Traumatic optic neuropathy: an evolving understanding

Neuroprotective effects and mechanisms of action of artemisinin in retinal ganglion cells in a mouse model of traumatic optic neuropathy

Introduction

Traumatic optic neuropathy is known to be a critical condition that can cause blindness; however, the specific mechanism underlying optic nerve injury is unclear. Recent studies have reported that artemisinin, considered vital in malaria treatment, can also be used to treat neurodegenerative diseases; however, its precise role and mechanism of action remain unknown. Therefore, in this study, we aimed to investigate the impact and probable mechanism of action of artemisinin in retinal ganglion cells (RGCs) in a mouse model of traumatic optic neuropathy induced by optic nerve crush (ONC).

Methods

ONC was induced in the left eye of mice by short-term clamping of the optic nerve; oral artemisinin was administered daily. The neuroprotective effect of the drug was assessed using Tuj-1 staining in RGCs. In addition, the inflammatory response and the expression levels of phosphorylated tau protein and tau oligomers were observed using RT-qPCR, TUNEL assay, and fluorescence staining to investigate the underlying mechanisms.

Results

Artemisinin increased the survival rate of RGCs 14 days after ONC. Artemisinin significantly reduced the levels of inflammatory factors such as CXCL10, CXCR3, and IL-1β in the retina and decreased the apoptosis of RGCs. Moreover, downregulation of the phosphorylation of tau proteins and the expression of tau oligomers were observed after artemisinin treatment.

Conclusion

Our results suggest that artemisinin can increase the survival rate of RGCs after ONC and reduce their apoptosis. This effect may be achieved by inhibiting the inflammatory response it triggers and downregulating tau protein phosphorylation and tau oligomer expression. These findings suggest the potential application of artemisinin as a therapeutic agent for neuropathy.

Intraretinal microvascular alterations in indirect traumatic optic neuropathy using optical coherence tomography angiography

PURPOSE

To quantitatively evaluate macular and peripapillary microvascular alterations in patients with indirect traumatic optic neuropathy (TON) compared to normal controls using optical coherence tomography angiography (OCT-A) and determine their associations with other ocular parameters.

METHODS

We enrolled 33 eyes of 33 patients with TON and 34 eyes of 34 healthy controls. OCT-A was used to generate microvascular structure images of the superficial retinal capillary plexus (SRCP), deep retinal capillary plexus (DRCP), and radial peripapillary capillary (RPC) segment in the macula and peripapillary area. Functional and structural parameters such as best-corrected visual acuity, visual field, peripapillary retinal nerve fibre layer (pRNFL) thickness, macular ganglion cell-inner plexiform layer (mGCIPL) thickness, OCT-A variables were compared between TON patients and controls. Age, gender, and spherical equivalent refractive errors were statistically adjusted for the analysis.

RESULTS

OCT-A revealed a significant reduction of the average vessel density in the RPC segment in TON patients compared to controls (48.5% ± 6.28 vs. 57.88% ± 3.06%, P < 0.0001, corrected P < 0.0001). When comparing sectors, the vessel density of the RPC segment in TON patients was also significantly lower in all four quadrants compared to healthy controls. The inferior sector vessel density of the RPC segment was significantly associated with visual field defects (P = 0.0253) and visual acuity (P = 0.0369). The temporal sector vessel density of DRCP was also associated with visual field defects (P = 0.0377). The RPC segment in the superior and inferior sector vessel density displayed a significant association with the corresponding regional pRNFL thickness (P = 0.0248 and <0.0001, respectively).

CONCLUSIONS

Patients with indirect TON exhibit significant microvascular alterations compared to controls. This study confirms that TON can induce intraretinal microvascular changes and suggests that OCT-A may serve as a useful biomarker for assessing visual functional and structural changes.

Effects of light perception on visual function recovery in patients with traumatic optic neuropathy

This study aimed to assess the impact of light perception presence or absence on visual function recovery in patients with traumatic optic neuropathy (TON). A retrospective analysis was conducted on the clinical data of 206 TON patients. Based on the presence or absence of light perception after injury, patients were categorized into a light perception group and a non-light perception group. A comparison was made between the two groups regarding visual acuity recovery before and after treatment. The non-light perception group comprised 63 patients, with a treatment effectiveness rate of 39.68%. The light perception group consisted of 143 patients, with a treatment effectiveness rate of 74.83%. The difference between the two groups was statistically significant (χ2 = 23.464, P < 0.01). Subgroup analysis indicated that surgical treatment appeared to be more effective than steroid hormone therapy for patients with light perception. Conversely, for patients without light perception, there was no significant difference in the effectiveness of the two methods. The total effectiveness rate of the light perception group was significantly higher than that of the non-light perception group, suggesting that patients with light perception before treatment experience better outcomes compared to those without light perception. Treatment choices should be individualized to ensure optimal results.

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.

Comparison of Surgical Decompression and Steroid Therapy for the Management of Traumatic Optic Neuropathy: A Systematic Review and Meta-Analysis

Study Design

A systematic review and meta-analysis.

Objective

Treatment of traumatic optic neuropathy (TON) has been a subject of debate for many decades due to the scarcity of evidence-based treatment protocols. This review compares surgical decompression (SD) and steroid therapy (ST) as treatment approaches in TON patients.

Methods

A PRISMA-guided systematic review using PubMed, Embase, Ovid and Scopus databases was performed till the last search date of July 31st 2021. The outcome of interest was an improvement in visual acuity. A meta-analysis of the odds ratio was performed using a random-effect model and sub-group analysis based upon criteria for assessment of improvement in visual acuity.

Results

Sixteen studies (including 1046 patients) were included in the review. The review could identify 590 patients treated with SD and 456 treated with ST. In addition, there was a second cohort of patients presenting with NLP (no light perception). A meta-analysis with a sub-group analysis revealed that there was statistically no significant difference between the two treatment approaches in terms of improvement in VA.

Conclusions

There is no difference in treatment results of SD or ST for TON. Several treatment protocols and different criteria for assessing visual acuity led to difficulty in generating evidence for selecting the correct treatment approach.

Emerging Gene Therapy Technologies for Retinal Ganglion Cell Neuroprotection

ABSTRACT

Optic neuropathies encompass a breadth of diseases that ultimately result in dysfunction and/or loss of retinal ganglion cells (RGCs). Although visual impairment from optic neuropathies is common, there is a lack of effective clinical treatments. Addressing a critical need for novel interventions, preclinical studies have been generating a growing body of evidence that identify promising new drug-based and cell-based therapies. Gene therapy is another emerging therapeutic field that offers the potential of specifically and robustly increasing long-term RGC survival in optic neuropathies. Gene therapy offers additional benefits of driving improvements following a single treatment administration, and it can be designed to target a variety of pathways that may be involved in individual optic neuropathies or across multiple etiologies. This review explores the history of gene therapy, the fundamentals of its application, and the emerging development of gene therapy technology as it relates to treatment of optic neuropathies.

