Feasibility and efficacy of endoscopic transorbital optic canal decompression for meningiomas causing compressive optic neuropathy.

OBJECTIVE: The endoscopic transorbital approach (ETOA) and transorbital anterior clinoidectomy have been suggested as novel procedures through which to reach the superolateral compartments of the orbit, allowing optic canal decompression. However, there is limited literature describing the technical details and surgical outcomes of these procedures. In this study, the authors aimed to analyze the feasibility and efficacy of endoscopic transorbital decompression of the optic canal through anterior clinoidectomy for compressive optic neuropathic lesions. METHODS: Between 2016 and 2022, the authors performed ETOA for compressive optic neuropathic lesions in 14 patients. All these patients underwent transorbital anterior clinoidectomy through the surgically defined "intraorbital clinoidal triangle," which is composed of the roof of the superior orbital fissure, the medial margin of the optic canal, the medial border of the superior orbital fissure, and the optic strut. Demographic data, tumor characteristics, pre- and postoperative imaging, pre- and postoperative visual examinations, and surgical outcomes were retrospectively reviewed. RESULTS: The mean age at the time of ETOA was 53.3 years (range 41-64 years), and the mean follow-up was 16.8 months (range 6.7-51.4 months). The inclusion criterion in this study was having a meningioma (14 patients). In the preoperative visual function examination, 7 patients with a meningioma showed progressive visual impairment. After endoscopic transorbital optic canal decompression, visual function improved in 5 patients, remained unchanged in 8 patients, and worsened in 1 patient. No new-onset neurological deficit was associated with ETOA and anterior clinoidectomy in any patients. CONCLUSIONS: Endoscopic transorbital decompression of the optic canal with extradural anterior clinoidectomy is a safe and feasible technique that avoids significant injury to the clinoidal internal carotid artery and surrounding neurovascular structures.

Sarcoid optic neuropathy.

A 45-year-old woman presented with sudden complete vision loss in her left eye and retroorbital pain worsened by eye movements. A previous milder episode of vision loss had occurred in the same eye 1 year before, with complete recovery after high-dose intravenous methylprednisolone. She had no light perception in the left eye with a swollen optic disc, but with a normal right optic disc. There were no systemic manifestations or infections. MR scan of the brain showed extensive enlargement and enhancement of the left optic nerve and optic chiasm. After excluding infections and autoimmune markers, a left optic nerve biopsy confirmed non-caseating granulomas, leading to a diagnosis of neurosarcoidosis.

Topographic comparison of the retinal microvascular changes between patients with compressive and glaucomatous optic neuropathies.

We investigated the difference in optical coherence tomography angiography characteristics between the patients with compressive optic neuropathy (CON, n = 26) and glaucomatous optic neuropathy (GON, n = 26), who were matched for the severity of visual field defect. The peripapillary retinal nerve fiber layer (pRNFL) thickness in the nasal and temporal sectors was thinner in the CON group, whereas the inferior pRNFL thickness was thinner in the GON group. Accordingly, the CON group had lower peripapillary vessel density (pVD) in the nasal and temporal sectors, and the GON group in the inferior sector. In the macular area, the CON group had a thinner macular ganglion cell-inner plexiform layer in the superior and nasal sectors, whereas the GON group in the inferior sector. However, the CON group did not have a lower macular VD than the GON group in any sector, whereas the GON group exhibited lower superficial capillary plexus VD in the superior, inferior, and temporal sectors. Comparison of the structure-vasculature correlation revealed a significant difference in the nasal and temporal peripapillary areas and superior and nasal macular sectors; a decrease in VD was greater in the GON group than in the CON group when the comparable structural change occurred.

OCT and OCTA in dysthyroid optic neuropathy: a systematic review and meta-analysis.

