Dataset Information

Optic nerve head blood flow autoregulation during changes in arterial blood pressure in healthy young subjects.

ABSTRACT:

Aim

In the present study the response of optic nerve head blood flow to an increase in ocular perfusion pressure during isometric exercise was studied. Based on our previous studies we hypothesized that subjects with an abnormal blood flow response, defined as a decrease in blood flow of more than 10% during or after isometric exercise, could be identified.

Methods

A total of 40 healthy subjects were included in this study. Three periods of isometric exercise were scheduled, each consisting of 2 minutes of handgripping. Optic nerve head blood flow was measured continuously before, during and after handgripping using laser Doppler flowmetry. Blood pressure was measured non-invasively in one-minute intervals. Intraocular pressure was measured at the beginning and the end of the measurements and ocular perfusion pressure was calculated as 2/3*mean arterial pressure -intraocular pressure.

Results

Isometric exercise was associated with an increase in ocular perfusion pressure during all handgripping periods (p < 0.001). By contrast no change in optic nerve head blood flow was seen. However, in a subgroup of three subjects blood flow showed a consistent decrease of more than 10% during isometric exercise although their blood pressure values increased. In addition, three other subjects showed a consistent decline of blood flow of more than 10% during the recovery periods.

Conclusion

Our data confirm previous results indicating that optic nerve head blood flow is autoregulated during an increase in perfusion pressure. In addition, we observed a subgroup of 6 subjects (15%) that showed an abnormal response, which is in keeping with our previous data. The mechanisms underlying this abnormal response remain to be shown.

SUBMITTER: Boltz A

PROVIDER: S-EPMC3855769 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Optic nerve head blood flow autoregulation during changes in arterial blood pressure in healthy young subjects.

Boltz Agnes A Told Reinhard R Napora Katarzyna J KJ Palkovits Stefan S Werkmeister René M RM Schmidl Doreen D Popa-Cherecheanu Alina A Garhöfer Gerhard G Schmetterer Leopold L

PloS one 20131206 12

<h4>Aim</h4>In the present study the response of optic nerve head blood flow to an increase in ocular perfusion pressure during isometric exercise was studied. Based on our previous studies we hypothesized that subjects with an abnormal blood flow response, defined as a decrease in blood flow of more than 10% during or after isometric exercise, could be identified.<h4>Methods</h4>A total of 40 healthy subjects were included in this study. Three periods of isometric exercise were scheduled, each ...[more]

PMID: 24324774

Similar Datasets

Project description:Intraocular pressure (IOP) is an important risk factor for glaucoma, and the response of the ONH and surrounding tissues to elevated IOP are often investigated to better understand pathophysiology. In vivo structure including that of the optic nerve head (ONH) and surrounding tissue of the eye are often assessed using optical coherence tomography (OCT). With advances in OCT technology, both large vessels and capillaries can be imaged non-invasively (OCT Angiography). Because a significant portion of retinal thickness is comprised of vasculature, the purpose of the current study was to investigate OCT structural and vascular changes in healthy non-human primate eyes with systematic graded increases and decreases in IOP. Six healthy animals with no previous experimental intervention were used. The pressure in the anterior chamber was adjusted from 10?mmHg to 60?mmHg and back to 10?mmHg in 10?mmHg steps every 10?min. Using optical coherence tomography (OCT), retinal nerve fiber layer (RNFL) thickness, minimum rim width (MRW), Bruch's membrane opening (BMO) size and relative height, anterior lamina cribrosa surface (ALCS) depth, choroidal thickness, and angiography (OCTA) were quantified. With IOP challenge there were significant changes in all morphological measures quantified (p?<?0.01) other than BMO size (p?=?0.30) and RNFL thickness (p?=?0.29). Specifically, the position of the BMO was sensitive to both an increase and decease in IOP. The inner retinal capillary density gradually decreased with increasing IOP, reaching statistical significance when pressure exceeded 50?mmHg, but returned when IOP was reduced. The average choroidal thickness around the ONH decreased for elliptical annuli 500-1000??m and 1000-1500??m, from the BMO, with increasing IOP (p?<?0.01). For the 1000-1500??m annulus, choroid thickness did not return to baseline with IOP reduction. Similarly, the MRW decreased with increase in IOP, but with pressure reduction did not return, and at the final 10?mmHg time point was thinner than at baseline (p?<?0.01). The results from this experiment illustrate differences in ONH neural rim tissue, RNFL and vessel density changes with acute IOP challenge. Overall, vessel collapse could not completely account for changes in RNFL or ONH MRW thickness. The study supports the hypothesis neural rim compression may be an important part of IOP-induced damage.

Dataset Information

Optic nerve head blood flow autoregulation during changes in arterial blood pressure in healthy young subjects.

Aim

Methods

Results

Conclusion

Publications

Optic nerve head blood flow autoregulation during changes in arterial blood pressure in healthy young subjects.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure