A Systematic Literature Review on Traumatic Optic Neuropathy

Navigation-guided transcaruncular orbital optic canal decompression in indirect traumatic optic neuropathy: long-term outcomes

PURPOSE

To determine the surgical outcomes using navigation-guided transcaruncular orbital optic canal decompression (NGTcOCD) and investigate the relationship between visual prognosis. visual evoked potential (VEP), association with DeLano type of optic canal and Onodi cells in patients with indirect traumatic optic neuropathy (TON).

DESIGN

Prospective observational.

METHODS

Fifty-two consecutive patients with indirect TON unresponsive to steroid therapy were divided into three groups where Group I comprised of cases with optic canal fracture who underwent NGTcOCD, Group II without optic canal fracture who underwent NGTcOCD and Group III, no-decompression group who chose not to undergo NGTcOCD. An improvement in visual acuity (VA) at 1 week, 3 months and 1 year and amplitude and latency of VEP at 1 year were considered as primary and secondary outcomes, respectively.

RESULTS

The mean VA improved from 2.55±0.67 and 2.62±0.56 LogMAR at presentation to 2.03±0.96 and 2.33±0.72 LogMAR at final follow-up among Group I and Group II patients, respectively (p<0.001 and p=0.01). Statistically significant improvement observed among both the Groups in VEP amplitude (p=<0.01) and among Group II in VEP latency (p<0.01). Both Group I and Group II patients have better outcomes than patients in no-decompression group. VA at presentation and Type 1 DeLano optic canal were observed as significant prognostic factors.

CONCLUSIONS

NGTcOCD serves as a minimally invasive transcaruncular route to the optic canal which enables ophthalmologists to perform decompression from the anterior-most orbital end under direct visualisation. Patients with indirect TON with or without optic canal fracture and unresponsive to steroid therapy when managed with NGTcOCD have shown comparable and superior outcomes.

Effect of astrocyte GPER on the optic nerve inflammatory response following optic nerve injury in mice

Activated astrocytes are a primary source of inflammatory factors following traumatic optic neuropathy (TON). Accumulation of inflammatory factors in this context leads to increased axonal damage and loss of retinal ganglion cells (RGCs). Therefore, in the present study, we explored the role of the astrocyte G protein-coupled estrogen receptor (GPER) in regulating inflammatory factors following optic nerve crush (ONC), and analyzed its potential regulatory mechanisms. Overall, our results showed that GPER was abundantly expressed in the optic nerve, and co-localized with glial fibrillary acidic proteins (GFAP). Exogenous administration of G-1 led to a significant reduction in astrocyte activation and expression of inflammation-related factors (including IL-1β, TNF-α, NFκB, and p-NFκB). Additionally, it dramatically increased the survival of RGCs. In contrast, astrocytes were activated to a greater extent by exogenous G15 administration; however, RGCs survival was significantly reduced. In vitro, GPER activation significantly reduced astrocyte activation and the release of inflammation-related factors. In conclusion, activation of astrocyte GPER significantly reduced ONC inflammation levels, and should be explored as a potential target pathway for protecting the optic nerve and RGCs after TON.

Endoscopic transnasal approach to remove an intraorbital bullet: systematic review and case report

Introduction

Intraorbital foreign bodies (IOFBs) represent a clinical challenge: surgical management can be controversial and different strategies have been proposed. When removal is recommended, depending on the location and nature of the IOFB both external and endoscopic approaches have been proposed, with significantly different surgical corridors to the orbit and different morbidities.

Methods

We performed a literature review of cases of IOFBs that received exclusive endoscopic transnasal surgical treatment to evaluate the role of this surgery in these occurrences. We also present a case of an intraorbital intraconal bullet that was successfully removed using an endoscopic transnasal approach with good outcomes in terms of ocular motility and visual acuity.

Results

A limited number of cases of IOFBs have been treated with an exclusive endoscopic transnasal approach. When in the medial compartment, this approach appears to be safe and effective. In our case, two months after surgery the patient showed complete recovery with no significant long-term sequelae.

