Erratum

Erratum in: “Higher Order Aberrations in Children with Down Syndrome” by Sara J. McCullough, Julie-Anne Little, and Kathryn J. Saunders (Invest Ophthalmol Vis Sci. 2013;54:1527-1535) doi:10.1167/iovs.12-10597  

Calculation of the Visual Strehl ratios was conducted using Thibos and Applegate's Getmetrics 2.5 software (Visual Optics Institute, University of Houston, Houston, Texas). In this calculation one of the input parameters was pupil radius, but the authors inadvertently used pupil diameter in their calculations, and thus, the Visual Strehl values reported for both the control and the DS groups in McCullough et al. were higher than they should have been. However, the conclusion and interpretation of the results remain the same. 

In the Results, under the heading “Visual Strehl Ratios and Equivalent Defocus Values,” the first two paragraphs should read as follows: 

“Table 4 outlines the VSX and equivalent defocus values for the control and DS groups over 3-mm and 5-mm pupil diameters. For both 3-mm and 5-mm pupil diameters, the VSX and equivalent defocus are significantly poorer in the DS group compared with controls (P < 0.032 for all conditions). 

“Linear regression analysis showed a strong relation between Visual Strehl ratio for 3-mm and 5-mm pupil diameters for both groups of children (DS F _(1,28) = 8.87, R ² = 0.24, P = 0.0059, control F _(1,196) = 119.14, R ² = 0.38, P < 0.0001; Fig. 3). Within the DS group, 24 children (80%, 3-mm pupil data) showed a Visual Strehl ratio to be less than the average Visual Strehl ratio for the control group.” 

In the third paragraph of the Discussion, the second sentence should read: “Although there were subtle differences between the average values for each group, the majority of children with DS (80%) showed lower than the average Visual Strehl ratios for the control group.” 

The corrected Table 4 and Figure 3 are published below, as follows.1552 1552  

Figure 3

 

VSX for 3-mm pupil diameter plotted against VSX for 5-mm pupil diameter for the children with DS (black X) and typically developing children (gray O). Vertical and horizontal lines represent the group averages, and diagonal dashed lines denote the linear regression of the data (DS, black; control, gray).

Table 4

 

Median, IQR, and Minimum-to-Maximum Values for VSX and Equivalent Defocus Values for the DS and Control Groups over 3-mm and 5-mm Pupil Diameters

	DS Group		Control Group		Mann-Whitney U test
	Median	IQR Minimum to Maximum	Median	IQR Minimum to Maximum
3-mm pupil diameter
VSX	0.616	0.43 to 0.69	0.719	0.61 to 0.79	z = 3.56, P = 0.0004*
		0.21 to 0.89		0.35 to 0.94
Equivalent defocus	0.339 (D)	0.31 to 0.43	0.277	0.22 to 0.34	z = −3.93, P = 0.0001*
		0.18 to 0.62 (D)		0.12 to 0.55 (D)
5-mm pupil diameter
VSX	0.214	0.14 to 0.33	0.257	0.17 to 0.37	z = 2.15, P = 0.031*
		0.05 to 0.44		0.02 to 0.67
Equivalent defocus	0.377 (D)	0.29 to 0.45 (D)	0.310 (D)	0.24 to 0.38 (D)	z = −2.84, P = 0.0046*
		0.24 to 0.78 (D)		0.13 to 0.98 (D)

*  Denotes statistically significant differences between the two groups (M-W, P < 0.05).

Citation: McCullough SJ, Little J-A, Saunders KJ. Erratum in: Higher order aberrations in children with Down syndrome. Invest Ophthalmol Vis Sci. 2013;54:1527-1535. DOI:10.1167/iovs.12-10597a