In this pilot study, the advantages of adopting intravenous erythropoietin (EPO) as an option for the treatment of indirect optic neuropathy, especially in cases where steroids are contra-indicated, have been explored. Indirect optic neuropathy is common and usually responds to treatment with 40–60% of cases having visual recovery.[1] Electro-physiological tests such as visual evoked potential (VEP) and electro-retinography (ERG) are helpful tools not only for diagnosis but also for predicting prognosis. In addition to the use of EPO in traumatic optic neuropathy, it has also been tried in cases of optic neuritis, non-arteritic arterior ischemic optic neuropathy (NAION), and methanol optic neuropathy. In optic neuritis, Lagrèze et al.’s[2] study on 103 patients found no added beneficial effect as compared to I/V methylprednisolone. In NAION also, EPO was tried by Modarres et al.,[3] and they found beneficial effects in improving the best corrected visual acuity (BCVA) at 3 months follow-up, which was retained at 6 months follow-up. However, in a study by Nikkhah et al.,[4] they did not find any significant difference in the outcome of BCVA between the three groups, that is, I/V EPO, oral prednisolone, and placebo. However, Pakdel et al.[5] in a phase 2 clinical trial reported beneficial effects of I/V EPO in cases of methanol optic neuropathy.
The major therapeutic option currently in practice for the treatment of traumatic optic neuropathy is the use of corticosteroids. Apart from the various side effects that the use of intravenous corticosteroids entails, there are also various contra-indications to their use. EPO has been shown to have neuro-protective action, especially when given early. “Several studies have highlighted the neuro-protective function of EPO in extra-hematopoietic tissues, especially the retina. EPO could interact with its heterodimer receptor (EPOR/bcR) to exert its anti-apoptosis, anti-inflammatory, and anti-oxidative effects in preventing retinal ganglion cell death through different intracellular signalling pathways.”[6] It has thus been hypothesized that EPO may improve visual functions in indirect traumatic optic neuropathy by reducing apoptosis of retinal ganglion cells and by promoting neuro-regeneration in the damaged axons.[7]
The author has demonstrated the possibility of the use of EPO in indirect optic neuropathy in a small pilot study; however, further research as case control studies is essential to confirm the beneficial effects of EPO in indirect optic neuropathy.
References
- 1.Yu-Wai-Man P. Traumatic optic neuropathy-clinical features and management issues. Taiwan J Ophthalmol. 2015;5:3–8. doi: 10.1016/j.tjo.2015.01.003. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Lagrèze WA, Küchlin S, Ihorst G, Grotejohann B, Beisse F, Volkmann M, et al. Safety and efficacy of erythropoietin for the treatment of patients with optic neuritis (TONE):A randomised, double-blind, multicentre, placebo-controlled study. Lancet Neurol. 2021;20:991–1000. doi: 10.1016/S1474-4422(21)00322-7. [DOI] [PubMed] [Google Scholar]
- 3.Modarres M, Falavarjani KG, Nazari H, Sanjari MS, Aghamohammadi F, Homaii M, et al. Intravitreal erythropoietin injection for the treatment of non-arteritic anterior ischaemic optic neuropathy. Br J. Ophthalmol. 2011;95:992–5. doi: 10.1136/bjo.2010.191627. [DOI] [PubMed] [Google Scholar]
- 4.Nikkhah H, Golalipour M, Doozandeh A, Pakravan M, Yaseri M, Esfandiari H. The effect of systemic erythropoietin and oral prednisolone on recent-onset non-arteritic anterior ischemic optic neuropathy:A randomized clinical trial. Graefe's Archive Clin Exp Ophthalmol. 2020;258:2291–7. doi: 10.1007/s00417-020-04781-x. [DOI] [PubMed] [Google Scholar]
- 5.Pakdel F. Erythropoietin in methanol associated optic neuropathy:A phase-2 clinical trial. Invest Ophthalmol Vis Sci. 2019;60:4807. [Google Scholar]
- 6.Lai YF, Lin TY, Ho PK, Chen YH, Huang YC, Lu DW. Erythropoietin in optic neuropathies:Current future strategies for optic nerve protection and repair. Int J Mol Sci. 2022;23:7143. doi: 10.3390/ijms23137143. doi:10.3390/ijms23137143. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Entezari M, Esmaeili M, Yaseri M. A pilot study of the effect of intravenous erythropoetin on improvement of visual function in patients with recent indirect traumatic optic neuropathy. Graefes Arch Clin Exp Ophthalmol. 2014;252:1309–13. doi: 10.1007/s00417-014-2691-6. [DOI] [PubMed] [Google Scholar]