I believe you need funds in the bank to apply for the Retirement visa and maybe the DTV visa. But not for the non-o which gives you 30 days to open the bank account and funds. To be held in the account for the retirement visa application.
i don’t understand the 25k. I did not do the non-oa but I believe you do still need to show sufficient finances in a bank of your home country. Plus medical insurance and police report
In my experience, getting medical I treatment is more cost-effective here. I’ve been to the eye hospital in Bangkok twice with really good results and low-cost.
However, in my experience again, by eyeglasses in Thailand, will not save you any money