Effect of mean ocular perfusion pressure on primary open-angle glaucoma: A hospital-based case–control study in South India
Aswathi Vijayan, Saritha Valsala KrishnankuttyABSTRACT
Purpose:
To determine whether reduced ocular perfusion pressure (OPP) rather than intra-ocular pressure (IOP) alone is associated with primary open-angle glaucoma (POAG) in an Indian cohort.
Methods:
In this prospective, case–control study, 78 patients with untreated POAG and 78 age-matched controls underwent paired Goldmann applanation tonometry and blood-pressure measurements at 05:00, 11:00, 14:00, 18:00, and 23:00. Mean arterial pressure, systolic (SPP), diastolic (DPP) and mean ocular perfusion pressures (MOPP = ⅔ MAP – IOP) were calculated. Primary outcome was inter-group difference in mean MOPP; secondary outcomes were diurnal fluctuation amplitudes and independent predictors of POAG on multivariable logistic regression.
Results:
Mean IOP was higher in POAG eyes than controls (18.3 ± 2.0 vs 14.0 ± 1.3 mmHg, P < 0.001). Mean MAP (87.9 ± 5.8 vs 90.3 ± 2.9 mmHg, P < 0.001), MOPP (46.4 ± 4.2 vs 50.8 ± 1.9 mmHg), SPP (102.9 ± 8.6 vs 108.5 ± 4.5 mmHg) and DPP (53.0 ± 5.7 vs 60.1 ± 3.5 mmHg) were significantly lower in POAG group (P < 0.001). Diurnal IOP and MOPP ranges were wider in POAG than controls. Multivariable analysis showed each 1 mmHg decrease in MOPP raised POAG odds by 18% (OR 1.18; 95% CI 1.10–1.26); elevated IOP and reduced DPP were additional independent predictors.
Conclusion:
South Indian eyes with POAG were found to have persistently lower and labile ocular perfusion pressures than healthy eyes. These findings support the hypothesis that vascular insufficiency, particularly nocturnal hypoperfusion, may contribute to disease process alongside IOP.