your analogy between hearing aids and eye glasses is illogical.  most eye sight loss is correctable to original specs, but hearing loss is not correctable, hearing aids are merely microphone that amplify sounds; it cannot tune out unwanted sounds or focus on a specific sound when many sounds are present, which can be done only by the brain.  so using a hearing aid is only partially helpful in certain circumstances, in the many different hearing environments, it is largely ineffective.  hearing aids do not slow or stop hearing loss, nor does it restore hearing loss, but as an aid in certain situations if does help some.