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| Name | Class |
|---|---|
| The University of Hong Kong | OTHER |
| University of Waterloo | OTHER |
| University of Magdeburg | OTHER |
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Glaucoma is a complex disease that can result in progressive vision loss. It is the second leading cause of blindness, accounting for 23% of permanent blindness in Hong Kong. There are no treatments that restore vision lost to glaucoma. However, recent studies have shown that vision can be improved by perceptual learning (PL) and transcranial electrical stimulation (tES). This study will examine the effect of perceptual learning and tES on improving quality of life, visual function and functional performance in patients with peripheral field loss due to glaucoma. It is phase 2 of Glaucoma Rehabilitation Using ElectricAI Transcranial Stimulation (GREAT) project.
Study design:
This study uses a prospective, double-masked, randomized, placebo-controlled training RCT design.
The eligible participants will be randomly allocated into 3 groups:
(A) Placebo-Perceptual learning + Sham-tES; (B) Real-Perceptual learning + Sham-tES; (C) Real-Perceptual learning + Real-tES.
All participants will complete forty-three study visits:
Visit 1: Eligibility assessment (refer to the recruitment criteria); Visit 2-3: Outcome measures (Pre-intervention/ baseline); Visit 4-13: 10 sessions intervention (1st batch); Visit 14-15: Interim 1 Outcome measures; Visit 16-25: 10 sessions intervention (2nd batch); Visit 26-27: Interim 2 Outcome measures; Visit 28-37: 10 sessions intervention (3rd batch); Visit 38-39: Post-training 1 Outcome measures; Visit 40-41: Post-training 2 Outcome measures (to evaluate the retention effect after 1 month); Visit 42-43: Post-training 3 Outcome measures (to evaluate the retention effect after 2 months).
Six sessions of assessment will be conducted: (1) Baseline; (2) Interim-1 (after 10-sessions training); (3) Interim-2 (after 20-sessions training); (4) Post-1 (after 30-sessions training); (5) Post-2 (1-month post training); and (6) Post-3 (2-month post training).
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Real-PL + Real-tES (tDCS) | Experimental | Participant will receive 30 training sessions with real PL and real tES (tDCS): 3-4 sessions per week, about 1 hour per session |
|
| Real-PL + Sham-tES (tDCS) | Experimental | Participant will receive 30 training sessions with real PL and sham tES (tDCS): 3-4 sessions per week, about 1 hour per session |
|
| Placebo-PL + Sham-tES (tDCS) | Placebo Comparator | Participant will receive 30 training sessions with placebo PL and sham tES (tDCS): 3-4 sessions per week , about 1 hour per session |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Real-PL training + Real-tES(tDCS) | Other | PLtraining : around 40mins, tDCS: 20mins |
|
| Measure | Description | Time Frame |
|---|---|---|
| Visual field test | Visual field test is measured monocularly using the 24-2 Swedish interactive threshold algorithm (SITA) standard tests by Humphrey Visual Field Analyzer (HFA, Carl Zeiss Meditec Inc., California). The mean deviation (MD), pattern standard deviation (PSD), and visual field index (VFI) are recorded and the MD of 24-2 visual field test is used as primary outcome of intervention effectiveness. | Change from baseline at 5weeks, change from baseline at 10weeks, change from baseline at 15weeks, change from baseline at 19weeks, changes from baseline at 23weeks |
| Measure | Description | Time Frame |
|---|---|---|
| High Resolution Perimetry (HRP) | The current HRP is a valid and reliable computer-based visual field assessment based upon a previously well-established program. The revised HRP uses circular geometry instead of a rectangle to present stimuli, while maintaining its high-resolution advantage. During the HRP test, suprathreshold stimuli are presented in a radial pattern within 20 degrees, with a step size of 3 degrees. These stimuli are presented monocularly at a total of 98 positions, with the order of presentation randomized. To ensure a stable result and accurate assessment of participants' responses, the HRP test is repeated five times. Throughout the HRP test, fixation is monitored by an infrared eye tracker (SR Research, Eyelink Portable Duo). |
| Measure | Description | Time Frame |
|---|---|---|