PURPOSE: To explore the current research about the role of optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in dysthyroid optic neuropathy (DON). METHODS: Studies in the literature that focused on OCT, OCTA and DON were retrieved by searching PubMed, EMBASE, Cochrane databases and Clinical Trial before 20 June 2023. The methodological quality was assessed using the Newcastle-Ottawa scale. The quantitative calculation was performed using Review Manager V.5.3. RESULTS: Twelve studies met the eligibility criteria and were included. DON group presented lower macular ganglion cell complex in the overall, superior and inferior hemifields compared with the non-DON group. Furthermore, the ganglion cell layer and inner plexiform layer in DON group was thinner in contrast to the non-DON group. The optic nerve head vessel density was lower in the DON group than that in the non-DON group. A reduction of radial peripapillary capillary vessel density could be seen in the DON group than the non-DON group in overall, inside disc, peripapillary, superior-hemifield, temporal and nasal. Besides, the macular superficial retinal capillary layer of non-DON and DON is lower than the healthy control group. CONCLUSIONS: This study supported the potential value of OCT and OCTA metrics as novel biomarkers of DON. Ophthalmologists should comprehensively consider the retinal structure and microvasculature in dealing with DON. ETHICS AND DISSEMINATION: This systematic review included data from published literature and was exempt from ethics approval. Results would be disseminated through peer-reviewed publication and presented at academic conferences engaging clinicians. PROSPERO REGISTRATION NUMBER: CRD42023414907.

Extraocular muscle volume index at the orbital apex with optic neuritis: a combined parameter for diagnosis of dysthyroid optic neuropathy.

OBJECTIVES: To evaluate the diagnostic performance of the extraocular muscle volume index at the orbital apex (AMI) and the signal intensity ratio (SIR) of the optic nerve in dysthyroid optic neuropathy (DON). METHODS: Clinical data and magnetic resonance imaging were collected retrospectively from 63 Graves' ophthalmopathy patients, including 24 patients with DON and 39 without DON. The volume of these structures was obtained by reconstructing their orbital fat and extraocular muscles. The SIR of the optic nerve and axial length of eyeball were also measured. The posterior 3/5 of the retrobulbar space volume was used as the orbital apex to compare parameters in patients with or without DON. Area under the receiver operating characteristic curve (AUC) analysis was used to select the morphological and inflammatory parameters with the highest diagnostic value. A logistic regression was performed to identify the risk factors of DON. RESULTS: One hundred twenty-six orbits (35 with DON and 91 without DON) were analyzed. Most of the parameters in DON patients were significantly higher than in non-DON patients. However, the SIR 3 mm behind the eyeball of the optic nerve and AMI had the highest diagnostic value in these parameters and are independent risk factors of DON by stepwise multivariate logistic regression analysis. Combining AMI and SIR had a higher diagnostic value than a single index. CONCLUSIONS: Combining AMI with SIR 3 mm behind the eyeball's orbital nerve can be a potential parameter for diagnosing DON. CLINICAL RELEVANCE STATEMENT: The present study provided a quantitative index based on morphological and signal changes to assess the DON, allowing clinicians and radiologists to monitor DON patients timely. KEY POINTS: The extraocular muscle volume index at the orbital apex (AMI) has excellent diagnostic performance for dysthyroid optic neuropathy. A signal intensity ratio (SIR) of 3 mm behind the eyeball has a higher AUC compared to other slices. Combining AMI and SIR has a higher diagnostic value than a single index.

Three-Dimensional Ultrasound Elastography Detects Age-Related Increase in Anterior Peripapillary Sclera and Optic Nerve Head Compression During IOP Elevation.

