Restoration of vision by combined experimental antithymocyte therapy, and orbital radiation with high-dose steroids for severe, acute, steroid-refractory, congestive thyroid orbitopathy.

PURPOSE: We report diagnostic and therapeutic dilemmas in the difficult case of compressive optic neuropathy with severe visual acuity and visual field loss with subsequent visual recovery in both eyes, in a patient with Graves' orbitopathy (GO) by a combination of experimental antithymocyte therapy, orbital radiotherapy with high-dose steroids. METHODS: A 72-year-old man presented with severe vision loss in both eyes. The visual symptoms had appeared over a year before the GO diagnosis. He was initially misdiagnosed with neuroborreliosis and optic neuritis based on brain and orbital magnetic resonance imaging. There was no exophthalmos. The ophthalmological examination included visual acuity, visual field, tonometry in primary and upgaze eye position, optical coherence tomography (OCT), pattern electroretinogram (PERG), pattern, and flash visual evoked potentials (PVEP and FVEP). The patient received experimental therapy with ATG, followed by high-dose of intravenous steroids and orbital radiotherapy. RESULTS: Delayed VEP peaks became shorter after treatment. After systemic and local therapy lowering of intraocular pressure was achieved. Abnormal PERG has been found three months before ganglion cells atrophy was detected in OCT. Visual acuity and visual field improvement occurred in both eyes after therapy, despite partial left optic nerve atrophy. The patient regained full decimal visual acuity (1.0 right from as poor as 0.3  to 1.0 in the right eye and from hand movements to 0.9 in the left. Severe visual field loss with advanced absolute scotomata has improved to slight relative scotomata. The duration of follow-up time after the treatment was 4 months. CONCLUSIONS: Intensive treatment of steroid-resistant Graves' orbitopathy (GO) may prevent total optic nerve atrophy. Despite severely advanced optic neuropathy, this report emphasizes the necessity of therapy even with nearly complete visual function loss hence there is always a possibility to regain full visual acuity and visual field. Patients with tense orbital septum may not present with significant exophthalmos, thus delaying the correct diagnosis of orbitopathy. A supporting sign of GO was the difference in intraocular pressure in the primary and upgaze eye positions. Electrophysiological examinations are helpful in the diagnosis and monitoring of GO therapy. To our knowledge, this is the first report of this kind presenting visual function restoration and structural recovery in a patient with advanced optic neuropathy in GO.

Real-World Experience With Teprotumumab in Patients With Dysthyroid Optic Neuropathy.

BACKGROUND: Teprotumumab, an insulin-like growth factor I receptor inhibitory antibody, improved proptosis, diplopia, inflammatory signs/symptoms, and quality of life in patients with active thyroid eye disease (TED) in clinical trials. The trials excluded patients with dysthyroid optic neuropathy (DON). Recently, many case reports and case series have reported the successful use of teprotumumab to treat DON. Here, we review the data from published cases and our clinical experience in treating patients having DON with teprotumumab. METHODS: A literature search was conducted of patients with DON treated with teprotumumab from January 2020 through September 2022. Data from DON patients from the authors' (M.A.T. and C.A.B.) clinical practice were included. Primary outcome measure was mean (SD) improvements for visual acuity, color vision, and visual fields. Improvements in proptosis and clinical activity score (CAS) and diplopia were compared before and after teprotumumab administration. RESULTS: Ten observational studies/case reports were identified along with 2 patients in our practice. In all, there were 24 active TED patients with DON (37 eyes) who were treated with teprotumumab. Mean (SD) age was 66.5 (13.6) years and 13 (54%) were females, disease duration ranged from 2 months to >15 years. 22/24 patients had none, minimal improvement or progression of visual loss with intravenous/oral corticosteroids, orbital decompression (n = 9), and orbital radiation (n = 2). There were 2 patients who received teprotumumab as the only therapy. Overall, 88% (21/24) reported improvement in visual acuity after teprotumumab and in 75% (18/24), improvement in vision was observed after just 2 infusions of teprotumumab. Three eyes had decompression surgery in close proximity to teprotumumab infusions and were excluded from analyses. Mean (SD) improvement in visual acuity was 3.73 lines (SD 3.74), range 2-15 lines in 33 eyes. The mean (SD) improvement in the mean deviation on visual field testing in 15 eyes was 5.6 db (3.0 db). Mean (SD) improvement in proptosis was 4.37 mm (SD: 2.11) (20 patients, 32 eyes); and clinical activity score: mean reduction of 5.1 (1.3) for 18 patients. Teprotumumab was well tolerated in all but one patient. Adverse events reported included fatigue, dysgeusia, hearing loss, nausea, hyperglycemia, and muscle spasms. CONCLUSIONS: Teprotumumab is an effective treatment for DON in our experience and in published cases in whom treatment with steroids, surgery, or orbital radiation was unsuccessful.

