I tend to wear glasses all year round as when it's not bugs then streaming eyes in the cold winter winds aren't brilliant either.
Another set of cheap and reasonably effective glasses are
these in Argos. Not polycarbonate safety lenses but mine took a decent whack at 20+mph when i had a crash and survived ok.
They come with three sets of lenses, clear, yellow and grey.
Otherwise I've just bought some new ones from
Decathlon which are pretty good and are more substantial lenses I think they were 10 with a set of clear and dark grey lenses.