Conclusions

When feasible, an endoscopic transnasal approach for intraorbital foreign bodies represents a valid surgical technique with optimal outcomes and satisfactory recovery.

Surgical Outcome in Patients with Traumatic and Atraumatic Optic Neuropathy Following Endoscopic Optic Nerve Decompression

Endoscopic optic nerve decompression is a highly effective and reliable approach for patients with select cases of optic neuropathy. It reduces the hydrostatic pressure and helps in relieving the compressive forces within the intracanalicular portion of the optic nerve consequently preserving and arresting the deterioration of vision. The advantages of the endoscopic approach over other procedures include preservation of olfaction, quick recovery, lack of external scars and less morbidity. The objective of the study is to assess the surgical outcome of endoscopic optic nerve decompression in patients with traumatic and atraumatic optic neuropathy. The case records of consequent patients attending ENT department with defective vision due to traumatic and atraumatic causes were reviewed. The outcome was measured in terms of improvement in visual acuity by log MAR scale. Among the 14 patients studied, 57% were females and the median age of presentation was 33 years. As compared to preoperative baseline visual acuity, the overall improvement was achieved in 11 patients, with an effective rate of 78.5% postoperatively. Patients presenting with no light perception and residual vision had significant improvement in visual acuity after surgery. Trans-nasal endoscopic surgery helps in decompressing the optic nerve with proper exposure of the orbital apex and optic canal without any intracranial or intra-orbital complications. Further, being a minimally invasive procedure has great advantage in cases of optic neuropathy.

The Association Between Craniofacial Fracture Patterns and Traumatic Optic Neuropathy

Traumatic optic neuropathy (TON) is a rare but potentially devastating complication of craniofacial trauma. Approximately half of patients with TON sustain permanent vision loss. In this study, we sought to identify the most common fracture patterns associated with TON. We performed a retrospective review of craniomaxillofacial CT scans of trauma patients who presented to the R Adams Cowley Shock Trauma Center from 2015 to 2017. Included were adult patients who had orbital fractures with or without other facial fractures. Patients diagnosed with TON by a formal ophthalmologic examination were analyzed. Craniofacial fracture patterns were identified. Bivariate analysis and multivariate logistic regression were performed to identify craniofacial fracture patterns most commonly associated with TON. A total of 574 patients with orbital fractures who met inclusion criteria [15 (2.6%)] were diagnosed with TON. The median [interquartile range (IQR)] age was 44 (28-59) years. Patients with optic canal fractures and sphenoid sinus fractures had greater odds of TON compared with patients who did not have these fracture types [adjusted odds ratio (aOR) 95% confidence interval (CI) 31.8 (2.6->100), 8.1 (2.7-24.4), respectively]. Patients who sustain optic canal and sphenoid sinus fractures in the setting of blunt facial trauma are at increased odds of having a TON. Surgeons and other physicians involved in the care of these patients should be aware of this association.

Visual conservation treatment dilemmas in neuroblastoma with bilateral blindness

OBJECTIVE

To investigate the clinical features, treatment strategies, and prognosis of neuroblastoma with bilateral blindness.

METHODS

The clinical data of five patients with bilateral blindness neuroblastoma admitted to Beijing Children's Hospital from April 2018 to September 2020 were retrospectively collected to summarize their clinical characteristics.

RESULTS

All patients were female and the median age at presentation was 25 (23, 41) months. The median intervention time from the onset of symptoms of bilateral blindness to the start of treatment was 10 (10, 12) days. All five cases were staged as stage M and grouped as high risk. Four cases were MYCN gene amplification and one case was MYCN acquisition. Five children were treated according to a high-risk neuroblastoma treatment protocol. Four children did not recover their vision after treatment, and one case improved to have light perception. All patients were effectively followed up for a median of 20 (12, 31) months, with three deaths, one tumor-free survival, and one recurrent tumor-bearing survival.