Purpose: High-frequency ultrasound elastography offers a tool to resolve the complex and heterogeneous deformation through the full thickness of the optic nerve head (ONH) and peripapillary sclera (PPS). Using this tool, we quantified the three-dimensional deformation of the ONH and PPS in human donor eyes and evaluated age-associated changes. Methods: The ONH and PPS in 15 human donor globes were imaged with a 50-MHz ultrasound probe while increasing intraocular pressure (IOP) from 15 to 30 mm Hg. Tissue displacements were obtained using correlation-based ultrasound speckle tracking. Three-dimensional spherical strains (radial, circumferential, meridional, and respective shear strains) were calculated for the ONH and PPS volumes segmented from three-dimensional ultrasound images. Age-related trends of different strains in each region of interest were explored. Results: The dominant form of IOP-induced deformation in the ONH and PPS was radial compression. High-magnitude localized out-of-plane shear strains were also observed in both regions. Most strains were concentrated in the anterior one-half of the ONH and PPS. The magnitude of radial and volumetric strains increased with age in the anterior ONH and anterior PPS, indicating greater radial compression and volume loss during IOP elevation in older age. Conclusions: The age-associated increase of radial compression, the predominant form of IOP-induced deformation in anterior ONH and PPS, may underlie age-associated glaucoma risk. High-frequency ultrasound elastography offers a useful tool to quantify all types of deformation comprehensively in all regions of ONH and PPS, which may improve our understanding of the biomechanical factors contributing to glaucoma risk.

Bilateral Rhinogenous Optic Neuropathy Caused by the Regrowth of a Large Sphenoid Sinus Mucocele.

A 59-year-old man, who had a history of left blind at 36 years old, suddenly lost right visual acuity. Magnetic resonance imaging revealed a large left sphenoid sinus cyst, which protruded intracranially. The cyst was fenestrated by endoscopic sinus surgery, but his right vision did not recover. Ten cases of bilateral rhinogenous optic neuropathy caused by mucocele have been reported, and the cause was sphenoid sinus in 9 cases. Postoperative visual acuity in these cases was poor, especially in slow progressive cases, because it was diagnosed as an unknown cause, and surgery was delayed. Rhinogenous optic neuropathy caused by mucocele should be differentiated from bilateral visual impairment of unknown cause. The authors highlight the importance of early diagnosis of sphenoid sinus mucocele and fully informing patients about the future risk of bilateral visual impairment, even if they are asymptomatic or have been treated.

Longitudinal stability of inter-eye differences in optical coherence tomography measures for identifying unilateral optic nerve lesions in multiple sclerosis.

INTRODUCTION: Optical coherence tomography (OCT)-derived peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell+inner plexiform layer (GCIPL) thickness inter-eye differences (IEDs) are robust measurements for identifying clinical history acute ON in people with MS (PwMS). This study investigated the utility and durability of these measures as longitudinal markers to identify optic nerve lesions. METHODS: Prospective, multi-center international study of PwMS (with/without clinical history of ON) and healthy controls. Data from two sites in the International MS Visual System Consortium (IMSVISUAL) were analyzed. Mixed-effects models were used to compare inter-eye differences based on MS and acute ON history. RESULTS: Average age of those with MS (n = 210) was 39.1 ± 10.8 and 190 (91%) were relapsing-remitting. Fifty-nine (28.1%) had a history of acute unilateral ON, while 9/210 (4.3%) had >1 IB episode. Median follow-up between OCT scans was 9 months. By mixed-effects modeling, IEDs were stable between first and last visits within groups for GCIPL for controls (p = 0.18), all PwMS (p = 0.74), PwMs without ON (p = 0.22), and PwMS with ON (p = 0.48). For pRNFL, IEDs were within controls (p = 0.10), all PwMS (p = 0.53), PwMS without ON history (p = 0.98), and PwMS with history of ON (p = 0.81). CONCLUSION: We demonstrated longitudinal stability of pRNFL and GCIPL IEDs as markers for optic nerve lesions in PwMS, thus reinforcing the role for OCT in demonstrating optic nerve lesions.

Discrimination of glaucomatous from non-glaucomatous optic neuropathy with swept-source optical coherence tomography.