Tocilizumab use for optic nerve compression in thyroid eye disease: a prospective longitudinal cohort.

PURPOSE: To assess the effectiveness of tocilizumab in reverting the signs and symptoms of dysthyroid optic neuropathy (DON) in thyroid eye disease and the need for emergency orbital decompression. The secondary outcomes are to identify the optimal number of tocilizumab cycles to achieve the primary outcome, to analyze the association between thyroid stimulating immunoglobulin (TSI), clinical activity score (CAS) and proptosis in response to the treatment and the need for rehabilitative orbital decompression. METHODS: Prospective longitudinal cohort study that included 13 patients who had unilateral or bilateral dysthyroid optic neuropathy (DON) due to severe and progressive sight-threatening thyroid eye disease based on the CAS system. Patients were seen in this facility starting from July 2017, and all had received intravenous tocilizumab. RESULTS: Initial visual acuity mean was 0.52 ± 0.38 and the final were 0.93 ± 0.11 with a mean difference of 0.41 and P < 0.00245. The mean CAS prior to the initiation of the treatment was 7.92 ± 0.66 and the final was 2.85 ± 1.03 with mean difference of 5.07 and P < 0.00001. Initial mean proptosis was 24.85 ± 2.31 and the final was 21.78 ± 2.18 with a mean difference of 3.07 and P < 0.000497. No emergency orbital decompression was performed. TSI was high initially in all cases with a wide range of 2.4 to 40 IU/L and with a mean of 10.70 ± 13.40. The final TSI mean was 2.90 ± 3.90 with a mean difference of 7.81 and significant P value (P < 0.0272). CONCLUSION: Tocilizumab use in optic nerve compression showed promising results as it can be the primary or an alternative treatment option.

Outcomes of systemic bevacizumab in radiation-induced optic neuropathy, case series.

PURPOSE: Optic neuropathy is a rare, delayed complication after radiation with no universally accepted treatment modality. We report the outcomes of 6 patients with radiation-induced optic neuropathy (RION) who were treated with systemic bevacizumab. METHODS: This is a retrospective series of 6 cases of RION, treated with intravenous (IV) bevacizumab. "Improved" or "worse" visual outcomes were defined as a change in best corrected visual acuity of ≥ 3 Snellen lines. Otherwise, the visual outcome was noted as "stable". RESULTS: In our series, RION was diagnosed 8 to 36 months after radiotherapy. IV bevacizumab was initiated as treatment within 6 weeks of the onset of visual symptoms in 3 cases and after 3 months in the other cases. Although no improvement in visual function was observed, stabilization of vision was noted in 4 of the 6 cases. In the other 2 cases, the level of vision declined from counting fingers to no light perception. In 2 cases, bevacizumab treatment was discontinued prior to completion of the planned course due to renal stone formation or worsening of renal disease. One patient developed ischemic stroke 4 months after bevacizumab completion. CONCLUSION: Systemic bevacizumab may stabilize vision in some patients with RION, though the limitations of our study do not allow us to draw this conclusion definitively. Therefore, the risks and potential benefits of using IV bevacizumab should be considered in each individual case.

Optic neuropathy after COVID-19 vaccination: a report of two cases.

