Abstract
Abstract: :
Purpose: Intraocular pressure may be under systemic vascular control. This study sought to determine if patients with autonomic dysfunction have significant changes in intraocular pressure as position changes to suggest any correlation between blood and intraocular pressures. Methods: Eleven patients with three types of confirmed autonomic dysfunction (multiple system atrophy [MSA], pure autonomic failure [PAF], and baroreflex failure [BF]) were compared to age- and sex-matched controls and had intraocular pressures (IOP), systolic and diastolic blood pressures, heart rates, and calculated mean arterial (MAP) and mean ocular perfusion pressures (MOPP) measured in the supine, sitting, and standing positions. Data were analyzed using a general linear model repeated-measures ANOVA. Results: All pressures for all patients showed a dramatic, significant decline (p < 0.001) from supine to standing (MAP –31 ± 14 mmHg; IOP –6 ± 3 mmHg; MOPP –25 ± 14 mmHg) compared to control pressures (MAP +4 ± 7 mmHg; IOP –1 ± 2 mmHg; MOPP +6 ± 7 mmHg). There was no significant change in heart rates from supine to standing for the patients compared to controls (p = 0.65). Within both the MSA (n = 5) and PAF (n = 4) groups, all initial pressures were similar to control pressures in the supine position, while BF (n = 2) tended to have much higher mean pressures than their respective controls in the supine position. Conclusions: In autonomic failure, a large decrease in MAP correlates with a large decrease in IOP. These data suggest that the autonomic nervous system, through its influence on systemic blood pressure, has a significant role in the control of intraocular pressure.
Keywords: intraocular pressure