Pupillary Dilation During Post-Auricular Vagal Nerve Stimulation

Inclusion Criteria: Patients undergoing cochlear implantation: * will be undergoing surgery for a cochlear implant * is over the age of 18 * is willing to participate in the study Patients undergoing vagal nerve stimulator implantation: * will be undergoing implantable vagal nerve stimulation * is over the age of 18 * is willing to participate in the study Exclusion Criteria: Patients undergoing cochlear implantation: * is under the age of 18 * has history of prior ear surgery, congenital ear malformation, or cochlear implantation * pregnant or breastfeeding patients cannot undergo the standard-of-care implantation procedures required for participation in the study. * medical comorbidities resulting in exclusion are guided by the AANS exclusion criteria for VNS and include the following: * One vagus nerve * Receiving other concurrent forms of brain stimulation * Heart arrhythmias or other heart abnormalities * Dysautonomias (abnormal functioning of the autonomic nervous system) * Lung diseases or disorders (shortness of breath, asthma, etc.) * Ulcers (gastric, duodenal, etc.) * Vasovagal syncope (fainting) * Pre-existing hoarseness Patients undergoing vagal nerve stimulator implantation: * is under the age of 18 * has history of prior ear surgery, congenital ear malformation, or cochlear implantation * pregnant or breastfeeding * medical comorbidities resulting in exclusion are guided by the AANS exclusion criteria for VNS and include the following: * One vagus nerve * Receiving other concurrent forms of brain stimulation * Heart arrhythmias or other heart abnormalities * Dysautonomias (abnormal functioning of the autonomic nervous system) * Lung diseases or disorders (shortness of breath, asthma, etc.) * Ulcers (gastric, duodenal, etc.) * Vasovagal syncope (fainting) * Pre-existing hoarseness