Why are glasses from opticians so expensive?

Could you explain why glasses prescribed by opticians often come with a hefty price tag? Are there specific factors that contribute to their cost, such as the materials used, the technology involved, or the level of expertise required for the fitting process? It seems as though these costs have been steadily rising over the years, and I'm curious about the underlying reasons behind this trend. Could you also provide some insights into how patients can potentially find more affordable options, while still ensuring they receive high-quality eyewear that meets their individual needs?