In 1995, Paul was certified to practice by the American Board of Ophthalmology (ABO).[26] In 1992, the ABO changed its certification program, which had previously awarded lifetime certifications, now required ophthalmologists to recertify every 10 years. Those who had already been given lifetime certification were not required to recertify. Paul felt this was unfair and began an aggressive campaign to have all ophthalmologists recertify every ten years. In 1997 he set up the National Board of Ophthalmology (NBO) to offer an alternative certification system, at a cost substantially lower than that of the ABO.[27][28][29] Its certification exam, an open book take-home test that Paul helped write, was described by one taker as "probably harder" and "more clinically relevant" than the ABO's exam.