Here are all the driving licence categories together with the vision requirements for each category (listed under medical requirements):
(D/F/I: )
http://www.fuehrerausweise.ch/asa-se...head=1&canton=
Most categories have their own special requirements regarding vision. Category D (bus > 16 seats) has the highest requirements, eliminating even people who have good vision with correction, if the correction required exceeds a certain level.
If your current driving licence is for a car, it would only act anyway as a provisional licence for lorries (>3.5 tons) and large passenger vehicles (>8 seats) so unless you are taking up a career in the transport industry, it should not affect you.