Steroid Treatment of Optic Neuropathies

Traumatic optic neuropathy: a review of current studies

Traumatic optic neuropathy (TON) is a serious complication of craniofacial trauma that directly or indirectly damages the optic nerve and can cause severe vision loss. The incidence of TON has been gradually increasing in recent years. Research on the protection and regeneration of the optic nerve after the onset of TON is still at the level of laboratory studies and which is insufficient to support clinical treatment of TON. And, due to without clear guidelines, there is much ambiguity regarding its diagnosis and management. Clinical interventions for TON include observation only, treatment with corticosteroids alone, or optic canal (OC) decompression (with or without steroids). There is controversy in clinical practice concerning which treatment is the best. A review of available studies shows that the visual acuity of patients with TON can be significantly improved after OC decompression surgery (especially endoscopic transnasal/transseptal optic canal decompression (ETOCD)) with or without the use of corticosteroids. And new findings of laboratory studies such as mitochondrial therapy, lipid change studies, and other studies in favor of TON therapy have also been identified. In this review, we discuss the evolving perspective of surgical treatment and experimental study.

Methanol-induced optic neuropathy: a still-present problem

Methanol-induced optic neuropathy (Me-ION) is a serious condition that may result in long-term or irreversible visual impairment or even blindness secondary to damage and loss of function of the optic nerve and retina. Me-ION shows a tendency to occur as mass poisonings around the world with a clear predilection for poor societies in developing countries. The main mechanism underlying the molecular basis of Me-ION is the inhibition of the mitochondrial oxidative phosphorylation process through the binding of the toxic metabolite of methanol—formic acid—with the key enzyme of this process—cytochrome c oxidase. However, other mechanisms, including damage to the eye tissues by oxidative stress causing the intensification of the oxidative peroxidation process with the formation of cytotoxic compounds, as well as an increase in the synthesis of pro-inflammatory cytokines and influence on the expression of key proteins responsible for maintaining cell homeostasis, also play an important role in the pathogenesis of Me-ION. Histopathological changes in the eye tissues are mainly manifested as the degeneration of axons and glial cells of the optic nerve, often with accompanying damage of the retina that may involve all its layers. Despite the development of therapeutic approaches, persistent visual sequelae are seen in 30–40% of survivors. Thus, Me-ION continues to be an important problem for healthcare systems worldwide.

Traumatic Optic Neuropathy Management: A Survey Assessment of Current Practice Patterns

Introduction:

The treatment of traumatic optic neuropathy (TON) is highly controversial with a lack of substantiated evidence to support the use of corticosteroids or surgical decompression of the optic nerve. The aim of the study was to determine if there was a general consensus in the management of TON despite controversy in the literature.

Methods:

An anonymous survey of members of the American Society of Ophthalmic Plastic and Reconstructive Surgery and the North American Neuro-Ophthalmology Society regarding their practice patterns in the management of patients with TON was performed.

Results:

The majority of 165 respondents indicated that they treated TON with corticosteroids (60%) while a significant minority (23%) performed surgical interventions (P < 0.0001). Subgroup analysis comparing rates of treatment with steroids among oculoplastic surgeons and neuro-ophthalmologists (67% vs. 47%) was not significant (Fisher's Exact test [FET], P =0.11) while results did suggest that a higher proportion of oculoplastic surgeons (33%) than neuro-ophthalmologists (11%) recommended surgical intervention (FET, P =0.004). In cases where visual acuity exhibited a downward trend treatment with steroids was the most commonly employed management. In general, neuro-ophthalmologists trended toward observation over treatment in TON patients with stable visual acuity while oculoplastic surgeons favored treatment with corticosteroids.

Conclusions:

In spite of the lack of class I evidence supporting intervention of TON, the majority of respondents were inclined to offer corticosteroid treatment to patients whose visual acuity showed progressive decline following injury.

Vitamins are Indeed Vital Amines: A Discussion of 3 Deficiencies With Neurologic Manifestations

Optimal functioning of the human nervous system depends on a constant supply of nutrients, vitamins, and minerals. In the developed world, nutritional deficiencies are relatively rare and infrequently present with neurologic manifestations. These neurologic disorders can be mistaken for inflammatory and/or autoimmune phenomena. This manuscript describes 2 pediatric cases with neurologic signs/symptoms arising from vitamin deficiencies-(1) optic neuropathy and (2) Wernicke encephalopathy associated with a Guillain-Barre-like pattern of weakness. The 2 cases and the subsequent discussion of vitamin A, B1, and B12 deficiencies underscore the value of taking a thorough dietary history and emphasize risk factors for these 3 nutritional deficiencies.

