In Vivo Measurement Of Retinal Neurovascular Changes With Transcorneal Electrical Stimulation Using Optical Coherence Tomography

Transcorneal electrical stimulation(TES),which as a noninvasive approach of retinal electrical stimulation,can activate releasing of neurotrophic factors and regenerate injured retinal neurons,has become a potential therapeutic method for retinal diseases.However,the neurovascular responses of TES and the mechanism of TES on the regeneration of retinal neurons has not been completely determined.Responses can’t be recorded by ERG because of the artifact by TES,and responses of different retinal layers can’t be acquired by fundus camera.To solve the problem,our study detected the retinal neurovascular responses simultaneously by neurovascular imaging based on optical coherence tomography(OCT)OCT is a noninvasive high-resolution imaging technique that capable of capturing three-dimension pictures of highly scattering biological tissue.In the experiments,the cat retinae were imaged by our custom-designed spectral-domain OCT.We detected the neurovascular responses under TES of different intensities.The results show that a significant increase of both positive and negative Intrinsic Optical Signals(IOS)in each layer.The greatest changes were found in the subretina and the smallest changes were found in the outer retina.By excluding imaging quality and retinal image dislocation,we concluded the scattering change were related to neural activities in the retina,while the changes of average blood flow before,during and 7 seconds after TES were not obvious,althoughthe blood flow was increased under flicker stimulation.The results in our study provide experimental data of neurovascular alterations under TES,which will benefit the study of the therapeutic mechanism of TES and provide a new method in clinical treatment and technology of detecting neurovascular responses under retina stimulation.