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.

Anatomical Study and Clinical Application of Optic Canal Decompression Via Transethmoid-sphenoid Approach Under Endoscope

This study aimed to evaluate the safety and accuracy of the endoscopic transethmoid-sphenoid approach for optic canal decompression. Twelve sides of 6 adult cadaveric heads fixed in formalin were selected to simulate optic canal decompression using the endoscopic transethmoid-sphenoid approach. Furthermore, this approach was used for optic canal decompression in 10 patients (11 eyes) with optic nerve canal injury. Related anatomical structures were observed using a 0-degree endoscope, and the anatomical characteristics as well as the surgical data were collected. The maximum effective widths of the cranial opening, orbital opening, and middle segment of the canal that could be drilled open endoscopically were 7.82±2.63, 8.05±2.77, and 6.92±2.01 mm, respectively. The angle between the line linking the center point of the tubercular recess with the midpoint of the cranial opening of the optic canal and the horizontal coordinate was 17.23±1.34 degrees. At the orbital opening of the optic canal, the ophthalmic artery was located directly inferior to the optic nerve in 2 cases (16.7%) and laterally inferior to the optic nerve in 10 cases (83.3%). Six of the operational eyes were effective while the remaining 5 were ineffective. No postoperative complications such as bleeding, infection, or cerebrospinal fluid leakage were observed during the follow-up period (6-12 mo). In conclusion, optic canal decompression positively impacts the prognosis of partial traumatic optic neuropathy. Furthermore, the endoscopic transethmoid-sphenoid approach for optic canal decompression is a minimally invasive procedure that provides direct access and adequate decompression. This technique is easy to master and suitable for clinical applications.

Diagnosis and treatment of transnasal endoscopic optic canal decompression for traumatic optic neuropathy

Objective

To investigate the clinical efficacy and prognostic factors of transnasal endoscopic optic decompression in the treatment of traumatic optic neuropathy (TON).

Methods

A retrospective analysis was performed on 13 TON patients in The Seventh Affiliated Hospital of Sun Yat-sen University and Shenzhen Eye Hospital in Shenzhen City (China) from June 2020 to April 2022. These patients had received transnasal endoscopic optic decompression, and hormonal and neurotrophic drugs were given after surgery. Visual acuity (VA) improvement was used as the criterion to judge clinical efficacy.

Results

In a total of 13 patients, 13 injured eyes (12 men and 1 woman; mean age, 28.0 ± 11.8 years) received transnasal endoscopic optic decompression. After surgery, nine patients had improved VA, whereas four patients failed to show any improvement, resulting in a total effective rate of 69.2%. Of the six patients with no light perception preoperatively, three had effective results after the operation, giving an effective rate of 50.0%. Of the seven patients with residual light sensation preoperatively, six had effective results after the operation, giving an effective rate of 85.7%. Of the 10 patients operated on within 7 days after injury, seven had effective results, giving an effective rate of 70%. Of the three patients injured and operated on after 7 days, two had effective results, giving an effective rate of 66.7%.

Conclusion

Transnasal endoscopic optic nerve decompression is an effective treatment method for TON. The presence of residual light perception and the timing of surgery within 7 days are crucial to the prognosis.

Cerebral revascularization for complex middle cerebral artery aneurysms: surgical strategies and outcomes in a single center

Cerebral revascularization is the ultimate treatment for a subset of complex middle cerebral artery (MCA) aneurysms. The decision for the revascularization strategy should be made during the treatment process. This study aimed to summarize the revascularization strategies for different types of complex MCA aneurysms and their outcomes. The clinical data of patients with complex MCA aneurysms who underwent cerebral revascularization since 2015 were analyzed retrospectively. The aneurysms were classified according to the location and other main characteristics that affect the selection of surgical modalities. The corresponding surgical modalities and treatment outcomes were summarized. A total of 29 patients with 29 complex MCA aneurysms were treated with cerebral revascularization from 2015 to 2022. Treated aneurysms were located at the prebifurcation segment in 7 patients, bifurcation segment in 12 patients, and postbifurcation segment in 10 patients. Surgical modalities in the prebifurcation segment included four high-flow extracranial-to-intracranial (EC-IC) bypasses with aneurysm trapping or proximal occlusion, two IC-IC bypasses with aneurysm excision, and one combination bypass with aneurysm excision. In the bifurcation segment, surgical modalities included two low-flow EC-IC bypasses with aneurysm excision or trapping, six IC-IC bypasses with aneurysm excision, three combination bypasses with aneurysm excision, and one constructive clipping with IC-IC bypass. In the postbifurcation segment, surgical modalities included nine IC-IC bypasses with aneurysm excision and low-flow EC-IC bypass with aneurysm trapping. The revascularization strategy for prebifurcation aneurysms was determined based on the involvement of lenticulostriate arteries, whereas the strategy for bifurcation aneurysms was determined based on the number of distal bifurcations and the shape of the aneurysm. The location of the aneurysm determined the revascularization strategy for aneurysms in the postbifurcation segments. Angiography demonstrated that aneurysms were completely obliterated in 26 cases and shrank in 3 cases, and all bypasses except one were patent. The mean follow-up period was 47.5 months. Three patients developed hemiplegic paralysis, and one developed transient aphasia postoperatively due to cerebral ischemia. No new neurological dysfunction occurred in the other 25 patients with no recurrence or enlargement of aneurysms during the follow-up. Prebifurcation aneurysms involving the lenticulostriate arteries require proximal occlusion with high-flow bypass. Most of the other aneurysms can be safely excised or trapped by appropriate revascularization strategies according to their location and orientation.

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.

Retinal peripapillary microvasculature in indirect traumatic optic neuropathy predicted prognosis of endoscopic trans-ethmosphenoid optic canal decompression

PURPOSES

The purpose of this study is to quantify the alteration of retinal peripapillary microvasculature and structure in unilateral indirect traumatic optic neuropathy (ITON) and figure out predicted factors of visual improvement for ITON patients with endoscopic trans-ethmosphenoid optic canal decompression (ETOCD) after one month.

METHODS

Twenty healthy controls and 72 unilateral ITON patients were included. Optical coherence tomography angiography was used to analyse radial peripapillary capillary (RPC) density, peripapillary retinal nerve fibre layer (pRNFL) thickness, superficial retinal capillary plexus (SRCP) and deep retinal capillary plexus (DRCP) density. Associations between preoperative parameters and postoperative best-corrected visual acuity (BCVA) were determined. The receiver operating characteristic (ROC) curves were used to figure out predicted factors of visual improvement for ITON after ETOCD one month.

RESULTS

In ITON eyes, the preoperative global RPC density, pRNFL thickness and SRCP density were reduced compared with unaffected eyes (p ≤ 0.001). Multivariate linear regression showed that preoperative global RPC density (Standardized β = -0.273), SRCP density (Standardized β = -0.183), DRCP density (Standardized β = -0.098) and preoperative BCVA (Standardized β = 0.795) were associated with the postoperative BCVA (All p < 0.001). The area under the curve (AUC) of preoperative global RPC density to predict visual improvement after ETOCD was 0.816, while the AUCs of preoperative BCVA, global pRNFL thickness, SRCP and DRCP density were 0.575, 0.756, 0.516 and 0.615, respectively.

