Purpose: To determine whether transcorneal electrical stimulation (TES) has neuroprotective effects on photoreceptors and preserves retinal function in Royal College of Surgeons (RCS) rats.
Methods: Three-week-old RCS rats received TES through a contact lens electrode on the left eye weekly for 2 to 6 weeks. The right eyes received sham stimulation on the same days. Electroretinograms (ERGs) were recorded from the rats at 3 weeks (before TES), and at 5, 7, and 9 weeks of age. After the ERG recordings, the rats were killed for morphologic analyses of the retina.
Results: Morphologic analyses showed that the mean thickness of the outer nuclear layer (ONL) at each time point was significantly thicker in eyes treated with TES of 100 muA than in eyes with sham stimulation (TES 100 muA versus sham: 5, 7, and 9 weeks of age; P < 0.001). ERG studies showed that TES also significantly preserved retinal function up to 7 weeks of age, but did not preserve retinal function at 9 weeks of age.
Conclusions: TES prolongs the survival of photoreceptors and delays the decrease of retinal function in RCS rats. Although further investigations are necessary before using TES on patients, these findings indicate that TES may be a therapeutic treatment for some patients with diseases of the photoreceptors such as retinitis pigmentosa.