuation and initial PSD score.
Conclusions: Clinical factors other than IOP were associated with VF progression in our series of medically treated NTG eyes. Twenty-four-hour MOPP fluctuation was the most consistent prognostic factor for glaucoma progression.