Carmen Barnhardt, O.D., M.S., a Sandra S. Block, O.D., M.Ed., b Beth Deemer, O.D., a Amy Jo Calder, O.D., a and Paul DeLand, Ph.D.

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1 Optometry (2006) 77, Color vision screening for individuals with intellectual disabilities: A comparison between the Neitz Test of Color Vision and Color Vision Testing Made Easy Carmen Barnhardt, O.D., M.S., a Sandra S. Block, O.D., M.Ed., b Beth Deemer, O.D., a Amy Jo Calder, O.D., a and Paul DeLand, Ph.D. c a Southern California College of Optometry, Fullerton, California; b Illinois College of Optometry, Chicago, Illinois; and c California State University, Fullerton, California. KEYWORDS: Intellectual disability; Mental retardation; Developmental disabilities; Color vision defects/ diagnosis; Color perception tests/ methods; Vision screening/methods Abstract BACKGROUND: The Neitz Test of Color Vision (Neitz) and Color Vision Testing Made Easy (CVTME) were compared to determine which test was more effective in evaluating patients with intellectual disability (i.e., mental retardation) and developmental delay. METHODS: Two hundred eight Special Olympics floor hockey athletes were screened in San Diego, California, and 93 athletes were screened in Long Beach, California for a total of 301 athletes. Each athlete was administered the CVTME and the Neitz tests. RESULTS: The pass rate for the CVTME was 94.6% (n 93) at Long Beach and 96.2% (n 208) at San Diego. Every athlete was able to complete the CVTME. The pass rate for the Neitz was 38.7% at Long Beach and 56.7% at San Diego. Additionally, 10.8% of the Long Beach athletes and 12.5% of the San Diego athletes were unable to understand the Neitz. In addition, there was a low level of agreement between the results from the 2 tests with kappa for the San Diego data and for the Long Beach data. CONCLUSIONS: This study suggests that the CVTME continues to be the screening test of choice in evaluating color vision in individuals with intellectual disability. The Neitz had more failing scores on the first attempt and more total failing scores leading to over-referrals, making it an inappropriate screening test for individuals with intellectual disability and developmental delay. Optometry 2006;77: Color vision testing is an important aspect of vision screenings. Color vision screening is especially important in the special needs population because some studies have found that this population tends to have a higher prevalence of color vision deficiencies. 1 Perez-Carpinell et al. 2 found that 23% of individuals with Down syndrome had a color vision defect when tested with the Ishihara Color Plates and Corresponding author: Carmen Barnhardt, O.D., M.S., 2575 Yorba Linda Blvd., Fullerton, California cbarnhardt@scco.edu the anomaloscope. However, Erickson and Block 3 found that only 7.5% of males and 0.6% of females in the special needs population have abnormal color vision, using the Color Vision Testing Made Easy (CVTME; TL Wagner, Home Vision Care, USA, Anaheim, California) test. These findings are consistent with the prevalence in the general population of 8% and 0.5%, respectively. 4 Several methods have been used to assess color vision in a screening environment; the most common among these are pseudoisochromatic designs. 5 These include the American Optical Hardy-Rand-Rittler (AO-HRR), the APT /06/$ -see front matter 2006 American Optometric Association. All rights reserved. doi: /j.optm

2 212 Optometry, Vol 77, No 5, May 2006 Table 1A Figure 1 The Color Vision Testing Made Easy. (LKC Technologies, Inc., Gaithersburg, Maryland) and the Ishihara test (Ishihara Color Vision Plate). Each of these tests presents a symbol comprised of colored dots surrounded by a background of different-colored dots. Although the directions provided with each test appear to be simple, color vision testing of individuals with intellectual disability (i.e., mental retardation) and developmental delays has been challenging. The primary concern in testing this population is their ability to understand what is expected from them while performing the test.2,6 Perez- Figure 2 The Neitz Test of Color Vision. Results of the CVMET by location Event Pass Rate Fail Rate Long Beach San Diego Total 94.6% (88/93) 96.2% (200/208) 95.7% (288/301) 5.4% (5/93) 3.8% (8/208) 4.3% (13/301) Carpinell et al.2 found that 79% of a population with Down syndrome was able to perform the Ishihara Color Vision Plate test. Additionally, data were reviewed from Archer s1 study along with IQ scores and a significant interaction between academic level and color blindness was found, leading the reviewer to believe that the failures could be attributed to the subjects inabilities to comprehend the test and maintain attention to it. 6 Limited comprehension of testing expectations on the part of the patient can lead to