In situ Monitoring of Laser Modification Process in Human Cataractous Lens and Porcine Cornea Using Coherence...

Area of Science:

• Biomedical Optics
• Laser-Tissue Interaction
• Ophthalmology

Background:

• Laser-based procedures are increasingly used for tissue modification and ablation in ophthalmology.
• Understanding the precise dynamics of these interactions is crucial for optimizing treatment outcomes and safety.
• Real-time monitoring of laser-tissue interactions can reveal critical parameters like swelling and crater formation.

Purpose of the Study:

• To demonstrate the utility of optical coherence tomography (OCT) as a diagnostic tool for monitoring laser-tissue interactions.
• To investigate pulse-to-pulse kinetics, preablation tissue swelling, crater formation, and thermally affected zone development during laser ablation.
• To apply OCT in situ for analyzing laser modification of biological tissues, specifically the human cataractous lens and porcine cornea.

Main Methods:

• Utilized in situ optical coherence tomography (OCT) to monitor laser-tissue interactions on a pulse-to-pulse basis.
• Applied OCT to study laser modification and ablation of human cataractous lenses (highly scattering) and porcine corneas (low scattering).
• Employed various laser wavelengths, including YAG:Er (2.94 μm), glass:Er (1.54 μm), YAG:Nd (1.32 μm and 1.44 μm), and Nd:YAP (0.216 μm).
• Combined OCT monitoring with probe beam shielding diagnostics for time-resolved observation of interaction dynamics.

Main Results:

• Demonstrated OCT's capability to provide convenient, real-time monitoring of laser-tissue interaction kinetics.
• Observed and characterized different modes of preablation tissue swelling, crater formation, and thermally affected zone development.
• Successfully applied OCT to both highly scattering (cataractous lens) and low-scattering (cornea) biological tissues.
• Correlated OCT findings with probe beam shielding data for comprehensive dynamic analysis.

Conclusions:

• Optical coherence tomography (OCT) is a valuable and convenient diagnostic tool for monitoring laser-tissue interactions in real-time.
• OCT enables detailed investigation of dynamic processes like swelling and crater formation during laser ablation.
• The technique is applicable to diverse biological tissues with varying optical properties, offering insights into laser modification mechanisms.