A 25-year prospective study of visual acuity in the Japan Air Self DefenseForce personnel

Background: In the japan Air Self Defense Force (JASDF), new vision standar ds for student pilots allow lower uncorrected monocular acuity (from 1.0 to 0.8). In flight environments, where the use of corrective lenses may prese nt problems, the risk of decreasing Visual acuity in pilots who should wear corrective lenses must be defined. Methods: We conducted a 25-yr prospecti ve study of visual acuity with regard to distance vision in 752 JASDF nonav iation personnel followed from ages 20 to 45. The test subjects were divide d into four groups according to their right monocular visual acuity at entr y: greater than or equal to 1.0, between 0.9 and 0.7, between 0.6 and 0.2, and <0.2. Results: At entry, 94.1% of all subjects had visual acuity greate r than or equal to 0.7. The proportion of subjects who required corrective lenses for distance increased with age from 15.8% to 37.1%. After 25-yr, 30 .2% of subjects with visual acuity greater than or equal to 1.0 at entry an d 62.7% of subjects with visual acuity between 0.9 and 0.7 at entry require d corrective lenses. Conclusions: Over 25 yr, the population with the best eyesight at age 20 bad a lower increase in the need for corrective lenses t han the population with visual acuity between 0.9 and 0.7 at age 20. These results suggest an increased risk of visual acuity loss in pilots over time as a result of the lower vision standards for student pilots in the JASDF.