There are public and private hospitals and private clinics in in Mazatlán. As of 2019, they are building a big brand new public hospital in the northern part of Mazatlán
There are optometrists in Mazatlan. We have used and highly recommend Optica Cientifica which is located Downtown on the far side of the plaza opposite the Cathedral. They speak english and do quality work.
There are many spas and massage locations in Mazatlan. Most of the big hotels will have a spa that will give massages and other spa services. In the Golden Zone, all you need to do is to walk down the street and there will be a spa on almost every block or two.