Nonarteritic anterior ischemic optic neuropathy: cause, effect, and management

Altered functional connectivity of the default mode network in non-arteritic anterior ischaemic optic neuropathy

The functional connectivity of the default mode network is important in understanding the neuro-pathophysiological abnormalities in patients with non-arteritic anterior ischaemic optic neuropathy. Independent component analysis can effectively determine within and between network connectivity of different brain components. Therefore, in order to explore the association between the default mode network and other brain regions, we utilized independent component analysis to investigate the alteration of functional connectivity of the default mode network. Thirty-one patients with non-arteritic anterior ischaemic optic neuropathy and 31 healthy controls, matched for age, sex and years of education, were recruited. For patients and healthy controls, functional connectivity within and between the default mode network and other brain regions were evaluated by independent component analysis. Compared with healthy controls, patients with non-arteritic anterior ischaemic optic neuropathy showed reduced functional connectivity within the default mode network in the right cerebellar tonsil and left cerebellum posterior lobe and increased functional connectivity in the left inferior temporal and right middle frontal gyri. Furthermore, patients with non-arteritic anterior ischaemic optic neuropathy showed reduced functional connectivity between the default mode network and other brain regions in the left cerebellar tonsil and increased functional connectivity in the right putamen, left thalamus, right middle temporal and left middle frontal gyri. In conclusion, negative correlations between several clinical parameters and functional connectivity of the default mode network were observed. The study contributes to understanding the mechanism of functional reorganization in non-arteritic anterior ischaemic optic neuropathy.

Hybrid deep learning and optimal graph search method for optical coherence tomography layer segmentation in diseases affecting the optic nerve

Accurate segmentation of retinal layers in optical coherence tomography (OCT) images is critical for assessing diseases that affect the optic nerve, but existing automated algorithms often fail when pathology causes irregular layer topology, such as extreme thinning of the ganglion cell-inner plexiform layer (GCIPL). Deep LOGISMOS, a hybrid approach that combines the strengths of deep learning and 3D graph search to overcome their limitations, was developed to improve the accuracy, robustness and generalizability of retinal layer segmentation. The method was trained on 124 OCT volumes from both eyes of 31 non-arteritic anterior ischemic optic neuropathy (NAION) patients and tested on three cross-sectional datasets with available reference tracings: Test-NAION (40 volumes from both eyes of 20 NAION subjects), Test-G (29 volumes from 29 glaucoma subjects/eyes), and Test-JHU (35 volumes from 21 multiple sclerosis and 14 control subjects/eyes) and one longitudinal dataset without reference tracings: Test-G-L (155 volumes from 15 glaucoma patients/eyes). In the three test datasets with reference tracings (Test-NAION, Test-G, and Test-JHU), Deep LOGISMOS achieved very high Dice similarity coefficients (%) on GCIPL: 89.97±3.59, 90.63±2.56, and 94.06±1.76, respectively. In the same context, Deep LOGISMOS outperformed the Iowa reference algorithms by improving the Dice score by 17.5, 5.4, and 7.5, and also surpassed the deep learning framework nnU-Net with improvements of 4.4, 3.7, and 1.0. For the 15 severe glaucoma eyes with marked GCIPL thinning (Test-G-L), it demonstrated reliable regional GCIPL thickness measurement over five years. The proposed Deep LOGISMOS approach has potential to enhance precise quantification of retinal structures, aiding diagnosis and treatment management of optic nerve diseases.

Clinical efficacy of dexamethasone parabulbar injection in patients with Nonarteritic anterior ischemic optic neuropathy

Background

Nonarteritic anterior ischemic optic neuropathy (NAAION) is a common optic neuropathy that often leads to significant visual acuity loss in patients. The present study evaluated the effects of parabulbar dexamethasone injection on visual outcomes in patients with NAAION.

Methods

This retrospective case-control study included patients diagnosed with NAAION between January 2019 and December 2022. Thirty-four patients with NAAION (34 eyes) received dexamethasone parabulbar injections, while 39 patients with NAAION (39 eyes) received oral corticosteroid treatment (control group). Best-corrected visual acuity (BCVA), visual field (VF) defect, and retinal nerve fiber layer (RNFL) thickness of the affected eye were compared between groups at baseline and 2, 6, and 12 weeks post-treatment.

