Mapping Pulsatile Optic Nerve Head Deformation Using OCT.

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Medical Imaging

Background:

• The optic nerve head (ONH) is crucial for vision, and its deformation can indicate disease.
• Current methods for assessing ONH health are limited in their ability to quantitatively measure dynamic changes.
• Cardiac contractions cause pulsatile deformation in the ONH, which may be a sensitive indicator of ocular health.

Purpose of the Study:

• To develop and validate a noninvasive technique for quantitatively assessing pulsatile deformation of the optic nerve head (ONH).
• To evaluate the feasibility of using this technique in a clinical setting for diagnosing optic nerve diseases.

Main Methods:

• A novel noninvasive technique combining high-frequency Optical Coherence Tomography (OCT) imaging and image processing algorithms was developed.
• The method was validated numerically and experimentally for sensitivity and robustness to noise.
• Deformation measurements were performed on healthy and myopic subjects in primary position and abduction, with head rotation measured by goniometry.

Main Results:

• The computational pipeline demonstrated good reproducibility, with an intraclass correlation coefficient of 0.99.
• The method showed acceptable accuracy with artificial deformations and varying noise levels.
• Median pulsatile displacement of the ONH in healthy subjects (<25 mm axial length) was 7.8 ± 1.3 μm in primary position and 8.9 ± 1.2 μm in abduction (P ≤ 0.005).

Conclusions:

• The developed noninvasive technique accurately maps pulsatile deformation of the optic nerve.
• This method has strong potential as a novel biomarker for the diagnosis and progression of optic nerve diseases.
• The technique's high reproducibility and ability to detect physiological changes support its translation to clinical practice.