Medical--vision question

A question for you legal beagles.

An acquaintance has a medical that states "Corrective lenses must be worn &
near vision lenses carried" The typical old farts who wear glasses
endorsement.

Well his vision has changed, a trip to the ophthalmologist confirmed that he
no longer needs the glasses for far vision. The new lenses will be plano on
top with the bi-focals only. (He's worn glasses so long that reading glasses
would be a pain)

Now where is he on the medical? If the present glasses are worn his vision
is actually degraded. If the new glasses with NO correction are worn then is
the medical valid?

So what now?? A new physical?? Will the plano glasses fulfill the
"Corrective lenses" portion of the medical?

Thanks

Paul