Pathogenesis of nonarteritic anterior ischemic optic neuropathy

Ophthalmic and Systemic Factors of Acute Nonarteritic Anterior Ischemic Optic Neuropathy in the Quark207 Treatment Trial

PURPOSE

We describe the baseline ophthalmic and cardiovascular risk factors across countries, race, and sex for the Quark207 treatment trial for acute nonarteritic anterior ischemic optic neuropathy (NAION).

DESIGN

Prospective, randomized controlled clinical trial.

PARTICIPANTS

Adults 50 to 80 years of age with acute NAION recruited from 80 sites across 8 countries.

MAIN OUTCOME MEASURES

Ophthalmic features of NAION and cardiovascular risk factors.

METHODS

We evaluated demographics and clinical and ophthalmologic data, including best-corrected visual acuity (BCVA) and average visual field total deviation (TD), in affected eyes and cup-to-disc ratio in fellow eyes at enrollment. We report the prevalence (mean and standard devition, and median and interquartile range [IQR]) of ophthalmic features and cardiovascular risk factors, stratified by country, race, and sex. We corrected for multiple comparisons using Dunn's test with Bonferroni correction for continuous variables and chi-square testing with Holm-Bonferroni correction for categorical variables.

RESULTS

The study enrolled 500 men and 229 women with a median age of 60 and 61 years (P = 0.027), respectively. Participants were predominantly White (n = 570) and Asian (n = 149). The study eye BCVA was 71 characters (IQR, 53-84 characters; approximately 0.4 logarithm of the minimum angle of resolution), and the TD was -16.5 dB (IQR, -22.2 to -12.6 dB) for stimulus III and -15.7 dB (IQR, -20.8 to -10.9 dB) for stimulus V. The vertical and horizontal cup-to-disc ratio was 0.1 (IQR, 0.1-0.3) for unaffected fellow eyes. The prevalence of cardiovascular risk factors varied among countries. The most notable differences were in the baseline comorbidities and ophthalmologic features, which differed between Asian and White races. Men and women differed with respect to a few clinically meaningful features.

CONCLUSIONS

The cardiovascular risk factors in the NAION cohort varied among the 7 countries, race, and sex, but were not typically more prevalent than in the general population. Ophthalmic features, typical of NAION, generally were consistent across countries, race, and sex, except for worse BCVA and TD in China. Men have a frequency of NAION twice that of women. Having a small cup-to-disc ratio in the fellow eye was the most prevalent risk factor across all demographics. This study suggests that factors, not yet identified, may contribute to the development of NAION.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Insights into Ocular Emergencies: case Series on Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION) Secondary to Acute Angle Closure Glaucoma

This case series aims to report the manifestation of acute secondary optic neuropathy attributed to optic nerve injury associated with a singular episode of markedly elevated intraocular pressure (IOP) during an acute glaucoma attack. The correlation between acute primary angle-closure (APAC) and non-arteritic anterior ischemic optic neuropathy (NAION) remains uncertain within the context of current knowledge. Definitive conclusions regarding the causal relationship between APAC and NAION or their mutual influence cannot be established based on the current evidence. The association between these conditions is recognized as a potential link, and comprehensive research is imperative to elucidate their interrelationship thoroughly. This case series emphasizes the importance of promptly addressing acute optic nerve injury and neuropathy associated with elevated intraocular pressure (IOP) in patients with crowded disc anatomical risk factors. It underscores the need for proactive interventions to prevent irreversible damage, highlighting the infrequent yet vision-compromising occurrence of non-arteritic anterior ischemic optic neuropathy (NAION) in acute primary angle-closure (APAC).

Peripapillary hyperreflective ovoid mass-like structures: multimodal imaging and associated diseases

Growing evidence has demonstrated that peripapillary hyperreflective ovoid mass-like structures (PHOMS) are novel structures rather than a subtype of optic disc drusen. They correspond to the laterally bulging herniation of optic nerve fibers and are believed to be the marker of axoplasmic stasis. PHOMS present in a broad spectrum of diseases, including optic disc drusen, tilted disc syndrome, papilloedema, multiple sclerosis, non-arteritic anterior ischemic optic neuropathy, optic neuritis, Leber hereditary optic neuropathy, and so on. We focus on the multimodal imaging features, pathophysiological mechanisms of PHOMS, and their association with multiple diseases and healthy people in this review to deepen the ophthalmologists' understanding of PHOMS. Additionally, we provide some new directions for future research.

Prevalence and Distribution of Macular Fluid with Central Retinal Artery Occlusion and Anterior Ischemic Optic Neuropathy

Purpose

To examine the prevalence and distribution of fluid within a cohort of eyes with acute central retinal artery occlusion (CRAO) and non-arteritic anterior ischemic optic neuropathy (AION) using optical coherence tomography (OCT).

Methods

A retrospective analysis of patient records and OCT imaging. Patients presenting with acute CRAO or AION who had available macular OCT imaging and no co-morbidities known to cause macular fluid were included in the analysis. Baseline characteristics, visual acuity (VA), and fluid presence and distribution among the retinal layers were recorded.

Results

In the 16 eyes with acute CRAO, fluid was noted in 5 eyes (31%), which was mainly subretinal (3 eyes) or intraretinal located within the outer retinal layers (3 eyes). Only one eye had inner retinal cysts. Of the 11 eyes with acute AION, fluid was present in 8 eyes (73%). Subretinal fluid was noted in 4 eyes and extended to the foveal area in 3 of them, and outer retinal versus inner retinal cysts were noted in 6 versus 3 eyes, respectively. None of the eyes showed hard exudate deposition. In the small subset of eyes with CRAO and macular fluid that were followed-up, VA improved, while in eyes with AION, VA remained stable.

Conclusion

Macular fluid on OCT is not an uncommon feature of acute CRAO and AION and is mainly distributed within the outer retinal layers or subretinal space. Fluid is an understudied feature of retinal and optic nerve head infarction and may have a role in predicting neuronal damage extent and visual outcome.

Papillary vitreous detachment as a possible accomplice in non-arteritic anterior ischaemic optic neuropathy

AIM

To evaluate the role of papillary vitreous detachment in the pathogenesis of non-arteritic anterior ischaemic optic neuropathy (NAION) by comparing the features of vitreopapillary interface between NAION patients and normal individuals.

METHODS

This study included 22 acute NAION patients (25 eyes), 21 non-acute NAION patients (23 eyes) and 23 normal individuals (34 eyes). All study participants underwent swept-source optical coherence tomography to assess the vitreopapillary interface, peripapillary wrinkles and peripapillary superficial vessel protrusion. The statistical correlations between peripapillary superficial vessel protrusion measurements and NAION were analysed. Two NAION patients underwent standard pars plana vitrectomy.

RESULTS

Incomplete papillary vitreous detachment was noted in all acute NAION patients. The prevalence of peripapillary wrinkles was 68% (17/25), 30% (7/23) and 0% (0/34), and the prevalence of peripapillary superficial vessel protrusion was 44% (11/25), 91% (21/23) and 0% (0/34) in the acute, non-acute NAION and control groups, respectively. The prevalence of peripapillary superficial vessel protrusion was 88.9% in the eyes without retinal nerve fibre layer thinning. Furthermore, the number of peripapillary superficial vessel protrusions in the superior quadrant was significantly higher than that in the other quadrants in eyes with NAION, consistent with the more damaged visual field defect regions. Peripapillary wrinkles and visual field defects in two patients with NAION were significantly attenuated within 1 week and 1 month after the release of vitreous connections, respectively.

CONCLUSION

Peripapillary wrinkles and superficial vessel protrusion may be signs of papillary vitreous detachment-related traction in NAION. Papillary vitreous detachment may play an important role in NAION pathogenesis.

Visual outcome of various dose of glucocorticoids treatment in nonarteritic anterior ischemic optic neuropathy- a retrospective analysis

BACKGROUND AND PURPOSE

The objective of this investigation was to assess the therapeutic efficacy of distinct glucocorticoid therapy dosages in the management of acute nonarteritic anterior ischemic optic neuropathy (NAION).

MATERIALS AND METHODS

This retrospective, unmasked, and non-randomized study included a total of 85 patients. The patients were categorized into four groups: Group 1 (control) consisted of 15 patients who did not receive glucocorticoids, Group 2 included 16 patients administered with oral prednisone at a dosage of 1 mg/kg/d for 14 days, Group 3 comprised 30 patients who received 250 units of methylprednisolone once daily for 3 days, followed by oral prednisone at a dosage of 1 mg/kg/d for 11 days, and Group 4 encompassed 24 patients who received 500 units of methylprednisolone once daily for 3 days, followed by oral prednisone at a dosage of 1 mg/kg/d for 11 days. The best-corrected visual acuity (BCVA) was assessed at baseline and the final follow-up (> 7 days post-treatment). The changes in visual acuity between baseline and the 7-14 day follow-up, as well as between baseline and the concluding appraisal, were employed as metrics for assessing the extent of visual enhancement.