PURPOSE: We report two cases of optic nerve pathology after the administration of the Pfizer-BioNTech and AstraZeneca-Oxford COVID-19 vaccines, respectively, and describe the implications for management of post-vaccination central nervous system (CNS) inflammation. CASE REPORTS: A 69-year-old woman presented with bilateral optic nerve head oedema, 16 days after the second dose of the Pfizer-BioNTech vaccine. She was diagnosed with post-vaccination CNS inflammatory syndrome and was treated for five days with intravenous methylprednisolone at a dose of 1 gram per day. Her optic disc swelling improved, and her vision stabilised. A 32-year-old woman presented six days after her first dose of the AstraZeneca-Oxford vaccine with two days of sudden onset of progressive blurring of vision in her left eye. Posterior segment examination revealed left optic disc swelling, and an MRI of the brain, orbit, and cervical spine was significant for left optic nerve enhancement. The patient was diagnosed with a unilateral post-vaccination optic neuritis. She was treated with a three-day course of intravenous methylprednisolone followed by oral prednisone. Her optic disc swelling and visual field improved, and she recovered 6/6 vision. CONCLUSIONS: Clinicians and patients should be aware of the potential for post-vaccination CNS inflammatory syndromes associated with COVID-19 vaccine administration. Neuroimaging and cerebrospinal fluid analysis may aid in the diagnosis of the cause of vision loss. Further studies are needed to evaluate the spectrum and frequency of optic nerve involvement associated with COVID-19 vaccination.

Orbital Radiation for Thyroid Eye Disease: A Report by the American Academy of Ophthalmology.

PURPOSE: To review the current literature on the safety and efficacy of orbital radiation for the management of thyroid eye disease (TED). METHODS: A literature search was conducted last in February 2021 of the PubMed database to identify all articles published in the English language on original research that assessed the effect of orbital radiation on TED. The search identified 55 articles, and 18 met the inclusion criteria for this assessment. A panel methodologist then assigned a level of evidence rating for each study, and all of them were rated level III. RESULTS: Two large retrospective studies demonstrated the efficacy of radiation treatment, with or without corticosteroid use, in preventing or treating compressive optic neuropathy (CON). Three studies highlighted the role of orbital radiation therapy (RT) to facilitate the tapering of corticosteroids. Several other studies showed a possible role for RT to improve diplopia and soft tissue signs. CONCLUSIONS: Although no level I or level II evidence exists, the best available evidence suggests that orbital radiation, used with or without corticosteroids, is efficacious in preventing CON, improving motility restriction, and decreasing clinical activity in TED. Orbital radiation also may facilitate a corticosteroid taper. Together, these studies show that RT seems to modify the active phase of TED. Short-term risks of orbital radiation are minor, but long-term outcome data are lacking.

Low-dosage ethambutol, less than 12.5 mg/kg/day, does not worsen the clinical outcomes of pulmonary Mycobacterium avium and Mycobacterium intracellulare disease: a retrospective cohort study.

OBJECTIVES: Multidrug chemotherapy is recommended for treating pulmonary Mycobacterium avium and Mycobacterium intracellulare disease. Although ethambutol has been demonstrated to inhibit macrolide resistance, the ethambutol dosage is sometimes decreased due to concerns about optic neuropathy. We aimed to assess whether lower ethambutol doses impact treatment outcomes. METHODS: Patients treated over 12 months between 2016 and 2020 were collected retrospectively. Clinical outcomes, including negative culture conversion, microbiological cure, adverse events, resistance to macrolides, and recurrence, were compared according to daily ethambutol dosage. RESULTS: Among 146 patients, 42 were treated with ethambutol dosages over 12.5 mg/kg/day, and 104 were treated with lower dosages. Negative culture conversion was achieved for 125 patients, and 90 patients achieved microbiological cure. Recurrence was identified in 16 patients who achieved microbiological cure. No macrolide resistance was observed, and no significant difference was observed in the percentage of negative culture conversion (P = 1.00) or microbiological cure (P = 0.67) between the high- and low-dosage ethambutol groups. Sputum smear positivity was associated with a lower adjusted odds ratio (aOR) of negative culture conversion (aOR: 0.48, 95% CI: 0.29-0.80). A lower aOR of microbiological cure was independently associated with sputum smear positivity (aOR: 0.52, 95% CI: 0.37-0.74) and with the use of an intermittent regimen (aOR: 0.60, 95% CI: 0.41-0.87). Daily ethambutol dosage was not identified as a prognostic factor for any of the outcomes. Optic neuropathy was observed in 7.1% of the high-dose ethambutol group and 1.0% of the low-dosage ethambutol group (P = 0.07). CONCLUSION: An ethambutol dosage of 12.5 mg/kg/day or less in guideline-based chemotherapy may reduce optic neuropathy without worsening clinical outcomes.