CONCLUSION

Neuroblastoma with bilateral blindness is rare in the clinic, mostly in children of young age, and is often associated with MYCN amplification and multiple metastases. Early hormone shock therapy and optic nerve decompression are beneficial for preserving the child's vision. A joint multi-disciplinary treatment may help in the formulation of treatment decisions. Achieving a balance between good visual preservation and survival within the short optic nerve neurotherapeutic window is extremely challenging.

Traumatic optic neuropathy from an air gun pellet injury: a case report

Orbital apex fractures are a debilitating condition that can cause vision problems and are often associated with intracranial injury. Traumatic Optic Neuropathy (TON), which results in vision loss following a traumatic injury to the optic nerve, can be caused by various mechanisms, but most cases involve injuries to the globe, orbit, or adnexa. We are reporting a case of an 18 year old male with a history of an air gun being accidentally discharged into his left eye. He was evaluated and found to have an Orbital apex fracture with left eye TON. Patient was administered high dose steroids. Detailed evaluation by Ophthalmology revealed a left eye traumatic stage I macular hole which was conservatively treated with visual improvement reported during patient follow up.

Clinical profile and visual outcome in patients with traumatic optic neuropathy

Purpose

To analyze the visual outcome in patients with traumatic optic neuropathy (TON) with respect to different treatment modalities, to study the correlation of initial visual loss with the final visual outcome, and to find out the predictor of final visual outcome in patients with indirect TON.

Methods

A retrospective analysis of 36 eyes with TON was done. Data on clinical profile, including demographics, mode of trauma, best corrected visual acuity (BCVA), pupillary reflex examination, and anterior and posterior segment examination, was collected. Presence and location of orbital and cranial fractures were identified from computed tomography scan. Visual outcomes following steroid therapy, optic nerve (ON) decompression, and in untreated patients were analyzed. Pre- and post-treatment BCVA were divided into three groups based on logarithm of the minimum angle of resolution (logMAR) as follows: group A: 3, group B: 2.9-1.3, and group C<1.3. BCVA values at follow-up visits were taken as the primary outcome measure. Association between various risk factors and final visual outcome in patients with indirect TON was also analyzed.

Results

Out of 34 patients whose 36 eyes were studied, three (8.8%) patients were females and 31 (91.2%) patients were males. Most common mode of trauma was road traffic accident (RTA; 91.2%), which was followed by fall (8.8%) and assault (2.9%). Pre- and post-treatment BCVA values of 36 eyes were compared, and improvement in BCVA after treatment was found to be statistically significant. Also, 28.6% of patients with presenting BCVA of no light perception showed improvement compared to 94.1% and 100% in groups B and C, respectively. Orbital wall fractures were seen in 80.5% (n = 29) of the patients, with lateral wall fracture being the most common (58.3%) followed by medial wall (33.3%), roof (27.7%), floor (27.7%), and optic strut (5%).

Conclusion

Baseline BCVA had significant association with final vision improvement. Lateral wall fracture was the most common fracture associated with indirect TON. Patients treated with high-dose corticosteroids, irrespective of the time of presentation, had a better visual outcome.

Oxidative Stress: A Suitable Therapeutic Target for Optic Nerve Diseases?

Optic nerve disorders encompass a wide spectrum of conditions characterized by the loss of retinal ganglion cells (RGCs) and subsequent degeneration of the optic nerve. The etiology of these disorders can vary significantly, but emerging research highlights the crucial role of oxidative stress, an imbalance in the redox status characterized by an excess of reactive oxygen species (ROS), in driving cell death through apoptosis, autophagy, and inflammation. This review provides an overview of ROS-related processes underlying four extensively studied optic nerve diseases: glaucoma, Leber's hereditary optic neuropathy (LHON), anterior ischemic optic neuropathy (AION), and optic neuritis (ON). Furthermore, we present preclinical findings on antioxidants, with the objective of evaluating the potential therapeutic benefits of targeting oxidative stress in the treatment of optic neuropathies.

