First of all you need an account on the ophthalmologia.be website. If you do not yet have an account, you need to contact the office and request an account to be made for you. You will need to supply a valid email address and you need to inform them your status (are you ophthalmologist, Resident in Training, Nurse, Orthoptist, Optometrist, ...). It is imperative that optometrist / orthoptist supply their visum nr or riziv nr. You can contact the office on firstname.lastname@example.org.
Once you have the account, you can log in with your email address along with a password of your choice.