If your son is suffering from refractive amblyopia, usually, the vision cannot be improved in 11 days after wearing the eyeglasses. Treatment of Amblyopia needs several months, some cases may also needs occlusion therapy.
However, the case of unexplainable amblyopia, will need to assess whether there is any problem in transmitting the retinal signal from the eye to the brain, electroretinography is sometimes useful to identify the problem. But you mention retinal scanning is another assessment, it should be an Optical Coherent Tomography, to assess the features of macular region. This test is to find out if there is any macular edema or abnormality.
Our centre does not provide ERG or OCT assessment, please wait for the appointment with the eye doctor in Government clinic.