Visual-evoked potential predicts the efficacy of the optical canal decompression for traumatic optic nerve neuropathy showing blindness: A case report

Background

The indication for surgical optic canal decompression (OCD) for traumatic optic neuropathy (TON) remains controversial because there is no reliable predictor of a good outcome. We report the case of a blind patient with TON whose remaining visual-evoked potential (VEP) suggested recovery potential of the injured optic nerve after OCD.

Case Description

A 48-year-old man had fallen from a height of 7 m, striking his head. He immediately complained of right-eye blindness. He had no light perception and the direct light reflex disappeared from the right pupil, although there was no fracture or traumatic lesion on computed tomography and magnetic resonance imaging. Because the amplitude of the VEP with the right eye stimulation remained unchanged, we performed the right OCD. During surgical OCD, the amplitude and latency of VEP began to improve. Finally, the visual field improved in almost all directions, and eyesight improved to 0.2.

Conclusion

The retained VEP activity in TON may suggest the recovery potential of the injured optic nerve, even in cases of blindness. It is possible that VEP is an indicator of aggressive treatment for TON such as OCD.

Valproate reduces retinal ganglion cell apoptosis in rats after optic nerve crush

The retinal ganglion cells of the optic nerve have a limited capacity for self-repair after injury. Valproate is a histone deacetylase inhibitor and multitarget drug, which has been demonstrated to protect retinal neurons. In this study, we established rat models of optic nerve-crush injury and injected valproate into the vitreous cavity immediately after modeling. We evaluated changes in the ultrastructure morphology of the endoplasmic reticulum of retinal ganglion cells over time via transmission electron microscope. Immunohistochemistry and western blot assay revealed that valproate upregulated the expression of the endoplasmic reticulum stress marker glucose-regulated protein 78 and downregulated the expression of transcription factor C/EBP homologous protein, phosphorylated eukaryotic translation initiation factor 2α, and caspase-12 in the endoplasmic reticulum of retinal ganglion cells. These findings suggest that valproate reduces apoptosis of retinal ganglion cells in the rat after optic nerve-crush injury by attenuating phosphorylated eukaryotic translation initiation factor 2α-C/EBP homologous protein signaling and caspase-12 activation during endoplasmic reticulum stress. These findings represent a newly discovered mechanism that regulates how valproate protects neurons.

Human amnionic progenitor cell secretome mitigates the consequence of traumatic optic neuropathy in a mouse model

Traumatic optic neuropathy (TON) is a condition in which acute injury to the optic nerve from direct or indirect trauma results in vision loss. The most common cause of TON is indirect injury to the optic nerve caused by concussive forces that are transmitted to the optic nerve. TON occurs in up to 5% of closed-head trauma patients and there is currently no known effective treatment. One potential treatment option for TON is ST266, a cell-free biological solution containing the secretome of amnion-derived multipotent progenitor (AMP) cells. We investigated the efficacy of intranasal ST266 in a mouse model of TON induced by blunt head trauma. Injured mice treated with a 10-day regimen of ST266 showed an improvement in spatial memory and learning, a significant preservation of retinal ganglion cells, and a decrease in neuropathological markers in the optic nerve, optic tract, and dorsal lateral geniculate nucleus. ST266 treatment effectively downregulated the NLRP3 inflammasome-mediated neuroinflammation pathway after blunt trauma. Overall, treatment with ST266 was shown to improve functional and pathological outcomes in a mouse model of TON, warranting future exploration of ST266 as a cell-free therapeutic candidate for testing in all optic neuropathies.

Traumatic Optic Neuropathy: Update on Management

Traumatic optic neuropathy is one of the causes of visual loss caused by blunt or penetrating head trauma and is classified as both direct and indirect. Clinical history and examination findings usually allow for the diagnosis of traumatic optic neuropathy. There is still controversy surrounding the management of traumatic optic neuropathy; some physicians advocate observation alone, while others recommend steroid therapy, surgery, or both. In this entry, we tried to highlight traumatic optic neuropathy's main pathophysiologic mechanisms with the most available updated treatment. Recent research suggests future therapies that may be helpful in traumatic optic neuropathy cases.

