Vol. 7, Issue 1, Part B (2025)

Background: Idiopathic Intracranial Hypertension (IIH) is characterized by elevated cerebrospinal fluid (CSF) pressure in the absence of an identifiable intracranial lesion. Increased CSF pressure in the intracranial subarachnoid space (SAS) transmits pressure to the orbital SAS, potentially compressing optic nerve axons and their vascular supply, leading to axoplasmic flow stasis. Optical coherence tomography (OCT) is a non-invasive technique offering structural assessment of the optic nerve head (ONH), retinal nerve fiber layer (RNFL), and macula. OCT provides high-resolution evaluation of optic disc swelling. The aim of this project was to evaluate changes in optic nerve head and peripapillary area using OCT in patients with IIH before and after treatment.

Methods: This is a prospective, longitudinal, case control study included Forty patients newly diagnosed with IIH and twenty age and sex-matched healthy persons were recruited from the Ophthalmology and Neurology departments of Tanta University Hospitals from March 2022 till February 2024. Only left eye was used for analysis for both patients and controls. Diagnosis followed modified Dandy criteria. Exclusion criteria included significant refractive errors, optic disc anomalies, or coexisting optic neuropathies or retinal vasculopathy. Participants underwent baseline neurological and neuro-ophthalmic evaluations and OCT of optic nerve head and macula. Patients were managed in the neurology department medically or surgically based on clinical indications and according to management they were divided into two subgroups; non-surgical subgroup (n=20) and surgical subgroup (n=20), and all were re-evaluated after three months.

Results: IIH patients had significantly higher BMI (mean 34.77 ± 2.89 p<0.001) compared to control group (mean 30.84 ± 3.73) and higher CSF opening pressure (mean 37.79 ± 7.32 cm water) compared to normal. Visual function (BCVA, VF MD), optic disc edema (Frisén grade) were significantly worse in IIH patients (p < 0.05). OCT analysis revealed significant alteration in Bruch’s membrane (BM) configuration, larger disc and rim areas, and thicker RNFL (p < 0.05) in IIH group. No significant differences were observed in GCC or PCT between IIH and control groups. However, surgical IIH patients had thinner GCC compared to non-surgical ones (p = 0.001). At three-month follow-up, the surgical group showed greater symptom resolution and more reduction in disc edema and RNFL thickness (p < 0.05). BM configuration improved significantly only in the surgical group. GCC correlated negatively with BCVA LogMAR and positively with VF MD. No significant changes in PCT were observed over time in either group.

Conclusion: OCT proves to be a valuable tool for structural assessment in IIH, detecting changes in BM configuration and RNFL thickness that reflect intracranial pressure dynamics. While GCC thickness did not differ significantly between groups, its correlation with visual acuity and field performance suggests potential as a biomarker of visual function. OCT may aid not only in diagnosing and monitoring papilledema but also in evaluating retinal ganglion cell integrity and predicting visual outcomes in IIH.