| Magnetic resonance spectroscopy (Optional) | Magnetic resonance spectroscopy (MRS) is a non-invasive imaging technique that can be used to study the chemical composition of tissues, including the brain. Changes in GABAergic and Glutamatergic concentrations within the MRS voxels will be used to evaluate the mechanistic changes in the brain. To study the mechanism of glaucoma, we plan to use MEGA-PRESS in primary visual cortex(V1) of the brain to understand the neural and metabolic mechanisms. |
Inclusion Criteria:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Allen Cheong, PhD | Contact | 852-27666108 | allen.my.cheong@polyu.edu.hk | |
| Melinna Mei, PhD | Contact | 852-34002309 | melinna.mei@polyu.edu.hk |
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| The Hong Kong Polytechnic University | Recruiting | Hong Kong | Hong Kong |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 39039582 | Derived | Jia S, Mei X, Chen L, Chan LH, Tsang C, Suen V, Li T, Zaw MW, Liu A, Thompson B, Sabel B, Woo G, Leung CKS, Yip SP, Chang DHF, Cheong AMY. Glaucoma Rehabilitation using ElectricAI Transcranial Stimulation (GREAT)-study protocol for randomized controlled trial using combined perceptual learning and transcranial electrical stimulation for vision enhancement. Trials. 2024 Jul 22;25(1):501. doi: 10.1186/s13063-024-08314-3. |
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available: 3mths after data complication
The requestor's affiliation and purpose are required to get the access.
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A prospective, double-masked, randomized, placebo-controlled training RCT design
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Masked investigators responsible for all outcome measures and unmasked investigators responsible for group allocation and intervention. A set of random numbers will be generated by computer and the simple random sampling method (which matches according to age and gender) will be used to allocate the eligible participants into 3 groups.
| Real-PL training + Sham-tES (tDCS) | Other | PL training : around 40mins, tDCS: 20mins |
|
| Placebo-PL training + Sham-tES (tDCS) | Other | PL training : around 40mins, tDCS: 20mins |
|
| Change from baseline at 5weeks, change from baseline at 10weeks, change from baseline at 15weeks, change from baseline at 19weeks, changes from baseline at 23weeks |
| Electroencephalography (EEG) | 64-channel electroencephalography(EEG) recordings from Neuroscan will be used to understand the electrophysiological changes in the intervention. A standard visual evoked potential task (VEP) and a specific designed SSVEP task will be used to assess the functional integrity of central vision and peripheral function. Besides, resting-state EEG will be recorded to measure the functional connectivity at different timepoints. ERP components (such as P100, N1 and N2) in VEP, tagging frequency response in SSVEP, and the power correlation in resting state will be analyzed as physiological indicators. | Change from baseline at 15weeks, change from baseline at 19weeks, changes from baseline at 23weeks |
| Gait Test | All participants will be asked to walk along a 7-m walkway at their normal pace. Two disturbing factors will be introduced while walking: visual searching task and obstacle crossing. For trials with visual search, visual stimuli will be presented on the monitor (located at the end of the walkway) when the participant crosses the obstacle. For trials with obstacle crossing, an obstacle with two different colors (grey for low contrast and yellow for high contrast obstacle) of two different heights (2.5x60x5 cm or 2.5x60x15 cm) are positioned at the middle of the walkway. Participants' gait parameters including hip flexion/extension (degree), knee Min/Max (degree), ankle flexion/extension (degree), head flexion/extension (degree), walking speed (mm/s), step width (mm), and toe clearance(mm) will be measured and analyzed for each condition. | Change from baseline at 15weeks, change from baseline at 19weeks, changes from baseline at 23weeks |
| Balance function | Balance function will be evaluated for the following two conditions:
| Change from baseline at 5weeks, change from baseline at 10weeks, change from baseline at 15weeks, change from baseline at 19weeks, changes from baseline at 23weeks |
