Exploring the utility of retinal optical coherence tomography as a biomarker for idiopathic intracranial hypertension: a systematic review

Abstract

This study aimed to examine the existing literature that investigated the effectiveness of optical coherence tomography (OCT) and optical coherence tomography angiography (OCT-A) as a biomarker for idiopathic intracranial hypertension (IIH). Our search was conducted on January 17th, 2024, and included the databases, Medline, Scopus, Embase, Cochrane, Latin American and Caribbean Health Sciences Literature (LILACS), International Standard Randomized Controlled Trial Number (ISRCTN) registry, and the International Clinical Trials Registry Platform (ICTRP). Our final review included 84 articles. In 74 studies, OCT was utilized as the primary ocular imaging method, while OCT-A was employed in two studies including eight studies that utilized both modalities. Overall, the results indicated that IIH patients exhibited significant increases in retinal nerve fiber layer (RNFL) thickness, total retinal and macular thickness, optic nerve head volume, and height, optic disc diameter and area, rim area, and thickness compared to controls. A significant correlation was observed between cerebrospinal fluid (CSF) pressure and OCT parameters including RNFL thickness, total retinal thickness, macular thickness, optic nerve head volume, and optic nerve head height. Interventions aimed at lowering CSF pressure were associated with a substantial improvement in these parameters. Nevertheless, studies comparing peripapillary vessel density using OCT-A between IIH patients and controls yielded conflicting results. Our systematic review supports OCT as a powerful tool to accurately monitor retinal axonal and optic nerve head changes in patients with IIH. Future research is required to determine the utility of OCT-A in IIH.

Keywords: Idiopathic intracranial hypertension; Optic nerve head; Optical coherence tomography; Optical coherence tomography angiography; Peripapillary vessel density; Retinal nerve fiber layer.

Fig. 1

Flow diagram of the systematic literature review search

Fig. 2

Optical coherence tomography (OCT) image of the retina showing the different layers. ILM inner limiting membrane; RNFL retinal nerve fiber layer; GCL ganglion cell layer; INL inner nuclear layer; IPL inner plexiform layer; ONL outer nuclear layer; OPL outer plexiform layer; ELM external limiting membrane; RPE retinal pigment epithelium. Macular thickness = distance between ILM and RPE; retinal thickness = distance between ILM and photoreceptor layer; choroidal thickness = distance between the outer border of RPE and choroidoscleral surface

Fig. 3

Optical coherence tomography (OCT) imaging of the optic disc. The white line is Bruch’s membrane opening, the blue line is lamina cribrosa surface depth, the yellow line is pre-laminar tissue thickness, and the red line is lamina cribrosa thickness

Fig. 4

A Optical coherence tomography (OCT) image of the optic nerve head. In healthy individuals, the peripapillary retinal pigment epithelium-basement membrane (ppRPE/BM) is V-shaped and angled away from the vitreous. B Optical coherence tomography (OCT) image of the optic nerve head showing a U-shape configuration of the peripapillary retinal pigment epithelium-basement layer (ppRPE/BM) in a patient with papilledema. C Optical coherence tomography angiography (OCT-A) image of the optic nerve head

Fig. 5

Optical coherence tomography angiography (OCT-A) image displays the segmentation of three capillary plexus, including superficial, deep, and choriocapillary plexus, both in en face (top row) and cross-sectional (bottom row). The segmentation boundaries for each layer are indicated by a pink line on the cross-sectional OCT-A image

Fig. 6

Optical coherence tomography (OCT) test results showing optic nerve head (ONH) and retinal nerve fibre layer (RFNL) thickness of right (OD) and left eye (OS)

Fig. 7

Optical coherence tomography (OCT) imaging test results showing A, macular thickness and B, ganglion cell complex (GCC) thickness