Results

Mean BCVA significantly improved after 6 and 12 weeks in the injection groups compared with the control group (all P < 0.01). The visual field indices, mean deviation and pattern standard deviation significantly improved in the injection group compared with the control group after 2, 6, and 12 weeks (all P < 0.01). The RNFL showed a remarkable decrease in edema after 6 weeks (superior and nasal P values 0.005 and 0.013, respectively) in the injection group compared with the control group. Significant RNFL thinning was also observed in superior, inferior, temporal, and nasal quadrants in the control group after 12 weeks (all P values < 0.01). Also, fewer side effects were observed in the injection group compared to the control group.

Conclusions

The results of this study suggested that dexamethasone parabulbar injection might be a safe and effective intervention for relieving visual acuity and VF in patients with NAAION.

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.

Blinding Optic Neuropathy Associated With Carboplatin Therapy: A Case Report and Literature Review

Various forms of cancer and chemotherapeutics are associated with optic neuropathy. Cisplatin is a platinum analogue chemotherapeutic commonly associated with ocular toxicity among many other serious adverse effects. Carboplatin is a more chemically stable platinum analogue that is generally better tolerated with a comparatively favorable side effect profile. There are very few reports of carboplatin precipitating optic neuropathy. This case report describes a rare occurrence of carboplatin-induced blinding optic neuropathy. We treated a patient receiving carboplatin for neuroendocrine bladder cancer who developed rapidly progressive bilateral optic neuropathy over the course of three days. Upon evaluation at our clinic, his visual acuity had declined to light perception only and 20/60 in his left and right eye, respectively. Carboplatin therapy was immediately held and steroids were initiated. Despite the intervention, the patient's visual deficits have not improved at the one-year follow-up. Although the mechanism by which carboplatin causes ocular toxicity remains speculative, arterial ischemia appears to be the likely mechanism given the irreversible nature of visual decline. As demonstrated by our patient's course, irreversible vision loss despite high-dose steroid intervention necessitates expeditious recognition and management of this rare adverse effect. ​​​​​.

Oxidative stress in the eye and its role in the pathophysiology of ocular diseases

Oxidative stress occurs through an imbalance between the generation of reactive oxygen species (ROS) and the antioxidant defense mechanisms of cells. The eye is particularly exposed to oxidative stress because of its permanent exposure to light and due to several structures having high metabolic activities. The anterior part of the eye is highly exposed to ultraviolet (UV) radiation and possesses a complex antioxidant defense system to protect the retina from UV radiation. The posterior part of the eye exhibits high metabolic rates and oxygen consumption leading subsequently to a high production rate of ROS. Furthermore, inflammation, aging, genetic factors, and environmental pollution, are all elements promoting ROS generation and impairing antioxidant defense mechanisms and thereby representing risk factors leading to oxidative stress. An abnormal redox status was shown to be involved in the pathophysiology of various ocular diseases in the anterior and posterior segment of the eye. In this review, we aim to summarize the mechanisms of oxidative stress in ocular diseases to provide an updated understanding on the pathogenesis of common diseases affecting the ocular surface, the lens, the retina, and the optic nerve. Moreover, we discuss potential therapeutic approaches aimed at reducing oxidative stress in this context.

Non-Arteritic Anterior Ischemic Optic Neuropathy (NA-AION): A Comprehensive Overview

Non-arteritic anterior ischemic optic neuropathy (NA-AION) represents one of the most important causes of blindness or severely impaired vision in middle-aged and elderly people. Unilateral optic disc edema and abrupt, painless vision loss are its defining features. It is commonly assumed that NA-AION is caused by an ischemic infarction of the optic nerve head, and, although the exact pathogenesis is still unknown, several risk factors and comorbidities associated with its development have been found. NA-AION occurs generally in patients older than 50 years who have small optic discs and vasculopathy risk factors. Even though numerous treatment options have been proposed, no available effective medical or surgical therapy or prophylactic measure for NA-AION currently exists. The purpose of present-day therapeutic strategies is therefore to identify and possibly control any underlying modifiable risk factors, aiming to prevent the development of new NA-AION episodes in the affected and fellow eye. A thorough assessment of NAION, including its history, epidemiology, etiology, pathophysiology, risk factors, associated comorbidities, clinical findings, diagnostic tests, treatment choices, prognosis, and future research, is the goal of this work.

