Contrast sensitivity: establishing normative data for use in screening prospective naval pilots
Grimson, J.M.; Schallhorn, S.C.; Kaupp, S.E.
Aviation Space and Environmental Medicine 73(1): 28-35
2002
ISSN/ISBN: 0095-6562 PMID: 11817617 Document Number: 544745
Background: Contrast sensitivity testing can be a useful supplement to standard visual acuity tests. Currently there are no standards for contrast sensitivity in military aviation. Student naval pilots, who often have better-than-average visual acuity, could be expected to have better-than-average contrast sensitivity. Any attempt to establish contrast sensitivity standards for military aviation should begin with establishing normative data, particularly data gathered from the military aviation community. Hypothesis: Student naval pilots differ from the general military population on Small Letter Contrast Test measurements. Methods: Contrast sensitivity was measured in a group of student naval pilots (n=107) and compared with results from aviation and non-aviation personnel. The Small Letter Contrast Test (SLCT) was used (19). Other subjects consisted of student naval flight officers (n=40), experienced naval pilots and flight officers (n=35 and 86, respectively), enlisted aircrew (n=175), and other military personnel tested before undergoing photorefractive keratectomy (n=185). Results: Data collected provide large-group demographic characteristics and normative values for contrast sensitivity measured with the SLCT. Of the non-aviation controls, 95% scored at least 0.62 (read at least 7 lines plus 2 of 10 letters on the 8th line of the chart), and 95% of the student pilots scored at least 0.81, (read at least 9 lines plus 1 letter on the 10th line). Conclusion: Student naval pilots scored significantly better on the SLCT than the military control population. The SLCT shows potential as a screening device during induction physical examinations of military pilots.