[Diagnosis and Treatment in frontobasal fractures]

Traumatic brain injury can result in frontobasal fractures (FBF). The goals of treatment for FBF are to eliminate primary morbidity and/or prevent secondary morbidity. Of particular importance in this regard is the proximity of important sensory organs for hearing, vision, smell, and taste, as well as their supplying nervous structures. Medical history, clinical findings, or CT scan are necessary and should lead to an individual evaluation. Depending on the severity of the fractures, the following disciplines may be involved in the treatment of FBF: neurosurgery, plastic surgery, oral and maxillofacial surgery, and/or otorhinolaryngology. Particularly less invasive endoscopic endonasal therapy is a specialty of otorhinolaryngologic surgeons and has not been widely established in other disciplines. The present work provides an overview of the current state of the art in terms of the following aspects, taking into account the current literature: anatomic principles, classification of fractures, diagnostics (in particular clinical examination, imaging, and laboratory chemistry tests), clinical symptoms, and treatment.

Surgical approach for traumatic chiasmal syndrome and complete third nerve palsy following severe head trauma

Traumatic chiasmal syndrome and traumatic third nerve palsies are rare entities usually caused by severe, high-speed, closed-head road accidents that require a thorough diagnostic work-up and complex medical and surgical management. This report presents the case of a young adult who was involved in a motorcycle accident and sustained blunt frontal head trauma, resulting in optical chiasmal syndrome and complete unilateral third nerve palsy. Ophthalmological examination demonstrated a right complete ptosis, a downward and outward position of the right eye with a fixed and dilated pupil, and bitemporal hemianopsia. In addition, funduscopy revealed bilateral optical nerve atrophy. After stabilisation and during follow-up, strabismus surgery was performed with improvement of ocular alignment in the primary position. Subsequently, eyelid surgery was carried out with good amplification of the visual field, particularly on the left side. Although challenging, surgical intervention in these cases should be considered for both functional and cosmetic reasons.

Current Review of Traumatic Optic Neuropathy and Traumatic Brain Injury among Military Service Members

Traumatic optic neuropathy (TON) is a form of optic nerve damage that while rare in the general population, is commonly associated with traumatic brain injury (TBI). With increasingly high rates of TBI in the military community, our service members and veterans represent a population where traumatic optic neuropathy is prevalent. Parachute jumpers have been identified as a high-risk group for under-reported head injury and therefore many cases of TBI are easily overlooked. With recent insights into the limitations of the veteran's disability exam, we review the current understanding of TON and propose an updated protocol for TON evaluation. We also urge for development of safer helmet design to reduce and prevent further cases of TBI, mTBI, and TON in our military personnel.

Electrophysiological Analysis of Traumatic Optic Neuropathy and Traumatic Brain Injury Among Active Military

Background

Traumatic Optic Neuropathy (TON) can cause persistent visual deficits and is a known sequala of Traumatic Brain Injury (TBI). Little is known regarding appropriate diagnosis, management, and treatment.

Methods

we performed a prospective cohort study with 356 active military personnel using electrophysiological Visual Evoked Potential (VEP) testing for TON in the context of known or suspected TBI. This was done with the intent to review and revise management protocol for patients who are susceptible to TON. This new VEP protocol was incorporated with kinetic and static visual field testing to uncover occult cases of TON previously missed in the current disability examination, as well as aid in evaluation of patients with borderline concussive cases that do not meet current diagnosis of mild, moderate, or severe TBI by the Veteran's Disability Exam.

Results

80 patients were diagnosed with TON. Average age of TON patients was 37.4 years, with most patients being male. Of those patients with TON, 45% had reported TBI, whereas an additional 54% had suspected history of concussion. Patients presented with bilateral TON (65.8%, n=52), while unilateral TON cases occurred less frequently (35.4%, n=28). Visual field defects were apparent in both static and kinetic visual field testing in 54% of cases. VEP sensitivity in our study was 88%. Military parachute jumpers (paratroopers) represent the highest risk group for undiagnosed TBI and TON.

