Retinal Temperature Determination Based on Photopic Porcine Electroretinogram

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Retinal Physiology

Background:

• Subthreshold retinal laser therapy (SLT) relies on controlled temperature elevation of the retinal pigment epithelium (RPE).
• Patient-specific variations in RPE pigmentation and choroidal perfusion cause inconsistent temperature increases during SLT.
• Precise temperature control is crucial for optimizing SLT's therapeutic benefits while minimizing risks.

Purpose of the Study:

• To develop and assess an electroretinography (ERG)-based method for real-time temperature estimation during SLT.
• To establish a model for controlling SLT temperature based on ERG response kinetics.
• To evaluate the feasibility of ERG-guided SLT for improved treatment outcomes.

Main Methods:

• Investigated temperature dependence of photopic ERG response kinetics ex vivo (pig retinas) and in vivo (anesthetized pigs).
• Developed a computational model for ERG-based temperature estimation.
• Assessed model feasibility for SLT control using simulations with varying laser exposure parameters.

Main Results:

• Photopic in vivo ERG signaling kinetics accelerated by 3.6–4.7%/°C, with ex vivo ERG showing a 5.0%/°C dependence (33–44°C).
• Simulations confirmed the method's suitability for steady-state temperature elevation control in SLT.
• Effective control was demonstrated for laser exposures > 30s and spot sizes > 3mm.

Conclusions:

• An ERG-based temperature estimation model can effectively control SLT parameters.
• This method is applicable to SLT treatments like transpupillary thermotherapy.
• The ERG-guided approach promises enhanced repeatability, safety, and efficacy in treating retinal disorders.