Non-Arteritic Anterior Ischemic Optic Neuropathy (NA-AION): A Comprehensive Overview

Non-arteritic anterior ischemic optic neuropathy (NA-AION) represents one of the most important causes of blindness or severely impaired vision in middle-aged and elderly people. Unilateral optic disc edema and abrupt, painless vision loss are its defining features. It is commonly assumed that NA-AION is caused by an ischemic infarction of the optic nerve head, and, although the exact pathogenesis is still unknown, several risk factors and comorbidities associated with its development have been found. NA-AION occurs generally in patients older than 50 years who have small optic discs and vasculopathy risk factors. Even though numerous treatment options have been proposed, no available effective medical or surgical therapy or prophylactic measure for NA-AION currently exists. The purpose of present-day therapeutic strategies is therefore to identify and possibly control any underlying modifiable risk factors, aiming to prevent the development of new NA-AION episodes in the affected and fellow eye. A thorough assessment of NAION, including its history, epidemiology, etiology, pathophysiology, risk factors, associated comorbidities, clinical findings, diagnostic tests, treatment choices, prognosis, and future research, is the goal of this work.

Neuroprotective Strategies for Nonarteritic Anterior Ischemic Optic Neuropathy: A Systematic Review

PURPOSE

Nonarteritic anterior ischemic optic neuropathy (NAION) is the second most common form of optic neuropathy. Most patients show no improvement over time. Until now, there is still no definitive therapy for NAION. The available literatures on the possible treatment of NAION are quite diverse and controversial. Neuroprotection strategies have been suggested as one of the potential treatments for NAION. This review aims to critically evaluate the literature on neuroprotective strategy for NAION.

METHODS

This report was written in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. We performed a systematic literature search in Pubmed, Science Direct, Proquest, and Cochrane databases. Only neuroprotective agents that directly work in protecting neurons were included. The outcome of interest in this review is retinal ganglion cell density and apoptosis for animal studies and retinal nerve fiber layer thickness for human studies.

RESULTS

The systematic search identified 591 studies of which 24 met the eligibility criteria, including 21 animal studies and three human studies. Only a few of the studies evaluated the same treatments, showing how diverse neuroprotector treatments are currently being evaluated as NAION treatment. From 21 animal studies, 14 studies showed significantly higher retinal ganglion cell density (1.49- to 2.81-fold) with neuroprotective treatment compared to control group. Two of three human studies in this review had also found a beneficial effect of preserving retinal nerve fiber layer thickness in NAION patients.

CONCLUSIONS

This review suggests the potential of neuroprotection as a viable option in the quest for an effective treatment strategy for NAION. Further studies, particularly clinical studies, are necessary to establish its efficacy in NAION patients.

Oxidative Stress: A Suitable Therapeutic Target for Optic Nerve Diseases?

Optic nerve disorders encompass a wide spectrum of conditions characterized by the loss of retinal ganglion cells (RGCs) and subsequent degeneration of the optic nerve. The etiology of these disorders can vary significantly, but emerging research highlights the crucial role of oxidative stress, an imbalance in the redox status characterized by an excess of reactive oxygen species (ROS), in driving cell death through apoptosis, autophagy, and inflammation. This review provides an overview of ROS-related processes underlying four extensively studied optic nerve diseases: glaucoma, Leber's hereditary optic neuropathy (LHON), anterior ischemic optic neuropathy (AION), and optic neuritis (ON). Furthermore, we present preclinical findings on antioxidants, with the objective of evaluating the potential therapeutic benefits of targeting oxidative stress in the treatment of optic neuropathies.

