I went to Specsavers for years.
I noticed some blurriness in my left eye and mentioned it to the optician who was doing the test, she said my eye was fine. But the new specs didn;t correct it, and after several more visits with no changes made I gave up.
Two years later covid struck.
Four years later I went to a small independent business who referred me to the hospital as an urgent case - I had a bleeding retinal vein or RVO.
There, I was soundly admonished for not reporting the problem earlier, as the sooner its treated the better the chance of full recovery.
I had to have an injection into my eyeball every 6 weeks (later reduced to 8 weeks and so on, until now its every 16 weeks) for life. It can be treated so that it won't get worse, but not cured. My other eye compensates and happily I can still drive.
So I pay extra for my frames, and smile.