Real-Time Temperature-Controlled Retinal Laser Irradiation in Rabbits

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Laser Medicine

Background:

• Subdamaging thermal laser therapy shows promise for retinal disease regeneration.
• Validated dosimetry is currently lacking for this therapeutic approach.
• Optoacoustic temperature monitoring and control could address this dosimetry gap.

Purpose of the Study:

• To investigate the first in vivo application of real-time optoacoustic temperature determination and control for thermal retinal laser therapy.
• To establish validated dosimetry for subdamaging thermal laser treatments.

Main Methods:

• A control module was integrated with a laser source and slit lamp for real-time temperature monitoring and power adjustment.
• Chinchilla rabbits underwent irradiations with target temperatures ranging from 45°C to 69°C.
• Optoacoustic feedback controlled laser power to maintain a constant retinal temperature rise.

Main Results:

• The system achieved precise temperature control, with a mean difference of -0.04°C ± 0.98°C between measured and target temperatures.
• Tissue effect correlated more strongly with temperature than laser power, indicating superior control.
• Established visibility thresholds for funduscopic (58.6°C), fluorescein angiography (57.7°C), and OCT (57.0°C) imaging.

Conclusions:

• Temperature-guided laser irradiations reliably controlled tissue effects better than power-controlled methods.
• This approach enhances the accuracy, safety, and reproducibility of thermal stimulating laser therapy.
• The study serves as a crucial link between preclinical research and clinical application.