A systematic review of optical coherence tomography findings in adults with mild traumatic brain injury
Authors: Lyons Hannah S. , Sassani Matilde , Hyder Yousef , Mitchell James L. , Thaller Mark , Mollan Susan P. , Sinclair Alexandra J. ,   mTBI Predict Consortium, Sinclair Alexandra , Finch Aliza , Hampshire Adam , Sitch Alice , Mazaheri Ali , Bagshaw Andrew , Palmer Andy , Strom Asha , Waitt Alice , Yiangou Andreas , Abdel-Hay Ahmed , Bennett Alexander , Clark Amy , Hunter Angus , Seemungal Barry , Witton Caroline , Dooley Caroline , Bird Deborah , Fernandez-Espejo Davinia , Smith Dave , Ford Dan , Sherwood Daniel , Holding Donna , Wilson Duncan , Palmer Edward , Golding John , Dehghani Hamid , Park Hyojin , Lyons Hannah , Smith Hazel , Brunger Helen , Ellis Henrietta , Idrees Iman , Varley Ian , Hubbard Jessica , Cao Jun , Deeks Jon , Mitchell James , Novak Jan , Pringle Jamie , Terry John , Rogers Jack , Read Tim , Fildes Jessikah , Mullinger Karen , Hill Lisa , Aurisicchio Marco , Thaller Mark , Wilson Martin , Pearce Mark , Sassani Matilde , Brookes Matthew , Mahmud Mohammad , Rayhan Ray , Jenkinson Ned , Karavitaki Niki , Capewell Nick , Grech Olivia , Jensen Ole , Hellyer Pete , Woodgate Philip , Coleman Sebastian , Reynolds Raymond , Blanch Richard J. , Morris Katie , Ottridge Ryan , Upthegrove Rachel , Dardis Ronan , Arachchige Ruwan Wanni , Berhane Sarah , Lucas Sam , Prosser Sophie , Sharifi Shayan , Dharm-Datta Shreshth , Mollan Susan , Ellmers Toby , Ghafari Tara , Goldstone Tony , Hawa Waheeda , Gao Yidian , Blanch Richard J. 
Published: January 2024

Mild traumatic brain injury (mTBI) is common with many patients suffering disabling long-term sequelae, with visual symptoms frequently reported. There are no objective biomarkers of mTBI that are routinely used in clinical practice. Optical coherence tomography (OCT) has been used in mTBI research, as it enables visualisation of the neuroretina, allowing measurement of the retinal nerve fibre layer and ganglion cell layer. This systematic review aims to appraise the available literature and assess whether there are significant changes within the retinal nerve fibre layer and ganglion cell layer in subjects after mTBI. A systematic review was carried out in accordance with PRISMA guidelines and registered with PROSPERO (Number: CRD42022360498). Four databases were searched for relevant literature published from inception until 1 September 2022. Abstracts and full texts were screened by three independent reviewers. Initial screening of databases yielded 341 publications, of these, three fulfilled all the criteria for inclusion. All three studies showed thinning of the retinal nerve fibre layer, whereas there were no significant changes in the ganglion cell layer. This systematic review demonstrated that thinning of the retinal nerve fibre layer (but not of the ganglion cell layer) is associated with mTBI. It provides preliminary evidence for the use of the retinal nerve fibre layer as a potential biomarker of damage to the visual system in mTBI. Further prospective longitudinal studies ensuring uniform diagnosis and accurate phenotyping of mTBI are needed to understand the effects on the visual system and potential of OCT as a prognostic biomarker.