Towards Automatically Controlled Dosing for Selective Laser Trabeculoplasty.

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Laser Physics

Background:

• Selective laser trabeculoplasty (SLT) is a key treatment for open-angle glaucoma.
• Current SLT relies on visual cues (macrobubbles) for energy assessment, lacking immediate confirmation of therapeutic effect.
• Microbubbles, forming at lower energy levels, are hypothesized to indicate therapeutic benefit.

Purpose of the Study:

• To investigate the hypothesis that microbubbles, not macrobubbles, indicate therapeutic benefit in SLT.
• To develop and validate methods for real-time detection of microbubble formation during SLT.

Main Methods:

• Porcine trabecular meshwork was irradiated with a laser (1.7 μs pulse duration, 100 Hz repetition rate).
• Optical and optoacoustic methods were developed to detect microbubble nucleation in real-time.
• Algorithms were investigated for accurate detection of microbubble onset.

Main Results:

• Both developed methods successfully detected microbubble nucleation.
• The threshold radiant exposure for microbubble formation was determined to be 310 ± 137 mJ/cm².
• Combining both methods achieved a sensitivity and specificity of 0.96 for microbubble detection.

Conclusions:

• The presented methods can detect microbubbles, potentially indicating therapeutic benefit in SLT.
• Real-time detection of microbubbles could enable automated feedback control of laser energy during SLT.
• This automation may unburden clinicians from manual energy dosing, improving treatment consistency and physician workflow.