Intranasal Neurostimulation in Ameliorating Symptoms of Neuropathic Corneal Pain (INSTANT)

Assessing the Efficacy of Intranasal Neurostimulation in Ameliorating Symptoms of Neuropathic Corneal Pain

This study is a prospective, interventional, open-label, single arm, non-randomized trial treating 30 patients with peripheral or mixed neuropathic corneal pain at their baseline exam and following 45 days and 90 days of daily use with the TrueTear™ ITN device.

Study Overview

• Status: Terminated
• Conditions: Cornea
• Intervention / Treatment: Device: TrueTear™ intranasal neurostimulator (ITN)

Detailed Description

The investigators hypothesize that the stimulation through the ethmoidal nerve in the nasal cavity may have an inhibitory effect on the primary TG interneurons and block the ocular pain signaling to the brain.

The investigators propose a non-randomized, open-label, single arm pilot trial for treatment of neuropathic corneal pain (NCP) with ITN with the following specific aims:

Specific Aims:

1. To elucidate the efficacy of ITN in ameliorating pain among neuropathic corneal pain patients.
2. To elucidate the safety, efficacy, longevity of ITN in ameliorating pain among neuropathic corneal pain patients during a 90-day period with daily use.
3. To assess quality of life changes by treating neuropathic corneal pain with ITN during a 90-day period with daily use.

• Study Type: Interventional
• Enrollment (Actual): 21
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02111
      • Tufts Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 22 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age >22
2. Ability to consent to study.
3. Symptoms of neuropathic corneal pain for at least 3 months, such as burning, stinging, light sensitivity, discomfort or pain.
4. Positive in vivo confocal microscopy (IVCM) findings for NCP such as presence of microneuromas and decreased nerve density.
5. Fifty percent or more relief of pain or discomfort after instillation of Proparacaine eye drops as measured by the Visual Analogue Scale (VAS).

Exclusion Criteria:

