Acute and Long-Term Visual Recovery Following Optic Nerve Sheath Fenestration for Severe Vision Loss

Abstract

Purpose : Optic nerve sheath fenestration (ONSF) is a surgical procedure that acutely relieves the pressure from cerebrospinal fluid around the optic nerve to preserve vision in patients with papilledema. Decision to utilize ONSF or ventriculoperitoneal (VP)/lumboperitoneal (LP) shunts or to combine both procedures largely remains institution/surgeon dependent. This study tested the hypothesis that ONSF acutely reverses vision loss after surgery and continues to improve months after the surgery.

Methods : Retrospective chart review was performed on 11 years of data from a single hospital system database utilizing current procedural terminology (CPT) for ONSF (2009 – 2020). Patients aged 18 and older who had undergone ONSF procedure for elevated intracranial pressure with severe vision loss were included in the study. Data was reviewed for a reduction in blindness (defined as logMar ≥ 1) and Humphrey/Goldmann visual fields immediately post-op, 3-9 months post-op, and at the latest visit.

Results : 34 eyes (24 patients) were included in this study. The average age was 36.0 years old (SD +/- 10.0 years). Nineteen patients were female (79.2%) and seventeen were Caucasian (70.8%). Seventeen of patients had a documented risk factor of obesity (70.8%), and the mean BMI of all patients was 34.2. The mean opening pressure at diagnosis was 39.4 cm H₂O. Average pre-op LogMar was 1.30 and 19 eyes (56%) were legally blind pre-operatively (LogMar ≥ 1). Average mean deviation on Humphrey visual field was -21. 36 (16 eyes) pre-operatively. 26 eyes (76.5%) had combined ONSF with VP shunt, 2 eyes (5.9%) with ventriculostomy, and 2 eyes (5.9%) with stenting of venous sinus. Immediately after surgery, 45.5% (15) of patients had improved visual acuity, 24.4% (8) had stable visual acuity, and 30.3% (10) had decreased visual acuity. The average post-operative change in LogMar visual acuity was +0.23. There was a 28% reduction in blindness (LogMar ≥ 1) immediately after surgery post-op and a 56% reduction in blindness in the most recent exam (average days from surgery to most recent visit: 690 days).

Conclusions : Visual recovery and reduction in blindness (LogMar ≥ 1) after an ONSF procedure increases over the postoperative period. It may be that as many as 50% of eyes blinded by IIH will recover useful vision with this surgery.

This is a 2021 ARVO Annual Meeting abstract.