LAUSR

A 22-year-old female presented with gradually progressive blurring of vision for 3 weeks. She also complained of continuous headaches and nausea that preceded the diminution of vision. The headaches were present all day and increased with straining and leaning forwards. She had no past ocular or medical history and was only taking acetaminophen for the headaches which provided minimal relief. Examination revealed a corrected distance visual acuity (CDVA) of 20/40 bilaterally. External ocular examination and pupillary exam were normal. Color vision testing was 16/20 in the right eye and 17/20 in the left using Ishihara plates. Anterior segment exam was unremarkable while posterior segment exam revealed bilateral grade IV papilledema (Frisén scale). Visual field testing showed enlargement of the blind spot with generalized field depression in both eyes. Magnetic resonance (MR) imaging of the brain and orbit revealed distended optic nerve sheaths while MR venography was normal. Lumbar puncture revealed a cerebrospinal fluid (CSF) opening pressure of 36 cm H2O with normal composition. The patient was diagnosed with idiopathic intracranial hypertension (IIH). She had a body mass index of 32 and so was strongly advised to lose weight. She also received medical treatment in the form of oral acetazolamide tablets for 1 month but did not tolerate its systemic side effects and so consented to perform optic nerve sheath fenestration (ONSF) in the right eye to prevent further vision loss in both eyes. Before the operation, optical coherence tomography (OCT) (Optos OCT SLO, Optos, Scotland, UK) of the optic nerve head (ONH) was done bilaterally and showed swelling of the peripapillary retinal nerve fiber layer (RNFL) compared to age-matched normative data with enlargement of the optic disc area (Fig. 1a, b). Right ONSF was performed through the medial transconjunctival orbital approach. Briefly, following a localized medial periotomy, the medial rectus muscle was disinserted on 6-0 Vicryl sutures and retracted, then the optic nerve sheath was exposed and multiple longitudinal slits were successfully done in the optic nerve sheath which was accompanied by a CSF gush and collapse of the dural sheath. The rectus muscle was then reinserted, and the conjunctiva closed. Postoperatively, the patient was prescribed topical antibiotic and steroid eye drops as well as an oral antibiotic. One month following the procedure, CDVA improved to 20/20 in the right eye and 20/30 in the left, color vision improved to 17/20 in the right eye and 18/20 in the left, and OCT showed a decrease of the peripapillary RNFL thickness to within normal limits in both eyes with decreased optic disc area (Fig. 1c, d). A follow-up after 3 months revealed continued stabilization of the condition. IIH is a condition characterized by increased intracranial tension without the presence of an intracranial mass lesion and with normal CSF composition [1]. It is more common in young obese females who frequently complain of transient visual obscurations, headaches, and tinnitus [2]. Papilledema is the main sign of IIH, and patients are at risk of developing optic atrophy if left untreated [3]. Treatment can be either medical or surgical depending on several factors including the severity and extent of the disease. The diagnosis and evaluation of papilledema has been mainly subjective and qualitative using clinical examination; however, OCT is a non-invasive imaging modality with very high axial resolution (up to 5 μm) which can obtain optical sections resembling histological sections using interferometry that has been successfully used to provide reliable objective and quantitative assessment of the severity of papilledema [4–6]. This is done by measuring the thickness of the peripapillary RNFL by comparing, interferometrically, the light reflected from the RNFL with light that traveled a known reference path * Ayman G. Elnahry [email protected]