Clinical Trial Details
— Status: Withdrawn
Administrative data
| NCT number |
NCT02555384 |
| Other study ID # |
EKNZ2015-264 |
| Secondary ID |
|
| Status |
Withdrawn |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
January 2020 |
| Est. completion date |
November 30, 2020 |
Study information
| Verified date |
June 2023 |
| Source |
University of Basel |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Amblyopia, affects 4% of the population. In the presence of a normal retina and optic nerve,
the visual cortex does not develop normally secondary to the amblyopic eye being at a
disadvantage in the sensitive period such as in strabismus. Amblyopia is associated with
visuospatial disorders, and poor to absent stereopsis. Amblyopia is treated by occlusion of
the non- amblyopic eye in childhood. The present study aims to evaluate the effectiveness of
perceptual learning (PL), that is a training of visual drawing tasks (12 sessions of 30
Minutes duration) with crowding (c) for children with amblyopia compared to an amblyopic
control group with a placebo drawing task.
Arm 1: Crowded (PLc)- Training with small spacing Arm 2: Uncrowded (PLu)- Training with large
spacing Prior to this, a small group will help optimize parameters such as contrast and
distance of visual objects presented
Description:
Outcome(s):
Primary endpoints: improvement of amblyopia,crowding ratio (CR) and visual acuity before and
after training, at 7 weeks, at 6 months Secondary outcome: hand-eye coordination, evaluated
with the Beery VMI test before and after training, at 7 weeks, at 6 months Tertiary outcome
over 6 years of age: macular structure measured with the OCT before and after training, at 7
weeks, at 6 months
Study design:
Cohort study, randomised controlled trial, single blind, active control, parallel groups
Inclusion / Exclusion criteria:
- 20 Children included to optimize test criteria (high vs low contrast and spacing).
- 40 Children for 2-armed study.
Measurements and procedures:
12 sessions (2x per week for 6 weeks, 30 Minutes each) where drawing tasks are performed
during their occlusion time.
Arm 1: Crowded - task with small spacing Arm 2: Uncrowded task with large spacing. Prior to
this, a small group will help optimize parameters such as contrast and distance of visual
objects presented The following parameters are evaluated at onset, at week 7 and at 6 months:
visual acuity with and without crowding, the Berry Test and in children over 6 years of age,
if possible: a reading task and OCT.
Statistical Considerations:
Patients will be randomized by letting a computer program perform the assignment of children
in a certain training group. However, some restrictions will be inserted on the amount of
randomization: equal number of children in our training groups, age- and acuity matched
groups, equal patching times.
The analysis is aimed at answering the primary question: Can the training reduce crowding and
improve visual acuity in children with amblyopia? In order to answer this question, a
repeated measures ANOVA is conducted in which the crowding ratio (CR) before and after
training will be entered as a within-subjects variable (2 levels: CR pre, and CR post/VA pre,
VA post). Training group will be entered as a between subjects variable (2 levels: control
and experimental). If there is an interaction effect, post hoc ANOVA's will be conducted to
disentangle the effect of training on the CR within training groups.
A secondary question is: Can the training improve hand-eye coordination in children with
amblyopia. To this regard the results of the Beery VMI test are being evaluated with a
repeated measures ANOVA.
Sample size Calculation. As the crowding ratio (CR) is to be expected more important than VA,
only this parameter will be powered.
Main parameter for the power calculation will be the difference (CRd) of the CR at the end of
the intervention period compared to the CR at screening.
A CR decrease of 0.3 between "control" and "learning" group is assumed to be of clinical
relevance.
The population standard deviation (SD) of CR is assumed to be 0.33. Assuming a moderate
correlation coefficient of 0.5 between timepoints, the within subject SD is calculated as
sqrt(0.33*0.33*0.5)=0.23. Therefore the SD of CRd is sqrt(2)*0.23=0.33. [Details are
described in Sample Sizes for Clinical Trials,Steven A . Julious,Chapman and Hall/CRC 2009].
Based on a sample size of 20 subjects for each study group, there is a power of 88% to detect
a CRd decrease of 0.3. This calculation is based on a one-sided T-test (alpha=5%).
GCP Statement: This study will be conducted in compliance with the protocol, the current
version of the Declaration of Helsinki, the ICH-GCP or ISO EN 14155 (as far as applicable) as
well as all national legal and regulatory requirements.
