Abstract
Purpose: :
To investigate the 24-hour systemic blood pressure (BP) and intraocular pressure (IOP) profiles in treated high and normal-tension glaucoma patients .
Methods: :
We studied 27 open-angle glaucoma patients (54 eyes) who underwent 24-hour tension curves . All patients had more than two years of follow-up . Patients were divided into two groups: high-tension (HTG) or normal-tension glaucoma (NTG, all known untreated IOP <21 mmHg). Data collected included age, systemic and ocular medications, systemic comorbidities, standard automated perimetry MD values, systolic and diastolic BP, and IOP measurements. Differences between groups regarding BP and IOP parameters, including minimum diastolic pressure, nocturnal ocular perfusion, mean IOP and IOP fluctuation were calculated using a general linear model (correcting for interocular dependence).
Results: :
Mean ± SD age for HTG and NTG were 71.9±11.1 and 62.4±15.2 years, respectively (p=0.072). There was no difference in MD, percentage of patients using topical prostaglandins analogues or systemic β-blockers (p>0.05) between groups. Although both groups had similar values for daytime ocular perfusion pressure (p=0.202), lower nocturnal perfusion values were observed in the NTG group (51.1±10.2 mmHg) compared to the HTG group (64.2±10 mmHg; p=0.003). Additionally, minimum diastolic BP was lower in the NTG group (51.1±9.3 vs 58.3±8.2 mmHg; p=0.044). There was no significant difference between mean IOP in HTG (12.7±2.3 mmHg) and NTG groups (13.7±3.7 mmHg; p=0.26). However, IOP fluctuation (8.0±2.5 vs 5.7±2.8 mmHg, p=0.002) and IOP standard deviation (2.4±0.8 vs 1.8±0.8 mmHg, p=0.004) were higher in NTG patients compared to HTG patients.
Conclusions: :
Treated NTG patients have lower nocturnal ocular perfusion than HTG patients. This difference seems to occur due to a combined systemic and ocular mechanism, as these patients have both decreased diastolic BP and higher IOP fluctuation.
Keywords: intraocular pressure • blood supply • circadian rhythms