Advances in the Treatment of Thyroid Eye Disease Associated Extraocular Muscle Myopathy and Optic Neuropathy.

PURPOSE OF REVIEW: To review emerging treatments for thyroid eye disease (TED) associated extraocular muscle myopathy and dysthyroid optic neuropathy (DON). RECENT FINDINGS: Emerging targeted biologic therapies may alter the disease course in TED. Teprotumumab, a type I insulin-like growth factor receptor inhibitor, is the most recent addition to the treatments available for TED-associated extraocular muscle myopathy causing diplopia. Small studies also suggest a potential therapeutic benefit for DON. Various recent studies have also expanded our knowledge on conventional TED therapies. The therapeutic landscape of TED and its sequelae has evolved in recent years. New targeted therapies have the potential to reduce the extraocular muscle and orbital volume expansion which can lead to diplopia and vision loss from optic nerve compression. Longer term efficacy and durability data is needed to determine the role biologics, such as teprotumumab, should play in the treatment of TED patients compared to the current standard of care.

Management of patients with dysthyroid optic neuropathy treated with intravenous corticosteroids and/or orbital decompression surgery.

PURPOSE: To assess the characteristics and long-term outcomes of adult patients with dysthyroid optic neuropathy (DON) who underwent orbital decompression surgery and/or received intravenous (IV) methylprednisolone. METHODS: Retrospective chart review of 98 eyes of 49 patients who were diagnosed and treated with bilateral DON between 2007 and 2018 at the Department of Ophthalmology and Optometry and Oral and Maxillofacial Surgery of the Medical University of Vienna. RESULTS: The mean follow-up period was 4.1 ± 2.7 years. The most common presenting symptoms were eyelid and periorbital swelling (45%) representing active inflammation. Upgaze restriction was the most common clinical finding (73%). At time of diagnosis, the mean clinical activity score was 4 ± 1/4 ± 1 (right/left eye, respectively). Sixty-three percent (31/49) of the patients were treated both with IV methylprednisolone and underwent orbital decompression surgery, 22% (11/49) were treated with IV methylprednisolone alone and 14% (7/49) underwent surgical decompression only. Seventy-one percent (30/42) of the patients underwent 3-wall decompression. The mean reduction of proptosis in patients treated with both IV methylprednisolone and orbital decompression surgery was 4/5 mm. Mean of reduction in proptosis in patients receiving IV methylprednisolone only was 1/0 mm and in patients with surgical decompression only was 5/5 mm. Mean VA was 0.1 ± 0.5/0.1 ± 0.5 logMAR at baseline and 0.05 ± 0.7/0.05 ± 0.7 at final follow-up. In 92% (45/49), VA was preserved or improved at final follow-up. CONCLUSIONS: The majority of patients with DON were treated both with IV corticosteroids and 3-wall decompression surgery. Vision could be successfully preserved in most cases and reduction of proptosis was achieved, especially after orbital decompression surgery.

Erythropoietin in Optic Neuropathies: Current Future Strategies for Optic Nerve Protection and Repair.

Erythropoietin (EPO) is known as a hormone for erythropoiesis in response to anemia and hypoxia. However, the effect of EPO is not only limited to hematopoietic tissue. Several studies have highlighted the neuroprotective function of EPO in extra-hematopoietic tissues, especially the retina. EPO could interact with its heterodimer receptor (EPOR/ßcR) to exert its anti-apoptosis, anti-inflammation and anti-oxidation effects in preventing retinal ganglion cells death through different intracellular signaling pathways. In this review, we summarized the available pre-clinical studies of EPO in treating glaucomatous optic neuropathy, optic neuritis, non-arteritic anterior ischemic optic neuropathy and traumatic optic neuropathy. In addition, we explore the future strategies of EPO for optic nerve protection and repair, including advances in EPO derivates, and EPO deliveries. These strategies will lead to a new chapter in the treatment of optic neuropathy.

A Small Natural Molecule S3 Protects Retinal Ganglion Cells and Promotes Parkin-Mediated Mitophagy against Excitotoxicity.

