Abstract
Purpose :
Photobiomodulation (PBM), is a non-invasive light therapy with wavelength between 630-1000nm. It has been found to exhibit beneficial effects in a wide range of neuronal and vascular diseases. This study aims to test whether PBM would limit secondary degeneration of neurons and restore the retinal function in glaucoma using a retinal ischemia-reperfusion injury rat model induced by acute intraocular pressure (IOP) elevation.
Methods :
8-9 week-old male albino Lewis rats were used. Acute IOP elevation of the right eye was induced by elevating an infusion bottle to 170cmH2O for 60 minutes. Rats were then assigned randomly to treatment group or non-treatment group. In the treatment group, animals received 4 minutes of daily 670 nm PBM from an LED source for 7 consecutive days. The non-treatment group received no PBM. On the 8th day, dark adapted ERG response was recorded. The rats were then sacrificed for retinal ganglion cell (RGC) counting. T test was used to compare the RGC count and ERG amplitude between the two groups. SPSS was used to analyze data (v23). A p-value of <0.05 is considered significant.
Results :
The PBM treatment group showed an improvement in photopic a-wave (9.61uV) and b-waves (20.68uV), compared to non-treatment group (a- wave: 7.47uV; b-wave: 16.39uV) (p<0.05). Scotopic (a- and b-waves) responses were not found significantly improved by PBM treatment. RGC loss in PBM treated retinas was partially limited (p>0.05) (Image 1).
Conclusions :
PBM treatment results in improvement in photopic response but not scotopic response. Treatment group shows a higher RGC count. However statistical significance is not reached.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.