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.

Erythropoietin as a treatment option for indirect traumatic optic neuropathy: A pilot study.

Purpose: Our study aims to evaluate the effectiveness of intravenous erythropoietin (EPO) in patients with indirect traumatic optic neuropathy (TON), assess the side effects, and compare the visual function results among three groups of patients who had received different treatment options - EPO, steroids, and observation. Methods: : Patients with indirect TON presenting to the neuro-ophthalmology clinic from August 2019 to March 2020, were assigned to three groups, with six patients in each group. In group 1, patients were recruited prospectively and received recombinant human erythropoietin, whereas, in groups 2 and 3, patients were recruited retrospectively and received intravenous methylprednisolone followed by oral steroids and multivitamins, respectively. Groups 1 and 2 included patients presenting within 2 weeks of trauma, whereas group 3 included those presenting beyond that. Best-corrected visual acuity, pupillary reaction, color vision, and visual fields following treatment were measured. Results: Initial visual acuity in the EPO group ranged from 20/80 to no perception of light (No PL). The mean initial BCVA (1.82 logMAR, standard deviation [SD] = 0.847) improved to 1.32, SD = 0.93 logMAR after treatment recorded at the third month (P = 0.0375), with no significant adverse effects. The initial BCVA of group 2 ranged from 20/120 to No PL. The mean initial BCVA (1.95, SD = 0.77 logMAR) improved to 1.45 logMAR, SD = 0.97 after treatment (P = 0.0435) but three patients had side effects of steroids. Initial visual acuity in Group 3 ranged from 20/40 to no PL. The mean initial BCVA (1.09 logMAR, SD = 1.10) worsened to 1.19 logMAR, SD = 1.06 after treatment after treatment (P = 0.0193). The improvement in BCVA when compared between the three groups was not significant. Conclusion: Both erythropoietin and steroids are effective in the management of traumatic optic neuropathy. However, erythropoietin shows lesser or no side effects when compared to steroids.

Traumatic Optic Neuropathy: The Forgotten Concussion.

Cerebral concussions are a well-recognized issue in military and civilian practice. Although most physicians are well versed in recognizing concussion symptoms, many are not as adept at diagnosing and managing comorbid traumatic optic neuropathy (TON). Traumatic optic neuropathy typically follows cerebral concussions but is often not diagnosed as its symptoms are attributed to brain injury or the presence of altered consciousness impedes its recognition. We hereby describe a soldier who sustained a cerebral concussion with an associated unrecognized TON. We review the epidemiology, pathophysiology, diagnosis, and management of TON.

FOCAL RETINAL ISCHEMIA REVEALED BY MULTIMODAL IMAGING AFTER TRAUMATIC PARTIAL OPTIC NERVE AVULSION.

PURPOSE: Traumatic optic neuropathy can have varying presentations. Blunt focal trauma can lead to optic nerve avulsion with underlying retinal findings. A case of partial optic nerve avulsion after finger poke injury leading to focal retinal ischemia is reported. METHODS: Visual acuity, fundus photography with fluorescein angiography, and spectral-domain optical coherence tomography were performed to document the findings in a 16-year-old man who presented after a finger poke injury to the left orbit during a water polo match. RESULTS: On initial presentation, examination revealed decreased visual acuity with a fixed left pupil and afferent pupillary defect by reverse. On slit-lamp examination of the left eye, a hyphema was present. Dilated fundus examination revealed layering vitreous hemorrhage over the posterior pole and an avulsed vitreous base. On follow-up, a gap temporal to the optic nerve head consistent with a partial optic nerve avulsion was noted once the vitreous hemorrhage cleared. Multimodal imaging revealed retinal ischemia temporal to the disc on fluorescein angiography with corresponding changes in the inner retinal layers and retinal nerve fiber layer using spectral-domain optical coherence tomography. CONCLUSION: Clinicians should have a high suspicion for optic nerve avulsion if a patient presents with new vitreous hemorrhage and afferent pupillary defect after a finger-poke injury. Optic nerve avulsion injury can cause retinal ischemia, likely because of interruption of retinal blood flow as a result of nerve shearing injury. Multimodal imaging can reveal focal retinal injury and aid in proper diagnosis and follow-up.

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.

[Optic nerve decompression-state of the art]. / Optikusdekompressionen ­ Stand der Technik.