Glutamate excitotoxicity may contribute to retinal ganglion cell (RGC) degeneration in glaucoma and other optic neuropathies, leading to irreversible blindness. Growing evidence has linked impaired mitochondrial quality control with RGCs degeneration, while parkin, an E3 ubiquitin ligase, has proved to be protective and promotes mitophagy in RGCs against excitotoxicity. The purpose of this study was to explore whether a small molecule S3 could modulate parkin-mediated mitophagy and has therapeutic potential for RGCs. The results showed that as an inhibitor of deubiquitinase USP30, S3 protected cultured RGCs and improved mitochondrial health against NMDA-induced excitotoxicity. Administration of S3 promoted the parkin expression and its downstream mitophagy-related proteins in RGCs. An upregulated ubiquitination level of Mfn2 and protein level of OPA1 were also observed in S3-treated RGCs, while parkin knockdown resulted in a major loss of the protective effect of S3 on RGCs under excitotoxicity. These findings demonstrated that S3 promoted RGC survival mainly through enhancing parkin-mediated mitophagy against excitotoxicity. The neuroprotective value of S3 in glaucoma and other optic neuropathies deserves further investigation.

Teprotumumab for Dysthyroid Optic Neuropathy: Early Response to Therapy.

A 45-year-old male presented with active progressive thyroid eye disease refractory to intravenous steroids and right orbital radiation. Visual acuity, left relative afferent pupillary defect, and Humphrey visual field defects were consistent with worsening left dysthyroid optic neuropathy. Orbital MRI demonstrated extraocular muscle enlargement and effacement of the left optic nerve sheath. After 2 infusions of teprotumumab, the patient's visual acuity, relative afferent pupillary defect, Humphrey visual fields, proptosis, and extraocular muscle size improved. This is the first report of dysthyroid optic neuropathy responsive to teprotumumab, and it supports the need for further studies to better understand the role of teprotumumab in treating sight-threatening thyroid eye disease.

Rituximab Monotherapy for Compressive Optic Neuropathy With Giant Ocular Adnexal Mucosa-Associated Lymphoid Tissue lymphoma.

A rare case of compressive optic neuropathy due to giant mucosa-associated lymphoid tissue lymphoma in the orbit was presented. A 87-year-old woman was aware of a slow progressive left ocular proptosis for 10 years and presented after becoming aware of a sudden progression of the proptosis accompanying visual disturbance over the previous 2 months. Orbital imaging and a biopsy of the tumor revealed a mucosa-associated lymphoid tissue lymphoma occupying her left orbit compressing and stretching the left optic nerve. Considering her age and the additional adverse effects of external beam radiation therapy to her damaged optic nerve, rituximab monotherapy was utilized. The intervention resulted in almost complete regression without any serious adverse effect, with left eye best-corrected visual acuity improving from 12/200 to 16/20. Rituximab monotherapy can be one of the first-choice treatment options for mucosa-associated lymphoid tissue lymphoma, especially in cases with the critical damage in the optic nerve.

Mirna Expression in Glaucomatous and TGFß2 Treated Lamina Cribrosa Cells.

Glaucoma is a group of optic neuropathies that leads to irreversible vision loss. The optic nerve head (ONH) is the site of initial optic nerve damage in glaucoma. ONH-derived lamina cribrosa (LC) cells synthesize extracellular matrix (ECM) proteins; however, these cells are adversely affected in glaucoma and cause detrimental changes to the ONH. LC cells respond to mechanical strain by increasing the profibrotic cytokine transforming growth factor-beta 2 (TGFß2) and ECM proteins. Moreover, microRNAs (miRNAs or miR) regulate ECM gene expression in different fibrotic diseases, including glaucoma. A delicate homeostatic balance between profibrotic and anti-fibrotic miRNAs may contribute to the remodeling of ONH. This study aimed to determine whether modulation of miRNAs alters the expression of ECM in human LC cells. Primary human normal and glaucoma LC cells were grown to confluency and treated with or without TGFß2 for 24 h. Differences in expression of miRNAs were analyzed using miRNA qPCR arrays. miRNA PCR arrays showed that the miR-29 family was significantly decreased in glaucomatous LC cell strains compared to age-matched controls. TGFß2 treatment downregulated the expression of multiple miRNAs, including miR-29c-3p, compared to controls in LC cells. LC cells transfected with miR-29c-3p mimics or inhibitors modulated collagen expression.

Neuroprotective Effect of Statins in a Rat Model of Chronic Ocular Hypertension.