confusion in the responses, which makes it difficult to determine whether a patient is manifesting a color deficiency or simply not understanding the instructions given to them. The CVTME test was developed to help improve the sensitivity of detecting color vision defects in young children.7 The CVTME uses a vanishing pseudoisochromatic plate design (the figure is not visible for an observer with a color vision defect) with shapes that are familiar to children instead of numbers. The shapes are a circle, square, and star (see Figure 1). The demonstration card may be used for matching purposes. The test is designed to detect malingering and guessing and allows the examiner to verify if the patient understands the directions by including at least 1 object on the first 6 of the 9 total cards that are not color sensitive.7 This means that on the first 6 cards, even colordeficient patients will be able to identify one of the objects. On the last 3 plates all of the figures are color sensitive. Cotter et al.8 concluded that the CVTME appeared to be as sensitive (90.5%) as the Ishihara test in identifying red green defects in adults, as well as, being an effective screening test in children. The specificity of the CVTME was found to be 100%. Although it has been reported that the CVTME has the tendency to pass very mild deuteranomals, the colorimetric design of the CVTME was found to be reasonable.9 It was also found to be highly testable in screening individuals with intellectual disability for color deficiencies at the Special Olympics Opening Eyes vision screening, having a 93.2% overall rate of testability for the 1,078 athletes screened.3 Because of the high sensitivity and specificity of this test, along with simple instructions, it is now the preferred screening device for individuals with intellectual disability.3 The Neitz Test of Color Vision (Neitz) is one of the newest methods of screening for color vision defects. Neitz and Neitz10 have shown the test to be an accurate means of identifying individuals with color vision deficiencies. The authors suggest that this test identifies more color vision defects than traditional pseudoisochromatic plate tests because it detects the 2 main classes of defects, red green and

3 Barnhardt et al Issue Highlight 213 Table 1B Results of the Neitz by location Event Pass Rate Fail Rate Not Testable Long Beach 38.7% (36/93) 50.5% (47/93) 10.8% (10/93) San Diego 56.7% (118/208) 30.8% (64/208) 12.5% (26/208) Total 51.1% (154/301) 36.9% (111/301) 12% (36/301) blue yellow. 11 It is also reported to differentiate between the 2 subtypes of red green defects, deutan and protan, as well as the ability to rate the severity, 11 whereas the CVTME only detects if a red green color defect is present. Advantages to the Neitz are that it may be administered in fluorescent light, daylight, or a combination; it is suitable for group administration; and is reported to take less than 5 minutes to administer and score. 11 The Neitz is a hybrid test using vanishing pseudoisochromatic and transformation (observers with normal and defective color vision identify different figures) designs. There are 3 different forms of the Neitz test; in each form, grayscale and colored dots are surrounded by a neutral background. Nine figures presented on a single page are shown to an individual who is instructed to put an X on the correct match from the multiple-choice options printed below each figure 11 (see Figure 2). The first figure is a demonstration item, 2 figures detect blue yellow defects, and the remaining 6 detect red green defects. Color vision deficiency is suggested by failing to identify the correct colored outline, either by choosing an incorrect shape or indicating that there is no shape. Special populations have a higher incidence of vision dysfunction and ocular pathology. 5 Color vision testing can assist in the diagnosis of decreased visual acuity of unknown cause, the progression of retinal disease, and the effect of retinotoxic medications. 12 Therefore, the detection of blue yellow defects could confirm suspicions of retinal problems during screening situations and lead to appropriate referral and care. Because the Neitz allows for the identification of blue yellow defects, this may prove to be a better test for this population because it provides for broader diagnosis of color vision problems. A review of the literature found no previously published study comparing results between the Neitz and the CVTME in the general or special needs populations. The primary purpose of this study was to investigate testability of the Neitz versus the CVTME in a population of individuals with intellectual disability. The secondary purposes were to evaluate if the Neitz does, in fact identify more color vision defects in individuals with intellectual disability than the CVTME and to investigate if one of the tests is easier than the other to administer in this population. Methods The Neitz and the CVTME were administered at the Special Olympics floor hockey tournament in San Diego, California, February 9 10, 2002 and at the Southern California Summer Games in Long Beach, California, June 15 16, The athletes participating in Special Olympics consist of individuals who are at least 8 years of age and who have 1 of the following conditions: intellectual disability, cognitive delays as measured by formal assessment, or significant learning or vocational problems owing to cognitive delay that require or have required specially designed instruction. 