I second the use of the Trend Airshield. Some find it uncomfortable but I have found that if you take a little time to adjust it it pays dividends. I had the same problem with face masks alone because without my specs I am hopeless. I do find the Drager half mask that Screw fix sell fits much better than the cheaper versions, it's full harness is more stable, and because the exhalation valves seem better it allows me to wear my 'specs without too much problem. I tend to use this fitted with a chemical filter if I am using something obnoxious because of course the Airshield and similar are dust filters and do not remove chemical fumes. ( CA and the like). Hope this helps.