Real-time Acoustic Biofeedback for Enhancing Fixation Stability: A Proof-of-concept Study to Improve Ophthalmic Imaging Diagnostic Quality
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: A device providing acoustic real-time biofeedback.
- Who it may be relevant to
- Registry conditions: Retinal Dystrophies, Geographic Atrophy, Blindness. Basic parameters: from 18 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Germany
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
Unsure about the terms? Read our patient guide →
Overview
The goal of this Proof of Concept Feasibility Study is to improve the fixation stability in patients with fixation loss due to blindness or central vision loss using a patented acoustic real-time feedback device. The main questions it aims to answer are: 1. Fixation guidance - can real-time acoustic biofeedback improve the fixation in healthy patients as well as patients with fixation loss? 2. Optimization of fixation guidance - testing of different stimuli to optimize an acoustic training protocol. 3. Optimization of imaging acquisition - testing improvement of both imaging quality and acquisition time using the acoustic feedback tool. For the proof-of-concept-study, patients are asked to fixate on a target point in a darkened room and keep up the fixation. We record patients eye movements with near-infrared-lighting and a camera. Fixation is tested in three conditions - visual target only, auditory feedback only, and visual target followed by auditory feedback. In between each set of trials, patients are asked to rate their subjective exhaustion on a Likert scale. At the end of each recording session, patients are handed a questionnaire for feedback on our proof-of-concept study and device settings. An ethics-approved extension phase is planned to further optimize device parameters and assess performance in a clinical setting.
Detailed description
The goal of this Proof of Concept Feasibility Study is to improve the fixation stability in patients with fixation loss due to blindness or central vision loss using a patented acoustic real-time feedback device. The main questions it aims to answer are:
1. Fixation guidance - can real-time acoustic biofeedback improve the fixation in healthy patients as well as patients with fixation loss? 2. Optimization of fixation guidance - testing of different stimuli to optimize an acoustic training protocol. 3. Optimization of imaging acquisition - testing improvement of both imaging quality and acquisition time using the acoustic feedback tool.
Primary endpoints: Fixation stability (in BCEA and distance from target center), fixation duration, time to fixate. We test fixation in two angles: neutral position (0°) and at 15° eccentricity. We compare three conditions: visual target only, combined visual and auditory feedback, and auditory feedback only.
Secondary endpoints: adaptation and training effects over time, exhaustion measured in a Likert scale. We measure changes of pupil diameter in response to acoustic and visual stimuli. We also compare efficacy between healthy subjects and subjects with fixation loss and compare efficacy between the three conditions.
For the proof-of-concept part of our study, patients are asked to fixate on a target point in a darkened room and keep up fixation for 10 seconds. We record patients eye movements with near-infrared-lighting and a camera. There are three blocks for each condition (visual, auditory, combined), each block consists of 10 trials per eye and per angle. In between each set of trials, patients are asked to rate their subjective exhaustion on a Likert scale. At the end of each recording session, we ask patients for their subjective feedback on which condition was easiest to keep up fixation, whether auditory stimuli were sufficient and open-ended questions on potential improvements of the setup.
An ethics-approved extension phase is planned to further optimize device parameters and assess performance in a clinical setting. We validate the findings of our proof-of-concept study and optimize the device settings by adding the acoustic fixation device to our imaging devices. We will compare the results to answer the question whether the acoustic fixation device will lead to an improved imaging quality and acquisition time.
Interventions
- Device A device providing acoustic real-time biofeedback
We use a camera and an eye tracking software, linked with our spatial-audio mapping tool. Participants receive real-time audio feedback on the location of their gaze. Negative feedback sounds are encoded to convey distance and direction of the deviation from the center. When the patients fixate on the target area, they receive a positive feedback sound.
Primary outcome measures
- Fixation stability - change from baseline fixation stability recorded without acoustic fixation device compared to fixation stability recorded with acoustic fixation device [Time frame: Day 1]
Secondary outcome measures (5)
- Change in time to achieve fixation over repeated trials [Time frame: Day 1]
- Subjective exhaustion rating (Likert scale, 1-10) [Time frame: Day 1]
- Difference in fixation stability (BCEA, time to fixate in ms) between blind and healthy participants across feedback conditions [Time frame: Day 1]
- Correlation between pupil diameter change (mm) and fixation stability (BCEA) [Time frame: Day 1]
- Comparison of fixation stability with clinical and imaging parameters [Time frame: Day 1]
Eligibility criteria
Inclusion criteria
Healthy participants:
- minimum age of 18 years
- no neurological or ophthalmological disease
- ability to perceive auditory feedback
- normal vision
- consent to participate in study
Patients:
- minimum age of 18 years
- existing ophthalmological diagnosis of fixation deficite or loss
- ability to perceive auditory feedback
- consent to participate in study
Exclusion criteria
- lack of ability to consent to participate in study
- reduced cooperation during examination or recording
- inability to perceive auditory feedback
- age below 18 years
- patients with nystagmus or inability to move eyes
- opacity of cornea or other ocular structures preventing successful eye tracking
- inability to communicate
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Allocation
- Non-randomized
- Model
- Parallel assignment
- Masking
- Open label
- Primary purpose
- Other
Study locations
Germany · 1 center
- EKFZ Else Kroener Fresenius Center for Optogenetic Therapies, University Medical Center Go — Göttingen
Identifiers
NCT: NCT07529041 · 17/5/25