Intraocular pressure, blood pressure, and retinal blood flow autoregulation

A mathematical model to clarify their relationship and clinical relevance

Giovanna Guidoboni, Alon Harris, Simone Cassani, Julia Arciero, Brent Siesky, Annahita Amireskandari, Leslie Tobe, Patrick Egan, Ingrida Januleviciene, Joshua Park

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

PURPOSE. This study investigates the relationship between intraocular pressure (IOP) and retinal hemodynamics and predicts how arterial blood pressure (BP) and blood flow autoregulation (AR) influence this relationship. METHODS. A mathematical model is developed to simulate blood flow in the central retinal vessels and retinal microvasculature as current flowing through a network of resistances and capacitances. Variable resistances describe active and passive diameter changes due to AR and IOP. The model is validated by using clinically measured values of retinal blood flow and velocity. The model simulations for six theoretical patients with high, normal, and low BP (HBP-, NBP-, LBP-) and functional or absent AR (-wAR, -woAR) are compared with clinical data. RESULTS. The model predicts that NBPwAR and HBPwAR patients can regulate retinal blood flow (RBF) as IOP varies between 15 and 23 mm Hg and between 23 and 29 mm Hg, respectively, whereas LBPwAR patients do not adequately regulate blood flow if IOP is 15 mm Hg or higher. Hemodynamic alterations would be noticeable only if IOP changes occur outside of the regulating range, which, most importantly, depend on BP. The model predictions are consistent with clinical data for IOP reduction via surgery and medications and for cases of induced IOP elevation. CONCLUSIONS. The theoretical model results suggest that the ability of IOP to induce noticeable changes in retinal hemodynamics depends on the levels of BP and AR of the individual. These predictions might help to explain the inconsistencies found in the clinical literature concerning the relationship between IOP and retinal hemodynamics.

Original languageEnglish
Pages (from-to)4105-4118
Number of pages14
JournalInvestigative Ophthalmology and Visual Science
Volume55
Issue number7
DOIs
StatePublished - May 29 2014

Fingerprint

Intraocular Pressure
Homeostasis
Theoretical Models
Blood Pressure
Hemodynamics
Retinal Vessels
Blood Flow Velocity
Microvessels
Hypotension
Arterial Pressure
Hypertension

Keywords

  • Autoregulation
  • Blood flow
  • Intraocular pressure
  • Mathematical model
  • Retina

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

Intraocular pressure, blood pressure, and retinal blood flow autoregulation : A mathematical model to clarify their relationship and clinical relevance. / Guidoboni, Giovanna; Harris, Alon; Cassani, Simone; Arciero, Julia; Siesky, Brent; Amireskandari, Annahita; Tobe, Leslie; Egan, Patrick; Januleviciene, Ingrida; Park, Joshua.

In: Investigative Ophthalmology and Visual Science, Vol. 55, No. 7, 29.05.2014, p. 4105-4118.

Research output: Contribution to journalArticle

Guidoboni, Giovanna ; Harris, Alon ; Cassani, Simone ; Arciero, Julia ; Siesky, Brent ; Amireskandari, Annahita ; Tobe, Leslie ; Egan, Patrick ; Januleviciene, Ingrida ; Park, Joshua. / Intraocular pressure, blood pressure, and retinal blood flow autoregulation : A mathematical model to clarify their relationship and clinical relevance. In: Investigative Ophthalmology and Visual Science. 2014 ; Vol. 55, No. 7. pp. 4105-4118.
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N2 - PURPOSE. This study investigates the relationship between intraocular pressure (IOP) and retinal hemodynamics and predicts how arterial blood pressure (BP) and blood flow autoregulation (AR) influence this relationship. METHODS. A mathematical model is developed to simulate blood flow in the central retinal vessels and retinal microvasculature as current flowing through a network of resistances and capacitances. Variable resistances describe active and passive diameter changes due to AR and IOP. The model is validated by using clinically measured values of retinal blood flow and velocity. The model simulations for six theoretical patients with high, normal, and low BP (HBP-, NBP-, LBP-) and functional or absent AR (-wAR, -woAR) are compared with clinical data. RESULTS. The model predicts that NBPwAR and HBPwAR patients can regulate retinal blood flow (RBF) as IOP varies between 15 and 23 mm Hg and between 23 and 29 mm Hg, respectively, whereas LBPwAR patients do not adequately regulate blood flow if IOP is 15 mm Hg or higher. Hemodynamic alterations would be noticeable only if IOP changes occur outside of the regulating range, which, most importantly, depend on BP. The model predictions are consistent with clinical data for IOP reduction via surgery and medications and for cases of induced IOP elevation. CONCLUSIONS. The theoretical model results suggest that the ability of IOP to induce noticeable changes in retinal hemodynamics depends on the levels of BP and AR of the individual. These predictions might help to explain the inconsistencies found in the clinical literature concerning the relationship between IOP and retinal hemodynamics.

AB - PURPOSE. This study investigates the relationship between intraocular pressure (IOP) and retinal hemodynamics and predicts how arterial blood pressure (BP) and blood flow autoregulation (AR) influence this relationship. METHODS. A mathematical model is developed to simulate blood flow in the central retinal vessels and retinal microvasculature as current flowing through a network of resistances and capacitances. Variable resistances describe active and passive diameter changes due to AR and IOP. The model is validated by using clinically measured values of retinal blood flow and velocity. The model simulations for six theoretical patients with high, normal, and low BP (HBP-, NBP-, LBP-) and functional or absent AR (-wAR, -woAR) are compared with clinical data. RESULTS. The model predicts that NBPwAR and HBPwAR patients can regulate retinal blood flow (RBF) as IOP varies between 15 and 23 mm Hg and between 23 and 29 mm Hg, respectively, whereas LBPwAR patients do not adequately regulate blood flow if IOP is 15 mm Hg or higher. Hemodynamic alterations would be noticeable only if IOP changes occur outside of the regulating range, which, most importantly, depend on BP. The model predictions are consistent with clinical data for IOP reduction via surgery and medications and for cases of induced IOP elevation. CONCLUSIONS. The theoretical model results suggest that the ability of IOP to induce noticeable changes in retinal hemodynamics depends on the levels of BP and AR of the individual. These predictions might help to explain the inconsistencies found in the clinical literature concerning the relationship between IOP and retinal hemodynamics.

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