Predictive Value of Intraocular Lens Power Calculation Formulae in Children

Figures & data

Table 1 The Illustration of Prediction Error and Absolute Prediction Error for Each Formula

Formula	Prediction Errors (D)			Absolute Prediction Errors (D)
	Mean ± SD	Median	Range	Mean ± SD	Median	Range
SRK II	0.24±1.96	0	-5.96–7.17	1.52±1.29	1.11	0.00–7.17
SRK–T	0.53±1.90	0.25	-6.00–7.50	1.42±1.32	1.00	0.00–7.50
Holladay I	0.70±2.05	0.50	-5.79–8.28	1.58±1.48	1.12	0.00–8.28
Hoffer Q	1.00±2.08	0.75	-5.91–8.89	1.70±1.55	1.25	0.00–8.89

Abbreviations: D, diopter; SRK, Sanders–Retzlaff–Kraff; SD, standard deviation.

Table 2 Subgroup Analysis Showing the Absolute Prediction Error (APE) for Each Formula in Diopters (D) Among Patients Who Had in the Bag Implanted Intraocular Lens (IOL) versus Those with Sulcus Implanted IOL

	IOL Implantation Site
	In the Bag Implanted IOL			Sulcus Implanted IOL
	Mean	SD	Median	Mean	SD	Median
APE SRK II	1.40	1.24	1.00	1.63	1.33	1.25
APE Holladay	1.36	1.34	1.00	1.79	1.57	1.39
APE Hoffer Q	1.43	1.41	1.00	1.96	1.64	1.50
APE SRK T	1.23	1.21	0.90	1.60	1.41	1.10

Abbreviations: SRK, Sanders–Retzlaff–Kraff; SD, standard deviation.

Table 3 Correlation Between the Age, Axial Length (AL), Average Keratometric (K) Readings and the Absolute Prediction Error (APE) for the 4 Formulae

Formula	Age		AL		Average K
	Coefficient	P Value	Coefficient	P Value	Coefficient	P Value
SRK II	0.131	0.021	0.011	0.842	0.057	0.317
SRK–T	0.080	0.162	0.058	0.309	0.134	0.019
Holladay I	0.039	0.497	0.047	0.416	0.159	0.005
Hoffer Q	0.074	0.196	0.016	0.778	0.120	0.035

Abbreviation: SRK, Sanders–Retzlaff–Kraff.

Table 4 Correlation Between the Age, Axial Length (AL), Average Keratometric (K) Readings and the Absolute Prediction Error (APE) for the 4 Formulae Among Patients Who Had in the Bag Implanted Intraocular Lens (IOL)

Formula		Age	Average K-Readings	AL
APE SRKII	Correlation Coefficient	0.203	0.022	0.003
	P value	0.013	0.791	0.974
	N	150	150	150
APE Holladay	Correlation Coefficient	0.013	0.131	0.090
	P value	0.874	0.110	0.274
	N	150	150	150
APE Hoffer Q	Correlation Coefficient	0.061	0.097	0.074
	P value	0.456	0.238	0.368
	N	150	150	150
APE SRK T	Correlation Coefficient	0.114	0.093	0.084
	P value	0.163	0.256	0.310
	N	150	150	150

Abbreviation: SRK, Sanders–Retzlaff–Kraff.

Table 5 Correlation Between the Age, Axial Length (AL), Average Keratometric (K) Readings and the Absolute Prediction Error (APE) for the 4 Formulae Among Patients Who Had Sulcus Implanted IOL

Formula		Age	Average K-Readings	AL
APE SRK II	Correlation Coefficient	0.062	0.064	0.014
	P value	0.443	0.428	0.861
	N	157	157	157
APE Holladay	Correlation Coefficient	0.050	0.122	0.013
	P value	0.533	0.129	0.870
	N	157	157	157
APE Hoffer Q	Correlation Coefficient	0.075	0.067	0.119
	P value	0.353	0.406	0.138
	N	157	157	157
APE SRK T	Correlation Coefficient	0.041	0.122	0.018
	P value	0.608	0.129	0.825
	N	157	157	157

Abbreviation: SRK, Sanders–Retzlaff–Kraff.

Figure 1 Comparison between the absolute prediction error (APE) of SRK II, Holladay I, Hoffer Q and SRK/T formulae.

Figure 2 Comparison between the absolute prediction error (APE) of SRK II, Holladay I, Hoffer Q and SRK/T formulae in the subgroup of patients with mean preoperative keratometric (K) readings <46.5 diopter (D) and in those with mean preoperative K-reading ≥46.5 D.

Figure 3 Comparison between the absolute prediction error (APE) of the SRK II, Holladay I, Hoffer Q and SRK/T formulae in different age groups.

Figure 4 Analysis of the absolute prediction error (APE) of the SRK II, Holladay I, Hoffer Q and SRK/T formulae according to the preoperative axial length.

Figure 5 Analysis of the absolute prediction error (APE) of the SRK II, Holladay I, Hoffer Q and SRK/T formulae according to the site of intraocular lens implantation (IOL).