Your shorthand description of your prescription was fine. Assuming it's accurate than I highly suspect you are over prescribed by about .75 diopters. Unless your eye doctor is compensating for cutting back a bit on your full distance rx, I would expect your bifocal Rx to be closer to closer to +1.75 not +2.50
I've been fitting bifocal contact lenses for years, they work quite well and not just for divers. There's a bit of a compromise in the distance and near vision for most patients, but the vast majority are willing to give up a little of the "sharpness" in exchange for not needing reading glasses. Contacts are designed to move on the eye about .5 to 1mm, most bifocal contacts have circular zones of distant and near prescription as compared to eyeglass bifocals which have the distance rx on the top and the reading prescription on the bottom.
I haven't seen Rx dive masks in quite some time. We used to send masks out to have the lenses bonded to the faceplate, but that was many years ago. Nowadays we don't do the work because divers send their masks directly to the companies. So I'm thinking about the older style I guess, thanks for clarifying.
There's a lot more too it then luck.
Among the more relevant contributing factors to a successful bifocal fit:
Skill and experience level of the practitioner, as well as their motivation. In general, a chain store optical employed optometrist will want you in and out of the chair as quickly as possible, they probably don't have the skills or desire to practice the more advanced forms of optometry; a self employed professional optometrist such as myself will go the distance because we value patient satisfaction and referrals and retention.
Bifocal contact lens patients must understand the vision will be a bit of a compromise and have patience to return for several followup visits to adjust the contact lens power and possibly the brand, as needed, it usually takes 2 or 3 trial sets before the Rx is finalized. My success rate with bifocal contact lenses is around 90%.