Glaucoma is an optic neuropathy in which the degeneration of retinal ganglion cells (RGCs) results in irreversible vison loss. Therefore, neuroprotection of RGCs from glaucomatous afflictions is crucial for glaucoma treatment. In this study, we aimed to investigate the beneficial effects of statins in the protection of RGCs using a rat model. Glaucomatous injury was induced in rats by chronic ocular hypertension (OHT) achieved after performing a circumlimbal suture. The rats were given either statins such as simvastatin and atorvastatin or a solvent weekly for 6 weeks. Retina sections underwent hematoxylin and eosin, Brn3a, or cleaved casepase-3 staining to evaluate RGC survival. In addition, modulation of glial activation was assessed. While the retinas without statin treatment exhibited increased RGC death due to chronic OHT, statins promoted the survival of RGCs and reduced apoptosis. Statins also suppressed chronic OHT-mediated glial activation in the retina. Our results demonstrate that statins exert neuroprotective effects in rat retinas exposed to chronic OHT, which may support the prospect of statins being a glaucoma treatment.

Effect of taxifolin on cisplatin-associated oxidative optic nerve damage in rats.

AIM: To investigate the effect of taxifolin on cisplatin-induced oxidative and proinflammatory optic nerve damage in rats. METHODS: A total of 18 albino Wistar male rats were assigned into 3 groups, as follows; Group 1: Control group, Group 2: Only cisplatin administered group for 14 days (Cisplatin group), and Group 3: Taxifolin + cisplatin administered group for 14 days (CIS + TAX group). Serum malondialdehyde (MDA), total Glutathione (tGSH), Nuclear Factor-Kappa B (NF-ƘB), Total Oxidative Status (TOS) and Total Antioxidant Status (TAS) levels were collected from the left eyes of rats. Rats' right eyes were enucleated for histopathological evaluations of optic nerves. RESULTS: NF-ƘB, MDA and TOS levels were statistically significantly higher (p < 0.001) in cisplatin group when compared to other 2 groups, the tGSH and TAS levels of which were statistically significantly lower (p < 0.001). Regarding these parameters, in cisplatin group NF-ƘB, MDA and TOS levels were statistically significantly increased with cisplatin administration and giving taxifolin concomitantly with cisplatin prevented this elevation. On the other hand, tGSH and TAS levels were statistically significantly decreased with cisplatin administration and routine simultaneous application of taxifolin with cisplatin prevented this decrease. In histopathological findings, haemorrhage was observed in the perineum of the injured optic nerves in the cisplatin treated group. And also edoema and degeneration in nerve fascicles in damaged optic nerves were seen in the cisplatin group. In the taxifolin treated group histopathological examinations were close to normal appearance, except mild edoema in nerve fascicles. CONCLUSION: Cisplatin causes oxidative stress on the rat optic nerves, and these changes lead to significant histopathological damage. Taxifolin, which we used to prevent oxidative damage to the optic nerves caused by cisplatin, has been emphasized as a powerful antioxidant agent in many previous scientific investigations. Concomitant administration of taxifolin may prevent these adverse effects of cisplatin, as well as histopathological damage. Further studies are needed to fully determine the effects of cisplatin and taxifolin on the eye.

Update in Pediatric Pseudotumor Cerebri Syndrome.

Pseudotumor cerebri syndrome (PTCS) is a rare condition in children presenting with headache and papilledema from increased intracranial pressure that can cause significant morbidity. This can be idiopathic, also known as idiopathic intracranial hypertension or primary intracranial hypertension, or can be secondary to medications and associated medical conditions. Given the threat to vision, early detection and treatment is needed in all age groups. However, identifying papilledema or pseudopapilledema in children presents unique challenges sometimes as a result of differences between prepubertal and postpubertal children, further elucidating the complex pathophysiology. Management requires brain imaging, lumbar puncture, and frequent eye exams with medical and rarely surgical treatment. Visual outcomes in children are favorable if caught early and management can be prolonged over years. Pediatric PTCS is different from adult PTCS in many ways, and this review will focus on the most updated definitions of the disease, theories of pathophysiology, management, and treatment in the pediatric population.

The rapid N-wave as a potentially useful measure of the photopic negative response.

