Visual function following neurosurgical optic nerve decompression for compressive optic neuropathy

Radiomics using multiparametric magnetic resonance imaging to predict postoperative visual outcomes of patients with pituitary adenoma

BACKGROUND

Preoperative prediction of visual outcomes following pituitary adenoma surgery is challenging yet crucial for clinical decision-making. We aimed to develop models using radiomics from multiparametric MRI to predict postoperative visual outcomes.

METHODS

A cohort of 152 patients with pituitary adenoma was retrospectively enrolled and divided into recovery and non-recovery groups based on visual examinations performed six months after surgery. Radiomic features of the optic chiasm were extracted from preoperative T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), and contrast-enhanced T1-weighted imaging (T1CE). Predictive models were constructed using the least absolute shrinkage and selection operator wrapped with a support vector machine through five-fold cross-validation in the development cohort and evaluated in an independent test cohort. Model performance was evaluated using the area under the curve (AUC), accuracy, sensitivity, and specificity.

RESULTS

Four models were established based on radiomic features selected from individual or combined sequences. The AUC values of the models based on T1WI, T2WI and T1CE were 0.784, 0.724, 0.822 in the development cohort, and 0.767, 0.763, 0.794 in the independent test cohort. The multiparametric model demonstrated superior performance among the four models, with AUC of 0.851, accuracy of 0.832. sensitivity of 0.700, specificity of 0.910 in the development cohort, and AUC of 0.847, accuracy of 0.800, sensitivity of 0.882 and specificity of 0.750 in the independent test cohort.

CONCLUSION

The multiparametric model utilizing radiomics of optic chiasm outperformed single-sequence models in predicting postoperative visual recovery in patients with pituitary adenoma, serving as a novel approach for enhancing personalized treatment strategies.

[Optic canal stenosis in Crouzon syndrome: a case report and literature review]

BACKGROUND

Incidence of Crouzon syndrome is 1 per 25.000-31.000 newborns. This syndrome is extremely rarely accompanied by optic canal stenosis.

OBJECTIVE

To present a patient with Crouzon syndrome and optic canal stenosis, to discuss the management of such patients considering own and literature data.

MATERIAL AND METHODS

A 6-year-old boy presented with Crouzon syndrome (verified by molecular genetic research, i.e. FGFR2 gene mutation). The patient underwent 3 surgeries for craniosynostosis and hydrocephalus. Nevertheless, visual acuity progressively decreased despite patent ventriculoperitoneal shunt. Examination revealed severe decrease in visual functions with optic disc congestion under secondary atrophy. MRI data on subarachnoid CSF accumulation over both optic nerves potentially indicated optic canal stenosis. This assumption was confirmed by 3D CT.

RESULTS

The patient underwent decompression of both optic canals with subsequent improvement of visual functions.

CONCLUSION

Vision decrease following Crouzon syndrome may be due to optic canal stenosis. Decompression may be effective, even in long-term course of disease, and improve visual functions.

CT analysis of predictors for visual acuity in optic neuropathy with mucocele

OBJECTIVE

To evaluate the causative and risk factors for optic neuropathy with mucocele via imaging studies.

METHODS

We included 21 patients with rhinogenous optic neuropathy with mucocele. We collected data on the sinus involved, age, sex, number of days from the onset of visual impairment to surgery, and computed tomography (CT) imaging findings (bone defects in the lamina papyracea, Onodi cell mucocele, exophthalmos, and optic nerve deviation). The results were compared between two groups, the one having nine patients with pre-operative visual acuity of <0.1 (the poor group) and the other having 12 patients with pre-operative visual acuity of ≥0.1 (the fair group). Whether or not there was a difference in pre-operative visual acuity between patients with and without Onodi cell mucocele was determined.

RESULTS

After surgery, visual acuity improved in 16/21 (76.2%) patients, and a correlation analysis showed a significant positive correlation between pre-operative and post-operative visual acuity. In imaging, the causative sinuses accounted for 85.7% of both posterior ethmoid and sphenoid sinuses. Bone defects of the lamina papyracea at the optic canal and the vertical downward deviation of the optic nerve at each location, especially in 6/9 patients with Onodi cell mucocele, were characteristic in the poor group. In these conditions, increasing the contact areas of the optic nerve and mucocele can leads to more chances of direct downward compression of the optic nerve and infection occurring, and it may lead to severe pre-operative visual impairment.