CONCLUSIONS

The alteration of peripapillary area, especially the reduced RPC density, occurred in ITON eyes. The preoperative RPC density was associated with postoperative BCVA and was shown to be highly predictive for visual improvement after ETOCD one month.

m6A Modification-Association with Oxidative Stress and Implications on Eye Diseases

Oxidative stress (OS) refers to a state of imbalance between oxidation and antioxidation. OS is considered to be an important factor leading to aging and a range of diseases. The eyes are highly oxygen-consuming organs. Due to its continuous exposure to ultraviolet light, the eye is particularly vulnerable to the impact of OS, leading to eye diseases such as corneal disease, cataracts, glaucoma, etc. The N6-methyladenosine (m6A) modification is the most investigated RNA post-transcriptional modification and participates in a variety of cellular biological processes. In this study, we review the role of m6A modification in oxidative stress-induced eye diseases and some therapeutic methods to provide a relatively overall understanding of m6A modification in oxidative stress-related eye diseases.

Trauma to the Eye: Diffusion Restriction on MRI as a Surrogate Marker for Blindness

Traumatic optic nerve injury may lead to almost instantaneous blindness. We describe a case of sight loss after a perforating injury to the eye. The case is unusual in that the patient remained conscious and the trauma to the eye was isolated. A full ophthalmological examination was therefore possible within hours as well as early magnetic resonance imaging of the facial skull. High-quality T1-weighted, T2-weighted, and diffusion-weighted imaging could be acquired. The latter included apparent diffusion coefficient maps. There was a loss of the subarachnoid space of the optic nerve, fluid in the retrobulbar fat of the affected eye, and signal changes in the optic nerve. Previous work has been contradictory on the signal of the optic nerve on apparent diffusion coefficient maps in sight loss, with an increase seen by one group and a decrease seen by another. Signal loss on the apparent diffusion coefficient map was seen in the case described here. Signal loss on apparent diffusion coefficient maps may thus be used as a surrogate marker of sight loss in patients who are unconscious or otherwise unable to cooperate in ophthalmological exams.

Oxidative stress in the brain and retina after traumatic injury

The brain and the retina share many physiological similarities, which allows the retina to serve as a model of CNS disease and disorder. In instances of trauma, the eye can even indicate damage to the brain via abnormalities observed such as irregularities in pupillary reflexes in suspected traumatic brain injury (TBI) patients. Elevation of reactive oxygen species (ROS) has been observed in neurodegenerative disorders and in both traumatic optic neuropathy (TON) and in TBI. In a healthy system, ROS play a pivotal role in cellular communication, but in neurodegenerative diseases and post-trauma instances, ROS elevation can exacerbate neurodegeneration in both the brain and the retina. Increased ROS can overwhelm the inherent antioxidant systems which are regulated via mitochondrial processes. The overabundance of ROS can lead to protein, DNA, and other forms of cellular damage which ultimately result in apoptosis. Even though elevated ROS have been observed to be a major cause in the neurodegeneration observed after TON and TBI, many antioxidants therapeutic strategies fail. In order to understand why these therapeutic approaches fail further research into the direct injury cascades must be conducted. Additional therapeutic approaches such as therapeutics capable of anti-inflammatory properties and suppression of other neurodegenerative processes may be needed for the treatment of TON, TBI, and neurodegenerative diseases.

Endoscopic Optic Nerve Decompression for Direct Traumatic Optic Neuropathy : Our 10 Years Experience

Traumatic optic neuropathy (TON) can be classified into direct or indirect types. Direct optic injury usually results from optic nerve avulsion ,laceration or compression by fracture, fracture segment impingement or a resultant hematoma. Indirect optic injury is caused by increased intracanalicular pressure resulting in ischemia and disruption of neurofeedback channels. The prognosis of TON is usually quite poor. To date, no standardized treatment protocol has been developed for TON. In this study we are assessing the visual improvement in patients with direct TON who underwent endoscopic optic nerve decompression in the last 10 years. A retrospective study of 32 cases of optic nerve decompression for direct TON in the last 10 years. Preoperative and postoperative visual assessment were done and followed up for 3 months. There was complete improvement in vision in 17% of patients when optic nerve decompression was done within 72 h of trauma; whereas 31% cases had only partial improvement when done between 3 and 7 days. And there was no improvement when done after 7 days. Endoscopic optic nerve decompression is a minimally invasive surgery for direct traumatic optic neuropathy; with minimal or no complications when done by an experienced ENT surgeon. Other important prognostic factors include timing of surgery and preoperative visual status.

Clinically relevant small-molecule promotes nerve repair and visual function recovery

Adult mammalian injured axons regenerate over short-distance in the peripheral nervous system (PNS) while the axons in the central nervous system (CNS) are unable to regrow after injury. Here, we demonstrated that Lycium barbarum polysaccharides (LBP), purified from Wolfberry, accelerated long-distance axon regeneration after severe peripheral nerve injury (PNI) and optic nerve crush (ONC). LBP not only promoted intrinsic growth capacity of injured neurons and function recovery after severe PNI, but also induced robust retinal ganglion cell (RGC) survival and axon regeneration after ONC. By using LBP gene expression profile signatures to query a Connectivity map database, we identified a Food and Drug Administration (FDA)-approved small-molecule glycopyrrolate, which promoted PNS axon regeneration, RGC survival and sustained CNS axon regeneration, increased neural firing in the superior colliculus, and enhanced visual target re-innervations by regenerating RGC axons leading to a partial restoration of visual function after ONC. Our study provides insights into repurposing of FDA-approved small molecule for nerve repair and function recovery.

Effect of orbital volume in unilateral orbital fracture on indirect traumatic optic neuropathy

PURPOSE

This retrospective study aimed to analyze the relationship between the volume of the fractured and the normal orbit in patients with unilateral orbital fractures with and without indirect traumatic optic neuropathy (TON).

SUBJECTS

Data of 25 patients with unilateral orbital fractures who underwent computer tomography between January 2016 and December 2020 were investigated. Emergency imaging was performed within 2 hours of arrival at the emergency room. The subjects were categorized into two groups: unilateral orbital fractures with and without TON.

METHODS AND MEASURES

The assessment of TON was performed during a comprehensive ophthalmologic examination by an ophthalmologist. The stereographic orbit was reconstructed, and the volume was calculated. Other variables examined included age, sex, and cause of orbital trauma. The variables were compared using paired t-tests. Statistical significance was set at p < 0.05.