Differentiating Occult Neuroretinitis and Non-Arteritic Anterior Ischaemic Optic Neuropathy: Clinical and Optical Coherence Tomography Characteristics

We report clinical and optical coherence tomography (OCT) differences among patients with occult neuroretinitis and non-arteritic anterior ischaemic optic neuropathy (NAAION). We retrospectively reviewed records of patients with a final diagnosis of occult neuroretinitis and NAAION seen at our institute. Data were collected regarding patient demographics, clinical features, concomitant systemic risk factors, visual function, and optical coherence tomography (OCT) findings at presentation and subsequent follow-up. Fourteen and 16 patients were diagnosed to have occult neuroretinitis and NAAION, respectively. Patients with NAAION were slightly older (median age 49, inter-quartile range [IQR]: 45-54 years, versus 41, IQR: 31-50 years) than patients with neuroretinitis. Seventy-five per cent of patients with NAAION were male versus 43% with neuroretinitis (p = 0.07). Systemic risk factors were present in 87.5% of patients with NAAION versus 21.4% in patients with neuroretinitis (p = 0.001). At presentation, all patients presented with blurred vision, had similar visual function, and had optic disc oedema. In addition, none of the patients had evident retinitis lesions, but 10 (71%) showed evident retinitis lesion at follow-up. Neuroretinitis patients had more often vitreous cells (64% versus 6%, p = 0.001), and subretinal fluid (78.6% versus 37.5%, p = 0.03) than the patients with NAAION. In summary, NAAION patients tended to be slightly older, more often male, and had associated systemic diseases more often than those with neuroretinitis. Neuroretinitis patients more often had posterior vitreous cells and subretinal fluid on OCT. However, larger prospective studies are needed.

Optical coherence tomography angiography in neuro-ophthalmology

PURPOSE OF REVIEW

Optical coherence tomography angiography (OCTA) is a novel, noninvasive imaging technique, which provides depth resolved visualization of microvasculature of the retina and choroid. Although OCTA has been widely used for the evaluation of a number of retinal diseases, its use in the field of neuro-ophthalmology has been less studied. In this review, we provide an update on the utility of OCTA in neuro-ophthalmic conditions.

RECENT FINDINGS

Peripapillary and macular microvasculature analyses have indicated that OCTA can be a promising tool for early detection of a number of neuro-ophthalmic diseases, differential diagnosis, and monitoring of disease progression. Recent studies have demonstrated that structural and functional impairment can develop at early stages in some conditions such as in multiple sclerosis and Alzheimer's disease even in the absence of overt clinical symptoms. Furthermore, this dye-less technique can be a valuable adjunct tool in the detection of complications commonly seen in some congenital entities such optic disc drusen.

SUMMARY

Since its introduction, OCTA has emerged as an important imaging approach shedding light on unrevealed pathophysiological mechanisms of several ocular diseases. The use of OCTA as a biomarker in the field of neuro-ophthalmology has recently gained considerable attention with studies supporting its role in clinical setting while larger studies are warranted for correlating these findings with traditional diagnostic procedures and clinical features and outcomes.

High Altitude as a Risk Factor for the Development of Nonarteritic Anterior Ischemic Optic Neuropathy

BACKGROUND

Episodic high-altitude exposure leads to optic disc edema and retinopathy. It is uncertain whether high-altitude exposure is a risk factor for nonarteritic anterior ischemic optic neuropathy (NAION).

METHODS

We performed a single-center, retrospective, cross-sectional case study of 5 patients with high-altitude-associated NAION (HA-NAION) from April 2014 to April 2019. Main study parameters included known vascular risk factors for NAION, evolution of visual acuity, visual field, optic disc, and macula measurements.