CONCLUSION

Imaging studies of optic neuropathy with mucocele help to determine the risk factors and perform early and precise diagnostic imaging and decision-making for surgery.

Population-Based Incidence and Outcomes of Compressive Optic Neuropathy

PURPOSE

Prior studies on compressive optic neuropathy (CON) have come from large tertiary centers, which may contain referral bias toward more severe or atypical disease. To our knowledge, there are no studies to determine the population-based etiologies and clinical outcomes of compressive optic neuropathy (CON). This study aims to bridge that gap using the Rochester Epidemiology Project database.

DESIGN

Retrospective, population-based cohort.

METHODS

Medical records of all residents living in Olmsted County, Minnesota, from January 1, 2000, through December 31, 2018, were screened for CON. Demographic and clinical information were collected before and after treatment.

RESULTS

Twenty-three patients had a confirmed diagnosis of CON during our study period, which provided an overall incidence of 1.14 per 100 000 per year. Average age at onset of CON was 51 years (SD 24), and 39% were male. The most common etiologies were pituitary adenoma and meningioma. There was significant improvement in visual fields (P < .003) but not in visual acuity (P = .08) after patients underwent treatment for CON. There was also a significant relationship between the time until treatment and the degree of visual field improvement at follow-up (Pearson correlation rho = -0.58, P < .047).

CONCLUSION

To our knowledge, this study provides the first population-based incidence of CON. The finding that earlier treatment leads to better visual outcomes stresses the importance of having CON on the differential diagnosis of patients with optic neuropathy.

Optical coherence tomography as a useful adjunct in the early detection of meningioma with optic nerve compression

A 48-year-old woman presented with persistent clouding vision in her lower field in the right eye for 5 months. A small retinal hemorrhage was initially reported. Her visual acuity was 20/30 in the right eye and 20/20 in the left, with normal color vision and pupil response. Fundus examination did not reveal any retinal hemorrhage. Although optical coherence tomography (OCT) showed normal macula and retinal nerve fiber layers in both eyes, asymmetric thinning of the ganglion cell inner plexiform layer was found in the superior macula of the right eye in ganglion cell analysis (GCA). Visual field examination revealed a subtle inferonasal scotoma. Compressive optic neuropathy (CON) was suspected. The visual evoked potential test revealed delayed P100 latency. A tuberculum sellae meningioma was found with right medial optic canal extension. The visual acuity of the right eye returned to 20/25 after decompression surgery. OCT can be used to differentiate between retinopathy and optic neuropathy. GCA can help in the early detection of CON and achieve a good visual outcome after surgery.

Longitudinal Changes in the Retinal Microstructures of Eyes With Chiasmal Compression

OBJECTIVE

To test the hypothesis that there was a temporal change in the retinal microstructure after decompression surgery for chiasmal compression, the 1-year longitudinal changes in the inner and outer retinal thickness after decompression surgery were analyzed using spectral-domain optical coherence tomography (SD-OCT) with linear mixed-effects models.

METHODS

SD-OCT was obtained from 87 eyes with chiasmal compression and compared to 100 healthy controls. The preoperative and 1-year postoperative longitudinal changes in the retinal layer thickness were measured. The thickness of each of the following retinal layers was analyzed: the macular retinal nerve fiber layer (RNFL), the ganglion cell layer (GCL), the inner plexiform layer (IPL), the inner nuclear layer, the outer plexiform layer, the outer nuclear layer, and the photoreceptor layer.

RESULTS

The RNFL, GCL, and IPL showed thinning at a rate of 1.068 μm/y (95% confidence interval [CI], 0.523, 1.613), 1.189 μm/y (95% CI 0.452, 1.925), and 1.177 μm/y (95% CI 0.645, 1.709), respectively, after decompression surgery. The preoperative thickness of the intraretinal layer was associated with postoperative visual field recovery (RNFL, odds ratio [OR] 1.221, 95% CI 1.058, 1.410; GCL, OR 1.133, 95% CI 1.024, 1.254; and IPL, OR 1.174, 95% CI 1.002, 1.376).

CONCLUSIONS

The changes in retinal microstructure persisted and progressed in eyes with chiasmal compression after decompression surgery. The findings provide insight into the biological and anatomical sequelae following chiasmal compression. The preoperative thickness of the inner retinal layers was associated with postoperative visual field recovery.

