Optic Nerve Sheath Fenestration: A Retrospective Review of Its Safety, Efficacy, and Impact on Optical Coherence Tomography

Purpose: This study aimed to evaluate the safety and efficacy of optic nerve sheath fenestration using visual acuity, perimetry, and optical coherence tomography. Methods: A retrospective review of patients who underwent an optic nerve sheath fenestration at an academic center between 2016 and 2021 was performed with institutional review board approval. Outcome measures included visual acuity, perimetric mean deviation, optic disc edema grade, improvement in symptoms, and intraoperative and postoperative complications. Optical coherence tomography data collected included macular ganglion cell volume and thickness, as well as retinal nerve fiber layer thickness. Preoperative baseline data and 1-, 6-, and 12-month postoperative data were collected. Repeated measures with a mixed-effects model were used for continuous data, and linear regression analyses were performed. Results: A total of 55 patients (86 eyes) underwent optic nerve sheath fenestration, via a medial transconjunctival approach by the same orbital surgeon. After 12-month follow-up, visual acuity (P < 0.05), perimetric mean deviation (P < 0.05), and optic disc edema (P < 0.001) improved in the operative eye. Retinal nerve fiber layer thickness decreased from a mean of 165 to 92 µm (P < 0.001). Macular ganglion cell volume was found to have a small decrease from baseline and correlated well with visual acuity, contrast sensitivity testing, and perimetric mean deviation (P < 0.001). Conclusions: Optic nerve sheath fenestration performed via a medial transconjunctival approach is a safe and effective method to preserve vision in patients with papilledema, particularly in cases of fulminant or progressive idiopathic intracranial hypertension. Quantitative measurements of the macular ganglion cell layer can serve as a useful adjunct to other diagnostic testing.