Relevant previous discussion: [1] https://news.ycombinator.com/item?id=17061380 I live in Portugal and I have needed prescription glasses since i was a child (I'm now in my 40s). I have always felt frames particularly are priced in a cartel like way. Of course for lenses there is more of a justification depending on the thickness/prescription (it is harder to make a more curved lens that is thinner and lighter). In f…
In my opinion, the best material for lenses is the cheapest: plain uncoated CR-39. It has the best Abbe number of any common material (lowest chromatic aberration), and good scratch resistance. I clean mine using a microfiber cloth (carefully pre-washed to remove any grit), hot water, and dish-washing detergent. This leaves them clean enough that water will "sheet" off them, leaving them visually flawless. I find dirt on the lens more annoying than reflections, so I'd rather have uncoated lenses than coated ones that won't survive aggressive cleaning.
I'd recommend CR-39 even for moderately high prescriptions. Weight of lenses increases super-linearly with size, and glasses inherently have bad off-axis performance, so there's little point wearing huge glasses where index of refraction makes a big difference. The low index of refraction of CR-39 also reduces reflections, which is important when you're omitting anti-reflective coatings. It's also worth considering that all glasses designs are trading optical performance for convenience; for maximum optical performance you need contact lenses.