Refining Operative Strategies for Optic Nerve Decompression: A Morphometric Analysis of Transcranial and Endoscopic Endonasal Techniques Using Clinical Parameters

BACKGROUND

Various approaches can be considered for decompression of the intracanalicular optic nerve. Although clinical experience has been reported, no quantitative study has yet compared the extent of decompression achieved by an endoscopic endonasal versus transcranial approach.

OBJECTIVE

Toward this aim, our morphometric analysis compared both approaches by quantifying the circumferential degree of optic canal decompression that is possible before any meningeal violation, which would result in cerebrospinal fluid (CSF) leak.

METHODS

From 10 cadaver heads, 20 optic canals were sequentially decompressed using an endoscopic endonasal approach and pterional craniotomy with extradural clinoidectomy. Dissections ended before violation of the sphenoid sinus during the transcranial approach, and before intracranial transgression from the endonasal corridor. Based on our study criteria, decompressions were not maximal for either approach, but were maximal before violating the other compartment. Decompression achieved from each approach was quantified using CT scans for each stage.

RESULTS

Greater circumferential bony optic canal decompression was obtained from transcranial (245.2°) than endonasal (114.8°) routes (P < .001). By endonasal perspective, the anatomical point where the optic nerve traverses intracranially was approximated by the medial border of the anterior ascending cavernous internal carotid artery.

CONCLUSION

Our morphometric analysis comparing optic canal decompression for endonasal and transcranial corridors provides important guidance for this location. Ample visualization and wide exposure can be achieved via a transcranial approach with limited risk of CSF leak. A landmark, where the intracanalicular segment ends and optic nerve traverses intracranially, can mark the extent of decompression safely obtained before risking CSF leak.

Navigation-assisted, endonasal, endoscopic optic nerve decompression for the treatment of nontraumatic optic neuropathy

BACKGROUND

Many authors have reported on therapeutic strategies for traumatic optic neuropathy and their experience with endonasal endoscopic optic nerve decompression for traumatic optic neuropathy. However, to our knowledge, few have described the therapeutic strategies for nontraumatic optic neuropathy and navigation-assisted endoscopic optic nerve decompression as a treatment for nontraumatic, compressive optic neuropathy. The aim of this study was to examine the advantages in treating nontraumatic optic neuropathy with the minimally invasive, image-guided, navigation-assisted, endonasal endoscopic optic nerve decompression.

METHODS

This was a retrospective study of 20 patients (21 eyes) diagnosed with nontraumatic optic neuropathy, undergoing an endonasal endoscopic approach to relieve space-occupying lesions and decompress the optic nerve under image-guided navigation. This article describes our research on the therapeutic strategies for nontraumatic optic neuropathy patients, with special focus on the advantages of navigation-assisted, endonasal, endoscopic optic nerve decompression for the treatment of nontraumatic optic neuropathy. Medical photographs were used to estimate the status of the patients.

RESULTS

In 18 of the 20 cases, space-occupying lesions were completely resected. In two cases, they were partially resected. All 20 cases (21 eyes) underwent image-guided, navigation-assisted, endonasal endoscopic optic nerve decompression. Visual acuity improved in 20 eyes (95.2%) and remained stable in one eye. There were no intraoperative or postoperative complications.

CONCLUSIONS

Optic nerve decompression is the main treatment strategy for nontraumatic optic neuropathy, to relieve space-occupying lesions and decompress the optic nerve, and to retain and/or improve visual acuity. Image-guided navigation can help doctors pinpoint the optic nerve when facing anatomical deformation caused by a space-occupying lesion. Navigation-assisted, endonasal endoscopic optic nerve decompression is a feasible, safe, practical, and minimally invasive approach.

Compressive optic neuropathy secondary to Ewing sarcoma in the paranasal sinus: A case report

RATIONALE

Ewing sarcoma localized in the paranasal sinuses, compressing the optic nerve, is very rare, with no prior case reports PATIENT CONCERNS:: A 68-year-old woman presented with decreased visual acuity in her left eye and paresthesia of the left face. Brain magnetic resonance imaging showed heterogeneously enhancing mass in the left paranasal sinuses with adjacent bone destruction, extending to the extraocular muscles and optic nerve of the left orbit. A biopsy of the nasal cavity confirmed Ewing sarcoma.

DIAGNOSIS

Compressive optic neuropathy secondary to Ewing sarcoma in the paranasal sinuses.