| Questionnaires for QoL | National Eye Institute Visual Function Questionnaire 25 (NEI-VFQ 25) and Low Vision Quality of Life (LVQoL) will be used to evaluate the patient-perceived outcome of the intervention on daily living. In NEI-VFQ 25, more positive person measures indicates greater visual ability, and more negative person measures have less visual ability. In the LVQoL, the completion results in a summed score between 0 (a low quality of life) and 125 (a high quality of life). | Change from baseline at 15weeks, change from baseline at 19weeks, changes from baseline at 23weeks |
| Change from baseline at 15 weeks |
| BDNF concentration in serum and tears (Optional) | Serum BDNF concentration will be measured using an enzyme-linked immunoassay (ELISA) kit and liquid chromatography-mass spectrometry(LCMS). DNA will be extracted from the leucocytes for the determination of BDNF Val66Met polymorphism (rs6265G>A) using a method based on polymerase chain reaction (PCR). Collection of tear sample by capillary tube (10 ul) or Schirmer Strip in labelled eppendorf tube and keep them frozen immediately. Tear BDNF concentration will be measured using an enzyme-linked immunoassay (ELISA) kit and liquid chromatography-mass spectrometry. | Change from baseline at 15 weeks |
| Cortisol concentration in serum and tears (Optional) | Cortisol concentration will be measured using an enzyme-linked immunoassay (ELISA) kit and liquid chromatography-mass spectrometry(LCMS). Collection of tear sample by capillary tube (10 ul) or Schirmer Strip in labelled eppendorf tube and keep them frozen immediately. Tear Cortisol concentration will be measured using an enzyme-linked immunoassay (ELISA) kit and liquid chromatography-mass spectrometry. | Change from baseline at 15 weeks |
| Questionnaire of psychological state | Perceived Stress Scale (PSS-10) and Patient Health Questionnaire - 9 (PHQ9) will be used to evaluated the stress and depression severity of the outcome of the intervention of participant. Individual scores on the PSS-10 can range from 0 to 40 with higher scores indicating higher perceived stress. In PHQ9, the completion results in a summed score between 0 (none minimal) to 27 (severe). | Change from baseline at 15weeks, change from baseline at 19weeks, change from baseline at 23weeks. |
| Questionnaire of fear of falling | Falling is a significant concern for glaucoma patients, with the fear of falling being a major contributing factor to the incidence of falls. Moreover, fear of falling is associated with a decreased physical and social activity. The Chinese version of the Falls Efficacy Scale- International (FES-I) is a validated and reliable questionnaire used to assess fear of falling in everyday life. This questionnaire includes sixteen items that are related to common daily activities, each graded on a scale of from 1 (not at all concerned) to 4 (very concerned). Higher scores indicate a greater concern about falling, which may indicate a poorer balance ability. | Change from baseline at 15weeks, change from baseline at 19weeks, change from baseline at 23weeks. |
| Kinetic visual field | The kinetic test is highly sensitive in detecting changes in the far peripheral visual field, which significantly correlates with balance function and gait performance. The binocular kinetic visual field is measured using Octopus 900 perimetry (Haag-Streit AG, Switzerland). Tests are done in the kinetic mode using the standard protocol (sixteen vectors), with a stimulus size of III4e moving at a speed of 5 degrees/sec to map the hill of vision. Any changes in the area of the isopter over time would indicate the effect of training on the kinetic visual field. | Change from baseline at 15weeks, change from baseline at 19weeks, change from baseline at 23weeks. |
| ID | Term |
|---|---|
| D005901 | Glaucoma |
| ID | Term |
|---|---|
| D009798 | Ocular Hypertension |
| D005128 | Eye Diseases |
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| ID | Term |
|---|---|
| D065908 | Transcranial Direct Current Stimulation |
| ID | Term |
|---|---|
| D004599 | Electric Stimulation Therapy |
| D013812 | Therapeutics |
| D003295 | Convulsive Therapy |
| D013000 | Psychiatric Somatic Therapies |
| D004191 | Behavioral Disciplines and Activities |
| D004597 | Electroshock |
| D011580 | Psychological Techniques |
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