Predicting potential acuities in amblyopes: predicting post-therapy acuity in amblyopes.

PURPOSE: Amblyopic patients, or their parents, often want to know the potential for success before committing to treatment. Recent reports have indicated that the pattern visual evoked potential (pVEP) can be used as a predictor of the success of amblyopia therapy. Unfortunately, these studies did not determine if acuity estimates from pVEPs could accurately predict the acuity post-treatment. Furthermore, pVEPs are not always practical to obtain because of the time necessary to acquire the data. Sweep VEPs (sVEP) offer the advantage of rapidly estimating visual acuity in amblyopic patients. In this retrospective study, the relationship between sVEP acuities measured pre-amblyopic therapy and Snellen acuities measured post-amblyopic therapy was determined. METHODS: Seventeen patients with amblyopia were studied. Monocular sVEP and Snellen acuities were determined pre-amblyopic therapy and Snellen acuities were determined post-amblyopic therapy. An Enfant 4010 computer system was used to produce the stimuli, record the VEPs, and extrapolate the acuity. The stimuli were horizontally oriented, sine wave gratings (11 spatial frequencies from 2 to 24 cpd) with a contrast of 80%, counterphased at 7.5 Hz. Standard VEP recording techniques were employed. Therapy consisted of the full refractive correction and occlusion combined with active vision therapy. RESULTS: The patients demonstrated a significant improvement in pre- to post-amblyopic therapy Snellen acuities (P < 0.00001). The intraclass correlation coefficient (r (i)) between the pre-therapy sVEP acuities and the post-therapy Snellen acuities was 0.73. A paired t-test did not find a significant difference between the two sets of data (P = 0.94). For the amblyopes in this study, the average difference (+/-SD) in the sVEP acuity estimate and the final Snellen visual acuity was +0.002 +/- 0.123 logMAR acuity lines. CONCLUSION: The results indicate that pre-amblyopic therapy sVEP acuity can be a good predictor of post-amblyopic therapy Snellen acuity.

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.

Validity and reliability of the revised convergence insufficiency symptom survey in adults.

PURPOSE: To assess the validity and reliability of the revised Convergence Insufficiency Symptom Survey (CISS) in adults aged 19-30 years. The CISS was developed to be the primary outcome measure for studies evaluating various treatments for convergence insufficiency (CI). METHODS: CISS mean scores from adults with symptomatic CI and adults with normal binocular vision (NBV) were compared to assess the survey's validity. Adults with symptomatic CI were given the CISS twice to evaluate reliability, which was assessed using intraclass correlation coefficient (ICC) and 95% limits of agreement. RESULTS: Forty-six adults with CI and 46 adults with NBV participated in the study. The mean CISS score for the CI group was 37.3 (S.D. = 9.3) and 11.0 (S.D. = 8.2) for the NBV group. These mean values were significantly different (p < 0.0001). Good discrimination (sensitivity = 97.8%, specificity = 87%) was obtained using a score of 21 or higher. For the CI group the ICC was 0.885 (95% CI of 0.798, 0.936) and the 95% limits of agreement were -9.0 to 7.6. CONCLUSIONS: Adults with symptomatic CI had a significantly higher CISS score than adults with NBV. The results of the study demonstrate that the CISS is a valid and reliable instrument that can be used clinically or as an outcome measure for research studies of adults with CI.

Validity and reliability of the revised convergence insufficiency symptom survey in children aged 9 to 18 years.

PURPOSE: To assess the validity and reliability of the Convergence Insufficiency Symptom Survey (CISS) in children aged 9 to 18 years. The CISS is the primary outcome measure for a pilot study evaluating two different treatments for convergence insufficiency (CI). METHODS: Children with CI were given the CISS twice to assess reliability. CISS scores for the first administration were also compared with scores from children with normal binocular vision to assess the validity of the CISS. RESULTS: Forty-seven children with CI and 56 children with normal binocular vision participated in the study. Reliability was assessed using intraclass correlation and 95% limits of agreement for the children with CI. For children with CI, the intraclass correlation was 0.77 (95% confidence interval, 0.613 to 0.873), and the 95% limits of agreement were -10.2 to +12.1. The mean (+/-SD) CISS score was 30.8 +/- 8.4 for the children with CI and 8.4 +/- 6.4 for the children with normal binocular vision. These means were significantly different (p < 0.0001). Good discrimination (sensitivity, 96%; specificity, 88%) was obtained using a score of >/=16. CONCLUSIONS: Children with CI showed a significantly higher CISS symptom score than children with normal binocular vision. The results of the study indicate that the CISS is a valid and reliable instrument to use as an outcome measure for children aged 9 to 18 who are enrolled in clinical research concerning CI.

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.