PURPOSE: The photopic negative response (PhNR) correlates with ganglion cell function and has previously been examined as an indicator of glaucomatous optic nerve damage. However, it is a prolonged response that is measured against baseline, and its clinical utility has been limited by extensive variability, poor repeatability, and baseline instability. We have observed a distinct brief negative wave ("N-wave") commonly present within the slow PhNR trough, which may provide practical and analytic advantages as a clinical measure. METHODS: We reviewed data from an interventional trial of 59 glaucoma patients who had 4 exams over an 8-month period. The PhNR was recorded with standard ISCEV stimuli (1 Hz and in some cases 4 Hz stimulation), and N-waves were measured manually, relative to return to baseline. RESULTS: N-waves, when present, could be measured easily despite shifting baselines and a degree of background noise. The PhNR median amplitude centered around 18 µV, while the N-wave median centered around 7 µV, with a distribution of responses skewed toward low or zero amplitudes. CONCLUSIONS: The N-wave appears to be a component of the longer PhNR, though its exact origin and significance remain unclear. As a rapid waveform that is independent of baseline, the N-wave is in many ways easier to measure accurately than the slower PhNR, which is highly dependent on baseline stability. The N-wave may prove useful clinically if further studies can optimize its stimulation, show its behavior in normal individuals and find correlation with markers of optic nerve disease.

Diagnosis and management of three optic neuropathies: a national survey.

BACKGROUND: We aimed to evaluate the current practice patterns of neuro-ophthalmologists in diagnosis and management of three optic neuropathies using a national survey in South Korea and to further compare the practices of neuro-ophthalmologists divided into junior and senior groups based on their clinical practice experience. METHODS: An anonymous, 15-question survey on the diagnosis and treatment of traumatic optic neuropathy (TON), nonarteritic anterior ischemic optic neuropathy (NAION), and Leber's hereditary optic neuropathy (LHON) was sent to all neuro-ophthalmologists registered with the Korean Neuro-ophthalmology Society. The questions addressed physician's practice duration as neuro-ophthalmologist, choices of MRI scans and laboratory tests for the diagnosis in suspected optic neuropathy, clinical experiences with steroids (e.g., side effects), and choices of treatment modalities and reason in in each optic neuropathy. All participants were classified into senior (≥ 10 years) and junior (< 10 years) groups. RESULTS: A total of 63 responders (response rate 78.8%) answered the questionnaire. All responders performed the basic blood tests and brain imaging for evaluating optic neuropathy. Observation was the most preferred option for TON (47.6%) and NAION (63.5%). Steroid use was the second most preferred, and the most selected indication of steroid was "when the patient wants" (58.7%) for TON and "severe visual loss or last eye" (66%) for NAION. The most preferred treatment for LHON was "prescribing idebenone" (69.7%) with a dose of 900 mg/day (63.8%). Forty-nine respondents (77.8%) experienced side effects of steroids. There was no significant difference between the senior and junior groups in all questionnaire answers (all p > 0.05). CONCLUSION: Optic neuropathies are being managed similarly by the two groups in South Korea, and many of them still use steroids. We provided reliable reasons for our results compared with other countries.

Predictors of the therapeutic effect of corticosteroids on radiation-induced optic neuropathy following nasopharyngeal carcinoma.

Radiation-induced optic neuropathy (RION) is a severe visual complication resulting from radiotherapy of the head and neck, which mostly occurs in patients with nasopharyngeal carcinoma (NPC) in the southern part of China. The mechanism of RION is unclear. Therefore, identifying risk factors for RION is an important step towards enhancing our understanding. In the current study, we retrospectively reviewed patients with NPC who were admitted to Sun Yat-Sen Memorial Hospital for visual loss between 2006 and 2017. The study included 38 participants (68 eyes) in the corticosteroid-effective group and 35 participants (64 eyes) in the corticosteroids-ineffective group. We analyzed potential risk factors for RION and developed a prediction model for the therapeutic effect of corticosteroid effect based on a random forests method. The prediction model showed a high accuracy with an area under the receiver operating characteristic curve of 0.932 (95% confidence interval = 0.889-0.975). Our results revealed that blood urea nitrogen (BUN) was significantly associated with RION and that RION patients with higher BUN levels responded better to corticosteroid treatment. Altogether, these results suggest that a prediction model, based on clinical factors, could be applied to estimate the therapeutic effect of corticosteroids on RION. Further investigation, however, is needed to confirm the study conclusion.