Rarely, but often with serious consequences for the patient, the optic nerve is affected during the course of head injuries. Traumatic optic nerve compression is always an emergency situation, which is why time is of the essence for both diagnosis and treatment. Precise knowledge of this accident sequelae but also of the resulting conditions, especially in terms of traumatic optic neuropathy, is indispensable for adequate patient care. The aim of this paper is to provide an overview of this clinical picture, particularly with regard to etiology, diagnosis, and treatment options, and to discuss this in the context of the current literature.

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.

Total Isolated Monocular Vision Loss in a Patient Who Suffered Closed Head Injury.

BACKGROUND: Head injuries are an important cause of morbidity and mortality in children and young adults. There are multiple sight-threatening complications of head injury, even in closed head injury without visible violation of the globe or orbits. One such entity is traumatic optic neuropathy. CASE REPORT: Herein we describe a case of traumatic optic neuropathy in an otherwise healthy teenage patient who suffered total monocular vision loss after a fall and without any other injuries on examination. Unfortunately, the prognosis for this condition is relatively poor in terms of visual recovery. Though much research has been conducted attempting to treat this condition, to date there have been no studies showing a clear benefit of medical or surgical intervention. Why Should an Emergency Physician Be Aware of This? Although there is no proven treatment for traumatic optic neuropathy, emergency physicians may encounter this in their practice while caring for both pediatric and adult patients presenting with head injury. Having more background knowledge on this condition will enhance emergency physicians' ability to consult with subspecialist providers as well as to educate patients and their families on their condition and prognosis.

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.

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.

Traumatic optic neuropathy in orbital wall fractures- diagnostic parameters and treatment outcomes: A prospective observational study.

INTRODUCTION: The aim of the study was to evaluate the associated patterns of orbital wall fractures, diagnostic parameters of Traumatic optic neuropathy and its progress with Mega dose steroid therapy. MATERIALS AND METHODS: 25 patients with unilateral orbital wall fractures of traumatic aetiology were evaluated with ophthalmologic and radiographic parameters. All patients were prescribed Mega Dose Intravenous steroids irrespective of the timing of presentation. Ophthalmic assessment was repeated for same parameters every alternate day upto 2 weeks. RESULTS: Lateral orbital wall was found to be most commonly involved. Visual acuity, Pupillary Reactivity, Visual Field and Visual Evoked Potential showed statistically significant improvement post steroid therapy in early as well as late presenters. DISCUSSION: Highest incidence of Traumatic optic neuropathy was noted in multiple linear orbital wall fractures with highest incidence with lateral orbital wall involvement. Literature regarding Choice and timing of initiation of steroids based on timing of presentation is inadequate to justify skipping steroids to observe or undertake surgical intervention. In the present study marked improvement was noted post steroid therapy regardless of timing of presentation. The authors conclude that Visual evoked potential should be objectively tested and Mega dose steroid therapy should be initiated for all patients with Traumatic optic neuropathy for maximum benefit to the patient.

Longitudinal In Vivo Changes in Retinal Ganglion Cell Dendritic Morphology After Acute and Chronic Optic Nerve Injury.

Purpose: To characterize in vivo dendritic changes in retinal ganglion cells (RGCs) after acute (optic nerve transection, ONT) and chronic (experimental glaucoma, EG) optic nerve injury. Methods: ONT and EG (microbead model) were carried out in Thy1-YFP mice in which the entire RGC dendritic arbor was imaged with confocal fluorescence scanning laser ophthalmoscopy over two weeks in the ONT group and over two and six months, respectively, in two (groups 1 and 2) EG groups. Sholl analysis was used to quantify dendritic structure with the parameters: area under the curve (AUC), radius of the dendritic field, peak number of intersections (PI), and distance to the PI (PD). Results: Dendritic changes were observed after three days post-ONT with significant decreases in all parameters at two weeks. In group 1 EG mice, mean (SD) intraocular pressure (IOP) was 15.2 (1.1) and 9.8 (0.3) mmHg in the EG and untreated contralateral eyes, respectively, with a significant corresponding decrease in AUC, PI, and PD, but not radius. In group 2 mice, the respective IOP was 13.1 (1.0) and 8.8 (0.1) mmHg, peaking at two months before trending towards baseline. Over the first two months, AUC, PI, and PD decreased significantly, with no further subsequent changes. The rates of change of the parameters after ONT was 5 to 10 times faster than in EG. Conclusions: Rapid dendritic changes occurred after ONT, while changes in EG were slower and associated with level of IOP increase. The earliest alterations were loss of inner neurites without change in dendritic field.

Optic Nerve Engraftment of Neural Stem Cells.

