Abstract
Purpose: :
To investigate whether transcorneal electrical stimulation (TES) using a gold-ring contact lens electrode has effects on retinal function recovery in rats after strong light exposure.
Methods: :
Eight Sprague-Dawley rats (age 4 weeks, weight 80-100g) were dark adapted for >12 hrs before 6 hours intense light exposure (20000 lux). Extended ISCEV protocol electroretinograms (ERGs) were recorded one and two weeks after light exposure. Animals were assigned into two groups: control (n=5) and TES (n=3). TES was applied once via a custom made contact lens electrode with a gold ring on the right eye, immediately before 6 hours light exposure. A neuro-stimulator (TWISTER) was used with the following settings: 1 ms-biphasic current pulses; 30 min duration; frequency 20 Hz; current 0.1 mA.
Results: :
After two weeks dark adapted ERG values of a saturating rod flash (3 cd*s/m²) differed significantly in the right eyes of the two groups (control vs. TES; mean±SEM): a-wave amplitude (µV): 77.02±24.64 vs. 149.66±17.00; a-wave implicit time (ms): 12.00±3.05 vs. 16.33±0.33; b-wave amplitude (µV): 273.90±75.47 vs. 598.59±75.29; b-wave implicit time (ms): 50.00±8.07 vs. 73.00±1.53; oscillatory potentials (µV x ms): 575.88±156.67 vs. 1184.99±154.80. Values of a Naka-Rushton fit also differed significantly: Vmax (µV): 327.11±28.33 vs. 565.86±65.31; k (log cd*s/m²): -2.86±0.09 vs. -2.57±0.00. There was no statistically significant difference in a-wave, b-wave or OP in the left eyes of the two groups after scotopic and photopic ERG measurement.
Conclusions: :
Our data show that transcorneal electrical stimulation improves retinal recovery after strong light exposure, which indicates a potential neuroprotective effect, improving the tolerance of retinal function to light damage.
Keywords: retina • neuroprotection • electrophysiology: non-clinical