RESULTS

The orbital volume of the non-fractured orbit was 27.50  ± 2.26 and 27.48  ±  2.64 cm³ in the groups with and without TON, respectively. The average volume of the fractured orbit in the TON group was 27.78  ± 2.56 cm³, and there was no significant volumetric difference between the fractured and non-fractured sides in this group. However, the average volume of the fractured orbit without TON was 28.76  ±  3.18 cm³, larger than that of the non-fractured orbit (p = 0.016).

CONCLUSIONS

Non-expansion of the fractured orbit was a risk factor for indirect TON in patients with unilateral orbital fractures. Volumetric analysis from primary imaging would expedite the diagnosis and treatment of TON, resulting in optimal outcomes.

Analysis of retinal vasculature changes in indirect traumatic optic neuropathy using optic coherence tomography angiography

AIM

To assess the retinal vasculature alterations in indirect traumatic optic neuropathy (ITON) patients following craniofacial trauma by optic coherence tomography angiography (OCTA).

METHODS

Patients diagnosed of monocular ITON were recruited from August 2016 to May 2020. OCTA was performed using the AngioVue OCT-A system for two cube scans centered at the optic nerve head and fovea. OCTA data included thicknesses of peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC), as well as proportion of capillary perfusion and data were analyzed for correlation with post-injury timepoints: within 7, 8-30, 31-90, and 91-365d.

RESULTS

A total of 73 ITON patients were studied. Significant thinning of RNFL and GCC layers and attenuation of microvascular perfusion were observed in ITON eyes as compared to contralateral unaffected eyes (for most of the analyzed sectors and quadrants, P<0.05). Without respect to surgical intervention and vision recovery, the decrease in retinal layer thicknesses and microvascular perfusion was time-dependent, and most significant within three months (P<0.001).

CONCLUSION

ITON presents with time-dependent thinning of retinal layers and attenuation of microvasculature, indicating possible degeneration of retinal ganglion cells due to reduced retinal blood supply.

High-Mobility Group Box 1 Inhibitor BoxA Alleviates Neuroinflammation-Induced Retinal Ganglion Cell Damage in Traumatic Optic Neuropathy

Traumatic optic neuropathy (TON) is a significant cause of vision loss and irreversible blindness worldwide. It is defined as retinal ganglion cell death and axon degeneration caused by injury. Optic nerve crush (ONC), a well-validated model of TON, activates retinal microglia and initiates neuroinflammation. High-mobility group box 1 (HMGB1), a non-histone chromosomal binding protein in the nucleus of eukaryotic cells, is an important inducer of microglial activation and pro-inflammatory cytokine release. The purpose of this study was to examine the protective effects and mechanism of the HMGB1 inhibitor BoxA to neuroinflammation-induced retinal ganglion cells (RGCs) damage in traumatic optic neuropathy. For that purpose, an optic nerve crush model was established in C57BL/6J mice at 10–12 weeks. Model mice received an intravitreal injection of PBS and the HMGB1 inhibitor BoxA. Our data demonstrated that HMGB1 expression increased after optic nerve crush. Retinal ganglion cell function and morphology were damaged, and retinal ganglion cell numbers were reduced after optic nerve crush. Intravitreal injection of BoxA after ONC can alleviate damage. Furthermore, BoxA reduced microglial activation and expression levels of nuclear factor κB (NF-kB), nucleotide-binding domain, leucine-rich repeat containing protein 3 (NLRP3), and apoptosis-associated speck-like protein containing a CARD (ASC) in experimental ONC mice. In summary, HMGB1 mediates NLRP3 inflammasome via NF-kB to participate in retinal inflammatory injury after ONC. Thus, intravitreal injection of BoxA has potential therapeutic benefits for the effective treatment of RGC death to prevent TON.

Prognosticators of Visual Acuity After Indirect Traumatic Optic Neuropathy

BACKGROUND

The purpose of this study is to determine whether there are radiographic and systemic clinical characteristics that can predict final visual outcomes in patients with indirect traumatic optic neuropathy (iTON).

METHODS

This study is a retrospective, multicenter case series of adult patients with iTON treated initially at large, urban, and/or academic trauma centers with follow-up at an affiliated ophthalmology clinic. In addition to detailed cranial computed tomography characteristics, demographics, systemic comorbidities, coinjuries, blood products administered, and intracranial pressure, along with other factors, were gathered. LogMAR visual acuity (VA) at the initial presentation to the hospital and up to 12 months follow-up was collected.

RESULTS

Twenty patients met inclusion criteria; 16 (80%) were men with a mean age of 40.9 years (±20.9). Mean initial VA was 1.61 logMAR (∼20/800, ± 0.95), and final VA was 1.31 logMAR (∼20/400, ± 1.06). Three patients (4 eyes) had no light perception (NLP) VA at presentation and remained NLP at final follow-up. Of the predictors analyzed, only the initial VA was found to be a significant predictor of visual outcome. The presence of orbital fractures, intraconal and/or extraconal hemorrhage, as well as systemic comorbidities, were not found to significantly affect visual outcome.

CONCLUSIONS

After evaluating multiple factors, initial VA was the only factor associated with visual prognosis in iTON. This knowledge may better enable clinicians to predict visual prognosis and set reasonable expectations with patients and families at the time of injury.

Endoscopic trans-ethmosphenoid optic canal decompression is an optimal choice to save vision for indirect traumatic optic neuropathy

Purpose

To evaluate and compare the effectiveness of endoscopic trans‐ethmosphenoid optic canal decompression (ETOCD) and steroid pulse therapy (SPT) for indirect traumatic optic neuropathy (ITON).

Design

Prospective interventional case series.

Methods

Total 140 monocular ITON patients from January 2017 to June 2019 were recruited, including 100 patients received ETOCD (56 patients received ETOCD only and 44 patients received ETOCD combined with SPT before surgery), and 40 patients received SPT only. Their visual acuity (VA) and visual evoked potential (VEP) were analysed before and after treatments. Initial VA, lag time, causes of injuries and age were analysed for evaluating prognosis of treatment.

Results

In contrast with patients received SPT only (15/40 = 38%), the effective rate of patients received ETOCD only and patients received ETOCD combined with SPT were both significantly better (46/56 = 82%, p < 0.001 and 30/44 = 68%, p = 0.005). Whether with SPT before ETOCD or not, after ETOCD, patients with VA improvement showed no significant difference. And 59/76 (77.6%) patients showed improvement within 24 hours. Patients who had residual visions achieved higher effective rate than those with no light perception (56/58 = 97% and 20/42 = 48%; p < 0.001) after ETOCD. For patients with long lag time of 21–90 days, 23/32 (72%) patients presented with vision improvement. Moreover, VEP was significantly improved after ETOCD. No severe complications were observed.

Conclusions

Endoscopic trans‐ethmosphenoid optic canal decompression (ETOCD) is an effective and safe therapy for ITON, which is more effective than SPT. Even for patients with failure in responding to SPT, the successfully physical decompression is the most effective way to rescue optical nerve from permanent damage.

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.

