A Study Using Transorbital Alternating Current Stimulation for People With Glaucoma

This pilot study will test the preliminary efficacy and feasibility of an intervention protocol for one method of electric current stimulation, repetitive transorbital alternating current stimulation (rtACS), to treat visual impairment in people with glaucoma. We will evaluate a study protocol to use in future clinical trials to test the effectiveness of rtACS to ameliorate the progressive effects of vision loss both structurally and functionally in the eye, the visual pathway, and in regard to people's independence (i.e., functional ability). In this prospective, randomized controlled, double-masked pilot study, we will: 1) determine an effect of rtACS on ophthalmic structure and function (from retina to visual brain), 2) assess the methodology of procedures for assessment of people's functional ability and quality of life (QoL) to determine an effect of rtACS, and 3) assess the feasibility and implementation of the pilot study protocol for a larger multi-site, randomized controlled trial.

Participants will engage in baseline, intervention, post-intervention, and follow-up visits over the span of approximately 8 weeks. The expected outcomes for this project are that (1) rtACS activates viable but poorly or non-functional retinal ganglion cells to improve their structural and functional capabilities, (2) measures of retinal, optic nerve, and visual brain structures and function will correspond with improvement in visual function, and (3) changes in visual function following rtACS will be associated with improvements in participants' functional ability and QoL. rtACS has successfully been used in the rehabilitation of visual impairments in people with optic neuropathies; however, we do not know the clinical value of rtACS specifically for people with glaucoma, including the effect of rtACS on people's functional ability and QoL.

Eligibility Criteria:
Inclusion Criteria:

* Live in a community, residential setting (i.e., non-institutionalized, not homeless)
* Diagnosis of glaucoma (not type-specific, excluding traumatic glaucoma): Moderate defect or worse in both eyes but not total blindness
* Visual field defects present for at least 6 months
* Best-corrected visual acuity of 20/200 (1.0 logMAR) or better in at least one eye
* Commitment to comply with study procedures (2 week period of intervention sessions) with baseline, post-intervention, and follow-up visits

Exclusion Criteria:

* Other optic comorbidity than glaucoma
* End-stage organ disease or medical condition with subsequent vision loss (e.g., diabetes, stroke)
* Other diseases of the retina or cataracts responsible for worse than 20/70 best-corrected visual acuity
* Photosensitivity to flickering lights
* Intraocular Pressure (IOP) \> 27 mmHg at baseline

  \* Medically diagnosed memory disorder or Telephone Interview for Cognitive Status-modified (TICS-m) score ≤ 27
* Electric or electronic implants (e.g., cardiac pacemaker)
* Metallic artifacts/implants in head and/or torso
* Diagnosed epilepsy
* Epileptic seizure within the past 3 years of enrollment date
* Auto-immune disease, acute stage (e.g., rheumatoid arthritis)
* Metastatic disease
* Certain mental diseases/psychiatric conditions (e.g., schizophrenia) that would preclude reliable testing and participation
* Unstable medical conditions (e.g., diabetes, diabetes causing diabetic retinopathy)
* Claustrophobia (to limit functional neuroimaging)
* Received rtACS in the past