Parametric transfer function analysis and modeling of blood flow autoregulation in the optic nerve head

Area of Science:

• Ophthalmology
• Physiology
• Biomedical Engineering

Background:

• Optic nerve head (ONH) blood flow (BF) autoregulation is crucial for maintaining vision.
• Understanding the relationship between ocular perfusion pressure (OPP) and ONH BF is vital for diagnosing and treating optic neuropathies.

Purpose of the Study:

• To establish a parametric transfer function describing the relationship between OPP and ONH BF.
• To model the dynamic and static autoregulation of ONH BF within the lower OPP range.

Main Methods:

• A third-order parametric theoretical model was developed.
• Experimentally induced BF response to rapid intraocular pressure (IOP) increase in 6 rhesus monkeys was analyzed.
• Model data was fitted against actual experimental data.

Main Results:

• The developed third-order transfer function accurately described the ONH OPP-BF relationship.
• Both linear and nonlinear features of dynamic and static autoregulation were captured.
• Full BF autoregulation was observed when OPP was > 40 mmHg, with incomplete function below this threshold.

Conclusions:

• The proposed parametric transfer function effectively models ONH autoregulation within the studied OPP range.
• This model provides insights into the functional limits of BF autoregulation in the ONH.
• The model can be a valuable tool for investigating ONH autoregulation under various experimental conditions.