Does anybody have any market data, at least or the US? E.g., are there enough visually impaired people to sustain such a service, e.g., for $20-50/month? Can Me

Does anybody have any market data, at least or the US? E.g., are there enough visually impaired people to sustain such a service, e.g., for $20-50/month? Can Medicare/Medicaid cover part of the costs?