Interesting post, we used to have an optician that used to post here some years ago and I have been wanting some inside gen.
I use a private high street optician (the past 40 years) but I rarely need to change the spec and then only slightly but I find after three years or so the lens is what I would describe as dirty, the plastic lens seems to not be sharp, I suspect the plastic lens deteriorates. Is that so?
Every shop ought to have a face mask too.
At less than a tenner it's daft not to.
Don't machine grind or turn with just specs
I have a library of gory face injuries from angle grinder accidents to get over the point at work. And you would not believe how common those things mutilate people
I agree. 'Googling' injuries is an unpleasant but sobering method to drive home safe working practices. The only near miss I've had with any tool was enough to convince me a face mask is essential (cutting disc in an angle grinder shattered, sending a chunk to be ejected up and break my safely goggles).