Traumatic Optic Neuropathy (TON) and Ayurveda - A case study

The vision loss in the Traumatic Optic Neuropathy is the impact of deformational forces. This occurs due to direct or indirect injuries during trauma to skull. The use of high dose corticosteroids is the primary line of treatment in such injuries still remains a matter of debate. Traumatic Optic Neuropathy is yet an unexplored topic of study in Ayurveda. The Traumatic Optic Neuropathy can be correlated with Abhighatajanya Vataprakopaj Drishtinash. The treatment principles of Vataprakopaj Vyadhi are Snehan (massage), Swedan (sudation), Basti (enema) and Nasya (oleation through nasal route). A 50 year old male patient came to outpatient department suffered from motorcycle accident and had a forehead trauma followed by loss of vision in both eyes after 5 days and diagnosed as Traumatic Optic Neuropathy. An electrophysiological assessment showed absence of waveform in Visual Evoked Potential (VEP). According to Ayurveda patient was diagnosed primarily as Abhighatajanya Vataprakopaj Drishtinash and started to follow the protocol of Vataprakopaj Vyadhi. Patient received Ayurvedic formulations in morning, after meal and at night for 12 months and a course of Yapan Basti (medicated decoction enema) followed by Netratarpan (eye satiation), Nasya and Abhyanga (body and foot massage). Patient showed an improvement in the visual quality from no perception of light to perception of light and rays in right eye in 9 month. Patient had improvement in P100 latencies of right eye in VEP report and subjective improvement in quality of vision to perceive the images and objects. Application of Ayurvedic principles and Panchakarma therapy resulted in improvement of the case. An early management of Traumatic Optic Neuropathy with Ayurvedic treatment can have a significant impact on the clinical/visual outcome in terms of recovery in damaged optic nerve fibers.

[Orbital Trauma]

Orbital trauma is a common medical emergency with potentially sight-threatening complications. Due to the confined orbital conditions, any direct injury or space-consuming lesion may cause serious tissue damage. Possible complications are orbital fractures, foreign body injuries, development of orbital compartment syndrome and traumatic optic neuropathy. Clinical signs include periorbital hematoma or emphysema, subconjunctival hemorrhage, proptosis, decreased ocular mobility, decreased vision, increased intraocular pressure and relative afferent pupillary defect. Ophthalmic status and low-dose CT-imaging provide key information regarding the therapeutic decision. Treatment options include surgical exploration, reconstruction or decompression or a conservative approach with anti-inflammatory or anti-glaucomatous medication. Rapid interdisciplinary diagnostics and therapy is critical for early detection and prevention of irreversible functional loss respectively. Considering the frequent association with life-threatening comorbidities diagnosis may be complicated.

Trauma der Orbita

Die Behandlung orbitaler Verletzungen gehört zum Alltag der medizinischen Akutversorgung. Bei 10 – 25% aller Gesichtsverletzungen ist die Orbita beteiligt. Dieser Beitrag gibt einen Überblick über die möglichen Pathologien nach Orbitatrauma sowie das primärdiagnostische Vorgehen und die therapeutischen Optionen.

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.

Protective effects of intravitreal administration of mesenchymal stem cell-derived exosomes in an experimental model of optic nerve injury

Traumatic optic neuropathy results in the loss of retinal ganglion cells (RGCs), leading to unavoidable visual impairment. However, there is no effective therapy by far. Accumulated studies support the perception that mesenchymal stem cells (MSCs) secrete exosomes that serve as a protective paracrine factor. The study aimed to explore and evaluate the potential therapeutic effects of intravitreal transplantation of MSC-derived exosomes (MSC-exos) in an experimental model of optic nerve crush (ONC). Exosomes were isolated from rat MSCs and characterized by transmission electron microscope and western blotting. At the onset of ONC, a single intravitreal injection of exosomes or PBS was administered to the rats. At day 30, hematoxylin and eosin staining, immunohistochemistry, and βIII-tubulin staining were performed to evaluate the survival of RGCs. Moreover, TUNEL assay was used to examine the apoptosis of RGCs. Inflammation-relevant factors were identified via quantitative polymerase chain reaction. The expression levels of cell apoptosis-related molecules and key members of the PI3K/AKT signaling pathway were determined via western blot analysis. We found that MSC-exos exhibited typical characteristic morphologies (cup-shaped) and sizes (peak size of 93 nm). Furthermore, they exhibited substantial expression of the exosome markers CD63 and TSG101, but lacked the expression of the cellular marker GM130. Treatment with intravitreal MSC-exos notably promoted the survival of RGCs in ONC rats. The level of pro-inflammatory cytokines, including TNF-α, IL-1β, IL-6, IL-8, and MCP-1, were reduced, whereas those of the anti-inflammatory factor IL-10 were increased. Moreover, the apoptosis induced by ONC was decreased by the administration of MSC-exos via upregulation of the Bcl-2/Bax ratio and downregulation of caspase-3 activity. Furthermore, MSC-exos significantly stimulated AKT phosphorylation, whereas LY294002 restored the apoptosis-preventing effects of MSC-exos. The results of our results demonstrated that intravitreal administration of MSC-exos ameliorates ONC-induced injury in a rat model. These findings might aid in the development of effective exosome-based therapeutic strategies for the treatment of optic nerve degeneration.

Visual recovery following optic nerve crush in male and female wild-type and TRIF-deficient mice

BACKGROUND

There is growing evidence that the TIR-domain-containing adapter-inducing interferon-β (TRIF) pathway is implicated in the modulation of neuroinflammation following injuries to the brain and retina. After exposure to injury or to excitotoxic pathogens, toll-like receptors (TLR) activate the innate immune system signaling cascade and stimulate the release of inflammatory cytokines. Inhibition of the TLR4 receptor has been shown to enhance retinal ganglion cell (RGC) survival in optic nerve crush (ONC) and in ischemic injury to other parts of the brain.

OBJECTIVE

Based on this evidence, we tested the hypothesis that mice with the TRIF gene knocked out (TKO) will demonstrate decreased inflammatory responses and greater functional recovery after ONC.

METHODS

Four experimental groups -TKO ONC (12 males and 8 females), WT ONC (10 males and 8 females), TKO sham (9 males and 5 females), and WT sham (7 males and 5 females) -were used as subjects. Visual evoked potentials (VEP) were recorded in the left and right primary visual cortices and optomotor response were assessed in all mice at 14, 30, and 80 days after ONC. GFAP and Iba-1 were used as markers for astrocytes and microglial cells respectively at 7 days after ONC, along with NF-kB to measure inflammatory effects downstream of TRIF activation; RMPBS marker was used to visualize RGC survival and GAP-43 was used as a marker of regenerating optic nerve axons at 30 days after ONC.

RESULTS

We found reduced inflammatory response in the retina at 7 days post-ONC, less RGC loss and greater axonal regeneration 30 days post-ONC, and better recovery of visual function 80 days post-ONC in TKO mice compared to WT mice.

