Can't say anything about dentists in Algodones, but I have an opinion on optometrists.
I have a high prescription and wear progressive (no-line)lenses and was wary about having glasses made there. "Best Optical" told me "no problem". I paid extra for ultra thin lenses which were to be special ordered. The lenses came in on time and I returned to check the RX. The glasses were the ugliest I have ever seen (and I used to work in an optometrist office). My lenses were literally twice as thick as I have at present, the lab ignored my request to not polish the edges of the lenses and my (own new and very expensive titanium) frame was broken in assembly. I had to fight for reimbursement and a refund of the purchase price.
Having said all that, my husband who has a low prescription, had two pairs of glasses made and is very happy
Be aware that what is called an opthalmologist in Mexico is nearer to an optometrist in Canada (and presumably US), and an optometrist in Mexico is closer to an optician. They will check your vision and do a pressure check for glaucoma, but there is no detailed eye health exam. My advice is have a qualified optometrist check your eyes in Canada or the US and take your RX to have the glasses made, with the knowledge that your eyes have been properly checked for underlying problems.
Rona