Ocular biometry through fully refocused steady-state magnetic resonance imaging sequence: reliability and agreement with the IOLMaster 500.

PURPOSE

To evaluate the reliability and agreement between Fully Refocused Steady-State magnetic resonance sequences (FRSS) and the IOLMaster 500 optical biometer for measuring anterior chamber depth (ACD) and axial length (AL).

METHODS

In a sample of 32 healthy volunteers, separate observers measured the ACD and AL of both eyes using both techniques (inter-method) and through repeated FRSS measurements (interobserver) and by the same observer (intraobserver). We employed the Bland-Altman method to determine the agreement between FRSS and partial coherence interferometry (using the IOLMaster) and the interobserver and intraobserver variability, providing the limits of agreement (LoA, or mean difference ± 1.96 SD). Correlation coefficients and intraclass correlation coefficients were also provided.

RESULTS

For ACD measurements with FRSS in pseudo-color scale, we obtained an LoA of 0.016 ± 0.266 mm compared with partial coherence interferometry. For AL with FRSS in greyscale, the LoA was 0.019 ± 0.383 mm. Maximum interobserver variability showed a  - 0.036 ± 0.247 mm LoA for ACD with FRSS in pseudo-color scale. Maximum intraobserver variability was 0.000 ± 0.157 mm LoA for AL with FRSS in greyscale.

CONCLUSIONS

ACD and AL measurements using FRSS sequencing present high LoA and reliability when compared with partial coherence interferometry using the IOLMaster 500. The results were better for FRSS in pseudo-color scale in ACD determination and for FRSS in greyscale in AL determination. FRSS would not be recommended for IOL power calculation due to variability of AL measurement.