J Korean Ophthalmol Soc JKOS Journal of the Korean Ophthalmological Society 0378-6471 2092-9374 The Korean Ophthalmological Society 10.3341/jkos.2020.61.2.214 Case Report Non-glaucomatous Retinal Nerve Fiber Layer Defect Associated with Paravascular Inner Retinal Defect Kim Gye Jung MD Son Dong Hwan MD Kim Jin-Soo MD Shin Min Chul MD PhD Department of Ophthalmology, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, Chuncheon, Korea. Address reprint requests to Jin-Soo Kim, MD. Department of Ophthalmology, Chuncheon Sacred Heart Hospital, #77 Sakju-ro, Chuncheon 24253, Korea. Tel: 82-33-240-5931, Fax: 82-33-241-8063, plastichaos@live.com 02 2020 18 02 2020 61 2 214 220 22 10 2019 28 10 2019 20 01 2020 ©2020 The Korean Ophthalmological Society 2020 The Korean Ophthalmological Society This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Purpose

To report a case of non-glaucomatous retinal nerve fiber layer (RNFL) defect associated with paravascular inner retinal defect (PIRD) in a patient with idiopathic epiretinal membrane (ERM).

 Case summary

A 70-year-old male who was diagnosed with ERM in his right eye and pseudoexfoliative glaucoma in his left eye visited our clinic. His intraocular pressure was 14 mmHg in both eyes while using topical hypotensive medications in both eyes. His right eye showed no glaucomatous change of the optic disc head, and also no glaucomatous visual field defect on standard automated perimetry. Red-free fundus photography and swept-source optical coherence tomography showed an ERM and wedge-shaped RNFL defect starting from the PIRD, not the optic disc head. He was diagnosed with non-glaucomatous RNFL defect in the right eye and was told to stop using topical hypotensive medication for the right eye. After 2 years of discontinuing the medication, the IOP was within the normal range, the RNFL defect showed no progression, and the visual field remained stationary.

 Conclusions

A non-glaucomatous RNFL defect can develop in association with PIRD in patients with idiopathic ERM. Examinations for PIRD as well as evaluation of the optic disc head are therefore necessary in patients with ERM and RNFL defect.

 Epiretinal membrane Non-glaucomatous retinal nerve fiber defect Paravascular inner retinal defect

The authors have no conflicts to disclose.

 Oray M Onal S Bayraktar S Nonglaucomatous localized retinal nerve fiber layer defects in Behcet uveitis Am J Ophthalmol 2015 159 475 481 Jonas JB Schiro D Localized retinal nerve fiber layer defects in nonglaucomatous optic nerve atrophy Graefes Arch Clin Exp Ophthalmol 1994 232 759 760 Choi JA Ko SH Park YR Retinal nerve fiber layer loss is associated with urinary albumin excretion in patients with type 2 diabetes Ophthalmology 2015 122 976 981 Jeon SJ Kwon JW La TY Characteristics of retinal nerve fiber layer defect in nonglaucomatous eyes with type II diabetes Invest Ophthalmol Vis Sci 2016 57 4008 4015 Muraoka Y Tsujikawa A Hata M Paravascular inner retinal defect associated with high myopia or epiretinal membrane JAMA Ophthalmol 2015 133 413 420 Chihara E Chihara K Apparent cleavage of the retinal nerve fiber layer in asymptomatic eyes with high myopia Graefes Arch Clin Exp Ophthalmol 1992 230 416 420 Komeima K Kikuchi M Ito Y Paravascular inner retinal cleavage in a highly myopic eye Arch Ophthalmol 2005 123 1449 1450 Hood DC Fortune B Mavrommatis MA Details of glaucomatous damage are better seen on OCT en face images than on OCT retinal nerve fiber layer thickness maps Invest Ophthalmol Vis Sci 2015 56 6208 6216 Hood DC De Cuir N Mavrommatis MA Defects along blood vessels in glaucoma suspects and patients Invest Ophthalmol Vis Sci 2016 57 1680 1686 Kim JH Kang SY Kim NR Prevalence and characteristics of glaucoma among Korean adults Korean J Ophthalmol 2011 25 110 115 Lee SH Kim GA Lee W Vascular and metabolic comorbidities in open-angle glaucoma with low- and high-teen intraocular pressure: a cross-sectional study from South Korea Acta Ophthalmol 2017 95 e564 e574 Demer JL Clark RA Suh SY Magnetic resonance imaging of optic nerve traction during adduction in primary open-angle glaucoma with normal intraocular pressure Invest Ophthalmol Vis Sci 2017 58 4114 4125 Wang X Teoh CKG Chan ASY Biomechanical properties of Bruch's membrane-choroid complex and their influence on optic nerve head biomechanics Invest Ophthalmol Vis Sci 2018 59 2808 2817 Hwang YH Kim YY Kim HK Sohn YH Characteristics of eyes with inner retinal cleavage Graefes Arch Clin Exp Ophthalmol 2015 253 215 220 Jung KI Kim SJ Park CK Systemic vascular risk factors for multiple retinal nerve fiber layer defects Sci Rep 2018 8 7797 Burgoyne CF Downs JC Bellezza AJ The optic nerve head as a biomechanical structure: a new paradigm for understanding the role of IOP-related stress and strain in the pathophysiology of glaucomatous optic nerve head damage Prog Retin Eye Res 2005 24 39 73 Ophthalmic examinations performed at the first visit. (A, B) Disc photography of the patient shows intact neuroretinal rim (NRR) in the right eye and narrowing of superotemporal and inferotemporal NRR in the left eye. (C, D) Red-free fundus photography shows nasal extrafoveal epiretinal membrane with multiple retinal nerve fiber layer (RNFL) defect in the right eye that are not connected to the optic disc head border, and diffuse RNFL thinning in the left eye. (E) Circumpapillary scan image of spectral-domain optical coherence tomography of the right eye shows focal narrow RNFL thinning (marked as yellow line) just nasal to the superotemporal retinal venous arcade, which corresponds to the most nasally located slit-like RNFL defect seen in the red-free fundus photography. Other RNFL defects seen in the red-free fundus photography are not detected on the scan circle of 3.5 mm diameter. TS = superotemporal; NS = superonasal; T = temporal; N = nasal; G = general; TI = temporal inner; NI = nasal inner; TMP = temporal; SUP = superior; NAS = nasal; INF = inferior. Comparisons between 2017 and 2019.(A) The en-face 52 µm slab image of swept-source optical coherence tomography (OCT) shows epiretinal membrane and paravascular inner retinal defect (PIRD) along the retinal vascular arcades. It also shows retinal nerve fiber layer (RNFL) defect connected to the PIRD, but not the optic disc head. There was no definite change in PIRD and RNFL defect between results of 2017 and 2019. (B) Red-free fundus photography also showed no change between 2017 and 2019. Note that locations of OCT B-scans in the en-face 52 µm slab image are also indicated as red horizontal lines in the red-free fundus photography. (C) Standard automated perimetry results did not show development of glaucomatous visual field defect between 2017 and 2019.