There is no easy answer when it comes to deciding whether a biometric eye scan or multi factor authentication is more secure. Both have their own benefits and drawbacks that need to be considered.
Multi factor authentication generally refers to using multiple methods to verify a user's identity. This could include something like a password and a fingerprint scan. The advantage of this approach is that it is more difficult for someone to spoof or hack all of the different methods that are being used. The downside is that it can be more inconvenient for users, as they need to remember multiple passwords or use multiple devices to access their account.
Biometric eye scans, on the other hand, are generally more accurate than other forms of biometric authentication such as fingerprints. This is because it is very difficult tofake an iris. However, they can be fooled by high quality fakes or by someone who has access to the iris scan database.