OBJECTIVE: To assess the ability of optic nerve head (ONH) parameters, peripapillary retinal nerve fiber layer (pRNFL), and macular ganglion cell layer (GCL) thickness measurements with swept-source optical coherence tomography (SS-OCT), to discriminate between glaucomatous and non-glaucomatous optic neuropathy (GON and NGON). METHODS: This retrospective cross-sectional study involved 189 eyes of 189 patients, 133 with GON and 56 with NGON. The NGON group included ischemic optic neuropathy, previous optic neuritis, and compressive, toxic-nutritional, and traumatic optic neuropathy. Bivariate analyses of SS-OCT pRNFL and GCL thickness and ONH parameters were performed. Multivariable logistic regression analysis was employed to obtain predictor variables from OCT values, and the area under the receiver operating characteristic curve (AUROC) was calculated to differentiate between NGON and GON. RESULTS: Bivariate analyses showed that the overall and inferior quadrant of the pNRFL was thinner in the GON group (P=0.044 and P<0.01), while patients with NGON had thinner temporal quadrants (P=0.044). Significant differences between the GON and NGON groups were identified in almost all the ONH topographic parameters. Patients with NGON had thinner superior GCL (P=0.015), but there were no significant differences in GCL overall and inferior thickness. Multivariate logistic regression analysis demonstrated that vertical cup-to-disc ratio (CDR), cup volume, and superior GCL provided independent predictive value for differentiating GON from NGON. The predictive model of these variables along with disc area and age achieved an AUROC=0.944 (95% CI 0.898-0.991). CONCLUSIONS: SS-OCT is useful in discriminating GON from NGON. Vertical CDR, cup volume, and superior GCL thickness show the highest predictive value.

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.

Discriminating Between Compressive Optic Neuropathy With Glaucoma-Like Cupping and Glaucomatous Optic Neuropathy Using OCT and OCTA.

Purpose: To discriminate between compressive optic neuropathy with glaucoma-like cupping (GL-CON) and glaucomatous optic neuropathy (GON) by comparing the peripapillary retinal nerve fiber layer (pRNFL) thickness and retinal microvasculature using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). Methods: In this retrospective cross-sectional study, OCT scans were performed on 28 eyes of GL-CON, 34 eyes of GON, and 41control eyes to determine the pRNFL thickness, ganglion cell complex thickness, and cup/disc ratio. OCTA scans were conducted for 12 eyes of GL-CON, 15 eyes of GON, and 15 control eyes to measure the vessel density of the peripapillary and macular areas. Analysis of covariance was used to perform the comparisons, and the area under the curve was calculated. Results: The GON eyes had a significantly thinner pRNFL in the inferior quadrant and greater vertical cup/disc ratio than the GL-CON eyes. In the radial peripapillary capillary segment, the vessel density of the GON in the inferior sectors was significantly lower than in the GL-CON. The superficial macular vessel density in the whole-image, peritemporal, perinasal, and peri-inferior sectors was significantly smaller in the GON group than in the GL-CON group. The best parameter for discriminating between GL-CON and GON was the superficial macular vessel density in the peritemporal sector. Conclusions: GL-CON eyes showed a characteristic pattern of pRNFL and retinal microvascular changes. Translational Relevance: GL-CON can be effectively distinguished from GON by detecting the alterations in the pRNFL and retinal microvasculature using OCT and OCTA.

Pearls & Oy-sters: Trigeminal Cystic Schwannoma Presenting With Foster Kennedy Syndrome, Sixth Nerve Palsy, and Focal Seizures.

Foster Kennedy syndrome refers to a finding of optic atrophy in one eye from direct compression of the optic nerve by a mass lesion and contralateral papilledema in the nonatrophic optic nerve caused by an increased intracranial pressure. When the fundoscopy finding is not due to a direct compressive mass, the term pseudo-Foster Kennedy syndrome is used; this can be caused by any process or processes that result in optic atrophy in one eye and optic disc edema in the other. Identifying Foster Kennedy syndrome in a patient calls for expedient neuroimaging looking for an intracranial mass lesion. In this article, we present the case of a patient presenting with vision loss and Foster Kennedy syndrome who was found to have a large trigeminal cystic schwannoma. While several other accompanying symptoms were not evident from the patient complaint, a careful history and physical examination revealed additional localizing clues: unilateral sensory changes in the face and pterygoid and masseter atrophy, unilateral cranial nerve VI palsy, and episodes of intense déjà vu sensation, which were presumed to represent temporal lobe-onset focal aware seizures. Trigeminal schwannomas are a rare entity, and they are even more rarely cystic. This case highlights an unusual scenario where a slow expansion of the tumor ultimately resulted in vision loss and presentation of the patient to medical attention.

