One of the biggest reasons an optometrist's claims are rejected is because they put the wrong provider information on the claim. This can be avoided, however, by properly credentialing your company. I typically suggest organizing as a group and credentialing with all insurance companies as that group. This helps you to stay organized and makes it more or less a no-brainer when you, your staff or your outsourced biller (think opticXpress) has to file a claim for your patients.
In offices where your numbers might be too low to file as group or you just don't want too you are going to have a harder time. Generally, when you are not a group, credentialing tends to be all over the place. Forms may be filled out with the primary practitioner as the credentialed party. You may have another provider working for you that came from another practice credentialed for a particular insurance, or the forms are filled out with some having your credentials and others not, leading to huge nightmares for those who have to file your claims.
Bottom line: take the time to organize yourself as a group and credential as many of your insurances under that group as possible. Many of your current insurance companies will allow to simply update your status with a copy of a w9, Medicare will be a pain but that's nothing new. If you can't credential with an insurance company as a group then establish a set name, as in spelling, and address that you will use as your backup credentialing for those insurance companies and share the information with your staff and biller(s). Following this advice will make you more money and save a lot of time in the long-run, plus your biller (opticXpress) will thank you!