RESULTS

We studied 5 eyes of 5 patients with HA-NAION that occurred at 7,000-9,000 ft above sea level, 28 patients with classic NAION that developed at sea level (normal altitude NAION or NA-NAION), and 40 controls. All 5 patients with HA-NAION had clinically confirmed NAION by a neuro-ophthalmologist within 3-21 days of onset and comprehensive follow-up evaluations (average follow-up of 23 months). Other than high-altitude exposure, 4 of 5 patients had undiagnosed obstructive sleep apnea (OSA, apnea-hypopnea index 5.4-22.2) and 1 had systemic vascular risk factors. All patients had disc-at-risk in the contralateral eye. The best-corrected distance visual acuity was 20/20 to 20/70 (median logMAR 0) at presentation and 20/70 to counting finger (median logMAR 0) at ≥6 months. Automated static perimetry revealed average mean deviation of -18.6 dB at presentation and -22.1 dB at ≥6 months. The average retinal nerve fiber layer was 244 µm (80-348 µm) at onset and 59 µm (55-80 µm) at ≥6 months. The average ganglion cell complex thickness was 50 µm (43-54 µm) at onset and 52 µm (50-55 µm) at ≥6 months. The patients with OSA were started on home continuous positive airway pressure treatment. Visual outcomes were similar in patients with HA-NAION and NA-NAION. - After addressing all NAION risk factors, no new events occurred in the HA-NAION group within 2-8 years with or without repeat high-altitude exposure.

CONCLUSIONS

NAION can occur under high-altitude conditions. HA-NAION is associated with relatively younger age at onset, disc-at-risk, and OSA. These patients exhibit a relatively progressive course of vision loss after initial onset and severe thinning of optic nerves on optical coherence tomography. Treatment for OSA is recommended, especially with repeated high-altitude exposure.

Therapeutic effects of herbal medicines in different types of retinopathies: A systematic review

Objective

Retinopathy is an ocular manifestation of systemic diseases such as diabetes and vascular diseases. Herbal drugs have been considered as an effective therapeutic option with minimal side effects for the treatment of retinopathy by reducing the symptoms and improving visual acuity. The purpose of this systematic review was to collect studies on the effectiveness of medicinal plants in the treatment or prevention of retinopathy.

Materials and Methods

A systematic literature search was performed in PubMed, Scopus, Google Scholar, and other databases in April 2021 using "herbal products" and "Retinopathy" with all their equivalent and similar terms. For this purpose, human clinical trials with the English language were included and articles with subject irrelevancy were excluded from further evaluation.

Results

Overall, 30 articles with 2324 patients were studied for possible effects of herbal therapy on retinopathy. From 30 included articles, different herbal products had been evaluated. Out of 30 selected articles, 11 articles were for the treatment of age-related macular degeneration (AMD), 14 articles covered patients with diabetic retinopathy, and the other five studies were for other retinal disorders. The outcomes in majority of the studies include changes in visual acuity (VA), fundus performance, best-corrected visual acuity (BCVA), central macular thickness (CMT), focal electroretinogram (fERG), supplements and adjuvant medications appeared to be more beneficial in patients with AMD and diabetic maculopathy.

Conclusion

Herbal therapy can be considered as a potential candidate in the adjuvant and complementary therapies of retinopathy. However, further studies are required to verify such efficiency.

Optical coherence tomography angiography (OCT angiography) in anterior ischemic optic neuropathy (AION): A systematic review and meta-analysis

PURPOSE

To summarize the evidence available on optical coherence tomography angiography (OCTA) in patients with anterior ischemic optic neuropathy (AION).

METHODS

Systematic searches were conducted on PubMed, Embase, Web of Science, Scopus, Cochrane, and Google Scholar Databases. The quality assessment of the included studies was performed using Newcastle -Ottawa Scale. The data were extracted to an Excel sheet. Vessel density (VD) data were pooled by random effects model, presented as pooled percentage change (PPC), and weighted mean differences (WMD). Additional subgroup analysis was also conducted.

RESULTS

In initial searches in online databases, we found 3535 citations, and after screening and checking the titles and abstracts, 26 articles were ultimately eligible for our meta-analysis. The overall PPC of Intra-optic-disc (IOD) VD (-10.73%; p = 0.017, I² = 0.0%; p = 0.898) was lower than that of radial peripapillary (RP) VD (-17.57%; p < 0.001, I² = 44.3%; p = 0.002). The overall PPC of peripapillary choroid VD (-6.99%; p < 0.001, I² = 0.0%; p = 0.766) was significant, but noticeably lower than the pooled percentage change of RPVD and IOD VD. The WMD of RPVD was significant when non-affected fellow eyes were compared to the healthy subjects' eyes (-36.26; p < 0.001, I² = 0.0%; p = 0.706).