Purpose: To evaluate the integrative potential of neural stem cells (NSCs) with the visual system and characterize effects on the survival and axonal regeneration of axotomized retinal ganglion cells (RGCs). Methods: For in vitro studies, primary, postnatal rat RGCs were directly cocultured with human NSCs or cultured in NSC-conditioned media before their survival and neurite outgrowth were assessed. For in vivo studies, human NSCs were transplanted into the transected rat optic nerve, and immunohistology of the retina and optic nerve was performed to evaluate RGC survival, RGC axon regeneration, and NSC integration with the injured visual system. Results: Increased neurite outgrowth was observed in RGCs directly cocultured with NSCs. NSC-conditioned media demonstrated a dose-dependent effect on RGC survival and neurite outgrowth in culture. NSCs grafted into the lesioned optic nerve modestly improved RGC survival following an optic nerve transection (593 ± 164 RGCs/mm2 vs. 199 ± 58 RGCs/mm2; P < 0.01). Additionally, RGC axonal regeneration following an optic nerve transection was modestly enhanced by NSCs transplanted at the lesion site (61.6 ± 8.5 axons vs. 40.3 ± 9.1 axons, P < 0.05). Transplanted NSCs also differentiated into neurons, received synaptic inputs from regenerating RGC axons, and extended axons along the transected optic nerve to incorporate with the visual system. Conclusions: Human NSCs promote the modest survival and axonal regeneration of axotomized RGCs that is partially mediated by diffusible NSC-derived factors. Additionally, NSCs integrate with the injured optic nerve and have the potential to form neuronal relays to restore retinofugal connections.

In vivo evaluation of outer retinal function and structure after retrobulbar optic nerve crush by lateral orbitotomy in goats.

Large animal model of optic nerve crush (ONC) plays an important role in translating novel therapeutic strategies developed in rodent model to clinical application. Due to the poor accessibility of the optic nerve (ON) in humans and large animals, lateral orbitotomy is needed to expose the retrobulbar ON. This study was to explore the effects of ONC and ON exposure with lateral orbitotomy (sham surgery) on the outer retinal function and structure in goats by using standard flash electroretinogram (FERG) and spectral-domain optical coherence tomography (SD-OCT). We found that ONC led to a transient reduction in FERG amplitudes at 1 week post injury (wpi), which recovered gradually over 2 months afterwards. Sham surgery alone also caused a similar pattern of amplitude reduction in FERG, although not as significantly as ONC did. Transient outer retinal thickening following ONC occurred at 4 wpi (when progressive thinning of the ganglion cell complex began), peaked at 8 wpi, then recovered gradually at 12 wpi. In contrast, outer retinal thickness remained unchanged statistically 3 months after sham surgery. Fundus fluorescein angiography showed that neither ONC nor ON exposure with lateral orbitotomy significantly caused any significant delay or absence of central retinal vascular filling. In summary, ONC with lateral orbitotomy affects outer retinal function and structure transiently.

The retinal vasculature pathophysiological changes in vision recovery after treatment for indirect traumatic optic neuropathy patients.

PURPOSE: To evaluate the retinal vasculature pathophysiological changes of indirect traumatic optic neuropathy (ITON) patients after effective surgery. METHODS: Monocular ITON patients who underwent endoscopic trans-ethmosphenoid optic canal decompression (ETOCD) or conservative treatments in Zhongshan Ophthalmic Center from January 2017 to June 2020 were recruited. Visual acuity (VA), visual evoked potential (VEP), oxygen saturation of retinal blood vessels (SO2), and optical coherence tomography angiography (OCT-A) were measured. All patients were followed up at least 3 months after treatments. RESULTS: A total of 95 ITON patients were recruited, including 77 patients who underwent ETOCD and 18 patients who underwent conservative treatments. After treatments, more patients received ETOCD (59/77 = 76.6%) presented with improved VA compared with the patients with conservative treatments (6/18 = 33.3%). Compared with the pre-therapeutic measurements, VEP were significantly improved after surgery in ETOCD-treated patients (P < 0.05). Latent periods of P1 and N2, as well as amplitude of P2 of VEP parameters, showed more sensitive to vision recovery (P < 0.05). Retinal artery SO2 and the differences between arteries and veins were improved in ETOCD-treated patients (P < 0.05). Meanwhile, with OCT-A examination, the retinal thickness and retinal vessel density were notably better in ETOCD-treated patients after surgery than that in patients received conservative treatments (P < 0.05). CONCLUSIONS: Vision recovery after effective treatment of ITON patients was associated with the increased oxygen saturation of retinal vessels, better availability of oxygen in the retina, greater vessel density, and thicker retinas, which might further underlie the vasculature mechanism of vision recovery in ITON patients.

