The Effect of Visual Function on the Batting Performance of Professional Baseball Players.

This report evaluates the role of the combined visual abilities of acuity, contrast sensitivity and presentation time on plate discipline and baseball batting performance. A visual function test (EVTS) was performed on 585 professional baseball players. The results were compared to several common plate-discipline measures. The EVTS test provides a single measure combining target size, contrast and presentation time. Correlations (statistically significant) were found between this measure and several plate discipline metrics (InzoneSwingPct, inzoneFbSwingPct, ChasePct, FbChasePct, BBperPa). Years of major league service did not appear to be related to visual ability. When comparing the best and worst 20% groups based on visual ability, statistically significant improvements ranging from 11.6% in BBperPa to 3.5% in inzoneSwingPct were noted in the better visual function group. Effect sizes ranged from 0.278 to 0.387. These results demonstrate the relationship between basic visual function and batting performance. These are the first results, on a large group at the professional level, to demonstrate this relationship statistically. These results may aid player selection, indicating that batters with better visual function are more likely to be successful when batting and more productive for their team.

The Hand-eye Coordination of Professional Baseball Players: The Relationship to Batting.

SIGNIFICANCE: A visuomotor skill (eye-hand visual-motor reaction time [EH-VMRT]) important for baseball performance is described. Eye-hand visual-motor reaction time represents the integration of visual information, perceptually based decisions, and motor movements to accomplish a specific task. The speed at which this occurs depends on many factors, some visual, some perceptual, and some motor related. PURPOSE: The purpose of this study was to describe the EH-VMRT ability and evaluate its relationship to the baseball batting performance of professional baseball players. METHODS: A commercially available EH-VMRT system was used on 450 professional baseball players. Results were retrospectively compared with standard, career, plate discipline metrics. RESULTS: Statistically significant correlations were found between the EH-VMRT metrics and plate discipline batting metrics. Better EH-VMRT ability also correlated with longer service in, and likelihood to achieve, the major-league level. The better (top 20%) EH-VMRT group had three fewer at bats before gaining a walk (22% decrease), as well as swinging 10 to 12% less often at pitches outside the strike zone and 6 to 7% less often at pitches in the strike zone as compared with the bottom 20% group. In addition, EH-VMRT displays a threshold-like relationship with the ability to gain a walk. CONCLUSIONS: These results describe the EH-VMRT ability of professional baseball players and show a significant relationship between the EH-VMRT ability and batting performance. These results may suggest a possible role in player selection, indicating that batters with better EH-VMRT may be more likely to reach the major-league level and be more productive for their team. Further studies will be needed to demonstrate whether training better EH-VMRT results in improved batting performance.

A pre-application drop containing carboxymethylcellulose can reduce multipurpose solution-induced corneal staining.

PURPOSE: Use of polyhexanide based multipurpose solutions (MPSs) for contact lens disinfection has been linked to low-grade corneal staining. In vitro data suggest that carboxymethylcellulose (CMC) may neutralize polyhexanides. The purpose of this investigation was to determine whether a pre-application drop of CMC reduces polyhexanide staining in vivo. METHODS: Thirty adapted soft contact lens (SCL) wearers participated in this investigator-masked, randomized, two-way cross-over study. Subjects wore a new Group II lens (alphafilcon A, 66% water) daily for 4 weeks and disinfected lenses using a MPS containing 0.0001% polyaminopropyl biguanide. A lens lubricant containing either CMC or povidone as the primary viscolyzer was applied to the lens each day before lens wear. Biomicroscopic signs and symptomatology were assessed. The difference in scores, 0 to 4 weeks and the difference between lubricants were analyzed. RESULTS: The cumulative fluorescein staining scores for combined eyes demonstrated a significant increase over time (e.g., cumulative staining score; p=0.004 and p<0.001 for CMC and povidone, respectively, matched pairs t-test, two-tailed), suggesting that for both lubricants the staining worsened with wear. This effect was expected and likely driven by the MPS. However, the mean cumulative staining scores for CMC and povidone were 2.8 and 2.6 out of 20 possible at baseline, increasing to 4.9 and 7.1 at 4 weeks, respectively. The increases were significantly different (p=0.003, matched pairs t-test, two-tailed) suggesting a greater increase in corneal staining for the povidone lubricant. The symptom scores were not significantly different, 0 to 4 weeks by regimen or between preinstillation drops. CONCLUSIONS: These results suggest that a CMC-containing preapplication drop can reduce corneal staining resulting from disinfection with a polyhexanide MPS. This result is consistent with a proposed mechanism for CMC to neutralize cationic disinfectants and may offer clinicians another means to reduce this type of corneal staining.

Color vision screening for individuals with intellectual disabilities: a comparison between the Neitz Test of Color Vision and Color Vision Testing Made Easy.

BACKGROUND: The Neitz Test of Color Vision (Neitz) and Color Vision Testing Made Easy(trade mark) (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 = 0.081 for the San Diego data and 0.028 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.

Developmental Eye Movement Test: reliability and symptomatology.

BACKGROUND: The Developmental Eye Movement Test (DEM) is a widely used visual skill test, especially in the context of a vision therapy evaluation. It is intended to diagnose oculomotor dysfunction (OMD) and can also identify deficient rapid automatized naming. As such, its reliability and associated symptomatology are important. METHODS: The DEM test-retest reliability was investigated within two populations: a group of 53 office patients who were participating in vision therapy evaluation in a private optometry practice, and a smaller group of 13 subjects at their school. One to four weeks separated the test and retest for both groups. We also studied the relationship between results on a questionnaire of symptoms associated with OMD and DEM test performance in these two populations. RESULTS: The first administration of the DEM significantly correlated with the second for all four of its scores for both groups. The office group had higher intra-class correlation coefficients than the school group. There was good agreement between test and re-test in terms of pass-fail classification for the office group. Symptomatic subjects performed poorer than asymptomatic subjects on the DEM. Failing the DEM Ratio, the score used to diagnose OMD, identified 90% of the subjects who were symptomatic. CONCLUSIONS: The DEM has good intra-subject test-retest reliability for all four of its scores when it is administered in an office setting to patients participating in a vision therapy evaluation. It also has good consistency in classifying patients as pass or fail. Performance on the DEM relates to certain symptoms that are associated with OMD.

