Optic Nerve Sheath Fenestration: A Five Year Audit

Idiopathic intracranial hypertension (IIH), also known as benign intracranial hypertension (BIH) and pseudotumor cerebri, is a syndrome characterised by raised intracranial pressure (ICP) in the absence of an intracranial mass or ventricular abnormality and normal cerebrospinal fluid (CSF). Optic nerve sheath fenestration (ONSF) is advocated as a treatment for patients on maximal medical therapy with progressive visual field loss. We present the visual results of 13 patients undergoing ONSF on 27 eyes (primary, secondary and tertiary procedures) over a 5 year period. Overall 4 eyes (14.8%) had improved visual acuity after surgery, whilst 23 eyes (85.2%) were unchanged. Visual fields were improved in 18 eyes (66.7%), 2 (7.4%) were unchanged and 4 (14.8%) deteriorated despite surgery. Colour vision improved in 12 (44.4%), was unchanged in 3 (11.1%) and deteriorated in 7 (25.9%) eyes. 5 (18.5%) eyes had normal colour vision before and after surgery. 10 (77%) subjects were able to stop medical treatment after ONSF.