An adherent drug depot for retinal ganglion cell protection and regeneration in rat traumatic optic neuropathy models

Traumatic optic neuropathy (TON) describes an injury to the optic nerve following either blunt or penetrating trauma, and remains an important cause of vision loss. No generalized treatment of TON has been established so far to restore the injured optic nerve. We developed an adherent drug-encapsulated bi-layered depot (DBP) as a dual drug vehicle for local treatment to protect the residual retinal ganglion cells (RGCs) and regenerate axons following optic nerve damage. The inner layer of the depot was prepared by co-electrospinning poly(d,l-lactide-co-glycolide acid) (PLGA: 75 : 25) and collagen (COL) with the hydrophobic corticosteroid triamcinolone acetonide (TA) loaded. The outer layer was made of PLGA and the hydrophilic neuroprotective agent Fasudil (FA). The DBP showed suitable morphology, hydrophilicity and mechanical properties, and slowly released TA and FA in vitro by undergoing time-dependent degradation and swelling. All depots showed good biocompatibility with L929 mouse fibroblasts, and DBP was helpful in maintaining the morphology of RGCs in vitro. In addition, direct implantation of DBP at the injured optic nerve in a rat model mitigated inflammation and the death of RGCs, and increased the expression of nerve growth-related protein GAP-43. Therefore, DBP maybe a promising local therapy against TON in future.

Optic Canal Decompression with a Lateral Approach for Optic Nerve Injury Associated with Traumatic Optic Canal Fracture

Optic canal fracture (OCF) is a traumatic injury that requires urgent intervention because it can induce optic nerve damage and visual impairment. Despite the severity of OCF, a standard treatment method has not been established. In this article, we report a case of OCF and traumatic optic nerve injury in which visual acuity was recovered by releasing the optic canal using an unconventional lateral approach. A 43-year-old man presented with right lateral ethmoid fracture, right orbit blowout fracture, and OCF. The visual acuity was “hand motion” before surgery. Decompression was performed 10 hours after injury by approaching the right optic canal laterally from a coronal incision in front of the right ear, cutting along the border of the sphenoid bone, and scraping away some of the sphenoid wing and zygomatic bone. Steroid pulse therapy was added. Eventually, the visual acuity improved to 0.2 and the intraocular pressure decreased to 16.0 mm Hg. Compared with conventional methods, this method associates with better safety because (1) it causes relatively little bleeding and cerebrospinal fluid leak; (2) once the sphenozygomatic suture is identified, the distance to the optic canal is relatively short; and (3) if the fracture point is on the outer optic canal, the fracture line can be observed directly. Steroid pulse therapy may also have contributed to the good visual outcome. This is the first report of a novel lateral approach to OCF that is safe, effective, and only requires plastic surgery skills.

The development of optic neuropathy after chronic rhinosinusitis: A population-based cohort study

Background

To evaluate the risk of developing optic neuropathy (ON) in patient with both non-surgery and surgery-indicated chronic rhinosinusitis (CRS) via the national health insurance research database in Taiwan.

Methodology/Principal findings

44,176 Patients with a diagnostic code of CRS was selected, which included 6,678 received functional endoscopic sinus surgery (FESS) regarded as the surgery-indicated CRS. Each individual in the study group was matched to two non-CRS patients by age and gender. The outcome was set as the occurrence of ON according to the diagnostic codes occurred after the index date. Poisson regression was used to calculate the adjusted relative risk (aRR) and conditional Cox proportional model was used to estimate the adjusted hazard ratio (aHR). There were 131 and 144 events of ON occurred in the study group and the control group respectively during the follow-up period. The whole study group, whether received FESS or not, demonstrated both significant aRR and aHR compared to the control group after adjusting demographic data, prominent ocular diseases, and systemic co-morbidities. In addition, both the aRR and aHR were higher in CRS patient received FESS than those with CRS but without FESS management.

Conclusion

The existence of CRS, especially the surgery-indicated CRS is a significant risk factor for the following ON using multivariable analysis.