INTERVENTION

Neoadjuvant chemotherapy and radiotherapy were performed.

OUTCOMES

Resolution of the tumor and increased visual acuity and field of the left eye.

LESSONS

Primary head and neck Ewing sarcoma can lead to compressive optic neuropathy, but the tumor responded well to the chemotherapy. Early diagnosis and immediate treatment by close cooperation between the ophthalmologist and oncologist can prevent from permanent visual loss.

Endoscopic Management of Paranasal Sinus Mucoceles: Meta-analysis of Visual Outcomes

Objective Paranasal sinus mucoceles are benign cystic lesions originating from sinus mucosa that can impinge on adjacent orbital structures, causing ophthalmic sequelae such as decreased visual acuity. Definitive treatment requires surgery. We present the first meta-analysis quantifying the effect of preoperative visual function and time to surgery on postoperative visual acuity outcomes. Data Sources PubMed, Ovid, Embase, Web of Science, and the Cochrane Library. Methods Two independent authors systematically reviewed articles describing outcomes after endoscopic sinus surgery for paranasal sinus mucoceles presenting with visual loss. Available data from case reports and series were combined to analyze the associations among preoperative visual acuity, time to surgery, and postoperative outcomes. Results Eighty-five studies were included that provided data on 207 patients. The average presenting visual acuity was 1.57 logMAR (logarithm of the minimum angle of resolution), and the average postoperative visual acuity was 0.21 logMAR, with visual improvement in 71.5% of cases. Preoperative visual acuity ≥1.52 logMAR correlated with postoperative improvement >1 logMAR ( R = 0.4887, P < .0001). A correlation was found between a time to surgery <6 days and postoperative improvement ( R = 0.297, P < .0001). Receiver operator curve analysis of these thresholds demonstrated a moderately accurate prognostic ability (area under the curve: 75.1 for preoperative visual acuity and 73.1 for time to surgery). Conclusion Visual loss resulting from paranasal sinus mucoceles is potentially reversible in most cases, even those presenting with poor vision. When possible, surgery should be performed promptly after diagnosis, but emergency surgery does not appear to be necessary for vision restoration.

Endoscopic Endonasal Optic Nerve Decompression for Fibrous Dysplasia

Objective To evaluate visual outcomes and potential complications for optic nerve decompression using an endoscopic endonasal approach (EEA) for fibrous dysplasia. Design Retrospective chart review of patients with fibrous dysplasia causing extrinsic compression of the canalicular segment of the optic nerve that underwent an endoscopic endonasal optic nerve decompression at the University of Pittsburgh Medical Center from 2010 to 2013. Main Outcome Measures The primary outcome measure assessed was best-corrected visual acuity (BCVA) with secondary outcomes, including visual field testing, color vision, and complications associated with the intervention. Results A total of four patients and five optic nerves were decompressed via an EEA. All patients were symptomatic preoperatively and had objective findings compatible with compressive optic neuropathy: decreased visual acuity was noted preoperatively in three patients while the remaining patient demonstrated an afferent pupillary defect. BCVA improved in all patients postoperatively. No major complications were identified. Conclusion EEA for optic nerve decompression appears to be a safe and effective treatment for patients with compressive optic neuropathy secondary to fibrous dysplasia. Further studies are required to identify selection criteria for an open versus an endoscopic approach.

Predictive factors for vision recovery after optic nerve decompression for chronic compressive neuropathy: systematic review and meta-analysis

Objectives Surgical optic nerve decompression for chronic compressive neuropathy results in variable success of vision improvement. We sought to determine the effects of various factors using meta-analysis of available literature. Design Systematic review of MEDLINE databases for the period 1990 to 2010. Setting Academic research center. Participants Studies reporting patients with vision loss from chronic compressive neuropathy undergoing surgery. Main outcome measures Vision outcome reported by each study. Odds ratios (ORs) and 95% confidence intervals (CIs) for predictor variables were calculated. Overall odds ratios were then calculated for each factor, adjusting for inter study heterogeneity. Results Seventy-six studies were identified. Factors with a significant odds of improvement were: less severe vision loss (OR 2.31[95% CI = 1.76 to 3.04]), no disc atrophy (OR 2.60 [95% CI = 1.17 to 5.81]), smaller size (OR 1.82 [95% CI = 1.22 to 2.73]), primary tumor resection (not recurrent) (OR 3.08 [95% CI = 1.84 to 5.14]), no cavernous sinus extension (OR 1.88 [95% CI = 1.03 to 3.43]), soft consistency (OR 4.91 [95% CI = 2.27 to 10.63]), presence of arachnoid plane (OR 5.60 [95% CI = 2.08 to 15.07]), and more extensive resection (OR 0.61 [95% CI = 0.4 to 0.93]). Conclusions Ophthalmologic factors and factors directly related to the lesion are most important in determining vision outcome. The decision to perform optic nerve decompression for vision loss should be made based on careful examination of the patient and realistic discussion regarding the probability of improvement.

