Abstract
Purpose :
The King-Devick Test (KD) has been studied as a remove-from-play sideline test in college-age athletes and older; however, studies in junior high and high school athletes are limited. A prospective, observational study of the KD and other vision correlates was completed on school-aged athletes during pre-season physicals for a variety of sports to determine the repeatability and variability of the KD. The study also evaluated how convergence, alignment, or pupil function contributed to a slower King-Devick baseline reading.
Methods :
786 athletes underwent vision screenings by trained/certified staff who were doctors of optometry, optometry students, and athletic trainers as part of the pre-season physicals to be cleared for play in the upcoming academic year. Testing took place in a hospital or school. 623 had KD testing completed per the manufacturer’s suggested protocol and repeated. Other baseline vision testing included visual acuity, Modified Thorington testing for alignment, convergence testing, and pupil function using the NeurOptics (NPI-200®) NPi, a proprietary index based on 7 pupil functions.
Results :
The mean fastest, error-minimized KD time for all participants was 44.2 seconds (+/-11.1s) (range 24-120). Mean KD time got faster(+) with age (p <.001). The inter-class correlation coefficient for all scores was 0.59. The mean time difference was 1.4 seconds +/- 4.6 (range -38 to +24) in 6th-9th grade and was 1.7 seconds +/- 2.8 (range -11 to +11). The 95% limits of agreement for the KD was (+13.4/-11.5) in the younger age group and (+9.3 /-5.9)in the older age group. There was no association between the KD and reduced NPC (p=.85) or the KD and Modified Thorington’s measure of phoria (p = 040). 85 % had VA better than 20/30 in both eyes. The average NPi for both eyes was 4.1(0.3) did not correlate with a best KD time.
Conclusions :
King-Devick score in junior high and high-school athletes is variable but gets faster and more repeatable with increasing age. The KD does not correlate significantly with reduced convergence, alignment, or pupil function. Based on grouped data, a slowing of 12 seconds for younger athletes and 6 seconds for older athletes on a second administration represents a true difference in testing speed. Within player variability should be considered when removal-from-play decisions are influenced by KD results.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.