We recently discovered that 10 of 310 (3.2%) participants were erroneously enrolled in the Convergence Insufficiency Treatment Trial – Attention and Reading Trial (CITT-ART) as they did not meet the eligibility criterion for the blur values of positive fusional convergence. However, the blur values (used to characterise within- and between-group change in fusional vergence) of ineligible participants (mean = 13.0 Δ) were similar to those of eligible participants (mean = 11.4 Δ). Thus far, we have not found the inclusion of the ineligible participants to have a meaningful effect on any of our published results. Eight of the 10 ineligible participants were included in the dataset used for the analyses presented in the manuscript titled Effectiveness of Vergence/Accommodative Therapy for Accommodative Dysfunction in Children with Convergence Insufficiency.1
Sensitivity analyses excluding these eight participants demonstrated no meaningful differences in the results. Table 2 below (table number corresponds to the table number in the published paper) shows the inclusion of the participants in the reported results had minimal impact on baseline demographic and clinical characteristics of participants by treatment group. Tables 3 to 5 below also show no changes in the status of statistical significance of various comparisons in accommodative amplitude or facility between time points and between treatment groups. The small changes in effect size are not meaningful.
Table 2.
Baseline demographics and clinical characteristics of participants with reduced accommodative (a) amplitude, (b) facility by treatment group
| (2a) Reduced accommodative amplitude | Vergence/Accommodative Therapy (N = 113) |
Placebo Therapy (N = 63) |
Overall (N = 176) |
|---|---|---|---|
| Age (years), mean (S.D.) | 10.8 (1.5) | 10.9 (1.4) | 10.9 (1.5) |
| Convergence Insufficiency Symptom Survey score, mean (S.D.) | 30.4 (8.7) | 32 (8.7) | 30.9 (8.7) |
| Monocular Accommodative Amplitude (D), mean (S.D.) | 7.6 (1.7) | 7.2 (1.7) | 7.4 (1.7) |
| Monocular Accommodative Facility (cpm), mean (S.D.) | 6.8 (4.2) | 6.9 (5) | 6.8 (4.5) |
| Exodeviation at distance (Δ), mean (S.D.) | −2 (2.9) | −2.2 (4.3) | −2.1 (3.5) |
| Exodeviation at near (Δ), mean (S.D.) | −10 (4) | −10.2 (5.7) | −10.1 (4.7) |
| Near Point of Convergence (cm), mean (S.D.) | 16.2 (8.3) | 17 (8.2) | 16.5 (8.2) |
| Near Point of Convergence recovery (cm), mean (S.D.) | 19.9 (9.1) | 20.8 (8.9) | 20.3 (9) |
| Positive Fusional Vergence Blur/Break† (Δ), mean (S.D.) | 10.7 (4.2) | 11.2 (4.3) | 10.9 (4.2) |
| (2b) Reduced accommodative facility | Vergence/Accommodative Therapy (N = 68) |
Placebo Therapy (N = 34) |
Overall (N = 102) |
|---|---|---|---|
| Age (years), mean (S.D.) | 10.9 (1.4) | 10.7 (1.5) | 10.8 (1.4) |
| Convergence Insufficiency Symptom Survey score, mean (S.D.) | 30.5 (9.1) | 30.4 (8.8) | 30.5 (9) |
| Monocular Accommodative Amplitude (D), mean (S.D.) | 9.5 (3.4) | 8.4 (3.6) | 9.1 (3.5) |
| Monocular Accommodative Facility (cpm), mean (S.D.) | 2.9 (1.8) | 2.7 (1.9) | 2.8 (1.8) |
| Exodeviation at distance (Δ), mean (S.D.) | −1.5 (2.2) | −1 (1.6) | −1.3 (2.1) |
| Exodeviation at near (Δ), mean (S.D.) | −9.2 (3.6) | −9.1 (4.2) | −9.2 (3.8) |
| Near Point of Convergence (cm), mean (S.D.) | 15.2 (8.7) | 15.7 (8.2) | 15.4 (8.5) |
| Near Point of Convergence recovery (cm), mean (S.D.) | 19 (9.8) | 19.7 (8.7) | 19.2 (9.4) |
| Positive Fusional Vergence Blur/Break† (Δ), mean (S.D.) | 10.7 (4.2) | 10.9 (4.1) | 10.8 (4.1) |
The blur finding was used, but if blur was not reported, the break finding was used. SD, standard deviation; D, dioptres; cpm, cycles per minute; Δ, prism dioptres.
Table 3.