RESULTS

No significant differences were noted in the final visual outcomes or in the changes between final visual acuity and baseline across the four groups. In Group 1 (control), the best-corrected visual acuity (BCVA) remained unchanged during final follow-ups compared to baseline. Conversely, the intervention groups exhibited statistically significant enhancements in BCVA during final follow-up (p = 0.012, p = 0.03, and p = 0.009 for Group 2, Group 3, and Group 4, respectively) when compared to baseline. During the 7-14 day follow-up, there was a significant difference in the changes between baseline BCVA and follow-up BCVA across the groups (p = 0.035). Go a step further by Bonferroni correction for multiple comparisons, group 4 showed a greater change in vision compared with group1 (p = 0.045).

CONCLUSION

Our study on acute nonarteritic anterior ischemic optic neuropathy (NAION) showed no significant final visual outcome differences. Nevertheless, Groups 2, 3, and 4 demonstrated improved best-corrected visual acuity (BCVA) during the final follow-up. Notably, a 500-unit dose of methylprednisolone resulted in short-term BCVA enhancement. This suggests potential consideration of 500 units of methylprednisolone for short-term NAION vision improvement, despite its limited long-term impact.

Perioperative Blindness in Spine Surgery: A Scoping Literature Review

Perioperative vision loss (POVL) is a devastating surgical complication that impacts both the recovery from surgery and quality of life, most commonly occurring after spine surgery. With rates of spine surgery dramatically increasing, the prevalence of POVL will increase proportionately. This scoping review aims to aggregate the literature pertinent to POVL in spine surgery and consolidate recommendations and preventative measures to reduce the risk of POVL. There are several causes of POVL, and the main contribution following spine surgery is ischemic optic neuropathy (ION). Vision loss often manifests immediately following surgery and is irreversible and severe. Diffusion weighted imaging has recently surfaced as a diagnostic tool to identify ION. There are no effective treatments; therefore, risk stratification for counseling and prevention are vital. Patients undergoing prone surgery of long duration and/or with significant expected blood loss are at greatest risk. Future research is necessary to develop effective treatments.

Nonarteritic anterior ischemic optic neuropathy and incidence of Parkinson's disease based on a nationwide population based study

This study aimed to investigate the association between nonarteritic anterior ischemic optic neuropathy (NAION) and Parkinson's disease (PD) using a retrospective, nationwide, population-based cohort in South Korea. This study utilized data from the Korean National Health Insurance database, including 43,960 NAION patients and 219,800 age- and sex-matched controls. Cox proportional hazards regression models were used to assess the risk of developing PD in the NAION group compared to the control group after adjusting for various confounding factors. Subgroup analyses were conducted based on sex, age, and comorbidities. The incidence rate of PD was higher in the NAION group (1.326 per 1000 person-years) than in the control group (0.859 per 1000 person-years). After adjusting for confounding factors, the risk of developing PD was significantly higher in the NAION group (adjusted hazard ratio [aHR] 1.516, 95% confidence interval [CI] 1.300-1.769). Subgroup analyses did not reveal a significant difference in the risk of PD development based on sex, age, or comorbidities. This retrospective, nationwide, population-based cohort study revealed a significant association between NAION and an increased risk of developing PD in a South Korean population. The incidence rate of PD was observed to be higher in individuals diagnosed with NAION than in age- and sex-matched controls even after adjusting for potential confounding variables, with the risk being approximately 51.6% higher in the NAION group. Further research is necessary to elucidate the underlying pathophysiological mechanisms linking NAION to PD and to determine whether similar associations exist in other ethnic and geographical populations.

NAION or not NAION? A literature review of pathogenesis and differential diagnosis of anterior ischaemic optic neuropathies

PURPOSE

To offer a comprehensive review of the available data regarding non-arteritic anterior ischaemic optic neuropathy and its phenocopies, focusing on the current evidence to support the different existing aetiopathogenic hypotheses for the development of these conditions.

CONCLUSIONS AND IMPORTANCE

Due to the limited array of responses of the neural tissue and other retinal structures, different aetiopathogenic mechanisms may result in a similar clinical picture. Moreover, when the insult occurs within a confined space, such as the optic nerve or the optic nerve head, in which different tissues (neural, glial, vascular) are highly interconnected and packed together, determining the primary noxa can be challenging and may lead to misdiagnosis. Anterior ischaemic optic neuropathy is a condition most clinicians will face during their everyday work, and it is important to correctly differentiate among resembling pathologies affecting the optic nerve to avoid unnecessary diagnostic procedures. Combining a good clinical history and multimodal imaging can assist diagnosis in most cases. The key remains to combine demographic data (e.g. age), with ophthalmic data (e.g. refractive error), systemic data (e.g. comorbidities and medication), imaging data (e.g. retinal OCT) with topographic signs (e.g. focal neurology).

METHODOLOGY

Papers relevant for this work were obtained from the MEDLINE and Embase databases by using the PubMed search engine. One author (MPMG) performed the search and selected only publications with relevant information about the aetiology, pathogenic mechanisms, risk factors as well as clinical characteristics of phenocopies (such as vitreopapillary traction, intrapapillary haemorrhage with adjacent peripapillary subretinal haemorrhage or diabetic papillopathy) of non-arteritic anterior ischaemic optic neuropathy (NAION). The terms "non-arteritic ischaemic optic neuropathy/NAION", "vitreopapillary traction", "vitreopapillary traction AND non-arteritic ischaemic optic neuropathy/NAION", "posterior vitreous detachment AND non-arteritic ischaemic optic neuropathy/NAION", "central retinal vein occlusion AND non-arteritic ischaemic optic neuropathy/NAION", "disc oedema/disc oedema", "diabetes mellitus AND non-arteritic ischaemic optic neuropathy/NAION" and "diabetic papillopathy" were searched on PubMed. From each of these searches, publications were selected based on their title, obtaining a total of 115 papers. All papers not written in English were then excluded, and those whose abstracts were not deemed relevant for our review, according to the aforementioned criteria. Subsequent scrutiny of the main text of the remaining publications led us (MPMG, AP, ZS) to include references which had not been selected during our first search, as their titles did not contain the previously mentioned MeSH terms, due to their significantly relevant contents for our work. A total of 62 publications were finally consulted for our review. The literature review was last updated on 24-Aug-2022.

Synergistic Protection of Retinal Ganglion Cells (RGCs) by SARM1 Inactivation with CNTF in a Rodent Model of Nonarteritic Anterior Ischemic Optic Neuropathy

We evaluated whether inhibiting sterile alpha and (Toll/interleukin receptor (TIR)) motif-containing 1 (SARM1) activity protects retinal ganglion cells (RGCs) following ischemic axonopathy (rodent nonarteritic anterior ischemic optic neuropathy: rNAION) by itself and combined with ciliary neurotrophic factor (CNTF). Genetically modified SARM1(-) rats were rNAION-induced in one eye and compared against equivalently induced wild-type animals of the same background. Optic nerve (ON) diameters were quantified using optical coherence tomography (SD-OCT). RGCs were quantified 30 d post-induction using retinal stereology for Brn3a(+) nuclei. ON sections were analyzed by TEM and immunohistochemistry. SARM1(-)(-) and WT animals were then bilaterally sequentially rNAION-induced. One eye received intravitreal vehicle injection following induction; the contralateral side received CNTF and was analyzed 30 d post-induction. Inhibiting SARM1 activity suppressed axonal collapse following ischemic axonopathy. SARM1(-) animals significantly reduced RGC loss, compared with WT animals (49.4 ± 6.8% RGC loss in SARM1(-) vs. 63.6 ± 3.2% sem RGC loss in WT; Mann-Whitney one-tailed U-test, (p = 0.049)). IVT-CNTF treatment vs. IVT-vehicle in SARM1(-) animals further reduced RGC loss by 24% at 30 d post-induction, but CNTF did not, by itself, improve long-term RGC survival in WT animals compared with vehicle (Mann-Whitney one-tailed t-test; p = 0.033). While inhibiting SARM1 activity is itself neuroprotective, combining SARM1 inhibition and CNTF treatment generated a long-term, synergistic neuroprotective effect in ischemic neuropathy. Combinatorial treatments for NAION utilizing independent neuroprotective mechanisms may thus provide a greater effect than individual treatment modalities.

The Occurrence of Intraretinal and Subretinal Fluid in Anterior Ischemic Optic Neuropathy: Pathogenesis, Prognosis, and Treatment

PURPOSE

To describe the frequency and characteristics of intraretinal and subretinal fluid in nonarteritic anterior ischemic optic neuropathy (NAAION) and to assess the influence on the visual deficit and optic nerve fiber/ganglion cell loss.

DESIGN

A retrospective, single-center study.

PARTICIPANTS

Thirty-two patients with NAAION referred to our Neuro-ophthalmology Department between 2014 and 2021.

