Contrast Sensitivity: Establishing Normative Data for Use in Screening Prospective Naval Pilots

James M. Grimson, Steven C. Schallhorn, and Sandor E. Kaupp
Aviat Space Environ Med 2002; 73:28-35

Abstract

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.

Keywords: contrast sensitivity, vision testing, letter chart.


Information on subscribing, and on obtaining copies of an article or of an entire issue.

Table of Contents for Volume 73, Number 1 of the ASME journal.