cx medicals are in-house, and I am certain they allow glasses up to a certain limit.
Your wife may work legally in hong kong if she is sponsered by a company. Unfortunately the government has passed a ruling that spouses on dependant visa's (which would be applicable to her) can't get an automatic worker's status, so she would have to get it on her own by applying for a job and getting a sponsorship. This stupid ruling was brought on by the high unemployment rate in hong kong at the moment. As things are turning around here fast, this may change to your wife's favour in the future.
There are also many volunteer type jobs available.
hope this helps,
regards,
Oasis