METHODS

The study was carried out at the University Hospital of Liège, Belgium. For participants in whom subretinal fluid was identified on standard OCT (Carl Zeiss Meditec) an additional macular OCT (Spectralis Heidelberg) had been performed. The pattern and the maximal height of the retinal fluid were determined manually, and thicknesses of retinal layers were obtained using the OCT protocol analysis.

RESULTS

The mean age of the cohort was 60 years (standard deviation, ±12.5; range, 22-88 years), and 65.6% were male. In the 21 eyes (46.7%) in which retinal fluid was observed, macular OCT findings were categorized according to fluid localization: 19 cases had parafoveal fluid (of whom 9 also had subfoveal fluid). One patient had subfoveal fluid alone, and 1 patient had peripapillary subretinal fluid alone. Specific patterns of optic disc (OD) swelling were associated with the occurrence and distribution of retinal edema. Visual acuity, visual field loss, and foveal thresholds were stable over the period of observation (P = 0.74, P = 0.42, and P = 0.36, respectively). No difference was found in visual function at 6 months between patients with retinal fluid treated (n = 10) or not treated (n = 11) with corticosteroids (visual acuity, P = 0.13; foveal threshold, P = 0.59; mean deviation, P = 0.66).

CONCLUSIONS

Subretinal fluid is found in a high proportion of cases of NAAION. Visual function remained largely stable from presentation in this cohort. Corticosteroid intake at presentation did not influence visual recovery or timing of the resorption of tissue edema. Our findings do not support treatment of NAAION with corticosteroids with or without evidence of subretinal fluid acutely. With regard to pathogenesis, we propose that the volume of transudate generated at the OD is the critical factor rather than dysfunction of retinal mechanisms subserving reabsorption.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Non-arteritic anterior ischaemic optic neuropathy and obstructive sleep apnoea

Anterior ischaemic optic neuropathies (AIONs) are a common cause of permanent visual loss in the elderly population. The non-arteritic subtype has been intensively studied. While systemic associations such as hypertension and diabetes mellitus are commonly recognized and treated, others such as obstructive sleep apnoea (OSA) are largely overlooked in daily practice. A 60-year-old man who gave no history of any systemic illness presented to us 1 week following an uneventful cataract surgery with posterior chamber intraocular lens implantation in his right eye. The surgery was performed elsewhere by an eye-healthcare professional where the patient presented primarily with a history of progressively worsening diminution of vision in the same eye for 5 days and was diagnosed with a senile cataract. The postoperative visual gain was unsatisfactory; hence he sought another opinion. A diagnosis of non-arteritic AION (NAION) was established. Systemic evaluation revealed elevated diastolic blood pressure, dyslipidaemia and severe OSA. Prompt treatment with systemic steroids and simultaneous management of the accompanying systemic morbid conditions saved some useful vision in the affected eye. This also prevented involvement of the fellow unaffected eye. A comprehensive ocular examination with emphasis on systemic evaluation of the patient for coexisting illness is imperative before proceeding with any medical or surgical intervention. OSA is a definitive risk factor for the development of NAION, though it remains underdiagnosed and untreated. Cataract surgery has been shown to worsen underlying NAION. Systemic stabilization averts potentially blinding sequel in the unaffected eye of these patients.

Retinal Pigment Epithelial Tears after Ex-PRESS Filtration Surgery in a Glaucoma Patient with a History of Ischemic Optic Neuropathy

Background

To describe a case of retinal pigment epithelial tears (RPE tears) and serous retinal detachment (SRD) after Ex-PRESS filtration surgery for primary open-angle glaucoma (POAG) combined with ischemic optic neuropathy. Case Presentation. This case report involved a 69-year-old woman who underwent Ex-PRESS filtration surgery for right POAG. She had a history of systemic arteriosclerotic disease and subacute progressive visual field loss due to suspected ischemic optic neuropathy in her right eye. The right preoperative visual acuity was 0.7, and intraocular pressure (IOP) was 19 mmHg with maximum glaucoma eye drops. RPE detachment was not observed in the fundus. On day 9 after surgery, the IOP was 6 mmHg, and mild choroidal detachment was observed. On day 13, although IOP remained almost unchanged at 7 mmHg, bullous SRD was observed in the inferior retina, including the macula, and RPE tears were observed along the superior arcade vessel. While subretinal fluid gradually decreased with increasing IOP, tractional retinal folds persisted along the superior arcade, accompanied by macular degeneration.

Conclusion

We experienced a case of RPE tears after Ex-PRESS filtration surgery. In addition to choroidal detachment in the setting of hypotony, a pathologic condition causing structural fragility of the RPE layer may contribute to the development of RPE tears.

Vascular Changes in the Macula of Patients after Previous Episodes of Vision Loss Due to Leber Hereditary Optic Neuropathy and Non-Arteritic Ischemic Optic Neuropathy

PURPOSE

to assess the vasculature and thickness of the macula using OCT-A in patients who had experienced a previous episode of Leber hereditary optic neuropathy (LHON) or non-arteritic anterior ischemic optic neuropathy (NA-AION).

METHODS

twelve eyes with chronic LHON and ten eyes with chronic NA-AION and eight NA-AION fellow eyes were examined using OCT-A. The vessel density was measured in the superficial and deep plexus of the retina. Moreover, the full and inner thicknesses of the retina were assessed.

RESULTS

There were significant differences in all sectors between the groups in regard to the superficial vessel density and the inner and full thicknesses of the retina. The nasal sector of the macular superficial vessel density was affected more in LHON than in NA-AION; the same with the temporal sector of the retinal thickness. There were no significant differences between the groups in the deep vessel plexus. There were no significant differences between the vasculature of the inferior and superior hemifields of the macula in all groups and no correlation with the visual function.

CONCLUSIONS

The superficial perfusion and structure of the macula assessed with OCT-A are affected both in chronic LHON and NA-AION, but more in LHON eyes, especially in the nasal and temporal sectors.

Evaluation of Retinal Nerve Fiber Layer and Macular Ganglion Cell Layer Thickness in Relation to Optic Disc Size

To investigate whether optic nerve ganglion cell amount is dependent on optic disc size, this trial analyzes the correlation between Bruch's membrane opening area (BMOA) and retinal nerve fiber layer (RNFL) thickness as well as macular ganglion cell layer thickness (mGCLT). Additionally, differences in RNFL and mGCLT regarding various optic disc cohorts are evaluated. This retrospective, monocentric study included 501 healthy eyes of 287 patients from the University Hospital Münster, Germany, who received macular and optic disc optical coherence tomography (OCT) scans. Rank correlation coefficients for clustered data were calculated to investigate the relationship between BMOA and thickness values of respective retinal layers. Furthermore, these values were compared between different optic disc groups based on BMOA. Statistical analysis did not reveal a significant correlation between BMOA and RNFL thickness, nor between BMOA and mGCLT. However, groupwise analysis showed global RNFL to be significantly decreased in small and large discs in comparison to medium discs. This was not observed for global mGCLT. This study extends existing normative data for mGCLT taking optic disc size into account. While the ganglion cell amount represented by the RNFL and mGCLT seemed independent of BMOA, mGCLT was superior to global RNFL in displaying optic nerve integrity in very small and very large optic discs.

Nonarteritic Anterior Ischemic Optic Neuropathy

Purpose

Microcystic macular edema (MME), also known as retrograde maculopathy (RM), is associated with severe optic atrophy because of a range of causes. However, similar changes have also been described in primary retinal pathology and the pathogenesis of MME is debated.

Design

A retrospective observational case series.

Participants

Patients with nonarteritic ischemic optic neuropathy.

Methods

A retrospective observational case series was performed at the University Hospital of Liège, Belgium. The medical records of patients who were referred to our Neuro-ophthalmology department with a diagnosis of nonarteritic anterior ischemic optic neuropathy (NA-AION), between 2014 and 2021, were reviewed.

Main Outcome Measures

Ganglion cell complex thickness, acute and chronic inner nuclear change.

Results

In a cohort of 34 patients (mean age: 60 ± 12.5 years; 65.6% men) with NA-AION, we identified a transient microcystic change in the inner nuclear layer (INL) associated with optic disc swelling in 19 eyes at presentation. This early change was associated with a transudate of intraretinal and subretinal fluid originating from the optic disc. Among patients who had shown this transient change 3 subsequently developed MME, which remained fixed during the period of observation (range, 12–34 months). No MME was observed in patients without an early INL transient change. Microcystic macular edema was observed in patients with severe ganglion cell complex thinning at 6 months: mean (± SD) loss in superior hemimacula (−28.2 ± 5.2 μm [−33.3%, range, −22.3 to −30.3 μm]) and in inferior hemimacula (−30.7 ± 5.6 μm [−31.0%, range, −24.3 to 34.8 μm]).

Conclusions

Our study has revealed 2 causes of INL cystic change in the same patients experiencing NA-AION, 1 reversible and the other likely permanent. This finding highlights the distinction between genuine edema related to transudation of fluid (in this case secondary to ischemic optic disc swelling) and the phenomenon observed in RM that is related to the degree of retinal nerve fiber layer/ganglion cell complex thinning. Cystic change in the INL is associated with severe optic atrophy (MME). However, similar changes have been described in retinal pathology and the pathogenesis of MME is debated.