Surgical Treatment and Visual Outcomes of Adult Orbital Roof Fractures.

BACKGROUND: Fractures of the orbital roof require high-energy trauma and have been linked to high rates of neurologic and ocular complications. However, there is a paucity of literature exploring the association between injury, management, and visual prognosis. METHODS: The authors performed a 3-year retrospective review of orbital roof fracture admissions to a Level I trauma center. Fracture displacement, comminution, and frontobasal type were ascertained from computed tomographic images. Pretreatment characteristics of operative orbital roof fractures were compared to those of nonoperative fractures. Risk factors for ophthalmologic complications were assessed using univariable/multivariable regression analyses. RESULTS: In total, 225 patients fulfilled the inclusion criteria. Fractures were most commonly nondisplaced [n = 118 (52.4 percent)] and/or of type II frontobasal pattern (linear vault involving) [n = 100 (48.5 percent)]. Eight patients underwent open reduction and internal fixation of their orbital roof fractures (14.0 percent of displaced fractures). All repairs took place within 10 days from injury. Traumatic optic neuropathy [n = 19 (12.3 percent)] and retrobulbar hematoma [n = 11 (7.1 percent)] were the most common ophthalmologic complications, and led to long-term visual impairment in 51.6 percent of cases. CONCLUSIONS: Most orbital roof fractures can be managed conservatively, with no patients in this cohort incurring long-term fracture-related complications or returning for secondary treatment. Early fracture treatment is safe and may be beneficial in patients with vertical dysmotility, globe malposition, and/or a defect surface area larger than 4 cm2. Ophthalmologic prognosis is generally favorable; however, traumatic optic neuropathy is major cause of worse visual outcome in this population. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Isolated-check visual evoked potential: a more sensitive tool to detect traumatic optic neuropathy after orbital fracture.

PURPOSE: To establish a more sensitive diagnostic tool for traumatic optic neuropathy (TON), we explored the diagnostic efficacy of isolated-check visual evoked potential (ic-VEP) for TON in orbital fracture and compared ic-VEP with pattern-reversal visual evoked potential (P-VEP) testing. METHODS: This was a prospective single-center study. A total of 137 eyes from 131 patients diagnosed between December 2016 and October 2019 with orbital fractures were included in the study. Injury history, best-corrected visual acuity (BCVA), visual field, computed tomography (CT), P-VEP, and ic-VEP data were collected. Parameters of ic-VEP (signal-to-noise ratio [SNR]) and P-VEP (peak latency and amplitude of P100) were compared and diagnostic accuracy was analyzed. RESULTS: TON was associated with worse BCVA than non-TON (median 0.52 versus 0.10 logMAR, P < 0.001). SNRs were negatively associated with the P100 peak latency while positively associated with the P100 amplitude. The sensitivity of ic-VEP for TON (79.6%) was higher than that of P-VEP (61.2%, P = 0.049), although this difference was not statistically significant after Bonferroni correction. Using ic-VEP and P-VEP together could increase sensitivity (87.8%). Maximum areas under curve were obtained using the SNR criteria of 1.3, 1.47, and 1.54 at 8%, 16%, and 32% depth of modulation, respectively. CONCLUSION: ic-VEP was more sensitive than P-VEP in diagnosing TON, and a combination of the two examination tests was recommended. The use of ic-VEP as the new diagnostic standard technique for TON should be considered.

Reversal of vision loss after traumatic optic neuropathy.

Traumatic optic neuropathy is sinister sequelae of craniofacial trauma leading to vision loss. The decision between early medical or surgical intervention is usually individualised. Visual evoked potentials may guide the treatment plan. We describe a young male presenting 5 days after a road traffic accident with no perception of light vision in the right eye. He was managed medically with high dose of intravenous steroids. At the 3-month follow-up, he reported a reversal of vision loss with return of visual acuity to 3/60, which improved to 6/36 at 5 months and remained stable at 8 months.

Traumatic avulsion of the globe with optic nerve transection: an unusual presentation.

Complete globe extrusion, whether traumatic or spontaneous, is a rare clinical entity and if associated with optic nerve avulsion, it has a worse visual outcome, though repositioning of the globe may be attempted. We report a case of road traffic accident, wherein the patient presented with an extrusion of the globe, along with a complete transection of the optic nerve, about 4 cm from the optic nerve head, with only a residual attachment to the orbital rim via the unsevered lateral conjunctival flap, where the enucleation was completed and the conjunctiva was sutured.