ORIGINAL ARTICLE Reliability of the Developmental Eye Movement Test Gale Orlansky*, Kristine B. Hopkins † , G. Lynn Mitchell ‡ , Kristine Huang § , Marcela Frazier § , Catherine Heyman § , and Mitchell Scheiman § ABSTRACT Purpose. This study evaluated the repeatability of the Developmental Eye Movement Test (DEM) with three consecutive administrations on two separate visits to 181 children between the ages of 6 years and 11 years 11 months. Methods. Children with visual acuity of 20/25, normal binocularity, and accommodation were administered three different versions of the DEM test. One to 4 weeks after the first administration of the DEM, the children were tested again using the same order for the three versions of the DEM. Measures of within- and between-session repeatability for the vertical-adjusted time, horizontal-adjusted time, ratio, and error scores were determined. Results. The within-session repeatability for vertical- and horizontal-adjusted time were good to excellent but were poor to good for ratio, and poor to fair for errors. The between-session intraclass correlation coefficients were fair to good for both the vertical and horizontal scores but poor for the ratio and error scores. The repeatability of the pass-fail diagnostic classification within a single session for each subject on test and retest was compared. The percentage of patients who remained in the same classification ranged from 71 to 100% for both vertical and horizontal scores. Wider variability was seen with the ratio and error scores showing between 47 and 100% of the children remaining classified as pass or fail with repeated administrations of the DEM. Such findings would suggest that children in this age range may show improvements in all four test scores without any intervention. Conclusions. Although the DEM is widely used in optometric practice, the results of this study suggest that clinicians should be cautious about using the DEM test in isolation for reaching a diagnosis or monitoring the effectiveness of treatment for saccadic dysfunction. (Optom Vis Sci 2011;88:1507–1519) Key Words: reading eye movements, saccadic eye movements, Developmental Eye Movement (DEM) test E ye movement disorders in children are a diagnostic and man- agement concern of optometrists because of the effect such problems may have on reading and other academic func- tions. Unlike accommodative and binocular vision skills, which reach adult levels of development very early in infancy, clinical assessment indicates that eye movement development is consider- ably slower, continuing through the early elementary school years. 1,2 Because of the long developmental process of eye move- ment control, slow development can leave a child with inadequate skills to meet the demands of the classroom. 3 It is therefore important for clinicians to be able to evaluate eye movement function and to prescribe appropriate treatment if a disorder is detected. In the past three decades, several types of tests have been developed to evaluate eye movements required while reading. Tests may involve direct observation by the clinician, timed/standardized tests involving a visual-verbal format and objective eye movement recording using electro-oculographic in- struments. There are, however, advantages and disadvantages as- sociated with all three of these methods. Infrared limbal sensing procedures like the Visagraph III or the Readalyzer are expensive, not widely used, and may be difficult to use with young elementary school children. 4 Subjective techniques involving observation of the patient’s eye movements have been developed along with rating scales. The Southern California College of Optometry rating sys- tem tests for fixation maintenance, pursuits and saccades based on *OD, MEd † OD, MSPH, FAAO ‡ MAS, FAAO § OD, MPH, FAAO Pennsylvania College of Optometry at Salus University, Philadelphia, Pennsyl- vania (GO, MS), University of Alabama at Birmingham School of Optometry, Birmingham, Alabama (KBH, MF), The Ohio State University College of Optom- etry, Columbus, Ohio (GLM), and Southern California College of Optometry, Fullerton, California (KH, CH). 1040-5488/11/8812-1507/0 VOL. 88, NO. 12, PP. 1507–1519 OPTOMETRY AND VISION SCIENCE Copyright © 2011 American Academy of Optometry Optometry and Vision Science, Vol. 88, No. 12, December 2011