Hormone Replacement Therapy and the Incidence of Nonarteritic Anterior Ischemic Optic Neuropathy: a Nationwide Population-Based Study (2009-2018)

PURPOSE

This study aimed to assess the association between hormone replacement therapy (HRT) and the prevalence of nonarteritic anterior ischemic optic neuropathy (NAION) in menopausal women using national data from the entire Korean population.

METHODS

The health screening data of 1,381,605 women between 40 and 90 years of age collected by the National Health Insurance Service (NHIS) of Korea between January 1, 2009, and December 31, 2018, were retrospectively reviewed. Before data analysis, the potential cofounders were adjusted for among all participants. Based on HRT use and its duration (classified into four groups), the hazard ratio (HR) and 95% confidence interval (CI) of NAION development were calculated via a Cox proportional hazards regression analysis using the nonuser group as a reference.

RESULTS

Overall, 7824 NAION diagnoses were made during the mean follow-up of 8.22 years (standard deviation: 1.09 years) in 1,381,605 post-menopausal women. NAION was more common in the HRT group than in the non-HRT group (HR [95% CI]: 1.268 [1.197-1.344]). Furthermore, the risk of NAION increased along with increased HRT duration (p < 0.0001). In the multivariate analysis, the adjusted HRs of the < 2-year HRT group, the 2-5-year HRT group, and the ≥ 5-year HRT group were 1.19 (95% CI: 1.10-1.28), 1.3 (95% CI: 1.17-1.45), and 1.473 (95% CI: 1.31-1.65), respectively. Compared to women younger than 65 years, the HR of HRT for NAION was significantly higher than that of women older than 65 years (p < 0.0001).

CONCLUSION

Our population-based cohort study found that HRT was significantly associated with increased incidence of NAION. The incidence of NAION also increased with the duration of HRT.

Comparison of optic disc head vascular density status between crowded and normal discs: An optical coherence tomography angiography study

BACKGROUND

To compare the optic disc capillary vascular status between crowded and normal optic discs using optical coherence tomography angiography (OCT-A).

METHODS

A total of 101 eyes were included in this cross-sectional, comparative study. Fifty-one eyes with crowded optic discs (Group 1) were compared with 50 eyes with normal discs (Group 2). Peripapillary and optic disc head capillary vascular density measurements were obtained quantitatively with OCT-A.

RESULTS

Mean ages were 46.2 ± 6.2 years in Group1 and 45.9 ± 6.0 years in Group2 (p=0.796).Vertical disc diameters were 1.52±0.2 mm in Group 1 and 1.61±0.16 mm in Group 2 (p=0.022) whereas horizontal disc diameters were 1.53±0.17 mm in Group 1 and 1.61±0.13 mm in Group 2(p˂0.014). OCT-A findings were as follows: radial peripapillary capillary, vascular density whole image measurements (%); 49.6 ± 2.3 in Group 1 and 49.1 ± 2.3 in Group 2 (p=0.292), peripapillary capillary density; 53.3 ± 2.8 in Group 1 and 52.6 ± 2.6 in Group 2 (p=0.176), inside disc measurements 52.4 (48.7-54.7) in Group 1 and 46.5 (42.6-49.6) in Group 2 (p˂0.001). RNFL was 118.2 ± 12.2 µm in Group 1 and 110.8 ± 11.4 µm in Group 2(p=0.002).

CONCLUSION

The vascular density of the disc circumference in individuals with healthy crowded optic discs is not different from those with normal discs. However, inside disc measurements differ between crowded and normal size discs. This finding suggests that when the disc size is reduced, the amount of vessels in it does not decrease in a way that correlates with the size. Therefore, the vascular structures are suitable for compression in the narrow optic nerve head.

Peripapillary and macular microvasculature features of non-arteritic anterior ischemic optic neuropathy

Purpose

The hallmark of non-arteritic anterior ischemic optic neuropathy (NAION) is vascular compromise to the anterior optic nerve and thinning of the retinal nerve fiber layer (RNFL) and secondary degeneration of the retinal ganglion cell body or thinning of the ganglion cell complex (GCC). This study investigates optical coherence tomography (OCT) and OCT Angiography (OCTA) changes in chronic NAION and identifies imaging biomarkers that best predict disease.

Methods

We performed a retrospective case-control study of 24 chronic NAION eyes (18 patients) and 70 control eyes (45 patients) to compare both whole-eye and regional OCT, OCTA, static perimetry measurements. OCT measurements were quantified automatically using commercial software, and OCTA was analyzed using custom MATLAB script with large vessel removal to measure 154 total parameters per eye.

Results

We confirmed that static perimetry mean deviation (MD) was significantly worse in chronic NAION (-13.53 ± 2.36) than control (-0.47 ± 0.72; P < 0.001) eyes, and NAION eyes had 31 μm thinner RNFL (control: 95.9 ± 25.8 μm; NAION: 64.5 ± 18.0, P < 0.001), and 21.8 μm thinner GCC compared with controls (control: 81.5 ± 4.4 μm; NAION: 59.7 ± 10.5, P < 0.001). Spearman correlation analysis of OCTA parameters reveal that vessel area density (VAD) and flux are highly correlated with visual field MD and OCT measurements. Hierarchical clustering two distinct groups (NAION and control), where standardized measurements of NAION eyes were generally lower than controls. Two-way mixed ANOVAs showed significant interaction between patient status (control and chronic NAION) and structure (optic disk and macula) for annulus VAD and flux values and mean RNFL and GCC thickness. Post-hoc tests showed this effect stems from lower peripapillary values in NAION compared to controls. Separate logistic regression models with LASSO regularization identified VAD and flux are one of the best OCTA parameters for predicting NAION.

Conclusion

Ischemic insult to the optic disk is more severe likely from primary degeneration of the affected peripapillary region while macula is affected by secondary retrograde degeneration and loss of retinal ganglion cells. In addition to OCT measurements, peripapillary and macular vascular parameters such as VAD and flux are good predictors of optic nerve and retinal changes in NAION.

MRI signs helpful in the differentiation of patients with anterior ischaemic optic neuropathy and optic neuritis

BACKGROUND/AIMS

The aim of this study was to identify specific MRI characteristics of anterior ischaemic optic neuropathy (AION) and optic neuritis (ON) that would aid in the differentiation between these two diagnoses.

METHODS

We retrospectively analysed a consecutive case series including all patients with an MRI study of brain and orbit and the clinical diagnosis of either ON or AION. We examined the scans for restricted diffusion of the optic nerve, optic sheath diameter, enhancement and location of enhancement of the optic nerve and distribution of the white matter lesions.

RESULTS

Fifty patients met the inclusion criteria. We found an accuracy of 0.98 for the discrimination between AION and ON based solely on parameters extracted from MRI data. Dominance analysis to determine the most influential parameters showed that the enhancement pattern of the optic nerve and distribution of the white matter lesions had the biggest impact on the classification and led to a discrimination accuracy of 0.9 when used alone.

CONCLUSION

In patients with an inconclusive clinical diagnosis, optic nerve enhancement pattern and distribution of white matter lesions can aid in the diagnosis and differentiation between AION and ON. Diffusion-weighted imaging did not add significant information to the diagnosis or help to differentiate between the two conditions.

Peripapillary hyperreflective ovoid mass-like structures: Multimodal imaging-A review

Peripapillary hyperreflective ovoid mass-like structures (PHOMS) are a laterally bulging herniation of distended axons into the peripapillary region above the level of Bruch's membrane opening. Increased use of enhanced depth imaging-optical coherence tomography (EDI-OCT) in our evaluation of the optic nerve head (ONH) and greater recognition of the vast range of optic nerve pathologies with which PHOMS is associated provides convincing evidence that PHOMS is not just buried optic disc drusen (ODD) as previously described. The frequent coexistence of PHOMS with ODD, papilloedema, anterior ischaemic optic neuropathy, tilted optic disc syndrome, inflammatory demyelinating disorders and other diseases associated with axoplasmic stasis provides insight into its underlying pathophysiology. The present review will discuss the role of key imaging modalities in the differential diagnosis of PHOMS, explore the current literature on the relationship between PHOMS and common neuro-ophthalmic conditions, and highlight the gaps in our knowledge, with respect to disease classification and prognosis, to pave the way for future directions of research.

Peripapillary Microvascular and Structural Parameters in Atrophic Nonarteritic Anterior Ischemic Optic Neuropathy and Their Unaffected Fellow Eyes

BACKGROUND

This cross-sectional study aimed to evaluate the peripapillary vessel density (VD), peripapillary retinal nerve fiber layer (RNFL) thickness values of eyes with atrophic nonarteritic anterior ischemic optic neuropathy (NAION), and unaffected fellow eyes.

