A visual impairment (VI) means than wearing glasses will not be able to correct your vision.
It can be defined as a loss of clear vision. Most children / young people with vision impairment have some useful visual function and only a small proportion are totally blind.
If you are concerned that your child / young person may have a visual impairment which is impacting their learning, take them to an Optician and talk to your child / young person's school / college. Speak to the class teacher or Additional Learning Needs Coordinator (ALNCo) and they will be able to work with you and work out what happens next. If your child is under 5 years old, you need to speak to your Health Visitor.