Changes in multifocal electroretinograms induced by transpupillary thermotherapy

Area of Science:

• Ophthalmology
• Retinal Physiology
• Medical Technology

Background:

• Subfoveal choroidal neovascularization (CNV) is a significant cause of vision loss.
• Transpupillary thermotherapy (TTT) is a treatment modality for CNV, but its precise effects on retinal function require detailed evaluation.

Purpose of the Study:

• To assess retinal function following transpupillary thermotherapy (TTT) for subfoveal choroidal neovascularization (CNV).
• To utilize multifocal electroretinograms (mfERGs) as a tool to monitor functional changes in the retina post-TTT.

Main Methods:

• mfERGs were recorded in 9 patients before and at multiple time points after TTT (810 nm wavelength).
• Recordings were taken within the first hour, at 24 hours, and 1 week post-TTT.
• Analysis focused on mfERG responses from both the laser-irradiated central area and surrounding non-irradiated areas.

Main Results:

• A significant reduction in mfERG amplitude was observed in the irradiated area at 1 minute post-TTT, followed by rapid recovery.
• Peak mfERG response time was delayed at 15 minutes, recovered by 60 minutes, and showed a secondary delay at 24 hours and 1 week.
• mfERG responses in non-irradiated areas remained stable throughout the study period.

Conclusions:

• TTT causes immediate but transient amplitude reduction in the central retina, likely due to thermal effects.
• Delayed mfERG peak times suggest secondary physiological responses to TTT, possibly involving cellular and vascular changes.
• mfERGs are a valuable method for real-time assessment of retinal functional changes after TTT, aiding in treatment evaluation.