iStent insertion orientation and impact on trabecular meshwork motion resolved by optical coherence tomography...

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Medical Imaging

Background:

• The iStent is a key device for glaucoma treatment, creating a pathway for aqueous humor drainage.
• Accurate assessment of iStent implantation is crucial for patient outcomes.
• Current assessment methods for iStent surgery provide limited information.

Purpose of the Study:

• To develop novel assessment strategies for iStent implantation using optical coherence tomography (OCT).
• To evaluate the precise position and orientation of implanted iStents.
• To measure the biomechanical impact of iStents on the eye's fluid outflow system.

Main Methods:

• Utilized three-dimensional (3D) OCT structural imaging to visualize iStents in a glaucoma patient.
• Developed a semi-automated algorithm for iStent segmentation and measurement of position and orientation.
• Employed phase-sensitive OCT (PhS-OCT) to quantify biomechanical effects via cumulative displacement (CDisp) of trabecular meshwork motion.

Main Results:

• 3D OCT imaging precisely determined iStent position and orientation, showing significant variability.
• PhS-OCT revealed substantially increased CDisp in areas between iStents compared to distant regions.
• The imaging successfully characterized iStent placement and biomechanical alterations.

Conclusions:

• The proposed OCT-based structural imaging enhances characterization of iStent placement.
• Findings indicate challenges in achieving precise iStent insertion control.
• PhS-OCT imaging highlights potential biomechanical alterations caused by iStents, suggesting its clinical utility.