Optic Nerve Stimulation for Preventing Visual Deficits

Overseen By Ezequiel Goldschmidt, MD, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of California, San Francisco

Disqualifiers: Visual impairments, Prior cranial surgeries, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 2

20 Participants Needed

Trial Summary

What is the purpose of this trial?

Assessing the function of the optic nerve is paramount during various neurosurgical procedures. Effective optic nerve monitoring has remained elusive as Visual Evoked Potentials (the current existing tool) provides only diffuse and delayed assessment of nerve function. Here, the investigators propose a prospective study involving adult patients (aged 18 years and older) undergoing endonasal or open cranial approaches around the optic nerves, who will receive pre- and post-operative visual evaluations. During surgery, the optic nerve and chiasm will be stimulated, and the response will be recorded in both eyes and the occipital cortex via skin electrodes. The investigators aim to utilize anterograde optic nerve microstimulation to assess the nerve's integrity during open and endoscopic cranial approaches. Electrophysiological readings will be acquired, as is routine in the operating room, by our team of experts, and intraoperative findings will be correlated with post- surgical clinical outcomes. Our objective is to utilize existing technology in the operating room to safely and effectively monitor optic nerve function during surgery.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

What data supports the effectiveness of the treatment Optic Nerve Stimulation for preventing visual deficits?

Research shows that electrical stimulation, including optic nerve stimulation, can improve visual functions in patients with various vision disorders. For example, transcutaneous electrostimulation improved vision in 55.2% of neurosurgical patients with vision disorders, and transorbital alternating current stimulation enhanced visual field size and quality of life in patients with optic nerve damage. ^{1 2 3 4 5}

Is optic nerve stimulation generally safe for humans?

Research shows that optic nerve stimulation has been tested in humans, including a 68-year-old man with retinitis pigmentosa, using less invasive techniques than before. While the focus is on visual restoration, the studies suggest that the procedure can be performed safely with advancements in implantation techniques. ^{1 3 5 6 7}

How does Optic Nerve Stimulation differ from other treatments for preventing visual deficits?

Optic Nerve Stimulation is unique because it involves directly stimulating the optic nerve with electrical impulses to restore vision, unlike other treatments that may focus on different parts of the visual pathway or use non-invasive methods. This approach aims to bypass damaged areas and activate intact parts of the visual system, offering a novel way to potentially improve vision in patients with certain types of blindness. ^{1 5 6 8 9}

Research Team

Ezequiel Goldschmidt, MD, PhD

Principal Investigator

UCSF Department of Neurological Surgery

Eligibility Criteria

This trial is for adults over 18 who are undergoing surgery for skull base or pituitary tumors that may affect the optic nerve. Participants must be able to undergo pre- and post-operative visual evaluations.

Inclusion Criteria

I will undergo a surgery through my nose.

I have been diagnosed with a tumor in the brain region near the pituitary gland.

I do not have any lasting or temporary vision loss.

Exclusion Criteria

I have had brain surgery or radiation therapy on my head.

I am able to understand and consent to my treatment.

I have vision problems not caused by my cancer.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Surgery and Intraoperative Monitoring

Participants undergo endoscopic or open cranial approaches with optic nerve stimulation and monitoring

During surgery

1 visit (in-person)

Post-operative Evaluation

Participants receive post-operative visual evaluations to assess visual field and acuity

6 weeks

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after surgery

4 weeks

Treatment Details

Interventions

• Optic Nerve Stimulation

Trial Overview The study tests a new way to monitor the optic nerve during surgery by stimulating it and recording responses. This could provide real-time, accurate assessments of nerve function to prevent damage.

Participant Groups

Group I: Optic Nerve Stimulation Experimental Treatment 1 Intervention

The most significant procedure will be using an anterograde microstimulator and provoke stimulations to the optic nerve as the surgery proceeds. During surgery, the optic nerve and chiasm will be stimulated and the response recorded in both eyes and occipital cortex via skin electrodes. These responses will be monitored at all times by the neuromonitorig team who will inform if changes in neural responses change. The use of microstimulator has been proven safe in other surgical approaches.

Group II: No Intervention Active Control 1 Intervention

Patients receiving regular standard of care in endoscopic endonasal approaches within the same case series.

Who Is Running the Clinical Trial?

University of California, San Francisco

Lead Sponsor

Trials

2,636

Recruited

19,080,000+

Findings from Research

Noninvasive repetitive transorbital alternating current stimulation (rtACS) significantly improved detection ability in the visual field of patients with optic nerve damage, with a 41.1% increase compared to only 13.6% in the sham group, indicating its efficacy in vision restoration.

Patients receiving rtACS also reported greater improvements in vision-related quality of life, particularly in the 'general vision' subscale of the NEI-VFQ, suggesting that while visual field changes are important, other factors also influence overall quality of life related to vision.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Noninvasive transorbital alternating current stimulation improves subjective visual functioning and vision-related quality of life in optic neuropathy. Gall, C., Sgorzaly, S., Schmidt, S., et al.[2022]

Non-invasive stimulation techniques, such as transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (tDCS/tACS), have shown promise in modulating visual processing and restoring visual functions in patients with conditions like glaucoma and amblyopia, based on a review of their effects on both normal and damaged visual systems.

While these stimulation methods have demonstrated better responses than sham treatments in clinical studies, the variability in patient responses highlights the need for further research to understand their mechanisms of action and to personalize treatment protocols for improved efficacy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Vision modulation, plasticity and restoration using non-invasive brain stimulation - An IFCN-sponsored review. Sabel, BA., Thut, G., Haueisen, J., et al.[2021]

References

1. Japan pubmed.ncbi.nlm.nih.gov

Effect of transcorneal electrical stimulation in patients with nonarteritic ischemic optic neuropathy or traumatic optic neuropathy. [2022]

2. United States pubmed.ncbi.nlm.nih.gov

Noninvasive transorbital alternating current stimulation improves subjective visual functioning and vision-related quality of life in optic neuropathy. [2022]

3. United States pubmed.ncbi.nlm.nih.gov

Current research of C-Sight visual prosthesis for the blind. [2020]

4. Russia (Federation) pubmed.ncbi.nlm.nih.gov

[Transdermal electrostimulation of optic nerves in neurosurgical patients with vision disorders]. [2006]

5. United States pubmed.ncbi.nlm.nih.gov

Electrical devices for visual restoration. [2023]

6. United States pubmed.ncbi.nlm.nih.gov

Intraorbital implantation of a stimulating electrode for an optic nerve visual prosthesis. Case report. [2006]

7. England pubmed.ncbi.nlm.nih.gov

Electrical neurostimulation in glaucoma with progressive vision loss. [2022]

8. Netherlands pubmed.ncbi.nlm.nih.gov

Vision modulation, plasticity and restoration using non-invasive brain stimulation - An IFCN-sponsored review. [2021]

9. Italy pubmed.ncbi.nlm.nih.gov

Past, present, future: a review on visual prostheses. [2015]