Optic canal decompression with dural sheath release; a combined orbito-cranial approach to preserving sight from tumours invading the optic canal

PURPOSE

The purpose of this case series is to describe an orbito-cranial surgical approach for the management of optic nerve compression secondary to tumours extending into the optic canal.

METHOD

We present a retrospective, observational case series of 4 patients who underwent surgery aimed at improving or stabilising vision for tumours invading the optic canal. In all cases tumours were not amenable to complete resection due to their intrinsic relation to important structures including: the internal carotid artery, cavernous sinus, optic and oculomotor nerves. All patients underwent combined orbito-cranial surgery consisting of craniotomy, debulking of the tumour, transcaruncular orbital and optic canal decompression with release of the dural sheath overlying the optic nerve via the craniotomy approach. Visual acuity was the primary outcome measure.

RESULTS

Four patients, aged 42, 44, 61 and 78 years, three with spheno-orbital meningioma and one with cerebral sino-nasal adenocarcinoma were included in the study. Mean postoperative follow-up time was 26, 19 and 15.6 months. The fourth patient died at 2.9 months post-surgery due to high grade aggressive cerebral adenocarcinoma. Postoperative visual acuity improved by greater than 4 lines of Snellen acuity in 2 patients at 26 and 19.1 months. Two patients decreased from counting fingers vision to perception of light at last follow-up.

CONCLUSIONS

In cases of non-resectable meningioma extending into the optic canal with secondary optic nerve compression, a combined surgical approach with optic canal decompression and dural sheath release may help preserve and even improve vision in certain cases.

Paranasal sinus mucoceles with ophthalmologic manifestations: a 17-year review of 96 cases

BACKGROUND

The purpose of this study was to assess the characteristics of paranasal sinus mucoceles with ophthalmologic manifestations with a focus on optic neuropathy.

METHODS

From January 1993 to May 2010, 96 consecutive patients diagnosed with paranasal sinus mucoceles with ophthalmologic manifestations were investigated. Clinical and therapeutic factors and demographics were reviewed from medical records. Statistical associations between clinical and therapeutic factors and visual outcomes after surgery were also analyzed.

RESULTS

A total of 352 patients were diagnosed with paranasal sinus mucoceles and underwent surgical treatment. Ninety-six of them presented with ophthalmologic symptoms, and periorbital swelling and pain were the most common symptoms (36.4%) in those patients. Among the 96 patients with ophthalmologic manifestations, 18 (18.8%) were diagnosed with optic neuropathy based on the deterioration of their visual acuity and unilateral relative afferent papillary defect. Ten of these 18 patients showed improvements in their vision after surgical intervention. The statistical analysis of the association between clinical and therapeutic factors and visual outcomes showed that the presence of infection was the only significant factor (p = 0.023).

CONCLUSION

Paranasal sinus mucoceles present various ophthalmologic manifestations. Among them, optic neuropathy may be one of the most devastating conditions. In treating optic neuropathy caused by mucoceles, the presence of infection was the only factor that had any influence on postoperative visual outcomes. Therefore, we conclude that not only surgical drainage and ventilation of the sinus are necessary, but infection control is also a vital factor in treating mucoceles with optic neuropathy.

Visual recovery following optic nerve decompression for chronic compressive neuropathy

PURPOSE

Visual failure due to optic nerve compression is a common indication for decompressive surgery. Most data only refer to the odds of improvement, deterioration or remaining the same. However, patients frequently wish to know more detail about the outcomes of surgery. Our aim was to assess the visual outcome from optic nerve decompression for visual failure in detail in order to help counsel patients pre-operatively.

