Bardet-Biedl Syndrome, Visual Impairment
Conditions
Brief summary
In this prospective pilot study without control group children and young adults (10-25 years old) diagnosed with Bardet-Biedl syndrome and treated with Metformin for their adipositas will be evaluated for a possible additional effect of Metformin on visual acuity.
Detailed description
Within experiments with animals a positive effect of Metformin concerning the photo receptors was shown. Several patients of the university hospital Tübingen with Bardet-Biedl-Syndrome and Metformin therapy due to their adipositas reported a subjective improvement of the visual acuity which was confirmed by opthalmologic tests. This will be checked in a prospective pilot study without control group including children and young adults (10-25 years old) diagnosed with Bardet-Biedl syndrome and treated with Metformin for their adipositas. Therefore a possible additional effect of Metformin on visual acuity will be evaluated under controlled conditions.
Interventions
DRUGMetformin
500, 850 or 1000 mg depending on body weight once daily for 24 weeks
Sponsors
University Hospital Tuebingen
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Prospective pilot study without control group
Eligibility
Sex/Gender
ALL
Age
10 Years to 25 Years
Healthy volunteers
No
Inclusion criteria
* clinically confirmed Bardet-Biedl-syndrome * Visual acuity between 0.05 and 0.8 * Age \>=10 year to \<25 years * Visual field III4e or V4e with diameter \>=5°, if II4e not seen * informed consent of patient and/or legal representative
Exclusion criteria
* Hypoglycaemia (\<50mg/dl) * Therapy with Metformin within the last three months * Participation in another clinical trial * pregnancy, lactation * any contra indication concerning Metformin therapy * Renal failure (creatinine clearance \< 60ml/min) * any acute disorder accompanied by clouding of consciousness * acute or chronic disorders possible accompanied by tissue hypoxia * Liver insufficiency, alcohol abuse * not fluent in German language
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Visual acuity | Baseline to day 210 | Course of visual acuity according to appropriate table |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Results of Static perimetry | Baseline to day 210 | Course of results of static perimetry given by measurement of light contrast sensitivity within at least 5 central points. |
| Results of Kinetic perimetry | Baseline to day 210 | Course of results of kinetic perimetry given by mapping the visual field sensitivity boundaries using Goldmann perimetry |
| Electroretinogram (ERG) dim-flash | Baseline to day 210 | Course of values of ERG dim-flash |
| Electroretinogram (ERG) standard flash | Baseline to day 210 | Course of values of ERG standard flash at 3 ods/m2 |
| Electroretinogram (ERG) cone-single-flash | Baseline to day 210 | Course of values of ERG cone-single-flash at 30cd/m2 |
| Number of letters read | Baseline to day 210 | Course visual acuity defined as number of letters read |
| Visual evoked potential (VEP) - amplitude | Baseline to day 210 | Course of results of measurement of VEP amplitude |
| Visual evoked potential (VEP) - latency time | Baseline to day 210 | Course of results of measurement of VEP latency time |
| FST | Baseline to day 210 | Full-Field-Stimulus Threshold |
| optical coherence tomography (OCT) | Baseline to day 210 | Course of central thickness of retina measured by OCT |
| Electroretinogram (ERG) 30-Hz-Flicker | Baseline to day 210 | Course of values of ERG measured by 30-Hz-Flicker in all patients |
Outcome results
None listed