Visual Field Defects
Conditions
Brief summary
Visual impairments significantly impact individuals' activities of daily living (ADL) and quality of life (QoL). While perceptual learning (PL) has shown promise in vision rehabilitation, traditional PL usually involves a protracted training process, and its training effects may sometimes lack ecological validity. This study protocol outlines a two-arm, single-blind, randomized controlled trial to evaluate the efficacy of an innovative virtual reality (VR)-based PL therapy integrated with machine learning algorithms. Twenty participants with visual field deficits will be recruited and randomized in a 1:1 ratio into either the VR training group or a no-intervention control group. The intervention consists of six visits (1-7 days apart), each involving two training tasks (20 - 30 minutes per task). The VR training task is an Ecological Multiple Object Tracking task and a Dual task. Training stimuli are personalized to target each participant's transition zone (1\ 20 dB) based on the result of clinical visual field test. A Deep Reinforcement Learning (DRL) framework, specifically the Proximal Policy Optimization (PPO) algorithm, is utilized as an adaptive controller to dynamically modulate task difficulty and maintain participants in an optimal cognitive "flow state". The primary outcome is visual field area improvement (measured by Humphrey Field Analyzer). Secondary outcomes include pre- and post-intervention assessments of visual search, balance ability, fear of falling, ADL, and QoL. It is hypothesized that participants in the VR training group will obtain improvements in primary and secondary outcomes.
Interventions
BEHAVIORALVirtual Reality-based Perceptual Learning Training
Prior to the training session, participants' visual fields will be assessed using standard automated perimetry (e.g., Humphrey Field Analyzer, 30-2 or 24-2 grid). Based on the decibel (dB) sensitivity maps from the clinical results, each participant's visual field will be classified into three functional zones: the intact zone (normal sensitivity), the absolute blind zone (\<0 dB), and the transition zone or "gray area" (1\~20 dB; relative scotoma characterized by reduced but present sensitivity). One training session will be 20 \~30 minutes for each task. Participants will be asked to complete a total of 6 training sessions. In each training session, the participant will be asked to complete two tasks (i.e., ecological multiple object tracking task and dual task) which will take approximately one hour. Training sessions will be spaced at intervals of 1\~7 days.
Sponsors
Centre for Eye and Vision Research
The Hong Kong Polytechnic University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* Humphrey visual field analyzer (HFA) visual field loss (mean deviation of ≤-6 dB)
Exclusion criteria
* Comprehension disorder that does not allow understanding of tests or training (e.g., in severe aphasia) * Currently under other PL treatment
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Visual Area Improvement | Within one week after the training ends | Primary outcome is the visual area measured using the HVF (24-2, SITA-standard), where sensitivity increased by 6 dB or more relative to baseline in the defective hemifield or whole field. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Pre/post-intervention assessments of visual search | Within one week after the training ends | Visual search: Perceptual processing efficiency will be assessed using a visual search task - spatial configuration search task (Wolfe et al., 2010). In this task, participants were instructed to fixate on the centre of the screen and to locate a target. Each trial began with a short tone, followed after 500 ms by a search display. Participants pressed a key to report whether the target was present (in 50% of trials) or absent, responding as quickly and accurately as possible. Feedback-indicating response correctness-appeared for 500 ms after each trial. Trials were separated by a 1000-ms inter-trial interval. Set size was systematically varied across two conditions-6 items (1 target + 5 distractors) and 18 items (1 target + 17 distractors)-to quantify search efficiency. For each participant, reaction time (RT) was regressed on set size, and the resulting slope served as the primary index of perceptual processing efficiency: shallower slopes indicate higher efficiency. |
| Pre/post-intervention assessments of balance ability | Within one week after the training ends | Balance: The Bertec Balance Advantage™ system is used to assess participants' balance before and after training. During the test, participants are asked to stand under different challenging conditions. Balance-challenging conditions include (1) standing on a firm or foam surface (Fi/Fo); (2) standing surface with backward or forward translation (BT/FT); and (3) standing with their eyes close (EC). Outcome measures, including root mean square sway of the center of pressure in the anterior - posterior and medial -lateral directions (mm/s), total sway path length (mm), and maximum CoP displacement in the AP and ML directions (mm) |
| Pre/post-intervention assessments of fear of fall | Within one week after the training ends | Fear of fall: The English \& 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. The FES-I total score ranges from 16 to 64. Higher scores indicate greater concern about falling and therefore a worse outcome. |
| Pre/post-intervention assessments of quality of life (a) | Within one week after the training ends | The National Eye Institute 25-Item Visual Function Questionnaire (NEI-VFQ-25), English and Chinese versions. The NEI VFQ-25 scores range from 0 to 100. Higher scores indicate better visual functioning and better vision-related quality of life and therefore represent a better outcome. |
| Pre/post-intervention assessments of quality of life (b) | Within one week after the training ends | The Chinese version of the Low Vision Quality of Life Questionnaire (CLVQOL) is used to assess vision-related quality of life. The CLVQOL contains 25 items, each scored from 0 to 5, resulting in a theoretical total score ranging from 0 to 125. Higher scores indicate fewer vision-related difficulties and better vision-related quality of life and therefore represent a better outcome. |
Countries
Hong Kong
Contacts
CONTACTKe Zhang
Outcome results
None listed