Optic neuritis (ON) is an acute inflammatory, demyelinating attack of the optic nerve that triggers neurodegeneration in the entire visual pathway; translating into visual dysfunction. Currently, no neuroprotective therapy with satisfying evidence can be offered to patients. Repetitive transorbital alternating current stimulation (rtACS) is a methodology applied to electrically stimulate the retina and the optic nerve and is considered having neuroprotective- and restorative potential. The goal of this pilot study is to assess safety, tolerability and preliminary efficacy of rtACS as a treatment to improve visual functional as well as structural retinal outcomes in patients with a first-ever episode of autoimmune acute ON.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
2
For the active-rtACS treatment arm, a CE-certificated proprietary class IIa medical device will be used to apply transorbital symmetrical rectangular current pulses in bursts (NextWave® 1.1 system; EBS Technologies GmbH, Germany). The stimulation protocol will be patient-individualized, with a stimulation current strength of 125% of the phosphene threshold recorded during 5Hz stimulation and stimulation frequencies between the individual's EEG alpha frequency and their flicker fusion frequency.
For the sham-rtACS treatment arm, exactly the same medical device, setup, time schedule, etc. will be used as for the patients of the active-rtACS arm. However, sham-treated patients will receive no actual current stimulation during the therapy sessions.
Department of Neurology and Department of Ophthalmology, University Hospital Zurich
Zurich, Switzerland
The primary functional outcome measure will be low-contrast visual acuity [LogMAR] at 16 weeks (3 month follow-up) in ON eyes.
Time frame: 3 month follow-up (16 weeks after recruitment, i.e. 3 months after the last treatment day)
The primary structural outcome measure will be the mean change in macular ganglion cell and inner plexiform layer thickness [µm] of the affected ON eye at 16 weeks in comparison to baseline of the unaffected contralateral NON eye (pre-treatment).
Time frame: Baseline (pre-treatment, i.e. 1 week after recruitment), 3 month follow-up (16 weeks after recruitment, i.e. 3 months after the last treatment day)
The primary safety outcome measure will be the total number of adverse events during the entire study period
Time frame: up to 3 month follow-up (16 weeks after recruitment, i.e. 3 months after the last treatment day)
Low-contrast visual acuity [LogMAR] at 4 (post-treatment) weeks in ON eyes.
Time frame: post-treatment (4 weeks after recruitment, i.e. one week after the last treatment day)
The mean change in macular ganglion cell and inner plexiform layer thickness [µm] of the affected ON eye at 4 weeks in comparison to baseline of the unaffected contralateral NON eye (pre-treatment).
Time frame: Baseline (pre-treatment, i.e. 1 week after recruitment), post-treatment (4 weeks after recruitment, i.e. one week after the last treatment day)
High-contrast visual acuity [LogMAR] at 16 weeks (3 month follow-up) in ON eyes.
Time frame: 3 month follow-up (16 weeks after recruitment, i.e. 3 months after the last treatment day)
High-contrast visual acuity [LogMAR] at 4 weeks (post-treatment) in ON eyes.
Time frame: post-treatment (4 weeks after recruitment, i.e. one week after the last treatment day)
Colour vision [tritan] at 16 weeks (3 month follow-up) in ON eyes.
Time frame: 3 month follow-up (16 weeks after recruitment, i.e. 3 months after the last treatment day)
Colour vision [tritan] at 4 weeks (post-treatment) in ON eyes.
Time frame: post-treatment (4 weeks after recruitment, i.e. one week after the last treatment day)
Visual field testing [dB] at 16 weeks (3 month follow-up) in ON eyes.
Time frame: 3 month follow-up (16 weeks after recruitment, i.e. 3 months after the last treatment day)
Visual field testing [dB] at 4 weeks (post-treatment) in ON eyes.
Time frame: post-treatment (4 weeks after recruitment, i.e. one week after the last treatment day)
Recovery of pattern-reversal visual evoked potential conduction velocity of the affected optic nerve [ms] compared to the intra-individual baseline of the unaffected optic nerve at 16 weeks (3 month follow-up).
Time frame: Baseline (pre-treatment, i.e. 1 week after recruitment), 3 month follow-up (16 weeks after recruitment, i.e. 3 months after the last treatment day)
Patient-reported vision-related quality of life assessed by the National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25) at 16 weeks (3 month follow-up).
The questionnaire contains the following 12 sub-scales: general health, general vision, ocular pain, near activities, distance activities, vision-specific social functioning, vision-specific mental health, vision-specific role difficulties, vision-specific dependency, driving, colour vision and peripheral vision. The mean VFQ-25 composite score (calculated as an unweighted average of responses to all items except for the general health sub-scale) and selected sub-scale scores will be analysed. Each sub-scale, and also the composite score, will be quantified with values between 0-100, with zero being the worst and 100 being the best.
Time frame: 3 month follow-up (16 weeks after recruitment, i.e. 3 months after the last treatment day)
Patient-reported vision-related quality of life assessed by the National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25) at 4 weeks (post-treatment).
The questionnaire contains the following 12 sub-scales: general health, general vision, ocular pain, near activities, distance activities, vision-specific social functioning, vision-specific mental health, vision-specific role difficulties, vision-specific dependency, driving, colour vision and peripheral vision. The mean VFQ-25 composite score (calculated as an unweighted average of responses to all items except for the general health sub-scale) and selected sub-scale scores will be analysed. Each sub-scale, and also the composite score, will be quantified with values between 0-100, with zero being the worst and 100 being the best.
Time frame: post-treatment (4 weeks after recruitment, i.e. one week after the last treatment day)
The mean change in peripapillary retinal nerve fibre layer (pRNFL) thickness [µm] of the affected ON eye at 16 weeks (3 month follow-up) in comparison to baseline of the contralateral NON eye.
Time frame: Baseline (pre-treatment, i.e. 1 week after recruitment), 3 month follow-up (16 weeks after recruitment, i.e. 3 months after the last treatment day)
The mean change in peripapillary retinal nerve fibre layer (pRNFL) thickness [µm] of the affected ON eye at 4 weeks (post-treatment) in comparison to baseline of the contralateral NON eye.
Time frame: Baseline (pre-treatment, i.e. 1 week after recruitment), post-treatment (4 weeks after recruitment, i.e. one week after the last treatment day)
The mean change in macular inner nuclear layer (INL) thickness [µm] of the affected ON eye at 16 weeks (3 month follow-up) in comparison to baseline of the contralateral NON eye.
Time frame: Baseline (pre-treatment, i.e. 1 week after recruitment), 3 month follow-up (16 weeks after recruitment, i.e. 3 months after the last treatment day)
The mean change in macular inner nuclear layer (INL) thickness [µm] of the affected ON eye at 4 (post-treatment) weeks in comparison to baseline of the contralateral NON eye.
Time frame: Baseline (pre-treatment, i.e. 1 week after recruitment), post-treatment (4 weeks after recruitment, i.e. one week after the last treatment day)
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