METHODS

Peripapillary VDs and RNFL thicknesses in the peripapillary region and 4 sectors (superior, inferior, nasal, and temporal) were evaluated using optical coherence tomography angiography among 19 atrophic NAION eyes, 19 unaffected fellow eyes, and 22 age-matched and sex-matched healthy controls.

RESULTS

The NAION eyes had lower peripapillary VD and RNFL thickness values in all areas compared with both the fellow and the healthy control eyes ( P < 0.001 for all). The fellow eyes also demonstrated lower peripapillary VD values ( P = 0.02) despite similar RNFL thickness values ( P = 0.99) in the peripapillary region compared with the age-matched and sex-matched healthy controls. The peripapillary RNFL thickness values significantly correlated with peripapillary VD values in both NAION and fellow eyes.

CONCLUSIONS

Diminished RNFL thickness and peripapillary VD values were observed in atrophic NAION eyes. In addition, a tendency for a lower peripapillary VD despite similar RNFL thickness values in the fellow eyes may indicate the potential vascular risk factors for NAION.

Perioperative Care of the Patient with Eye Pathologies Undergoing Nonocular Surgery

The authors reviewed perioperative ocular complications and implications of ocular diseases during nonocular surgeries. Exposure keratopathy, the most common perioperative eye injury, is preventable. Ischemic optic neuropathy, the leading cause of perioperative blindness, has well-defined risk factors. The incidence of ischemic optic neuropathy after spine fusion, but not cardiac surgery, has been decreasing. Central retinal artery occlusion during spine fusion surgery can be prevented by protecting eyes from compression. Perioperative acute angle closure glaucoma is a vision-threatening emergency that can be successfully treated by rapid reduction of elevated intraocular pressure. Differential diagnoses of visual dysfunction in the perioperative period and treatments are detailed. Although glaucoma is increasingly prevalent and often questions arise concerning perioperative anesthetic management, evidence-based recommendations to guide safe anesthesia care in patients with glaucoma are currently lacking. Patients with low vision present challenges to the anesthesia provider that are becoming more common as the population ages.

Treatment of nonarteritic anterior ischemic optic neuropathy with an endothelin antagonist: ENDOTHELION (ENDOTHELin antagonist receptor in Ischemic Optic Neuropathy)—a multicentre randomised controlled trial protocol

Background

Nonarteritic anterior ischemic optic neuropathy (NAAION) is a major cause of blindness in individuals over 50 years of age, with no available effective treatment. The oral dual endothelin receptor antagonist, bosentan, increases retinal optic nerve head blood flow in healthy humans and glaucoma patients. The objective of this trial is to assess the efficacy of bosentan administered at the acute stage in improving outcomes in NAAION patients.

Methods

ENDOTHELION (ENDOTHELin antagonist receptor in Ischemic Optic Neuropathy) is a phase III, interventional, prospective, multicentre, placebo-controlled randomised double-blind clinical trial. The primary outcome is change in the visual field mean deviation (MD) at 3 months (Humphrey 30-2 SITA standard programme). Secondary outcomes include MD and visual acuity changes up to 24 months, changes in peripapillary retinal nerve fibre and macular ganglion cell layer thickness in the affected eye, as measured by optical coherence tomography, rate of NAAION bilateralisation at 2 years, and quality-of-life. Patients over 50 years of age presenting with typical NAAION of recent onset (less than 21 days) are randomly assigned to either 125 mg oral bosentan or placebo, twice a day, during 8 weeks. Besides visits during the treatment phase, patients attend follow-up visits at 2, 3, 6, 12 and 24 months. The inclusion of patients began in August 2015 at five French University hospital ophthalmology departments and two specialised ophthalmology centres. It is planned to include 86 patients in this trial. To date we have included 72 patients and 49 have completed the full follow-up process.

Discussion

An endothelin receptor antagonist is a potential approach to improving the anatomical and functional prognosis of patients with NAAION. This multicentre double-blind randomised controlled trial is an opportunity to assess (1) the effect of bosentan on the structure and function of the optic nerve in NAAION, at 3 months, (2) the effect of bosentan on the bilateralisation rate at 24 months and (3) the tolerance profile of bosentan in this population.

Trial registration

ClinicalTrials.gov NCT02377271. Registered on March 3, 2015.

Ischemic Optic Neuropathies: Current Concepts

Ischemic optic neuropathy (ION) is the term ascribed to optic nerve disease that is the result of a transient or permanent interruption of the blood supply to any portion of the optic nerve. Anterior ischemic optic neuropathy (AION) refers to ischemia of the optic nerve head, whereas posterior ischemic optic neuropathy (PION) indicates ischemia of the posterior optic nerve. IONs are primarily classified as arteritic ION and non-arteritic ION. A subset of ION that occurs around the time of surgery is termed peri-operative ION. These phenomena will be discussed as distinct entities.

Non-arteritic anterior ischemic optic neuropathy in COVID-19 infection – A case report

Purpose

To report a case of a non-arteritic anterior ischemic optic neuropathy (NAION) in the setting of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Observations

A 60-year-old healthy female without any risk factors for vasculopathy, presented with an acute painless diminution of vision noticed in the lower half of the visual field in the left eye. She was diagnosed with NAION in the setting of a recent SARS-CoV-2 infection.

Conclusions and importance

The purpose of this case report is to supplement our knowledge about the neuro-ophthalmological complications of COVID-19 in the form of NAION which might occur even in the early stages of the infection.

A Potential Role of Acute Choroidal Expansion in Nonarteritic Anterior Ischemic Optic Neuropathy

Purpose

Nonarteritic anterior ischemic optic neuropathy (NAION) has been associated with a thickened choroid at the optic nerve head (ONH). Here, we use computational modeling to better understand how choroidal expansion and choroidal geometry influence tissue deformation within the ONH relative to intraocular pressure (IOP) and intracranial pressure (ICP) effects.

Methods

Using a model of the posterior eye that included the sclera, peripapillary sclera, annular ring, pia mater, dura mater, neural tissues, Bruch's membrane, choroid, and lamina cribrosa, we examined how varying material properties of ocular tissues influenced ONH deformations under physiological and supra-physiological, or “pathological,” conditions. We considered choroidal expansion (c. 35 µL of expansion), elevated IOP (30 mm Hg), and elevated ICP (20 mm Hg), and calculated peak strains in the ONH relative to a baseline condition representing an individual in the upright position.

Results

Supra-physiological choroidal expansion had the largest impact on strains in the prelaminar neural tissue. In addition, compared to a tapered choroid, a “blunt” choroid insertion at the ONH resulted in higher strains. Elevated IOP and ICP caused the highest strains within the lamina cribrosa and retrolaminar neural tissue, respectively.

Conclusions

Acute choroidal expansion caused large deformations of the ONH and these deformations were impacted by choroid geometry. These results are consistent with the concept that compartment syndrome due to the choroid geometry and/or expansion at the ONH contributes to NAION. Prolonged deformations due to supra-physiological loading may induce a mechanobiological response or ischemia, highlighting the potential impact of choroidal expansion on biomechanical strains in the ONH.

The Protective Effects of n-Butylidenephthalide on Retinal Ganglion Cells during Ischemic Injury

Clinically, acute ischemic symptoms in the eyes are one of the main causes of vision loss, with the associated inflammatory response and oxidative stress being the key factors that cause injury. Nonarteritic anterior ischemic optic neuropathy (NAION) is the most common type of ischemic optic neuropathy (ION); however, there are still no effective or safe treatment options to date. In this study, we investigated the neuroprotective effects of n-butylidenephthalide (BP) treatment in an experimental NAION rodent model (rAION). BP (10 mg/kg) or PBS (control group) were administered on seven consecutive days in the rAION model. Rats were evaluated for visual function by flash visual evoked potentials (FVEPs) at 4 weeks after NAION induction. The retina and optic nerve were removed for histological examination after the rats were euthanized. The molecular machinery of BP treatment in the rAION model was analyzed using Western blotting. We discovered that BP effectively improves retinal ganglion cell survival rates by preventing apoptotic processes after AION induction and reducing the inflammatory response through which blood-borne macrophages infiltrate the optic nerve. In addition, BP significantly preserved the integrity of the myelin sheath in the rAION model, demonstrating that BP can prevent the development of demyelination. Our immunoblotting results revealed the molecular mechanism through which BP mitigates the neuroinflammatory response through inhibition of the NF-κB signaling pathway. Taken together, these results demonstrate that BP can be used as an exceptional neuroprotective agent for ischemic injury.

A Phase 1 study of GDC-0134, a dual leucine zipper kinase inhibitor, in ALS

Objective

Dual leucine zipper kinase (DLK), which regulates the c‐Jun N‐terminal kinase pathway involved in axon degeneration and apoptosis following neuronal injury, is a potential therapeutic target in amyotrophic lateral sclerosis (ALS). This first‐in‐human study investigated safety, tolerability, and pharmacokinetics (PK) of oral GDC‐0134, a small‐molecule DLK inhibitor. Plasma neurofilament light chain (NFL) levels were explored in GDC‐0134‐treated ALS patients and DLK conditional knockout (cKO) mice.