13 Permission to conduct the study was obtained through Special Olympics, Inc. and approved by the Institutional Review Board of the Illinois College of Optometry. For the CVTME, athletes were screened binocularly under a combination of natural and fluorescent lighting in San Diego, because the screening was indoors, and under natural lighting in Long Beach, because the screening was outdoors. The CVTME can be administered under natural sunlight or fluorescent lighting. 7 Screening distance was 40 to 75 cm but was not always maintained because of the habitual posture of each individual athlete. Each athlete was given a cotton swab and asked to point to the ball (circle) on the demonstration card as an orientation to the test, as well as, to verify that the athlete understood the directions. If the athlete responded correctly to the target, the athlete proceeded to the test in which the 9 test cards were shown in consecutive order. If the athlete correctly identified the target on 8 of 9 test plates, it was considered a pass. If the athlete identified less than 8 of the 9 test plates correctly, the plates were presented a second time. On the retest, the athlete needed to obtain a score of 9 of 9 to be considered to have normal color vision. 3 If there was a score of less Table 2A Results of the CVTME and Neitz (San Diego) Color Test Neitz, Pass Neitz, Fail Neitz, Untestable Total CVTME, pass 59% (118) 30% (60) 11% (22) 100% (200) CVTME, fail 0 50% (4) 50% (4) 100% (8) Total 56.7% (118) 30.8% (64) 12.5% (26) 100% (208)

4 214 Optometry, Vol 77, No 5, May 2006 Table 2B Results of the CVTME and Neitz (Long Beach) Color Test Neitz, Pass Neitz, Fail Neitz, Untestable Total CVTME, pass 39.8% (35) 50% (44) 10.2% (9) 100% (88) CVTME, fail 20% (1) 60% (3) 20% (1) 100% (5) Total 38.7% (36) 50.5% (47) 10.8% (10) 100% (93) than 9 on the second trial, the athlete was considered to have a red green color deficiency. For the Neitz test, athletes were screened binocularly under the same conditions described above. Each athlete was given 1 of the 3 forms of the test and a pencil. To assess the testability, each athlete was shown the example square, which is the first of 9 panels on the form. The athlete was instructed to put an X through the correct match or to trace the colored picture that was seen within the box. Tracing was sometimes easier for athletes who had a difficult time understanding the matching concept. The athlete was then asked to complete each of the remaining panels in the same manner. If the athlete made any error on the 8 remaining panels, the test was immediately administered again with a different test form. To be labeled as having normal color vision, all 8 panels had to be identified correctly. If fewer than 8 panels were correct, the athlete was classified as color deficient, and the type of color deficiency was categorized using the criteria provided by the scoring key. 11 Any athlete that had an initial score of 3 of 9 on the Neitz was labeled untestable. This score was chosen because many of the athletes thought that all of the panels were circles yet only 3 items had a circle as the correct response. These tests were performed at 2 Special Olympics Lions Club International Opening Eyes Vision screenings. Volunteers performed the standard color test, which for these screenings was the CVTME. The volunteers conducting the test did not know that the data were being used to compare 2 different color vision tests. Because the Neitz was the test being compared with the standard CVTME, the Neitz was only administered by 2 of the authors (A.C. and B.D.). These tests were performed at a screening and the order of the administration of the color vision tests was not controlled. Athletes went to the color vision station where they either completed the CVTME followed by the Netiz or the Neitz followed by the CVTME. The CVTME and the Neitz were administered to 208 athletes (age range, 12 to 57 years) at the San Diego games; 31% were female. These tests were also administered to 93 athletes (age range 9 to 68 years) at the Long Beach games; 46% were female. Results All athletes who completed both the CVTME and the Neitz test were included