achrn beat me to it , but anyway
Lens impact type markings ( ie EN 166 B = Medium)
S Increased robustness (toughened glass and thickened CR39)
F Low energy impact (polycarbonate and Trivex)
B Medium energy impact
A High energy impact
9 Non-adherence of molten metal and resistance to penetration of hot solids
K Resistance to damage by fine particles
N Non-fogging properties
T High speed particles at extremes of temperature
Areas of use ( Frame)
3 Liquids and chemical
4 Large dust particles
5 Gas and fine dust particles
8 Short circuit electrical arc
9 Molten metals and hot solids
Optical class
1 Continuous use
2 Intermittent use
3 Occasional use ( but must not be used continuously)
Note 1 - Safety glasses have side shields.
Note 2 - Lenses will be marked with manufacturers mark, followed by optical class then impact grade
Note 3 - Frames will have the standard EN166, and -F if they claim it meets low energy impact plus the CE mark.
Note 4 - Optical class for lenses 1 to 3 where 1 is the best
Note 5 - Complete unit marking say goggles will be marked EN166 1.B.3.4.9 - means optical 1,medium energy, for use for liquids, large dust and molten metal.
Note 6 - Goggles have a tendency to fog up easily, so trials may be appropriate ( and cheapest is normally not cost effective)
However as you have said you have class 1, when they site at the computer with the safety glasses on is there any reflections form lights etc ( site there any try it yourself). Otherwise they claim there is nothing rong with their eyes then tell them to go to the doctors , but keep using the glasses. I have come accross these people before. sometime hard to establish if real or just whinging.