Methods

The study included placebo‐controlled, single and multiple ascending‐dose (SAD; MAD) stages, and an open‐label safety expansion (OLE) with adaptive dosing for up to 48 weeks.

Results

Forty‐nine patients were enrolled. GDC‐0134 (up to 1200 mg daily) was well tolerated in the SAD and MAD stages, with no serious adverse events (SAEs). In the OLE, three study drug‐related SAEs occurred: thrombocytopenia, dysesthesia (both Grade 3), and optic ischemic neuropathy (Grade 4); Grade ≤2 sensory neurological AEs led to dose reductions/discontinuations. GDC‐0134 exposure was dose‐proportional (median half‐life = 84 h). Patients showed GDC‐0134 exposure‐dependent plasma NFL elevations; DLK cKO mice also exhibited plasma NFL compared to wild‐type littermates.

Interpretation

This trial characterized GDC‐0134 safety and PK, but no adequately tolerated dose was identified. NFL elevations in GDC‐0134‐treated patients and DLK cKO mice raised questions about interpretation of biomarkers affected by both disease and on‐target drug effects. The safety profile of GDC‐0134 was considered unacceptable and led to discontinuation of further drug development for ALS. Further work is necessary to understand relationships between neuroprotective and potentially therapeutic effects of DLK knockout/inhibition and NFL changes in patients with ALS.

Optical Coherence Tomography Angiography Characteristics and Predictors of Visual Outcomes in Patients With Acute and Chronic Nonarteritic Anterior Ischemic Optic Neuropathy

BACKGROUND

To investigate the correlation between optical coherence tomography angiography (OCTA) characteristics and visual outcomes in patients with acute and chronic nonarteritic anterior ischemic optic neuropathy (NAION).

METHODS

We retrospectively reviewed clinical data and OCTA images of 26 eyes of 26 patients who had been diagnosed with unilateral NAION. OCTA images were acquired from 17 eyes at the acute stage and from 21 eyes at the chronic stage of NAION. We analyzed the peripapillary vessel density (VD) and macular VD in various layers of the retina and choroid for all images. Possible correlations between the OCTA parameters and visual outcomes were investigated.

RESULTS

Among the OCTA parameters for the acute stage of NAION, the temporal peripapillary VD was found to be positively correlated with final visual acuity and visual field with statistical significance (P = 0.039 and 0.009, respectively). In the chronic stage of NAION, both peripapillary and superficial macular VDs were positively correlated with visual outcomes. The nasal perifoveal VD in the superficial capillary plexus (SCP) also had a significant correlation with final visual acuity for both acute and chronic stages (the Spearman correlation coefficient = 0.565 and 0.685, respectively).

CONCLUSIONS

In patients with NAION, significant correlations were found between OCTA parameters and visual outcomes. The temporal peripapillary VD measured during the acute stage was a significant predictor of final visual outcomes. The decreased nasal perifoveal VD in the SCP was strongly associated with poor visual prognosis.

Transient Visual Loss in Young Females with Crowded Optic Discs: A Proposed Aetiology

I present four cases of transient visual loss (TVL) in young females with crowded optic discs. One patient had asymmetrical cup-to-disc ratios and only experienced TVL in the eye with the more crowded disc. I review the evidence for blood flow autoregulatory dysfunction within crowded optic discs in combination with reduced ocular perfusion pressure to propose a possible aetiology for both unilateral and bilateral TVL in young females with crowded optic discs.

Association Between Ischemic Optic Neuropathy and Inflammatory Bowel Disease: A Population-Based Cohort Study in Taiwan

Background: Ischemic optic neuropathy (ION) is a possible extraintestinal manifestation (EIM) of inflammatory bowel disease (IBD). We investigate the relation between IBD and ION and possible risk factors associated with their incidence.

Methods: Medical records were extracted from the National Health Insurance Research Database (NHIRD) from January 1, 2000, to December 31, 2013. The main outcome was ION development. Univariate and multivariate Cox regression analyses were performed.

Results: We enrolled 22,540 individuals (4,508 with IBD, 18,032 without). The cumulative risk of developing ION was significantly greater for patients with IBD vs. patients without (Kaplan–Meier survival curve, p = 0.009; log-rank test). Seven (5%) and five (0.03%) patients developed ION in the IBD and control groups, respectively. Patients with IBD were significantly more likely to develop ION than those without IBD [adjusted hazard ratio (HR) = 4.135; 95% confidence interval: 1.312–11.246, p = 0.01]. Possible risk factors of ION development were age 30–39 years, diabetes mellitus (DM), hypertension, ischemic heart disease (IHD), atherosclerosis, and higher Charlson comorbidity index revised (CCI_R) value.

Conclusion: Patients with IBD are at increased risk of subsequent ION development. Moreover, for patients with comorbidities, the risk of ION development is significantly higher in those with IBD than in those without.

Oxidative Stress in Optic Neuropathies

Increasing evidence indicates that changes in the redox system may contribute to the pathogenesis of multiple optic neuropathies. Optic neuropathies are characterized by the neurodegeneration of the inner-most retinal neurons, the retinal ganglion cells (RGCs), and their axons, which form the optic nerve. Often, optic neuropathies are asymptomatic until advanced stages, when visual impairment or blindness is unavoidable despite existing treatments. In this review, we describe systemic and, whenever possible, ocular redox dysregulations observed in patients with glaucoma, ischemic optic neuropathy, optic neuritis, hereditary optic neuropathies (i.e., Leber's hereditary optic neuropathy and autosomal dominant optic atrophy), nutritional and toxic optic neuropathies, and optic disc drusen. We discuss aspects related to anti/oxidative stress biomarkers that need further investigation and features related to study design that should be optimized to generate more valuable and comparable results. Understanding the role of oxidative stress in optic neuropathies can serve to develop therapeutic strategies directed at the redox system to arrest the neurodegenerative processes in the retina and RGCs and ultimately prevent vision loss.

The Effects of Two Nrf2 Activators, Bardoxolone Methyl and Omaveloxolone, on Retinal Ganglion Cell Survival during Ischemic Optic Neuropathy

Nonarteritic anterior ischemic optic neuropathy (NAION) is one of the most common acute optic neuropathies that affect the over 55-year-old population. NAION causes the loss of visual function, and it has no safe and effective therapy. Bardoxolone methyl (methyl 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oate; CDDO-Me; RTA 402) is a semisynthetic triterpenoid with effects against antioxidative stress and inflammation in neurodegeneration and kidney disease that activates the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. Moreover, RTA 402 is an FDA-approved compound for the treatment of solid tumors, lymphoid malignancies, melanoma, and chronic kidney disease. Omaveloxolone (RTA 408) is an activator of Nrf2 and an inhibitor of NFκB, possessing antioxidative and anti-inflammatory activities in mitochondrial bioenergetics. RTA 408 is also under clinical investigation for Friedreich ataxia (FA). In this study, a rodent anterior ischemic optic neuropathy (rAION) model induced by photothrombosis was used to examine the therapeutic effects of RTA 402 and RTA 408. Treatment with RTA402 results in antiapoptotic, antioxidative stress, anti-inflammatory, and myelin-preserving effects on retinal ganglion cell (RGC) survival and visual function via regulation of NQO1 and HO-1, reduced IL-6 and Iba1 expression in macrophages, and promoted microglial expression of TGF-β and Ym1 + 2 in the retina and optic nerve. However, these effects were not observed after RTA 408 treatment. Our results provide explicit evidence that RTA 402 modulates the Nrf2 and NFκB signaling pathways to protect RGCs from apoptosis and maintain the visual function in an rAION model. These findings indicate that RTA 402 may a potential therapeutic agent for ischemic optic neuropathy.

Carotid disease and retinal optical coherence tomography angiography parameters in patients with non-arteritic anterior ischemic optic neuropathy

PURPOSE

In order to analyze the data and retinal microvasculature for non-arteritic anterior ischemic optic neuropathy (NAION), patients were referred to have carotid Doppler ultrasound (CDU) from 2016 to 2020.

METHODS

In this case-control observational study, 30 NAION patients were evaluated with CDU. Twenty-two NAION patients (at least 3 months after the onset of symptoms) and 9 normal subjects underwent a complete ophthalmic examination including optical coherence tomography (OCT) and optical coherence tomography angiography (OCT-A). NAION eyes and fellow eyes were further divided into two groups based on the presence of carotid stenosis (CS). NAION patients with CS were termed "CS-NAION"; and those without CS were termed "NCS-NAION." Measurements of radial peripapillary capillary vessel density (RPC VD), ganglion cell complex (GCC), retinal nerve fiber layer (RNFL) thicknesses were compared among groups.

