Introduction In patients with optic nerve hypoplasia (ONH), the visualisation of the optic disc can be challenging and the definitive diagnosis difficult to ascertain without fundus photography. The use of MRI for diagnosis has been reported as a diagnostic alternative with conflicting results. We retrospectively analysed a disease registry to determine the reliability of orbital MRI measurements of the optic nerve diameter to diagnose ONH, and the correlation with vision outcomes.
Materials and methods From a cohort of 140 patients with ONH (13% unilateral) that had reached age 5 years, we identified 43 subjects who had orbital MRI in addition to fundus photography performed prior to 2 years of age. We compared measurements of the optic nerve diameter from orbital MRI scans to the standard relative optic disc size (disc diameter/disc-macula (DD/DM) distance) by fundus photography. All patients had visual acuity tested at age 5 years. Spearman’s correlation coefficient was used to determine the correlation of orbital MRI measurements and fundus photography with the diagnosis of ONH, and with vision outcomes.
Results Relative disc size (DD/DM)<0.35 showed 100% sensitivity and 100% specificity for the diagnostic confirmation of ONH. The optic nerve diameter measurements by orbital MRI displayed a moderate correlation (rs=0.471; p<0.001) with DD/DM and moderate sensitivity for the diagnosis of ONH. Final visual acuity correlated well with DD/DM measurements by fundus photography (rs=−0.869; p<0.001) and moderately with optic nerve diameter by orbital MRI (rs=−0.635; p<0.001).
Discussion Orbital optic nerve diameter from MRI scans has moderate reliability in diagnosing ONH and predicting vision outcomes. Fundus photography for measurements of the optic nerve size should remain the reference for diagnostic confirmation of ONH. These data further support the prognostic value of fundus photography for eventual vision outcomes in this population.
- optic nerve
- child health (paediatrics)
- diagnostic tests/investigation
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Contributors MB, PG-F, MN and JK designed and conducted the study including patient recruitment, data collection and data analysis. All listed authors were involved in preparing the manuscript and all authors approved the final manuscript.
Funding This research was supported in part by Prevent Blindness America Foundation, The One Small Voice Foundation and Grant Number UL1TR000130, Children’s Hospital Los Angeles from the National Center for Advancing Translational Sciences at the National Institutes of Health.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information. All data are deidentified participant data.