CONCLUSIONS

Our study showed that the TRIF pathway is involved in post-ONC inflammatory response and gliosis and that deletion of TRIF induces better RGC survival and regeneration and better functional recovery in mice. Our results suggest the TRIF pathway as a potential therapeutic target for reducing the inflammatory damage caused by nervous system injury.

Afferent Visual Manifestations of Traumatic Brain Injury

Traumatic brain injury (TBI) causes structural and functional damage to the central nervous system including the visual pathway. Defects in the afferent visual pathways affect visual function and in severe cases cause complete visual loss. Visual dysfunction is detectable by structural and functional ophthalmic examinations that are routine in the eye clinic, including examination of the pupillary light reflex and optical coherence tomography (OCT). Assessment of pupillary light reflex is a non-invasive assessment combining afferent and efferent visual function. While a assessment using a flashlight is relatively insensitive, automated pupillometry has 95% specificity and 78.1% sensitivity in detecting TBI-related visual and cerebral dysfunction with an area under the curve of 0.69-0.78. OCT may also serve as a noninvasive biomarker of TBI severity, demonstrating changes in the retinal ganglion cell layer and nerve fiber layer throughout the range of TBI severity even in the absence of visual symptoms. This review discusses the impact of TBI on visual structure and function.

The Incidence of Traumatic Optic Neuropathy Associated With Subtypes of Orbital Wall Fracture

BACKGROUND

Traumatic optic neuropathy (TON) is a rare disease but leaves critical sequelae to patient. Purpose of this study is to evaluate the incidence of TON in each orbital wall fracture.

MATERIALS AND METHODS

Retrospective review of 2629 patients with orbital wall fracture was performed in from January 2010 to March 2019, based on diagnostic code, Korean Standard Classification of Diseases, 7th Revision. The orbital wall fractures were divided into 4 subtypes: superior, medial, inferior, and lateral wall. Incidence of TON is analyzed according to subtypes, single and multiple wall fracture.

RESULTS

Among 2629 patients with orbital wall fractures, 27 patients were diagnosed with TON with an incidence of 1.02%. In single wall fracture, only lateral wall showed significantly high TON incidence, which only zygomatic fracture was included in single lateral wall fracture. In multiple wall fracture, it was statistically significant in the superior wall.

CONCLUSIONS

Fracture on lateral and superior orbital wall showed a tendency to increase the incidence of TON. Based on the above results, radiologic evaluation and physical examination is necessary for patient who has lateral and superior orbital wall fracture.

Progression of optic atrophy in traumatic optic neuropathy: retrograde neuronal degeneration in humans

OBJECTIVE

We used optical coherence tomography (OCT) to document the time course of retrograde neuronal degeneration following indirect optic nerve injury.

METHODS

We retrospectively studied patients diagnosed with unilateral indirect traumatic optic neuropathy (TON). Patients with total or near-total optic atrophy were included. All patients underwent complete ophthalmological examinations, including OCT imaging, within 1 day and at 1, 2, 3, 4, 6, 8, 12, 24, and 48 weeks after trauma.

RESULTS

The mean thicknesses of the circumpapillary retinal nerve fiber layer (cpRNFL) and macular retinal ganglion cell-inner plexiform layer (mGCIPL) decreased significantly at 2 weeks after trauma (p = 0.027 and p = 0.043). Changes in mGCIPL thickness preceded changes in cpRNFL thickness. The rates of reduction in mGCIPL and cpRNFL thicknesses were greatest between 2 to 4 weeks and 4 to 6 weeks after trauma. The reduction in mGCIPL thickness then slowed, and stabilized at 12 weeks after trauma. The proportions of cpRNFL and mGCIPL losses at 2, 4, 6, 8, and 12 weeks compared to 24 weeks were 17.1, 33.7, 59.8, 77.9, and 87.9% and 30.0, 73.3, 76.1, 88.3, and 97.9%, respectively.

CONCLUSIONS

OCT revealed optic atrophy progression 2 weeks after trauma, which was most rapid from 2 to 6 weeks, and then gradually stabilized. Loss of retinal ganglion cell bodies and dendrites seemed to precede the axonal degeneration. Observations of morphological changes in retinal layers using OCT in TON patients improve our understanding of retrograde neuronal degeneration of the central nervous system.

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.

Surgical Decompression or Corticosteroid Treatment of Indirect Traumatic Optic Neuropathy: A Randomized Controlled Trial

BACKGROUND

Traumatic optic neuropathy (TON) is a rare cause of severe permanent visual impairment after injury. Traumatic optic neuropathy may occur due to sharp trauma (direct injury) that damages the optic nerve directly or due to damage from the transmitted forces after a concussive blow to the head or orbit (indirect injury). The management of indirect TON remains controversial. Either surgical decompression or mega dose corticosteroid is used for managing indirect TON. However, no consensus exists regarding the definitive treatment.

MATERIALS AND METHODS

We designed a randomized controlled trial study to investigate this issue. Only patients with indirect TON and normal vision before the injury were enrolled. The patients' data were recorded, and fine cut facial computed tomography scan was performed to exclude those with retrobulbar hematoma. All the study subjects were randomly allocated to either the mega dose steroid (30 mg/kg stat and 15 mg/kg every 6 hours for 3 days) group or the surgical decompression group. The patients were followed up at 1 week, 1 month, 3 months, 6 months, and 9 months. During each follow-up, the Snellen visual acuity (VA), visual field, color change, fundus findings, and intraocular pressure were evaluated. These data were compared and analyzed using the Mann-Whitney U test and odds ratio. The short form questionnaire was used to analyze the lift quality difference between the two groups.

RESULTS

Thirty patients were enrolled, 12 in the surgical group and 18 in the steroid treatment group. There were no significant differences in the improvement rate, improvement degree, and life quality between the groups. However, the odds ratios are 5, 10, 2.5, and nonavailable in the cutoff points of no light perception (NLP), light perception (LP), hand movement, and counting finger in surgery group. In steroid group, they are 1, 1, 1, 1.83 in each cutoff points. Patients with better VA than NLP had better life quality than those with NLP VA (P = 0.005). Other cutoff point groups had no significant difference.

CONCLUSIONS

Patients with worse initial VA (eg, NLP and LP) had a higher chance of benefiting from surgical treatment and experiencing improvements in the life quality.

The Role of the Flash Visual Evoked Potential in Evaluating Visual Function in Patients with Indirect Traumatic Optic Neuropathy

Purpose

To assess the value of the flash visual evoked potential (FVEP) in determining final visual prognosis in patients with indirect traumatic optic neuropathy (TON).

Subjects and Methods

We included 30 patients diagnosed with indirect TON. Within one week of the onset of the trauma, visual acuity was recorded, pupillary reactions were assessed, FVEP was performed in both eyes. The amplitudes (N1p1 and N2P2) and the latency of P2 for each eye were recorded and amplitude ratio of N2P2 between the affected and normal eye was calculated. In follow-up visits, the cases underwent a complete ophthalmic examination, assessment of visual acuity, pupillary reaction, and FVEP.