Conclusions

we recommend periodic static and kinetic visual field testing in high-risk individuals working in fields with high concussion rates. Focused collaboration for safer helmet design is imminent. By improving helmet design, we can reduce mTBI and related TON, as well as reduce costly medical care and disability payments after military discharge.

[Protective effect of Epothilone D against traumatic optic nerve injury in rats]

OBJECTIVE

To investigate the therapeutic effect of Epothilone D on traumatic optic neuropathy (TON) in rats.

METHODS

Forty-two SD rats were randomized to receive intraperitoneal injection of 1.0 mg/kg Epothilone D or DMSO (control) every 3 days until day 28, and rat models of TON were established on the second day after the first administration. On days 3, 7, and 28, examination of flash visual evoked potentials (FVEP), immunofluorescence staining and Western blotting were performed to examine the visual pathway features, number of retinal ganglion cells (RGCs), GAP43 expression level in damaged axons, and changes of Tau and pTau-396/404 in the retina and optic nerve.

RESULTS

In Epothilone D treatment group, RGC loss rate was significantly decreased by 19.12% (P=0.032) on day 3 and by 22.67% (P=0.042) on day 28 as compared with the rats in the control group, but FVEP examination failed to show physiological improvement in the visual pathway on day 28 in terms of the relative latency of N2 wave (P=0.236) and relative amplitude attenuation of P2-N2 wave (P=0.441). The total Tau content in the retina of the treatment group was significantly increased compared with that in the control group on day 3 (P < 0.001), showing a consistent change with ptau-396/404 level. In the optic nerve axons, the total Tau level in the treatment group was significantly lower than that in the control group on day 7 (P=0.002), but the changes of the total Tau and pTau-396/404 level did not show an obvious correlation. Epothilone D induced persistent expression of GAP43 in the damaged axons, detectable even on day 28 of the experiment.

CONCLUSION

Epothilone D treatment can protect against TON in rats by promoting the survival of injured RGCs, enhancing Tau content in the surviving RGCs, reducing Tau accumulation in injured axons, and stimulating sustained regeneration of axons.

Optic nerve injury in preoperative imaging is associated with visual improvement outcome in endoscopic optic nerve decompression

Objective

To evaluate potential clinical parameters having an impact on visual outcome after endoscopic optic nerve decompression in acute optic neuropathy patients.

Methods

A retrospective chart review of patients with acute optic neuropathy, who underwent endoscopic optic nerve decompression between June 2001 and November 2018 at an academic center was performed. Patients were divided into groups according to visual improvement after surgical treatment (yes/no). Following clinical parameters were compared between groups: perioperative steroid use, evidence of optic nerve affection in preoperative neuroimaging, additional optic nerve sheath incision, surgery delay and preoperative C-reactive protein (CRP) levels. Further subgroups analyses were conducted based on etiology (trauma/tumor).

Results

Among 32 included cases, 16 patients (50%) reported visual improvement after endoscopic optic nerve decompression. There was no significant difference in visual improvement between etiology subgroups (trauma: n = 9/20 (45%) vs. tumor: n = 7/12 (58.3%), p = 0.465). Tumor subgroup patients with visual improvement had a significantly higher prevalence of optic nerve affection in preoperative neuroimaging than those without visual improvement (p = 0.018, φ = 0.683). Perioperative steroid administration was negatively associated with visual outcome (p = 0.034, φ = 0.375). Nerve sheath incision, surgery delay and preoperative CRP levels did not have a significant impact on visual outcome (p > 0.05).

Conclusion

Radiological findings can help as an indicator for surgical treatment since an affected optic nerve in preoperative neuroimaging resulted in better visual outcome after surgery. The use of steroids should be considered more carefully since it did not show any beneficial effect.