How come I failed the vision test at the doctor's but passed the online one?

You might have a severe form of color blindness that the online test cannot identify. While the online test is a valid tool accessible to the general public and can accurately detect the presence of color deficiency, research indicates that it cannot determine the type or severity of the deficiency. Therefore, you still need a doctor to diagnose the type and extent of your color deficiency. Acquired color blindness may be linked to eye conditions such as optic nerve disorders and may necessitate more advanced testing by an ophthalmologist.