RESULTS

Fourteen of 30 NAION patients referred to have carotid Doppler were positive for CS with each one of such referrals having less than 50% stenosis. RNLF, GCC and RPC VDs were reduced in NAION patients' eyes, when compared to controls and the fellow eyes. RPC VD was significantly lower in the temporal-superior (P = 0.037) and the superior-temporal (P = 0.012) sectors of the NCS-NAION patients than in the CS-NAION patients. No significant differences were found between CS-fellow eyes and NCS-fellow eyes in terms of RPC VDs, RNLF or GCC.

CONCLUSION

Results of the study highlight the effect of the carotid artery stenosis on ocular perfusion pressure in the pathogenesis of NAION. More extensive studies are necessary.

Peripapillary vascular density in resolved non-arteritic anterior ischemic optic neuropathy: colocalization between structural and vascular parameters

INTRODUCTION/AIMS

Non-arteritic anterior ischemic optic neuropathy (NAION) is an acute infarction of the prelaminar anterior optic disc, resulting from the occlusion of posterior ciliary arteries. Here, we evaluated the correlation between structural and vascular features in a case of resolved NAION.

METHODS

Observational case report.

RESULTS

A 50-year-old male patient was referred at an Eye clinic due to an altitudinal visual field defect in the left eye, occurred 9 months before. Fundus examination was unremarkable, while structural SD-OCT reveals retinal nerve fiber layer (RNFL), ganglion cell complex (GCC) thinning associated with reduction of peripapillary vascular density at OCT Angiography.

DISCUSSION

We found a precise spatial correlation among RNFL and GCC thinning, peripapillary vascular reduction and visual field defects. This case demonstrates that OCTA represents a new, valid and non-invasive imaging technique in the diagnosis and follow-up of NAION, even after the resolution of the acute phase, in the absence of clinical signs at fundus examination.

Approaches to Potentiated Neuroprotective Treatment in the Rodent Model of Ischemic Optic Neuropathy

Nonarteritic anterior ischemic optic neuropathy (NAION) commonly causes sudden optic nerve (ON)-related vision loss. The rodent NAION model (rAION) closely resembles NAION in presentation and physiological responses. We identified early rAION-associated optic nerve head (ONH) inflammatory gene expression responses and the anti-inflammatory prostaglandin PGJ₂’s effects on those responses. We hypothesized that blocking pro-inflammatory prostaglandin (PGE₂) production by inhibiting monoacylglycerol lipase or cyclooxygenase activity and co-administering PGJ₂ would potentiate RGC survival following ischemic neuropathy. Deep sequencing was performed on vehicle- and PGJ₂-treated ONHs 3d post-rAION induction. Results were compared against responses from a retinal ischemia model. Animals were treated with PGJ₂ and MAGL inhibitor KML29, or PGJ₂ + COX inhibitor meloxicam. RGC survival was quantified by stereology. Tissue PG levels were quantified by ELISA. Gene expression was confirmed by qPCR. PGJ₂ treatment nonselectively reduced inflammatory gene expression post-rAION. KML29 did not reduce PGE₂ 1d post-induction and KML29 alone increased RGC loss after rAION. Combined treatments did not improve ONH edema and RGC survival better than reported with PGJ₂ alone. KML29′s failure to suppress PGE₂ ocular synthesis, despite its purported effects in other CNS tissues may result from alternative PG synthesis pathways. Neither KML29 nor meloxicam treatment significantly improved RGC survival compared with vehicle. While exogenous PGJ₂ has been shown to be neuroprotective, treatments combining PGJ₂ with these PG synthesis inhibitors do not enhance PGJ₂’s neuroprotection.

Intravitreal triamcinolone injections in non-arteritic anterior ischemic optic neuropathy - A retrospective report

BACKGROUND

Non-arteritic anterior ischemic optic neuropathy (NAION) is a common cause of vision loss but no treatment has demonstrated its efficiency. A preliminary study showed an improvement on the visual acuity (VA) in a group of patients who received intravitreal administration of triamcinolone acetonide (IVTA) versus a non-treated group. In the present series, the visual outcome of IVTA in NAION was evaluated on a larger group of patients.

METHODS

This retrospective, unmasked and non-randomized study took place at Reims University Hospital between 2009 and 2017. The data of consecutive patients presenting with isolated optic disc edema characteristic of recent NAION (<1month of visual acuity loss) were included. After informed consent, a single intravitreal injection of filtrated 4mg/0.1mL triamcinolone acetonide were administered. Twenty-seven control patients chose not to be injected and therefore served as controls. LogMar visual acuity (VA), VA rating (VAR) (1 line=0.1LogMAR=5 VAR letters), retinal nerve fiber layer thickness assessed by OCT and static visual field were evaluated at presentation, after 7days, after 3months and after 6months.

RESULTS

Sixty-eight patients with NAION were evaluated. Forty-one received IVTA, 29 were injected within 15days after the onset of symptoms and 12 after 15days. There was a higher proportion of patients improving VA of 2 lines or more (10 or more VAR letters) in the injected group (49%) compared with the non-injected group (11%, P=0.019). Among the patients injected before 15days, the proportion improving for 2 lines or more (55% vs. 11%, respectively, P=0.013) and for 3 lines or more (45% vs. 11%, respectively, P=0.035) were significantly higher than in the non-injected group. Also, comparing the VA at presentation with the VA after 6months in the injected eyes, it improved significantly (P=0.003) and also in the subgroup injected within 15days (P=0.0007) but not in the injected group after 15days (P=0.801). Visual field improvement was only observed in the subgroup of patients injected within 15days with a significant improvement of the mean deviation (dB) within 6months (P=0.015).

CONCLUSIONS

This follow-up study confirms the results of the previous series displaying an apparent benefit of intravitreal steroids injected in the acute phase of NAION. Only patients receiving IVTA within 15days from onset of NAION have a significant improvement of VA and visual field during the follow-up period of 6months.

Retinal toxicities of systemic anticancer drugs

Newer anticancer drugs have revolutionized cancer treatment in the last decade, but conventional chemotherapy still occupies a central position in many cancers, with combination therapy and newer methods of delivery increasing their efficacy while minimizing toxicities. We discuss the retinal toxicities of anticancer drugs with an emphasis on the mechanism of toxicity. Uveitis is seen with the use of v-raf murine sarcoma viral oncogene homolog B editing anticancer inhibitors as well as immunotherapy. Most of the cases are mild with only anterior uveitis, but severe cases of posterior uveitis, panuveitis, and Vogt-Koyanagi-Harada-like disease may also occur. In the retina, a transient neurosensory detachment is observed in almost all patients on mitogen-activated protein kinase kinase (MEK) inhibitors. Microvasculopathy is often seen with interferon α, but vascular occlusion is a more serious toxicity caused by interferon α and MEK inhibitors. Crystalline retinopathy with or without macular edema may occur with tamoxifen; however, even asymptomatic patients may develop cavitatory spaces seen on optical coherence tomography. A unique macular edema with angiographic silence is characteristic of taxanes. Delayed dark adaptation has been observed with fenretinide. Interestingly, this drug is finding potential application in Stargardt disease and age-related macular degeneration.

Inhibition of Retinal Ganglion Cell Loss By a Novel ROCK Inhibitor (E212) in Ischemic Optic Nerve Injury Via Antioxidative and Anti-Inflammatory Actions

Purpose

This study investigated the neuroprotective effects of administration of ROCK inhibitor E212 on ischemic optic neuropathy.

Methods

Rats received an intravitreal injection of either E212 or PBS immediately after optic nerve infarct. The oxidative stress in the retina was detected by performing superoxide dismutase activity and CellROX assays. The integrity of retinal pigment epithelium was determined by staining of zona occludens 1. The visual function, retinal ganglion cell (RGC) density, and RGC apoptosis were determined by using flash visual-evoked potential analysis, retrograde FluoroGold labeling, and TdT-dUTP nick end-labeling assay. Macrophage infiltration was detected by staining for ED1. The protein levels of TNF-α, p-CRMP, p-AKT1, p-STAT3, and CD206 were evaluated using Western blotting.

Results

Administration of E212 resulted in a 1.23-fold increase in the superoxide dismutase activity of the retina and 2.28-fold decrease in RGC-produced reactive oxygen species as compared to the levels observed upon treatment with PBS (P < 0.05). Moreover, E212 prevented the disruption of the blood-retinal barrier (BRB) in contrast to PBS. The P1-N2 amplitude and RGC density in the E212-treated group were 1.75- and 2.05-fold higher, respectively, than those in the PBS-treated group (P < 0.05). The numbers of apoptotic RGCs and macrophages were reduced by 2.93- and 2.54-fold, respectively, in the E212-treated group compared with those in the PBS-treated group (P < 0.05). The levels of p-AKT1, p-STAT3, and CD206 were increased, whereas those of p-PTEN, p-CRMP2, and TNF-α were decreased after treatment with E212 (P < 0.05).

Conclusions

Treatment with E212 suppresses oxidative stress, BRB disruption, and neuroinflammation to protect the visual function in ischemic optic neuropathy.

