A Spectral-Domain-OCT-Guided One-Year Follow-Up of Newly Diagnosed Pediatric Idiopathic Intracranial Hypertension Patients

<b>Background/Objectives:</b> To examine longitudinal changes in total retinal nerve fiber layer thickness (RNFLT) as the primary outcome measure in newly diagnosed pediatric idiopathic intracranial hypertension (IIH) patients using Spectral-Domain Optical Coherence Tomography (SD-OCT) at one-year follow-up. <b>Methods:</b> This is a prospective observational cohort study with cross-sectional control-group comparison. We included children with clinically definite IIH (IIH group) and children without papilledema and a normal neurological exam as a control group. Optic nerve parameters, including the primary outcome measure RNFLT and secondary outcome measures such as total retinal thickness (TRT) and optic disk area (ODA), were evaluated using SD-OCT (3D OCT-2000, Topcon, Topcon Corporation, Tokyo, Japan). Evaluations took place at presentation and, for the IIH group, before lumbar puncture (LP), at 1-day post-LP and at 1-, 3-, 6-, and 12-month follow-ups. <b>Results:</b> A total of 44 children aged 7-17 years were recruited (IIH group: N = 19, control group: N = 25). The mean baseline RNFLT was 133.1 ± 18.5 µm and 113.1 ± 8.7 µm for the IIH and control groups (<i>p</i> < 0.001), respectively. The IIH group showed a significant decline in RNFLT at the third-month follow-up. Between 3-month to one-year follow-up, mean total RNFLT showed an insignificant decline of 6 µm and did not differ from the RNFLT of the control group; however, segmental analysis of RNFLT showed a significant decline in the thickness of the nasal segments. At the one-year follow-up, two children had significant thinning of RNFLT at the superior quadrant. Intracranial pressure measured in the IIH group was directly correlated with RNFLT at the superior segment. <b>Conclusions:</b> SD-OCT is a useful non-invasive adjunct tool for the diagnosis and follow-up of IIH in children from primary school age onward. RNFL thickening resolved in most children at 3 months from IIH diagnosis. The study is constrained by specific methodological limitations, including a small sample size and non-contemporaneous evaluation of the control group compared with the IIH group. The significance of the segmental RNFL changes observed after one year should be further investigated with regard to long-term development, if possible with a larger prospective study that also considers the ganglion cell layer to explore for permanent axonal damage to the optic nerve.