as subjects in the study. No subjects were excluded owing to apparent pathologic cause or the presence of a color vision defect associated with ocular pathology. Tables 1A and B show, by location, the CVTME and Neitz test results, respectively. The San Diego and Long Beach samples have comparable CVTME results with 3.8% (8 of 208) and 5.4% (5 of 93) failure rates, respectively. These rates are not significantly different ( , df 1, p 0.55). In contrast, the response profiles on the Neitz test for the 2 locations are significantly different ( , df 2, p 0.004). While the nontestability rates for the Neitz were comparable for the 2 locations (at Long Beach 10.8% [10 of 93] were unable to complete the test versus 12.5% [26 of 208] at San Diego), the Long Beach failure rate was 50.5% (47 of 93), whereas for the San Diego sample it was 30.8% (64 of 208). In addition, the need for retests was significantly greater for the Neitz test than for the CVTME at both locations. At Long Beach, 64.5% of the subjects required a retest on the Neitz test, whereas 10.8% required a retest on the CVTME (p 0.001, McNemar Test). For the San Diego data, the analogous frequencies were 42.3% and 6.7% (p.001, McNemar Test). The tendency for the Long Beach athletes to do poorer and require more retests on the Neitz test than the San Diego athletes is consistent with differences found between the 2 settings and with the differences in the authors clinical impressions of the 2 sets of athletes. The San Diego screening was held indoors in an air-conditioned room, whereas Table 3 Failure rate on the CVTME and Neitz by gender San Diego Long Beach CVTME Neitz CVTME Neitz Male 8.00% (4/50) 27.8% (40/144) 4.86% (137/144) 44.00% (22/50) Female 2.33% (1/43) 37.5% (24/64) 1.56% (1/64) 58.10% (25/43) 2 Test Results , df 1 p , df 2 p , df 1 p , df 2 p.40

5 Barnhardt et al Issue Highlight 215 Table 4 Type of color defect identified by the Neitz Red Green Blue Yellow Both Long Beach San Diego the Neitz test results show a much higher prevalence of red green defects than do the CVTME results at both locations (for the Long Beach data, kappa and for San Diego, kappa 0.077). the Long Beach screening was held outdoors in a tent. The high outdoor temperature in Long Beach may have had a negative effect on the athletes performances. Additionally, although no intelligence testing results were available, the authors clinical impression was that the athletes at the San Diego games were functioning at a higher level than the athletes screened in Long Beach. The San Diego games consisted solely of floor hockey players who were capable of playing a complicated team game, whereas the athletes at the Long Beach games were only required to exhibit a single physical skill, for example swimming, walking, or running. Because these 2 samples do not appear to be similar, their data were not pooled and instead were analyzed separately. Tables 2A and B show the cross-classified frequencies on the CVTME and the Neitz test for each location. At both locations, the pass rate for the CVTME was high (96.2% [200 of 208] at San Diego and 94.6% [88 of 93] at Long Beach). The pass rates on the Neitz were considerably lower (56.7% [118 of 208] at San Diego and 38.7% [36 of 93] at Long Beach). Among those athletes who passed the CVTME, a substantial proportion failed the Neitz test (30% [60 of 200] at San Diego and 50% [44 of 88] at Long Beach). Likewise, many athletes who passed the CVTME were classified as untestable on the Neitz test (11% [22 of 200] at San Diego and 10.2% [9 of 88] at Long Beach). Table 3 shows the failure rates for each test by gender at the 2 locations. These rates are consistent with the overall failure rates, and the male and female rates were not significantly different for each test at both locations. Table 4 shows the frequency of defect types detected on the Neitz test at each location. Red green defects were the most common with only one subject exhibiting a blue yellow defect and not a red green defect. Tables 5A and B compare the CVTME and the Neitz test on the detection of red green defects. They show the cross-classified tallies of the 2 tests results on this defect for each location with those subjects having a nonspecific defect or only a blue yellow defect on the Neitz test excluded. Agreement between these 2 tests in the detection of a red green defect is low because Discussion The results of this study suggest that the Neitz Test of Color Vision test is not an appropriate test for evaluating color vision in individuals with intellectual disability and developmental delays. It is our opinion that the instructions were more difficult for the subjects to understand and required more time for them to comprehend than those for the CVTME. Even with this additional time required to explain the Neitz test, there was still a higher number