METHODS

Sixty-eight patients undergoing 71 operations to decompress 87 optic nerves between 1991 and 2007 were identified. Thirty-four decompressions were performed via a transzygomatic and 37 via a transbasal approach. Fifty-two patients had meningiomas, 3 pituitary adenomas, 3 craniopharyngiomas, 3 chordomas, 2 adenocarcinomas, 2 fibrous dysplasia, 1 schwannoma, 1 granular pituitary tumour and 1 olfactory neuroblastoma. Visual acuity and fields were recorded pre-operatively, immediately post-operatively, at first follow-up and at most recent follow-up.

RESULTS

Forty-three eyes (49.4%) experienced an improvement in either acuity or fields. Twenty-four (27.5%) were unchanged and 20 (22.9%) deteriorated. Average improvement was 0.88 Snellen lines (logMAR 0.13). Improvement was seen between immediate post-operative acuity and first follow-up in 52%, but 22% suffered a late deterioration after 1 year. There was no relationship between age, duration of symptoms, pathology, approach or redo surgery and visual outcome. There was a complex relationship between pre-operative visual acuity and post-operative improvement and outcome. Better pre-operative acuity predicted better outcome and greater odds of improvement, although patients with poor pre-operative vision had a greater average magnitude of improvement.

CONCLUSIONS

Patients experience significant benefit from optic nerve decompression irrespective of pre-operative visual status. Although early decompression is desirable, good results can still be obtained in patients with severe visual failure. Detailed data on visual outcome can help counsel patients pre-operatively to aid decision-making and set expectations.

The surgical management and outcomes for spheno-orbital meningiomas: a 7-year review of multi-disciplinary practice

AIMS/PURPOSE

Spheno-orbital meningiomas account for 9% of all adult intracranial meningiomas. Complete resection is extremely difficult with this condition. We report on our experience in the surgical management of spheno-orbital meningiomas.

METHODS

A retrospective review was performed of all patients with spheno-orbital meningiomas who underwent joint neurosurgical and ophthalmic procedures between January 2000 and December 2007. Radiological findings, presenting clinical signs, indications for surgery, surgical approach, histopathological findings, surgical complications and post-operative results were recorded.

RESULTS

Twelve patients were included in the study. Visual function deterioration was the main indication for surgery. Six patients underwent an optic canal decompression along with their initial tumour resection and all 12 patients underwent an extensive lateral orbital wall decompression. Post-operatively 6 patients had reduced proptosis. Two patients had an improvement in their visual acuity, 5 patients had a stable visual acuity and 5 patients had a progressive deterioration in visual acuity following surgery. Six patients maintained a stable visual field. Cranial nerve palsy was the commonest post-operative complication. Three patients required postoperative fractionated radiotherapy. Three patients required further surgery.

CONCLUSION

Spheno-orbital meningiomas are difficult tumours to manage. Surgical resection can reduce the degree of proptosis and stabilise visual function in patients with failing vision, although sustained improvement is difficult to achieve if the tumour behaves in an aggressive manner. The risk of post-operative visual loss is considerable, either due to surgery or tumour progression. Outcomes from surgical decompression may not necessarily be better than the natural history of these tumours.

The role of surgery in meningiomas involving the optic nerve sheath

OBJECTIVE

Clinical presentation, radiological appearance and treatment options of patients with optic nerve sheath meningiomas (ONSM) vary. To provide a baseline for treatment of this tumour entity a series of 24 patients with ONSM is presented.

METHOD

Clinical charts of the patients including surgical and histological records, imaging studies as well as meticulously focusing questionnaires of clinical outcome were reviewed.

RESULTS

Twenty four patients with ONSM were treated at the Neurosurgical Department from 1981 to 2002. Mean age at diagnosis was 44 years (14-69) with a female:male ratio of 7:1. The preoperative duration of symptoms was negatively correlated with the preoperative visual acuity. The microsurgical approach consisted of pterional craniotomy, intra-/extradural subtotal excision of the meningioma and bony decompression of the optic canal. Surgical results showed low surgical morbidity and preserved or even improved vision in 8/16 patients (50%) all of whom had rapid visual decline preoperatively. In the long-term, visual loss occur again occurred due to recurrence in about 20% of cases.

CONCLUSION

Microneurosurgery for treatment of ONSMs is still reserved for cases with intracranial extension, disfiguring proptosis and patients with rapid visual deterioration. Radiotherapy should be considered as treatment option in all other cases as it prolongs the time for functional vision in the affected eye with low morbidity.