Change in accommodative amplitude and facility by treatment group between successive examinations
| Therapy | Vergence/Accommodative | Placebo | ||
|---|---|---|---|---|
| Time Intervals | Change (95% CI)† | p Value | Change (95% CI)† |
p Value |
| Accommodative Amplitude (dioptres) | ||||
| Baseline to Week 4 | 6.2 (4.9, 7.4) | <0.001 | 2.9 (1.2, 4.5) | 0.01 |
| Week 4 to Week 8 | 2 (0.8, 3.2) | 0.03 | 1.1 (−0.6, 2.7) | 0.99 |
| Week 8 to Week 12 | −0.3 (−1.5, 1) | 0.99 | 0.5 (−1.2, 2.2) | 0.99 |
| Week 12 to Week 16 | 0.7 (−0.5, 2) | 0.33 | 5 (3.3, 6.6) | 0.99 |
| Baseline to Week 16 | 8.6 (7.4, 9.9) | <0.001 | 5 (3.3, 6.6) | <0.001 |
| Accommodative facility (cycles per minute) | ||||
| Baseline to Week 4 | 5.9 (4.7, 7.2) | <0.001 | 4.2 (2.5, 6) | <0.001 |
| Week 4 to Week 8 | 3.6 (2.3, 4.8) | <0.001 | 1.6 (−0.1, 3.4) | 0.71 |
| Week 8 to Week 12 | 2.9 (1.6, 4.1) | <0.001 | 0.1 (−1.6, 1.8) | 0.99 |
| Week 12 to Week 16 | 1 (−0.3, 2.2) | 0.91 | 1.6 (−0.1, 3.3) | 0.75 |
| Baseline to Week 16 | 13.4 (12.1, 14.6) | <0.001 | 7.5 (5.8, 9.3) | <0.001 |
Change was computed as the mean value for the later visit minus the mean value for the earlier visit. CI, confidence interval.
Table 4.
Treatment group difference at each time point
| Accommodative
Amplitude (dioptres) |
Accommodative
Facility (cycles per minutes) |
|||
|---|---|---|---|---|
| Time Point | Difference (95% CI)† |
p value | Difference (95% CI)† |
p value |
| Baseline | 0.3 (−1.6, 22) | 0.99 | 0.3 (−1.6, 2.2) | 0.99 |
| Week 4 | 3.6 (1.7, 5.5) | 0.004 | 2.0 (0.1, 3.9) | 0.47 |
| Week 8 | 4.5 (2.6, 6.5) | <0.001 | 4.0 (2.1, 5.9) | <0.001 |
| Week 12 | 3.8 (1.9, 5.7) | 0.002 | 6.7 (4.9, 8.6) | <0.001 |
| Week 16 | 3.9 (2, 5.8) | 0.01 | 6.1 (4.2, 8) | <0.001 |
Difference was computed as the mean value for the vergence/accommodative therapy group minus the mean value for the placebo therapy group at each time point. CI, confidence interval.
Table 5.
Proportion of participants reaching normal accommodative amplitude or facility by treatment group at each time point
| Time Point | Vergence/Accommodative % (95% CI) |
Placebo % (95% CI) |
|---|---|---|
| Normal Accommodative Amplitude† | ||
| Week 4 | 47% (38% to 57%) | 18% (9% to 29%) |
| Week 8 | 59% (49% to 68%) | 22% (12% to 34%) |
| Week 12 | 63% (53% to 72%) | 35% (23% to 48%) |
| Week 16 | 68% (59% to 77%) | 32% (21% to 45%) |
| Normal Accommodative Facility† | ||
| Week 4 | 38% (26% to 51%) | 15% (5% to 31%) |
| Week 8 | 67% (54% to 78%) | 36% (20% to 55%) |
| Week 12 | 86% (76% to 94%) | 32% (17% to 51%) |
| Week 16 | 84% (73% to 92%) | 47% (30% to 65%) |
Normal accommodative amplitude defined as amplitude ≥ 14 dioptres. Normal accommodative facility defined as facility ≥ 11 cycles per minute. CI, confidence interval.
The published paper also included the group comparisons of the proportion of participants attaining normal amplitude of accommodation or normal facility at week 16 and rate of change in accommodative amplitude or facility between the vergence/accommodative and placebo groups. Findings after excluding 8 ineligible participants are below. Again, the changes in effect size are not meaningful.
Treatment group differences in proportion achieving normal accommodative amplitude or facility at 16 weeks
| Difference (95% CI), p value |
|---|
| Accommodative amplitude 36.4% (22%, 50.9%), p<.0001 |
| Accommodative facility 37.3% (18.3%, 56.3%), p<.0001 |
Average rate of change in accommodative amplitude or facility per week for participants assigned to vergence/accommodative therapy
| Time Interval | Average Rate of Change per Week (95% CI) |
|---|---|
| Accommodative Amplitude (dioptres) | |
| Baseline to Week 4 | 1.55 (1.24, 1.86) |
| Week 4 to Week 16 | 0.2 (0.1, 0.31) |
| Accommodative Facility (cycles per minute) | |
| Baseline to Week 4 | 1.48 (1.18, 1.79) |
| Week 4 to Week 16 | 0.62 (0.51, 0.72) |
Reference
- 1.Chen AM, Roberts TL, Cotter SA, Kulp MT, Sinnott LT, Borsting EJ, Tea YC, Jones-Jordan LA, Hertle R, Mitchell GL, Arnold LE, Chase C, Scheiman MM, CITT-ART Investigator Group. Effectiveness of vergence/accommodative therapy for accommodative dysfunction in children with convergence insufficiency. Ophthalmic Physiol Opt 2021:41(1):21–32. [DOI] [PMC free article] [PubMed] [Google Scholar]