An Evaluation of Clinical Treatment of Convergence Insufficiency For Children With Reading Difficulties

Wolfgang A Dusek; Barbara K Pierscionek; Julie F McClelland

Disclosures

BMC Ophthalmol. 2011;11(21) 

In This Article

Results

Treatment category was not found to be associated with age, spherical or cylindrical refractive error, reading time, reading error score or near point of convergence (p > 0.05 using one way ANOVA). The Kolmogorov-Smirnov Test for normality demonstrated a normal distribution in all groups for all measurements.

Compliance

Compliance was assessed verbally, addressing both the parents and children. Both parents and subjects reported that spectacles were worn > 80% of time when undertaking near vision tasks. In addition, subjects prescribed the HTS were compliant at least 80% of the time.

Before Intervention

For all visual function measures there were no significant differences between the groups before intervention (one way analysis of variance [ANOVA] p > 0.05). Table 2, Table 3, Table 4, Table 5 and Table 6 provide mean values for each visual function parameter before intervention.

Before intervention the mean total reading time was 130.88 ± 61.46 seconds in the control group, 113.98 ± 48.83 seconds in the HTS group and 108.49 ± 48.68 seconds in the prism spectacle group. The mean reading error score was 5.34 ± 3.5 in the control group, 4.53 ± 3.06 in the HTS group and 4.92 ± 4.06 in the prism spectacles group. The mean amplitude of accommodation was 12.66 ± 2.3D in the control group, 11.86 ± 2.6D in the HTS group and 11.51 ± 2.5 in the prism spectacle group. The mean binocular accommodative facility score was 5.59 ± 3.2 cycles per minute in the control group, 6.20 ± 3.9 cycles per minute in the HTS group and 5.53 ± 2.9 cycles per minute in the prism spectacle group. The mean vergence facility test score was 5.44 ± 3.7 cycles per minute in the control group, 5.80 ± 4.6 cycles per minute in the HTS group and 4.96 ± 4.3 cycles per minute in the prism spectacle group.

Refractive Error

Refractive error profiles (sphere, cylinder and spherical equivalent) were normally distributed (one-sample Kolmogorov-Smirnov Test for normality). Spherical equivalent refractive errors (sphere + cylinder/2) ranged from -2.13D to +4.63D.

Factorial Analysis

Factorial analyses demonstrated statistically significant changes between results obtained for visits 1 and 2 for near phoria, near point of convergence and MEM retinoscopy (within subjects effects [time]) (Table 7).

Significant interaction effects were noted for the following outcome measures; total reading time, reading error score, amplitude of accommodation, binocular accommodative facility and vergence facility (Table 7). Further examination of simple main effects of the within factor (time) at each level of the between factors (treatment) indicated that significant improvements were noted between visits 1 and 2 for total reading time, reading error score, amplitude of accommodation, binocular accommodative facility and vergence facility for the prism spectacles and HTS groups (p < 0.05). The only significant effect noted between visits 1 and 2 for the control group was vergence facility (p = 0.026).

Significant differences were also demonstrated between treatment groups for total reading time, reading error score and binocular accommodative facility (between subjects effects [treatment]) (Table 7). Mean values for the first and second visits and mean differences between visits are presented in Table 2, Table 3, Table 4, Table 5 and Table 6. Figures 2, 3, 4, 5 and 6 represent the changes in outcome measures with each treatment.

Figure 2.

Box plots of total reading time at first and second visits for each subject group. The top of the box represents the 75th percentile, the bottom of the box represents the 25th percentile and the middle line represents the 50th percentile. The whiskers represent the highest and lowest values (excluding outliers). Outliers are represented by the closed circles. Asterisks represent extreme values.

Figure 3.

Box plots of reading error scores at first and second visits for each subject group. The top of the box represents the 75th percentile, the bottom of the box represents the 25th percentile and the middle line represents the 50th percentile. The whiskers represent the highest and lowest values (excluding outliers). Outliers are represented by the closed circles. Asterisks represent extreme values.

Figure 4.

Box plots of amplitude of accommodation at first and second visits for each subject group. The top of the box represents the 75th percentile, the bottom of the box represents the 25th percentile and the middle line represents the 50th percentile. The whiskers represent the highest and lowest values (excluding outliers). Outliers are represented by the closed circles. Asterisks represent extreme values.

Figure 5.

Box plots of binocular accommodative facility at first and second visits for each subject group. The top of the box represents the 75th percentile, the bottom of the box represents the 25th percentile and the middle line represents the 50th percentile. The whiskers represent the highest and lowest values (excluding outliers). Outliers are represented by the closed circles. Asterisks represent extreme values.

Figure 6.

Box plots of vergence facility at first and second visits for each subject group. The top of the box represents the 75th percentile, the bottom of the box represents the 25th percentile and the middle line represents the 50th percentile. The whiskers represent the highest and lowest values (excluding outliers). Outliers are represented by the closed circles. Asterisks represent extreme values.

Raw data are available as an additional file (Additional file 1).

processing....