Results

The study included 22 males (73.3%) and 8 females (26.7%). The right eye was involved in 16 patients (53.3%) and left eye was involved in 14 cases (46.7%). According to the findings of FVEP, there was a direct correlation between final visual acuity and initial amplitude of N1p1 and N2P2 and negative correlation with latency of P2 wave. In 20 patients in whom the N1P1 and N2P2 amplitude was within the normal range and amplitude ratio of N2P2 of normal and fellow eye was at least 0.5 and the P2 implicit time was less than 140 ms, they achieved better visual outcome and visual acuity improved in the affected eye. In other 10 patients in whom the N1P1 and N2P2 amplitude was below normal range and the N2P2 amplitude ratio between the normal and the affected eye was less than 0.5 and the P2 implicit time was more than 140 ms, the visual acuity in the affected eye was less than 0.01 and these patients achieved less or no improvement in their visual function.

Conclusion

Cases with TON usually present with severe loss of vision. FVEP is highly predictive of final visual outcome in patients having indirect TON given that the other eye is normal to be used as the patients’ internal control. More studies are needed to confirm these results.

Traumatic Optic Neuropathy

A host of different types of direct and indirect, primary and secondary injuries can affect different portions of the optic nerve(s). Thus, in the setting of penetrating as well as nonpenetrating head or facial trauma, a high index of suspicion should be maintained for the possibility of the presence of traumatic optic neuropathy (TON). TON is a clinical diagnosis, with imaging frequently adding clarification to the full nature/extent of the lesion(s) in question. Each pattern of injury carries its own unique prognosis and theoretical best treatment; however, the optimum management of patients with TON remains unclear. Indeed, further research is desperately needed to better understand TON. Observation, steroids, surgical measures, or a combination of these are current cornerstones of management, but statistically significant evidence supporting any particular approach for TON is absent in the literature. Nevertheless, it is likely that novel management strategies will emerge as more is understood about the converging pathways of various secondary and tertiary mechanisms of cell injury and death at play in TON. In the meantime, given our current deficiencies in knowledge regarding how to best manage TON, "primum non nocere" (first do no harm) is of utmost importance.

Microsphere antioxidant and sustained erythropoietin-R76E release functions cooperate to reduce traumatic optic neuropathy

Wild-type erythropoietin (EPO) is promising for neuroprotection, but its therapeutic use is limited because it causes a systemic rise in hematocrit. We have developed an EPO-R76E derivative that maintains neuroprotective function without effects on hematocrit, but this protein has a short half-life in vivo. Here, we compare the efficacy and carrier-induced inflammatory response of two polymeric microparticle (MP) EPO-R76E sustained release formulations based on conventional hydrolytically degradable poly(lactic-co-glycolic acid) (PLGA) and reactive oxygen species (ROS)-degradable poly(propylene sulfide) (PPS). Both MP types effectively loaded EPO-R76E and achieved sustained release, providing detectable levels of EPO-R76E at the injection site in the eye in vivo for at least 28 days. Testing in an in vitro oxidative stress assay and a mouse model of blast-induced indirect traumatic optic neuropathy (bITON) showed that PPS and PLGA MP-mediated delivery of EPO-R76E provided therapeutic protection. While unloaded PLGA MPs inherently increase levels of pro-inflammatory cytokines in the bITON model, drug-free PPS MPs have innate antioxidant properties that provide therapeutic benefit both in vitro and in vivo. Both PLGA and PPS MPs enabled sustained release of EPO-R76E, providing therapeutic benefits including reduction in inflammation and axon degeneration, and preservation of visual function as measured by electroretinogram. The PPS-based MP platform is especially promising for further development, as the delivery system provides inherent antioxidant benefits that can be harnessed to work in complement with EPO-R76E or other drugs for neuroprotection in the setting of traumatic eye injury.

Role of delayed wider endoscopic optic decompression for traumatic optic neuropathy: a single-center surgical experience

BACKGROUND

The aim of the present study was to discuss the efficacy of delayed wider endoscopic optic decompression in traumatic optic neuropathy (TON).

METHODS

A total of 479 patients were treated with corticosteroids and delayed wider endoscopic optic decompression, including the injury-to-surgery interval, within 2 weeks in patients with no light perception (NLP), and within 1 month in patients with residual eyesight. Based on the traditional decompression range, the superior wall of the optic canal was further decompressed. The preoperative and postoperative visual acuities (VAs) were reviewed, and the therapeutic efficacy was analyzed.

RESULTS

The final VA was 0.1 or better in 29 cases, finger count in 79 cases, hand motion in 99 cases, light perception (LP) in 25 cases, and NLP in 247 cases. A total of 136 patients (136/383, 35.5%) recovered after NLP treatment, and 78 patients (69/96, 71.9%) had improved residual eyesight. The improvement rate in patients with residual eyesight was significantly higher than that of patients with NLP (P<0.01). Moreover, the total VA after treatment was better than that before surgery (P<0.01).

CONCLUSIONS

Delayed wider optic nerve decompression plus corticosteroids remains an effective and safe therapeutic strategy for patients with delayed treatment intervals of more than 1 week, especially for those with residual eyesight within 1 month.

Traumatic Optic Nerve Injury Elevates Plasma Biomarkers of Traumatic Brain Injury in a Porcine Model

A diagnosis of traumatic brain injury (TBI) is typically based on patient medical history, a clinical examination, and imaging tests. Elevated plasma levels of glial fibrillary acidic protein (GFAP), ubiquitin c-terminal hydrolase L1 (UCH-L1), and neurofilament light chain (NFL) have been observed in numerous studies of TBI patients. It is reasonable to view traumatic optic neuropathy (TON) as a focal form of TBI. The purpose of this study was to assess if circulating GFAP, UCH-L1, and NFL are also elevated in a porcine model of TON. Serum levels of GFAP, UCH-L1, and NFL were measured immediately before optic nerve crush and 1 h post-injury in 10 Yucatan minipigs. Severity of optic nerve crush was confirmed by visual inspection of the optic nerve at time of injury, loss of visual function as measured by flash visual evoked potential (fVEP) at 7 and 14 days, and histological analysis of axonal transport of cholera toxin-β (CT-β) within the optic nerve. Post-crush concentrations of GFAP, UCH-L1, and NFL were all significantly elevated compared with pre-crush concentrations (p < 0.01, p = 0.01, and p < 0.01, respectively). The largest increase was observed for GFAP with the post-injury median concentration increasing nearly sevenfold. The use of these TBI biomarkers for diagnosing and managing TON may be helpful for non-ophthalmologists in particular in diagnosing this condition. In addition, the potential utility of these biomarkers for diagnosing other optic nerve and/or retinal pathologies should be evaluated.