of retests needed on the Neitz test compared with the CVTME. Neitz and Neitz 10 found that 18% (905 of 5,129) of their subjects required a second administration of the Neitz. In our sample, 42% (88 of 208) of the athletes in San Diego and 65% (60 of 93) of the athletes in Long Beach required a second administration. The grayscale design of the Neitz creates a set of darker dots on each plate intended to serve as a distracter. Unfortunately, this proved to be too distracting for our population. The Neitz test also had a higher number of total failures than the CVTME. Although one would expect the Neitz to have a higher number of total failures because it identifies more types of color vision defects, we found that it identified significantly more red green defects than the CVTME. In addition, the number of red green defects identified on the Neitz was no different for males versus females as one would expect given the prevalence of red green color vision defects. The number of blue yellow defects on the Neitz test was low (0.3%, 1 of 301) and did not contribute to the increased number of failures on the Neitz. Only 59.1% (123 of 208) of the San Diego athletes and 44.1% (41 of 93) of the Long Beach athletes had the same results on both tests (i.e., passed each test or failed each test). In particular, many of the athletes failed the Neitz yet passed the CVTME. This occurred in 27.9% (58 of 208) of the athletes in San Diego and in 49.5% (46 of 93) of the athletes in Long Beach. This explains the poor agreement between the results on the 2 tests at both screening sites. The results of our study show that the CVTME, with a higher testability rate, continues to be the preferred color vision screening test for individuals with intellectual disability and developmental delays. The results of this study Table 5A Detection of red green defects: CVTME versus Neitz (Long Beach) Color Test Neitz, Normal Color Vision Neitz, Red Green Defect CVTME, normal color vision (94.4%) CVTME, red green defect (5.6%) Total 46 (51.7%) 43 (48.3%) 89 Total

6 216 Optometry, Vol 77, No 5, May 2006 Table 5B Detection of red green defects: CVTME versus Neitz (San Diego) Color Test Neitz, Normal Color Vision Neitz, Red-Green Defect CVTME, normal color vision (95.9%) CVTME, red green defect (4.1%) Total 145 (75.1%) 48 (24.9%) 193 Total indicate that the Neitz test is not an appropriate screening test for this population because of the high rates of failure and untestability. In addition, the Neitz was found to be more difficult to administer and more frustrating for the athletes to complete. However, this study was done on individuals with intellectual disabilities and should not be generalized to other populations without further research. Acknowledgments The authors thank the Special Olympics Lions Club International Opening Eyes Organization for allowing them to participate in their vision screening. Additionally, the authors thank the Southern California College of Optometry, Illinois College of Optometry, and the California Chapter of the American Academy of Optometry for their financial support of this project. References 1. Archer RE. Color discrimination and association of educable mentally retarded children. Doctoral Dissertation. Colorado State College, Pueblo, CO (1964). 2. Perez-Carpinell J, de Fez MD, Climent V. Vision evaluation in people with Down s syndrome. Ophthalmic Physiol Opt 1994;14: Erickson GB, Block SS. Testability of a color vision screening test in a population with mental retardation. J Am Optom Assoc 1999;70: Flanagan J. Colour vision testing. In: Elliott DB, et al, (eds). Clinical procedures in primary eye care. New York: Butterworth-Heinemann, 1997: Scheiman M. Assessment and management of the exceptional child. In: Rosenbloom AA, Morgan MW, eds. Principles and practice of pediatric optometry. Philadelphia: Lippincott, 1990: Schein JD, Salavia JA. Colour blindness in mentally retarded children. Except Child 1969; 35: Waggoner TL. Color Vision Test Made Easy. Anaheim, California: Home Vision Care, Cotter SA, Lee DY, French AL. Evaluation of a new color vision test: color vision testing made easy. Optom Vis Sci 1999;76: Dain SJ. Evaluation of colour vision testing made easy. In: Mollon JD, Pokorny J, Knoblauch K, eds. Normal & defective color vision. New York: Oxford University Press, Neitz M, Neitz J. A new mass screening test for color-vision deficiencies in children. Color Res Application 26 (Suppl):S Neitz J, Summerfelt P, Neitz M. The Neitz Test of Color Vision Manual. Los Angeles, CA: Western Psychological Services Publishers Distributors. 12. Stout AU, Wright KW. Pediatric eye examinations. In: Wright KW, ed. Pediatric ophthalmology and strabismus. St. Louis: Mosby, 1995: Special Olympics website. Olympics Public Website/English/Compete/Eligibility/default.htm. Last accessed March 22, 2006.