I wonder if the use of a lensmeter makes you fall into a local optimum while missing out on a potential global optimum?
Let's say I go to a bad optician and get a pair of lenses that have something way off like the cylinder is the wrong way around, or toric lenses for astigmatism when you actually don't have it. Everything looks like crap but then you get used to it (the brain is amazing at adapting). Then a few years later you go get another pair, and they use the lensmeter reading as the baseline.
I think I have astigmatism, or do I? It took me more than two months until I stopped getting headaches after getting my first glasses and I could see decently. Every glasses since then are based on that first reading. Maybe I've just become used to it, and there exists a significantly better lens that I could become used to as well.