Galantamine protects against synaptic, axonal, and vision deficits in experimental neurotrauma

Our goal was to investigate the neuroprotective effects of galantamine in a mouse model of blast-induced indirect traumatic optic neuropathy (bITON). Galantamine is an FDA-approved acetylcholinesterase inhibitor used to treat mild-moderate Alzheimer's disease. We exposed one eye of an anesthetized mouse to repeat bursts of over-pressurized air to induce traumatic optic neuropathy. Mice were given regular or galantamine-containing water (120 mg/L) ad libitum, beginning immediately after blast and continuing for one month. Electroretinograms and visual evoked potentials were performed just prior to endpoint collection. Histological and biochemical assessments were performed to assess activation of sterile inflammation, axon degeneration, and synaptic changes. Galantamine treatment mitigated visual function deficits induced by our bITON model via preservation of the b-wave of the electroretinogram and the N1 of the visual evoked potential. We also observed a reduction in axon degeneration in the optic nerve as well as decreased rod bipolar cell dendritic retraction. Galantamine also showed anti-inflammatory and antioxidant effects. Galantamine may be a promising treatment for blast-induced indirect traumatic optic neuropathy as well as other optic neuropathies.

Newly onset indirect traumatic optic neuropathy-surgical treatment first versus steroid treatment first

AIM

To investigate the efficacy and safety of the treatment of endoscopic trans-ethmosphenoid optic canal decompression (ETOCD) with combination of steroid in patients with newly onset indirect traumatic optic neuropathy (ITON) and compare the outcome between immediate ETOCD treatment and ETOCD with preoperative steroid treatment.

METHODS

Patients presented as newly onset ITON (suffered trauma within 3d) at a tertiary medical center between Mar 1^st, 2016 and Mar 1^st, 2018 were enrolled in this study. All patients were equally and randomly divided into 2 groups. Cases in group A were performed ETOCD immediately after admition while cases in group B were prescribed by methylprednisolone (20 mg/kg · d) for 3d before ETOCD. Methylprednisolone (20 mg/kg · d) was used after surgery for 6d in group A and 3d in group B. Follow-up was up to 3mo in all cases. Visual acuity (VA) before and after treatment between the two groups were taken into comparison.

RESULTS

Complete postoperative data were acquired from 34 patients in group A and from 32 patients in group B. Group A had significantly higher effective rate in VA than group B (χ ²=4.905, P=0.027).

CONCLUSION

For patients with newly onset ITON, combination treatment of ETOCD with high-dose steroid is an effective and safe way. Immediate surgery will lead to better prognosis for these cases.

Transorbital penetrating injury of the skull base and cavernous sinus - defining a minimal invasive treatment

Introduction. A transorbital intracranial injury with a foreign body can be a very complex and controversial therapeutic problem. The orbit's content is susceptible to penetrating trauma, and neurovascular skull base structures are at high risk from injury. There are some traditional cranial surgical approaches, and more recently reported different endoscopic approaches for treating this kind of injury. Case report. We present a case of a 30-year-old male who had an accident at work when a piece of wood hit him in his head and entered through the medial aspect of his left orbit with skull base and cavernous sinus injury. Rapid and complete radiological and clinical assessments were performed, and the patient was treated in a minimally invasive manner. The foreign body was manually extracted with an endoscopic and endovascular team ready to treat adverse events. No postoperative complications were reported, and visual acuity increased at one month follow up. Conclusion. Penetrating wounds of the orbit represent a challenge that requires a multidisciplinary assessment and well-organized management. Combined endoscopic minimally invasive approaches should be considered during the treatment of this kind of injury.

An evolving perspective of endoscopic transnasal optic canal decompression for traumatic optic neuropathy in clinic

Traumatic optic neuropathy (TON) is a serious complication of craniofacial trauma, which damages the optic nerve indirectly and leads to dysfunction of visual acuity. The clinical intervention for a patient with TON includes optic canal decompression (with or without steroids), treatment with corticosteroids alone, or observation only. Currently, there is a controversy among clinicians as to which treatment is optimal. An increasing number of retrospective studies have unveiled that patients could experience significant improvement in visual acuity after optic canal decompression surgery, particularly endoscopic transnasal/transethmosphenoid optic canal decompression (ETOCD), either with or without corticosteroids. In this review, we discuss the evolving perspective on surgical treatment, specifically ETOCD, for the management of patients with TON and focus mainly on the therapeutic efficacy, safety, and resulting prognosis in the clinic.

Traumatic optic neuropathy-associated progressive thinning of the retinal nerve fiber layer and ganglion cell complex: two case reports

Background

Traumatic optic neuropathy (TON) is a form of optic nerve injury that occurs secondary to trauma and is etiologically associated with acute axonal loss with severe vision loss. Here, we reported longitudinal changes in the peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC) using wide-field swept source optical coherence tomography (SS-OCT) in two cases of TON and identified the source of the damage.

Case presentation

(Case 1) A 65-year-old man was admitted to the hospital due to an injury in the right eye (OD) and was subsequently diagnosed with indirect TON. He was then treated with high-doses of intravenous steroids. Wide-field SS-OCT was performed at the baseline and after 1 day, 2 days, 1 week, 1 month, and 4 months. The wide-field deviation map detected thinning earlier in the macular GCC than in the peripapillary RNFL. (Case 2) A 63-year-old man was admitted to the hospital with a fractured left maxilla-zygomatic complex attributed to blunt-force trauma to the head and loss of vision in his left eye (OS). He was diagnosed with indirect TON and treated with high-doses of intravenous steroids. Wide-field SS-OCT was performed at the baseline and after 1 week, 2 weeks, 2 months 5 months, and 7 months. The wide-field deviation map detected thinning earlier in the peripapillary RNFL than in the macular GCC.

Conclusions

Wide-field SS-OCT facilitated the identification of various sequential progression patterns in patients with TON. Furthermore, the area in which the structural damage was first detected was seen differently in the peripapillary and macular deviation maps for each case. Thus, wide-field imaging, which includes the macular and peripapillary areas, are useful in monitoring TON.

Apolipoprotein E-Mimetic Peptide COG1410 Enhances Retinal Ganglion Cell Survival by Attenuating Inflammation and Apoptosis Following TONI

Vision loss after traumatic optic nerve injury (TONI) is considered irreversible because of the retrograde loss of retinal ganglion cells (RGCs), which undergo inflammation and apoptosis. Previous studies have shown that COG1410, a mimic peptide derived from the apolipoprotein E (apoE) receptor binding region, shows neuroprotective activity in acute brain injury. However, the detailed role and mechanisms of COG1410 in RGC survival and vision restoration after TONI are poorly understood. The current study aimed to investigate the effects of COG1410 on inflammation and apoptosis in a mouse model of TONI. The results showed that TONI-induced visual impairment was accompanied by optic nerve inflammation, apoptosis, edema, and RGC apoptosis. COG1410 significantly prevented the decrease in visual from ever occurring, attenuated inflammation and apoptosis, and reduced optic nerve edema and RGC apoptosis compared with vehicle treatment. These data identify protective roles of COG1410 in the inflammatory and apoptotic processes of TONI, as well as strategies for its treatment.