Abstract
Purpose: :
To determine early changes in the local retinal function after laser photocoagulations (PCs) using multifocal electroretinograms (mfERGs).
Methods: :
mfERGs were recorded in 9 eyes in 7 patients with parafoveal telangioectasia, circinate exudate with diabetic retinopathy, or central serous chorioretinopathy (CSC). mfERGs were also repeatedly recorded at 1, 10, 60 minutes, 1 and 7 days after PCs (wavelength, 647 nm; diameter, 0.15–02 mm; duration, 0.2 seconds; power, 0.15–0.2 W, 4–22 shots). mfERGs from coagulated area and mfERGs from non–coagulated area were separated and analyzed.
Results: :
The peak time of mfERGs from coagulated area were delayed (> 1.7 ms) in 3 eyes at 1 minute and 6 eyes at 10 minutes after PCs. The delay was gradually expanded until 60 minutes after PCs up to 4.0 ms, then relatively unchanged at 1 and 7 days after PCs. The mfERGs in 3 eyes with CSC were stable and the mfERGs from non–coagulated area in all eyes were unchanged during the observation period.
Conclusions: :
1) reproducible mfERGs could be recorded even 1 minute after PCs as well as transpupillary thermotherapy (Shimada & Horiguchi 2005). 2) mfERGs from the coagulated retina noninvasively visualized functional changes in the local retina following PCs. 3) the delay in peak time in the coagulated retina gradually increased and reached a plateau until 60 minutes after PCs. 4) the subretinal fluid on the coagulated area in eyes with CSC probably prevents the local sensory retina from being thermal damaged by PCs.
Keywords: retina • laser • electroretinography: clinical