Background: Since 1982, the Canadian Civil Aviation Medicine Division has medically certified to Category 1 standard commercial and airline transport pilots whose visual correction was in excess of +/- 3.5 diopters (D).
Method: A review between the years 1982 and 1991 of the 253 pilots who had been medically certified, although they were outside the standard, was conducted. We determined if there was any difference in the accident/incident rate in this group as compared with the Canadian general aviation population standardized to a rate per 100,000 flying hours. The 253 pilots were divided into two groups with Group A having a refractive error outside the range +/- 5.7 D and Group B having a refractive error range of +/- 3.5 to +/- 5.6 D.
Results: The Group A rate was within the expected range of accidents and incidents per 100,000 flying hours. The accident/incident rate in Group B was significantly lower than the expected average.
Conclusion: In conclusion, the Canadian Civil Aviation Medicine Division's policy on granting "flexibility" to applicants with moderate to high refractive errors has not affected adversely the accident or incident rate and therefore has not compromised aviation safety.