Effect of Posture on Blood and Intraocular Pressures in Multiple System Atrophy, Pure Autonomic Failure, and Baroreflex Failure

Singleton, Chasidy; Robertson, David; Byrne, Daniel W.; Joos, Karen M.

doi:10.1161/01.cir.0000097114.11038.26

Cited by 33 publications

(29 citation statements)

References 18 publications

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“…The third limitation is that we did not assess blood pressure, and some authors have pointed out its relevance to the posture-induced IOP change. 7,29,30 In summary, there was no significant difference in postureinduced IOP changes among mostly medically treated eyes with OAG, PAC, and normal control eyes. The posture-induced IOP change also varied individually, which may explain why significant changes were not found.…”

Section: Discussionmentioning

confidence: 83%

Posture-Induced Intraocular Pressure Changes in Eyes with Open-Angle Glaucoma, Primary Angle Closure with or without Glaucoma Medications, and Control Eyes

Sawada¹,

Yamamoto²

2012

Invest. Ophthalmol. Vis. Sci.

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PURPOSE.To compare the posture-induced intraocular pressure (IOP) changes in eyes with open-angle glaucoma (OAG), primary angle closure (PAC) with or without glaucoma medications, and healthy control eyes with normal IOPs. METHODS.The IOP was measured in the sitting position (SP) and the lateral decubitus position (LDP) with a rebound tonometer. The IOP in the LDP was measured in the upper eyes 5 minutes after assuming this posture. RESULTS.Fifty-two patients with OAG, 52 with PAC, and 52 controls with normal IOPs were studied. The IOP in the SP measured with the rebound tonometer was 14.3 6 4.0 mm Hg in eyes with OAG, 15.8 6 4.5 mm Hg in eyes with PAC, and 13.9 6 3.7 mm Hg in eyes with normal IOPs. None of these differences was significant (P ¼ 0.060; ANOVA). The IOP in the LDP was significantly increased to 18.3 6 4.6 mm Hg in eyes with OAG, 19.3 6 4.4 mm Hg in eyes with PAC, and 17.3 6 3.5 mm Hg in eyes with normal IOPs (P ¼ 0.000 for all; paired ttests). The postural IOP difference was þ4.0 6 2.2 mm Hg in OAG eyes, þ3.5 6 2.2 mm Hg in PAC eyes, and þ3.4 6 1.8 mm Hg in normal eyes, and these increases were not significantly different among the three groups (P ¼ 0.309; ANOVA). The correlation between the posture-induced IOP changes and the axial length was not significant in each group.CONCLUSIONS. Postural IOP changes are comparable among eyes with OAG, PAC with and without glaucoma medications, and control eyes. (Invest Ophthalmol Vis Sci. 2012;53:7631-7635)

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Section: Discussionmentioning

confidence: 83%

Posture-Induced Intraocular Pressure Changes in Eyes with Open-Angle Glaucoma, Primary Angle Closure with or without Glaucoma Medications, and Control Eyes

Sawada¹,

Yamamoto²

2012

Invest. Ophthalmol. Vis. Sci.

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“…Although the exact interplay between blood pressure and IOP is still unclear, the altered response in blood pressure due to the baroreflex may influence or accompany changes in aqueous humor dynamics and IOP. Singleton et al, 21 have reported that in patients who had orthostatic hypotension with autonomic imbalance, postural change produced significant IOP changes by sudden fluctuation of blood pressure. Aging is known to be associated with a decreased sensitivity of the parasympathetic but not the sympathetic arm of the baroreflex.…”

Section: Discussionmentioning

confidence: 99%

Effects of Aging on 24-Hour Intraocular Pressure Measurements in Sitting and Supine Body Positions

Mansouri

Weinreb

Liu

2012

Invest. Ophthalmol. Vis. Sci.

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PURPOSE.To evaluate how aging alters 24-hour measurements of intraocular pressure (IOP) in the sitting and supine body positions. METHODS. Fifteen older volunteers with healthy eyes (ages, 53-71 years) were each housed for 1 day in a sleep laboratory. An 8-hour accustomed sleep period was assigned to each subject. Every 2 hours, measurements of IOP were taken in the sitting and supine positions. Sitting and supine patterns of 24-hour IOP were compared. Simulated 24-hour IOP rhythms in the same body position were determined using cosine fitting of individual 24-hour data. The average postural IOP effects during the diurnal/wake period and the nocturnal/sleep period were compared. Data from this group of older subjects were compared with previously collected data from 16 healthy younger subjects (ages, 18 -25 years) under the same experimental conditions. RESULTS. Within each age group, sitting and supine patterns of 24-hour IOP were similar and parallel. Compared to the younger subjects, the phase timing (simulated peak) of 24-hour IOP was significantly delayed for the older subjects in both body positions. The postural IOP effect for the older subjects was 4.7 Ϯ 0.8 and 4.8 Ϯ 0.8 mm Hg during the diurnal and nocturnal periods, respectively. These postural IOP effects were not significantly different from the postural effects in the younger subjects. CONCLUSIONS. Although aging can significantly delay the phase timing of the 24-hour IOP pattern toward the diurnal/awake period, it may not affect the postural IOP effect during the diurnal and the nocturnal periods. (Invest Ophthalmol Vis Sci. 2012;53:112-116) DOI:10.1167/iovs.11-8763 I ntraocular pressure (IOP) in the human eye is regulated by the rate of aqueous humor formation, the resistance of aqueous humor outflow, and the episcleral venous pressure. IOP varies throughout a 24-hour period due to changes in these physiologic parameters. In healthy younger and nonmyopic subjects, there is 24-hour variation of IOP with a peak value in most individuals occurring in the late nocturnal/sleep period in either sitting or supine body position, independent of posture.1,2 Postural IOP effects, the difference in IOP between the sitting and supine body positions, are not significantly different between the diurnal and nocturnal periods.1 However, an earlier study indicated that the 24-hour IOP variation in the aging population may be different from that in the younger subjects. 3Changes in 24-hour IOP measurements may occur because of age-related structural or functional changes, including alterations in hormonal and neural activities for the regulation of IOP. Circulating levels and timing of glucocorticoids and melatonin as well as the neuronal activities such as the baroreflex may affect the IOP pattern and its variation within a 24-hour period.4 -8 A reported age-related change is the postural IOP effect, 9,10 which is associated with the hydrostatic response in the episcleral venous pressure and the redistribution of body fluid including the choroidal vascular volume...

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“…This difference in height is thought to affect the episcleral venous pressure. [6][7][8][9] The increase of resistance in the aqueous out-flow is probably the cause for the IOP increase in the SUP. 10 The IOP measurement in the SUP is important in several situations, such as the establishment of a real circadian curve.…”

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confidence: 99%

IOP Variations in the Sitting and Supine Positions

Jorge

Marques

Lourenço

et al. 2010

Journal of Glaucoma

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Effect of Posture on Blood and Intraocular Pressures in Multiple System Atrophy, Pure Autonomic Failure, and Baroreflex Failure

Cited by 33 publications

References 18 publications

Posture-Induced Intraocular Pressure Changes in Eyes with Open-Angle Glaucoma, Primary Angle Closure with or without Glaucoma Medications, and Control Eyes

Posture-Induced Intraocular Pressure Changes in Eyes with Open-Angle Glaucoma, Primary Angle Closure with or without Glaucoma Medications, and Control Eyes

Effects of Aging on 24-Hour Intraocular Pressure Measurements in Sitting and Supine Body Positions

IOP Variations in the Sitting and Supine Positions

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