Ocular Optical Coherence Tomography in the Evaluation of Sellar and Parasellar Masses: A Review.

Compression of the anterior visual pathways by sellar and parasellar masses can produce irreversible and devastating visual loss. Optical coherence tomography (OCT) is a noninvasive high-resolution ocular imaging modality routinely used in ophthalmology clinics for qualitative and quantitative analysis of optic nerve and retinal structures, including the retinal ganglion cells. By demonstrating structural loss of the retinal ganglion cells whose axons form the optic nerve before decussating in the optic chiasm, OCT imaging of the optic nerve and retina provides an excellent tool for detection and monitoring of compressive optic neuropathies and chiasmopathies due to sellar and parasellar masses. Recent studies have highlighted the role of OCT imaging in the diagnosis, follow-up, and prognostication of the visual outcomes in patients with chiasmal compression. OCT parameters of optic nerve and macular scans such as peripapillary retinal nerve fiber layer thickness and macular ganglion cell thickness are correlated with the degree of visual loss; additionally, OCT can detect clinically significant optic nerve and chiasmal compression before visual field loss is revealed on automated perimetry. Preoperative values of OCT optic nerve and macular parameters represent a prognostic tool for postoperative visual outcome. This review provides a qualitative analysis of the current applications of OCT imaging of the retina and optic nerve in patients with anterior visual pathway compression from sellar and parasellar masses. We also review the role of new technologies such as OCT-angiography, which could improve the prognostic ability of OCT to predict postoperative visual function.

Functional and Morphological Brain Alterations in Dysthyroid Optic Neuropathy: A Combined Resting-State fMRI and Voxel-Based Morphometry Study.

BACKGROUND: Increasing evidence has indicated that the entire visual pathway from retina to visual cortex may be involved in dysthyroid optic neuropathy (DON) pathological mechanisms. PURPOSE: To explore the functional and morphological brain characteristics in DON and their relationship with ophthalmologic performance. STUDY TYPE: Retrospective. POPULATION: A total of 30 DON patients, 40 thyroid-associated ophthalmopathy (TAO) without DON patients and 21 healthy-controls (HCs). FIELD STRENGTH/SEQUENCE: A 3.0 T, 3D T1-weighted spoiled gradient-recalled echo and gradient-recalled echo-planar imaging. ASSESSMENT: Functional and structural alterations in brain regions were evaluated with fractional amplitude of low-frequency fluctuations, degree centrality (DC), and gray matter volume (GMV). Clinical activity score (CAS) is assessed across patients. STATISTICAL TEST: One-way analysis of variance with post hoc two sample t-tests (GRF-corrected, voxel level: P < 0.005, cluster level: P < 0.05) and correlation analysis (significance level: P < 0.05). RESULTS: Compared to HCs, DON patients had significantly decreased DC values in the bilateral BA17 and BA18 regions. Compared to the TAO group, DON patients had decreased GMV in the left anterior cingulate cortex, left middle frontal gyrus, left lingual gyrus, left parietal gyrus, right Rolandic operculum, left supplementary motor area, and right middle temporal gyrus. In addition, GMV in the right Rolandic operculum was significantly positively correlated with CAS (correlation coefficient: r = 0.448). DATA CONCLUSION: This study showed significant morphological and functional alterations in visual cortex and morphological alterations in partial default mode network regions of DON patients, which may provide insights into the mechanism of vision loss and may facilitate the diagnosis and treatment of DON. EVIDENCE LEVEL: 3. TECHNICAL EFFICACY: Stage 3.