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The purpose of this study is to investigate the effect of visual acuity degradation on the judgment of sport officials.

Visual acuity is the ability to clearly and distinctly see a stationary object enabling the identification and discrimination of certain objects at a distance. Visual acuity will be analyzed by a standard visual acuity wall chart. Visual judgment will be determined by a tennis ball line test where subjects had to determine if balls were judged as "in" or "out".


Twenty-two Texas A&M University – Corpus Christi sport officials from the intramural department, (age 20.86 ± .85 yrs.) participated in a line calling drill of 30 balls verbally stating, “in” or “out” for each ball. Of the twenty-two officials, 27% (n = 6) were females and 72% (n=16) were males. All subjects had two or more years of experience in officiating a variety of intramural sports. Subjects were not allowed to wear glasses but could wear their contact lenses due to the posttest’s demand of wearing the powered reading glasses.


Testing was administered at Texas A&M University – Corpus Christi’s Biomechanics Laboratory. Visual acuity was measured with an established visual acuity chart, the GUARDVISION™ 2012 LIFEGUARD VISION TEST #A apparatus. The pretest was performed with normal vision and the posttest was performed with a set of powered eye glasses (ranging from +1.75 to +2.75) designed to degrade vision to 20/50. The test protocol utilized a test administrator randomly dropping tennis balls on a line from a distance of 11.69m from the subject. The balls were intentionally dropped within three inches of the line to challenge the subjects to make the correct “in “ or “out” call. Each subject was required to judge 30 line calls.

Statistical Analysis

Means and standard deviations were calculated for both the pretest and the posttest. A paired-samples t test was calculated to compare the mean pretest (normal vision) score to the mean posttest (degraded vision) score. The statistical software package SPSS version 19.0 was used for the data analysis. The alpha level was set at p ≤ 0.05.


The twenty-two Texas A&M University – Corpus Christi sport officials (age 20.86 ± .85 yrs.) participated in visual acuity and line call tests. A paired-samples t test was calculated to compare the mean pretest score (normal vision) to the mean posttest score (degraded vision). The mean pretest score was 25.73 ± 2.16 and the mean posttest score was 16.91 ± 3.22. The results of the paired-samples t test determined a statistically significant difference between the pretest and posttest scores (t(21) = 2.69, p < .05). In addition, subjects experienced an average of 34% more incorrect line calls when their vision was degraded to 20/50.


The results of this study indicate that visual acuity degradation of sport officials to a level of 20/50 significantly reduces the ability to make correct line calls. The average subject experienced 34% more incorrect line calls with visual degradation. This is important to note since it is not uncommon for sport officials to work sport contests with acuity levels as low as 20/50 or more. Based on the results of this study it is recommended that all sport officials be administered standard visual acuity testing. It is also suggested that sport official governing bodies consider visual skills testing in addition to visual acuity testing for all sport officials. Suggestions for further research include testing the visual judgement of sport officials while they are in a dynamic state of motion (eg, basketball, soccer, etc.)


This data was analyzed with permission from the intramural department at Texas A&M University-Corpus Christi. Special thanks to the Visual Fitness Institute’s Barry Seiller, MD, and Kathy Puchalski, RN for their guidance and support of this project.