Abstract
Purpose:
The purpose of this study was to examine the intraocular pressure (IOP) asymmetry in patients with primary open angle glaucoma (POAG) compared to a control group to determine if asymmetric intraocular pressure is a risk factor for POAG.
Methods:
This was a retrospective chart review analysis conducted at one institution in Detroit, MI. 91 patients with POAG and 78 control patients were evaluated. Intraocular pressures from both eyes were recorded prior to initiation of therapy as well as cup/disc ratio. Various statistical analyses were employed including unpaired t test and regression analysis.
Results:
Patients with POAG had a statistically significant higher IOP asymmetry (0.9±1.0 vs 2.7±13.6, p<0.001). There was a statistically significant higher cup/disc ratio asymmetry in the POAG group (0.02±0.05 vs 0.07±0.07, p<0.001). Among three groups of IOP asymmetry > 1 mmHg, > 3 mmHg and > 5 mmHg the highest odds ratio (OR) was in the > 5 mmHg group (OR 24.9; 95% confidence interval, 1.46-423). A regression analysis showed a very weak correlation between IOP asymmetry and cup/disc ratio asymmetry in the control group (R=0.13) and an only slightly stronger correlation in the POAG group (R=0.22).
Conclusions:
Our results are consistent with previous studies, demonstrating that intraocular pressure asymmetry is more common among patients with glaucoma. An IOP asymmetry of greater than 5 mmHg conferred the highest risk of glaucoma. Patients with POAG have a higher cup/disc ratio asymmetry. IOP and cup/disc asymmetry were very weakly correlated. IOP asymmetry confers a greater risk of open angle glaucoma and should be considered a risk factor for the development of glaucoma when evaluating patients.