Evaluation of hemodynamic changes in nonarteritic anterior ischemic optic neuropathy using multimodality imaging

Background

Nonarteritic anterior ischemic optic neuropathy (NAION) patients experience hypo-perfusion in the short posterior ciliary arteries (SPCAs), however, the cause of hypo-perfusion is unclear. Real-time dynamic hemodynamic observations may provide clues into specific NAION pathogenic mechanisms. We aim to analyze hemodynamic changes occurring in NAION using multimodality imaging. Our specific focus is identifying pathogenic mechanisms underlying SPCA insufficiency in NAION.

Methods

Three-dimensional arterial spin labeling (3D ASL) magnetic resonance imaging (MRI) and three-dimensional time-of-flight (3D-TOF) magnetic resonance angiography (MRA) were performed on 25 NAION patients (50 eyes) and 22 (44 eyes) normal cases were recruited. The diameter of the initial part of the ophthalmic artery and internal carotid artery siphon were measured using MRA. Blood vessel identification and blood flow (BF) were detected using 3D ASL MRI. We measured BF values of the optic nerve head (ONH) region of the retina/choroid complex, optic nerve (ON), temporal lobe, and occipital lobe.

Results

We studied 32 NAION affected eyes, 18 NAION uninvolved eyes, and 44 normal eyes. Diameter of the initial part of ophthalmic artery in the NAION affected eyes was significantly larger than the uninvolved eyes (P=0.026). Diameter of the NAION eyes was 1.33±0.19 mm [mean ± standard deviation (SD)], uninvolved eyes were 1.15±0.21 mm. At a photolabeling delay times (PLD) of 1,500 and 2,500 ms, BF of the ONH and ON in NAION affected eyes was significantly less than uninvolved and normal eyes (pONH <0.001 both at 1,500 and 2,500 ms, pON <0.001 and pON =0.001 at 1,500 and 2,500 ms, respectively). ONH of uninvolved eyes was also significantly less than normal eyes. Additionally, BF of the ONH region correlated with temporal lobe BF, with an R²=0.3231 and 0.2397 at 1,500 and 2,500 ms, respectively. BF of the ONH region also correlated with occipital lobe BF, with an R²=0.2534 and 0.4397 at 1,500 and 2,500 ms, respectively. ON and temporal lobe BF also correlated, with an R²=0.226 and 0.1504 at 1,500 and 2,500 ms, respectively.

Conclusions

Abnormal hemodynamics of small cerebral vessels existed prior to the onset of NAION. A candidate mechanism underlying NAION appears to be transient insufficiency of blood supply and decompensation of ocular vascular regulation.

Peripapillary Retinal and Choroidal Perfusion in Nonarteritic Ischemic Optic Neuropathy Using Optical Coherence Tomography Angiography

SIGNIFICANCE

Nonarteritic ischemic optic neuropathy (NAION) has been linked with vascular insufficiency, although the pathophysiology remains elusive. Optical coherence tomography angiography (OCTA) is a promising technology that noninvasively evaluates optic disc perfusion and that may help to characterize peripapillary vascular changes in NAION.

PURPOSE

This study aimed to evaluate peripapillary vascularity in NAION eyes and to compare it with fellow unaffected eyes and healthy control eyes using OCTA.

METHODS

In this cross-sectional study, OCTA of the optic nerve head was obtained in 10 nonacute unilateral NAION and 12 healthy age-matched controls using ZEISS Angioplex. Quantitative analysis of peripapillary retinal and choroidal vascularity of NAION eyes was done using the instrument's inbuilt algorithm and ImageJ software and compared with fellow and control eyes.

RESULTS

Mean total peripapillary superficial retinal vessel and perfusion density as calculated by the instrument was significantly reduced in NAION eyes compared with fellow eyes (13.93 ± 4.27 mm/0.36 ± 0.07 for NAION eyes; 17.77 ± 1.26 mm/0.43 ± 0.08 for fellow eyes; P = .01/P = .05). Using the ImageJ software technique, the mean superficial retinal perfusion was found to be significantly reduced in NAION eyes (0.17 ± 0.07) compared with fellow eyes (0.25 ± 0.06; P < .01) and control eyes (0.25 ± 0.04; P < .01). At the level of choriocapillaris, it was not significantly affected in NAION eyes (0.37 ± 0.13) versus fellow (0.34 ± 0.14; P = .1) and control eyes (0.31 ± 0.34; P = .83). Analysis with the two techniques yielded differing results: the ImageJ analysis technique found a 32% reduction in superficial retinal perfusion in NAION eyes, whereas the instrument's inbuilt algorithm found a 16% reduction compared with fellow and control eyes (P ≤.01).

CONCLUSIONS

Peripapillary vascularity can be estimated both at the retinal and choroidal levels using ImageJ software to analyze OCTA images. Retinal peripapillary vascularity is compromised in NAION eyes, but vascularity is not significantly affected at the choroidal level.

Microvascular and structural alterations in the optic nerve head of advanced primary open-angle glaucoma compared with atrophic non-arteritic anterior ischemic optic neuropathy

PURPOSE

This cross-sectional study compared the peripapillary vessel density (VD), peripapillary retinal nerve fiber layer (RNFL) thickness, and optic nerve head (ONH) parameters between eyes with atrophic non-arteritic anterior ischemic optic neuropathy (NAION) and eyes with advanced primary open-angle glaucoma (POAG) matched for visual field mean deviation.

METHODS

Peripapillary VDs and RNFL thicknesses in the peripapillary region, and 4 sectors (superior, inferior, nasal, and temporal), and scanning laser ophthalmoscopy parameters of the ONH were evaluated with optical coherence tomography angiography (OCTA) among 21 atrophic NAION cases, 26 advanced POAG cases, and 30 age- and sex-matched healthy controls.

RESULTS

The POAG eyes had lower peripapillary VDs in all areas compared with the NAION eyes, which was most marked in the inferior and nasal sectors (p=0.005 for both). RNFL loss was similar between the 2 groups in all areas, except for a preserved thickness in the inferior sector in NAION eyes (p=0.01). Peripapillary VD demonstrated stronger correlations with global RNFL thickness in the peripapillary region in the NAION eyes compared with that of the POAG eyes (r=0.91 p<0.00001, r=0.42 p=0.03 respectively). In multivariate analysis, the peripapillary VD correlated with age and RNFL thickness in the POAG eyes while it correlated with SSI and RNFL thickness in the NAION eyes.

CONCLUSIONS

A tendency for a lower peripapillary VD despite similar visual field mean deviation values may infer a more prominent role of the vascular regression in POAG compared with NAION.

Ocular complications of perioperative anesthesia: a review

Ocular complications associated with anesthesia in ocular and non-ocular surgeries are rare adverse events which may present with clinical presentations vacillating between easily treatable corneal abrasions to more serious complication such as irreversible bilateral vision loss. In this review, we outline the different techniques of anesthetic delivery in ocular surgeries and highlight the incidence and etiologies of associated injuries. The changes in vision in non-ocular surgeries are mistaken for residual sedation or anesthetics, therefore require high clinical suspicion on part of the treating ophthalmologists, to ensure early diagnosis, adequate and swift management especially in surgeries such as cardiac, spine, head and neck, and some orthopedic procedures, that have a comparatively higher incidence of ocular complications. In this article, we review the literature for reports on the clinical incidence of different ocular complications associated with anesthesia in non-ocular surgeries and outline the current understanding of pathophysiological processes associated with these adverse events.

How curcumin affects hyperglycemia-induced optic nerve damage: A short review

Considered to be one of the most important non-contagious systemic diseases worldwide, diabetes mellitus is still a topical issue on the health agenda with the problems it causes. Exposure to long-term hyperglycemia causes diabetic complications (diabetic neuropathy, nephropathy and retinopathy). The optic nerve can suffer damage by both diabetic retinopathy and neuropathy during diabetes, both because it is formed by axons of retinal ganglion cells and these axons belong to the central nervous system. The issue of hyperglycemia on the optic nerve have been described as diabetic papillopathy, posterior ischemic optic neuropathy, nonarteritic anterior ischemic optic neuropathy and optic atrophy in clinical studies. Experimental studies indicated axon-myelin degeneration in addition to microvascular and ultrastructural changes caused by the hyperglycemia-induced optic nerve damage. Although there are several proposed biochemical mechanisms to cause these damages, oxidative stress emerges as an important factor among them. Oxidative stress leads to pathological state on the nerve cells by affecting the DNA, protein and lipids at different levels. These are causing deterioration on nerve conduction velocity, myelin sheath and nerve structure, neurotrophic support system, glial cells and nerve function. Curcumin, as an important antioxidant, can be an ideal prophylactic agent to eliminate damages on optic nerve. Curcumin helps to regulate the balance of antioxidant and reactive oxygen species by targeting various molecules (NF-κB, STAT3, MAPK, Mfn2, Nrf2, pro-inflammatory cytokines). In addition, it shows healing or preventive effects on myelin sheath damage via regulating ferritin protein in oligodendrocytes. It is also effective in preventing neurovascular damage.