The range of online authentication systems used is rapidly expanding from reliance on passwords to include password management by the operating system, browser or a standalone system, strength meters for passwords, CAPTCHAs (Completely Automated Public Turing test to tell Computers and Humans Apart), two-factor authentication (2FA), fingerprint and facial recognition authentication. These may have usability problems for all users, but potentially even greater problems for users with disabilities. The use and accessibility of a range of authentication components and systems was investigated with a sample of 81 visually disabled users from the USA, using an online survey. These users experienced considerable problems with most authentication methods, particularly CAPTCHAs and face recognition. Problems included entry fields and buttons not being labelled, confusing navigation, error messages not being accessible, timeouts, and audio challenges in CAPTCHAs not being understandable. Many of these problems are covered by web accessibility standards, but it is easy to understand why developers do not realize how these standards apply in the context of authentication systems, as the standards provide very general examples. A solution to this issue may be a guide to the web accessibility standards and universal design guidelines specifically for authentication systems, illustrating the problems that disabled users have and examples of how they can be solved.