How can you stop your glasses steaming up whilst wearing a face mask ?

Make sure your mask fits snugly. ...

Secure the mask around your nose. ...

Think your mask is too big? ...

Stop your glasses from slipping down your nose. ...

Breathe downwards into the mask. ...

Clean your lenses. ...

Use an anti-fog lens wipe or spray on your glasses. ...

Adjust your glasses.

wash yor glasses with soap. it will work for 3/4 hour

Quit wearing the stupid mask.

yes people can experiment

( try various actions and evaluate the results  )

  to find a SOLUTION to a problem  for  CONDENSATION

1-  use a NOSE CLIP  some are built into mask   or   stitch into existing mask using  pipe cleaners  or purchase  self adhesive  silicone clips on line

2- WASH your glasses with mild detergent or liquid soap  before putting on the glasses ( researchers have found a thin layer of  soap molecules remain on glasses that inhibit fog )

3- Spritz with anti fog LENS spray   commercially available  used by many   on swim goggles and diving mask

4-  TUCK in your mask   American Academy  of  Ophthalmology   recommends two strategies

a- slide your glasses further down your nose  for more air flow  and wear your glassed over the top edge of your mask

  b-  inch your mask upward a bit  and lower the bottom rim of the glasses  over the mask

  5- secure your mask with skin SAFE TAPE a slender strip of skin safe adhesive tape  will keep your mask in place  such as  athletic tape

6- try anti fog wipes  come  single packaged  use

Loosen the bottom of the mask just a little bit so that exhalations can exit. 

Clean them with windshield washer fluid like in your family car

I hang them from the end of my nose and tilt my head back. I look like an idiot, but that's what Boris wants.

The person who comes up with that answer, will become a millionaire overnight. There are lots of hacks out there, from defoggers to nose pieces. One may work for you, all may not. 

some granny got headlines by sewing a button to the  top of the mask creating a gap.

they claimed it worked.

The trick is to push the facemask high enough up your nose that the bridge of the glasses rests on the facemask, not just on the seam but just past the seam, like an eighth or quarter inch in. When you do that, any steam coming from your breath doesn't rise up and hit the lenses of your glasses but misses the lenses of your glasses by rising up behind them.