Relationship between visual-motor integration and spatial organization of written language and math.

PURPOSE: The relationship between visual-motor integration and academic achievement is not clearly understood. The purpose of this study was to assess the type and frequency of errors made by children with poor visual-motor integration during a written language and math task. METHODS: Eighteen children with normal visual-motor integration (> or =36%) and 19 children with low visual-motor integration (< or =16%) participated in the study. The two groups had similar ages, gender profiles, and cognitive and reading levels. Each group copied and solved math problems and copied a written passage. The errors for the math and writing task were combined into a total error score, and the time taken to complete each task was combined into a total time score. RESULTS: The low visual-motor integration group made more errors than the normal visual-motor integration group. However, the time taken to copy both tasks was not different between the two groups. A secondary analysis of the errors revealed that alignment of numbers (p = 0.02), organization of math problems (p = 0.05), and spacing errors of letters and words (p = 0.01) were more common in the low visual-motor integration group. CONCLUSIONS: The results suggest that reduced visual-motor integration may contribute to poor spatial organization of written work.

A reevaluation of the Developmental Eye Movement (DEM) test's repeatability.

PURPOSE: To investigate the repeatability of the Developmental Eye Movement (DEM) Test in a group of third grade elementary school students. METHODS: Thirty, third grade children who passed a modified clinical technique vision screening were given the DEM and then retested 2 weeks later. RESULTS: A clinically and statistically significant improvement in mean scores from test to retest was found on the vertical time, horizontal time, and ratio score. The intraclass correlation coefficient (ICC) and the 95% limits of agreement (LoA) suggest that the vertical (ICC, 0.60; LoA, -4.2 +/- 16.5 s) and corrected horizontal (ICC, 0.55; LoA, -8.3 +/- 17.4 s) times have fair to good repeatability, whereas the ratio score was found to have poor repeatability (ICC, 0.27; LoA, -0.08 +/- 0.39). Based on these results, large changes can be expected on retest, which may result in a change in diagnostic classification from pass to fail. CONCLUSIONS: These results suggest that the ratio score of the DEM had poor repeatability in the third grade children who were evaluated. Poor repeatability of the ratio score may affect the clinician's diagnostic decisions and ability to monitor the effects of saccadic treatment.

Association of symptoms and convergence and accommodative insufficiency in school-age children.

BACKGROUND: The purpose of this article was to investigate the association between convergence insufficiency (CI) and accommodative insufficiency (AI) and symptoms in a group of school-aged children. METHODS: Children ages 8 to 15 years were recruited from two public and 2 private elementary schools in Southern California. The CI Symptom Survey (CISS) was administered to all children before a Modified Clinical Technique vision screening. Children with normal visual acuity, minimal uncorrected refractive error, and no strabismus were tested for CI and Al. RESULTS: Four hundred sixty nine children were initially screened and 392 participated in testing for CI and AI. Fifty-five percent of the children (218) were classified as having normal binocular vision (NBV), 4.6% (18) had three signs of CI, 12.7% (50) had two signs of CI, 10.5% (41) were classified as AI (with no signs of CI), and 16.6% (65) were classified as other. The symptom score was 3.78 for the NBV group, 4.6 for the two-sign CI group, 6.67 for the three-sign CI group, and 6.37 for the Al group. The three-sign CI and the Al groups scored significantly higher than the NBV group on the CISS (p < or = 0.001). CONCLUSION: CI and AI are common conditions in school-age children and are associated with increased symptoms.

Reliability of binocular vision measurements used in the classification of convergence insufficiency.

PURPOSE: To evaluate the reliability of binocular vision measurements used in the classification of convergence insufficiency. METHODS: Two examiners tested 20 fifth and sixth graders in a school setting who passed a screening of visual acuity, refraction, and binocularity. The tests, conducted using a standard protocol, consisted of von Graefe near heterophoria (NH), phorometric positive fusional vergence (PFV), nearpoint of convergence (NPC), and monocular pushup accommodative amplitude (AA). Each examiner measured each child three consecutive times for each test, on two separate occasions, spaced approximately 1 week apart. Intraexaminer and interexaminer agreement was assessed using intraclass correlation coefficients (ICC), the median absolute difference (MAD), and the coefficient of repeatability (COR). RESULTS: The within-session reliability of the NH (ICC: 0.95 to 0.99), NPC (ICC: 0.94 to 0.98), and AA (ICC: 0.88 to 0.95) were good, whereas the PFV was less reliable (ICC: 0.71 to 0.94). The intraexaminer reliability between sessions was good for the NPC (ICC: 0.92 and 0.89), less reliable for NH (ICC: 0.81 and 0.81) and AA (ICC: 0.89 and 0.69), and much less reliable for PFV break (ICC: 0.59 and 0.53). Typical between-session PFV differences (MAD) were between 3 and 4 delta, whereas the COR differences were as large as 12 delta. CONCLUSIONS: Three of the four measures (NH, NPC, and AA) often used in the classification of convergence insufficiency generally have good within-session and between-session reliability. The PFV break was found to have only fair reliability with clinically significant differences between sessions. The large potential test-retest differences found could complicate clinical decision-making in regards to diagnosis and treatment.