Abstract
Purpose:
To evaluate the alteration of retinal function using multifocal electroretinogram (mfERG) over time after microsecond-pulsed selective retinal therapy (SRT) with automatic real-time reflectometry, and to compare the retinal function after both laser treatment modalities of continuous wave laser photocoagulation (CWPC) and SRT.
Methods:
SRT and CWPC were applied with 10x10 shots and 1/2 burn-width on the retina at 2 disc diameters inferiorly from optic nerve head, which regarded as visual streak, on right and left eyes of the 20 healthy Chinchilla Bustard rabbits, respectively. MfERG was performed before and at day 1, 7 and 30 after both laser treatments. The mean amplitudes and implicit times of N1, P1, N2 from laser-treated hexagon areas were compared among each period. Additionally, fundus color photography, optical coherence tomography (OCT) and fundus fluorescein angiography (FFA) were also carried out. Chorioretinal sections including optic nerve head were obtained at each examination period to observe the anatomical and morphologic changes after both laser treatments.
Results:
The mean N1 amplitudes from CWPC lesion were decreased significantly compared to baseline at day 30 (p<0.001); on the other hand, those from SRT lesion showed no difference from baseline (p=0.230). In addition, the mean P1 amplitudes from CWPC were significantly declined from baseline at day 7 and 30 (p<0.001, p<0.001, respectively), while those from SRT were sustained for 30 days after treatment. However, the mean implicit times of N1, P1, N2 and the mean amplitudes of P2 from SRT and CWPC lesions were not changed significantly in comparison with baseline for 30 days. OCT and chorioretinal section findings also revealed the structural preservation on SRT lesion compared to CWPC lesion with atrophic change on whole retinal layer.
Conclusions:
These results might suggest that SRT preserved retinal function as well as anatomical structure for 1 month after treatment.
Keywords: 578 laser •
688 retina