1. Clinically significant acute ocular surface diseases, such as active infectious keratitis or recent ocular surgery in the past 3 months.
2. Chronic or recurrent epistaxis, coagulation disorders.
3. Nasal or sinus surgery or significant trauma to the nose.
4. Severe nasal airway obstruction or vascularized nasal polyps.
5. Cardiac demand pacemaker, implanted defibrillator, or other implanted electronic device in the head or neck.
6. Chronic or recurrent nosebleeds
7. Bleeding disorder
8. Known hypersensitivity (allergy) to the hydrogel material
9. Disabling arthritis, neuropathy, or limited motor coordination affecting self-handling of the device.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: TrueTear™ intranasal neurostimulator (ITN)	Device: TrueTear™ intranasal neurostimulator (ITN); TrueTear™ intranasal neurostimulator (ITN)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change to Overall Pain by the Visual Analogue Scale (VAS) After Intranasal Neurostimulator (ITN) Stimulation at Baseline	The Visual Analogue Scale (VAS) is a 10 cm line, with one end labeled 'no pain' (which is equivalent to a score of 0 on the numerical scale) and the other end labeled 'worst pain imaginable' (which is equivalent to a score of 10 on the numerical scale). The patient is asked to mark the scale according to the intensity of their eye pain, and the examiner measures the distance in centimeters from the 'no pain' end of the line to score the VAS. The level of discomfort/pain before and after ITN was assessed using the VAS questionnaire (0-10). The changes in overall eye pain after ITN were recorded. Higher scores on the VAS indicate more intense pain and a worse outcome.	immediately before and after ITN on Day 1 (baseline)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change to Overall Pain by the Visual Analogue Scale (VAS) After Daily Intranasal Neurostimulator (ITN) Stimulation Over 45-day Period	The VAS is a 10 cm line, with one end labeled 'no pain' (which is equivalent to a score of 0 on the numerical scale) and the other end labeled 'worst pain imaginable' (which is equivalent to a score of 10 on the numerical scale). The patient is asked to mark the scale according to the intensity of their eye pain, and the examiner measures the distance in centimeters or millimeters from the 'no pain' end of the line to score the VAS. The level of discomfort/pain before and after ITN was assessed using the VAS questionnaire (0-10). The changes in overall eye pain after ITN were recorded. Higher scores on the VAS indicate more intense pain and a worse outcome.	immediately before and after ITN on Day 45
Change to Overall Pain by the Visual Analogue Scale (VAS) After Daily Intranasal Neurostimulator (ITN) Stimulation Over 90-day Period	The Visual Analogue Scale (VAS) is a 10 cm line, with one end labeled 'no pain' (which is equivalent to a score of 0 on the numerical scale) and the other end labeled 'worst pain imaginable' (which is equivalent to a score of 10 on the numerical scale). The patient is asked to mark the scale according to the intensity of their eye pain, and the examiner measures the distance in centimeters or millimeters from the 'no pain' end of the line to score the VAS. The level of discomfort/pain before and after ITN was assessed using the VAS questionnaire (0-10). The changes in overall eye pain after ITN were recorded. Higher scores on the VAS indicate more intense pain and a worse outcome.	immediately before and after ITN on Day 90
Quality of Life as Measured With OPAS at Baseline	The Ocular Pain Assessment Survey (OPAS) is a multidimensional questionnaire that assesses eye pain, non-eye pain, quality of life (QoL), aggravating factors, and associated factors. The QoL section evaluates seven dimensions, with the first six graded using numerical rating scales (0-10) and the final question expressed as a percentage (0-100). Higher scores indicate severe pain and lower QoL in the QoL section of OPAS questionnaire. Ranges: 0-10 for the "Reading and/or computer use", "Driving and/or watching TV", "General Activity", "Mood", "Sleep", "Enjoying Life/ Relationship. "Time spent thinking about pain" dimensions and 0-100. Higher scores indicate worse QoL.	Day 1 (Baseline)
Quality of Life as Measured Daily With OPAS at 45 Days	The Ocular Pain Assessment Survey (OPAS) is a multidimensional questionnaire that assesses eye pain, non-eye pain, quality of life (QoL), aggravating factors, and associated factors. The QoL section evaluates seven dimensions, with the first six graded using numerical rating scales (0-10) and the final question expressed as a percentage (0-100). Higher scores indicate severe pain and lower QoL in the QoL section of OPAS questionnaire. Ranges: 0-10 for the "Reading and/or computer use", "Driving and/or watching TV", "General Activity", "Mood", "Sleep", "Enjoying Life/ Relationship. "Time spent thinking about pain" dimensions and 0-100. Higher scores indicate worse QoL.	45 days
Quality of Life as Measured Daily With OPAS at 90 Days	The Ocular Pain Assessment Survey (OPAS) is a multidimensional questionnaire that assesses eye pain, non-eye pain, quality of life (QoL), aggravating factors, and associated factors. The QoL section evaluates seven dimensions, with the first six graded using numerical rating scales (0-10) and the final question expressed as a percentage (0-100). Higher scores indicate severe pain and lower QoL in the QoL section of OPAS questionnaire. Ranges: 0-10 for the "Reading and/or computer use", "Driving and/or watching TV", "General Activity", "Mood", "Sleep", "Enjoying Life/ Relationship. "Time spent thinking about pain" dimensions and 0-100. Higher scores indicate worse QoL.	90 days
Overall Change in Quality of Life as Measured Daily With OPAS	The Ocular Pain Assessment Survey (OPAS) is a multidimensional questionnaire that assesses eye pain, non-eye pain, quality of life (QoL), aggravating factors, and associated factors. The QoL section evaluates seven dimensions, with the first six graded using numerical rating scales (0-10) and the final question expressed as a percentage (0-100). Higher scores indicate severe pain and lower QoL in the QoL section of OPAS questionnaire. Percentage changes in the scores between baseline vs 45-day visit and baseline vs 90-day visit after daily intranasal neurostimulation are given below.	Baseline vs day 45 visit and Baseline vs day 90 visit
Percent Change From Pain Level Dimension Questions of the Ocular Pain Assessment Survey (OPAS)	The Ocular Pain Assessment Survey (OPAS) is a multidimensional questionnaire that assesses eye pain, non-eye pain, quality of life (QoL), aggravating factors, and associated factors. Eye pain intensity was assessed using a numerical scale (0-10) for the most, least, and average pain in the past 24 hours and 2 weeks. Higher scores indicate severe pain of OPAS questionnaire. The percent changes in pain intensity between baseline vs 45-day and baseline vs 90-day are provided below.	Baseline vs day 45 visit and Baseline vs day 90 visit
Overall Percent Change on Impact of Dry Eye in Everyday Life (IDEEL)	IDEEL Quality of Life Questionnaire is a 27-item questionnaire, designed specifically for DED and is divided into three parts. It assesses the quality of life in three aspects of life for the previous 2 weeks: daily activities, work and feelings. The quality of life is assessed on a scale of 0-5, with zero being inability to do the activity. The score is calculated between 0 - 100 with higher scores indicating a better quality of life. Percentage change in IDEEL questionnaire subheading between baseline and day 45 and baseline and day 90 were given below.	Baseline vs day 45 visit and Baseline vs day 90 visit
Change in the Intraocular Pressure (IOP) Measured in Each Visit.	Intraocular pressure will be measured by an applanation tonometer used on slit lamp (Goldmann) in mmHg. Change in IOP values between baseline and 90-day is provided below. A healthy eye pressure is between 10 and 21 millimeters of mercury. The differences in intraocular pressure between the baseline and day 45 visits, as well as between the baseline and day 90 visits, are presented below.	Baseline vs day 45 visit and Baseline vs day 90 visit
Number of Participants With Adverse Events (Safety)	For safety analyses during the study, patient-reported adverse events that developed after intranasal neurostimulation were recorded.	90 days
Number of Participants With Adverse Events (Tolerability)	Tolerability of Intranasal Neurostimulator (ITN) was evaluated by using Ocular Tolerability and Compliance Questionnaire. It assesses symptoms of discomfort in each eye after ITN use.	90 days
Reduction on Other Concomitant Pain Therapy	After daily intranasal neurostimulation, the change in the number of systemic pain medication between baseline vs 45-day visit and Baseline vs 90-day visit was evaluated.	Baseline vs 45 Day Visit and baseline vs 90 Day Visit

Collaborators and Investigators

• Sponsor: Tufts Medical Center
• Investigators: Principal Investigator: Pedram Hamrah, MD, Tufts Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): September 28, 2018
• Primary Completion (Actual): September 9, 2022
• Study Completion (Actual): September 9, 2023

Study Registration Dates

• First Submitted: September 12, 2018
• First Submitted That Met QC Criteria: September 14, 2018
• First Posted (Actual): September 18, 2018

Study Record Updates

• Last Update Posted (Actual): August 24, 2025
• Last Update Submitted That Met QC Criteria: August 6, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Keywords: Intranasal Neurostimulation
• Other Study ID Numbers: 12978

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No