CONCLUSIONS

The central retinal artery and its branches might be the main vessels which are affected in AION. The superficial retina was more affected than choroid layer in AION. Also, radial peripapillary retinal nerve fibre layer was more affected than the IOD area. OCTA might be a suitable tool for prediction of AION in susceptible eyes.

Analysis of Systemic Risk Factors and Post-Insult Visual Development in a Danish Cohort of Patients with Nonarteritic Anterior Ischemic Optic Neuropathy

Purpose

Nonarteritic anterior ischemic optic neuropathy (NAION) is associated with vascular as well as anatomical risk factors. Following the insult, the visual development varies from minor to severe deterioration. The aim of this study was to examine possible prognostic systemic risk factors and their eventual impact on post-insult visual development in NAION patients.

Methods

A retrospective chart review of all NAION patients (18–79 years at time of diagnosis) seen a minimum of two times in a tertiary eye department during a 10-year period in regard to systemic diseases, medication, lifestyle factors and ophthalmic examination was performed. Visual outcome was assessed according to the development of best corrected visual acuity (BCVA) and visual field from initial to final visit.

Results

There were 163 eligible patients. A greater proportion of the patients in the total cohort were over 50 years of age (79.8%) and men (66.3%). In total, 59.5% of the patients had a stable BCVA, while 25.8% experienced improvement, and 14.7% had deterioration. Seventy-two percent of the patients had a stable visual field, while 14% had improvement, and 14% had deterioration. No association between visual outcome and clinical characteristics, medication or systemic risk factors were identified.

Conclusion

We did not find any association between patient characteristics and systemic risk factors at time of diagnosis and visual development post-insult. This could suggest that the optic nerve head anatomy plays a larger role for visual outcome than previously estimated.

Metabolic syndrome and its components are associated with non-arteritic anterior ischaemic optic neuropathy

PURPOSE

To determine whether metabolic syndrome (MetS) is a risk factor for various forms of optic neuropathy including non-arteritic anterior ischaemic optic neuropathy (NAION).

METHODS

This population-based analysis identified patients ≥40 years of age in Olmsted County, Minnesota, USA using the Rochester Epidemiology Project 2005-2018. Patients with MetS were identified if three or more of the five standard criteria for diagnosing MetS were present: systemic hypertension, hyperglycaemia, hypertriglyceridaemia, reduced high-density lipoprotein cholesterol (hypoalphalipoproteinaemia) and central adiposity defined by increased body mass index. Charts of patients identified as having an optic neuropathy were reviewed to record specific diagnoses and compared with patients without ocular pathology other than cataract. The odds ratio (OR) of association with MetS was calculated and adjusted for age, sex and race with multivariate analysis for the various optic neuropathies.

RESULTS

Patients with MetS were more likely to have an optic neuropathy than those without (OR 2.2, p<0.001). After adjusting for age, sex and race, the only optic neuropathy found to be significantly associated with MetS was NAION (OR 6.17, p=0.002). For patients with NAION, though each individual component of MetS was individually significantly associated with MetS, further analysis suggested that hypertriglyceridaemia, hypoalphalipoproteinaemia and hyperglycaemia were likely the key drivers in the overall significance between NAION and MetS.

CONCLUSION

Patients with MetS were more likely to have NAION. Further studies are needed to determine whether MetS is a modifiable risk factor for NAION.

The Risk of Non-arteritic Ischemic Optic Neuropathy Post-intravitreal Bevacizumab Injection

OBJECTIVES

To report the incidence of non-arteritic ischemic optic neuropathy in diabetic patients treated with intravitreal bevacizumab injection.

METHODS

A prospective comparative analytic study was done in the King Hussein Medical Center during the period between June 2020 and June 2021. Inclusion criteria included diabetic patients who attended a retina clinic. Exclusion criteria included patients with pre-existing ischemic optic neuropathy. Patients were divided into two groups. The first group included diabetic patients who did not require bevacizumab injection and were treated either with follow-up visits or pan-retinal photocoagulation, and the second group included patients who were treated with intravitreal bevacizumab. Patients were followed up for a period of one year. Data collected in two groups included the total number of patients and the number of patients with non-arteritic ischemic optic neuropathy. Results were compared in both groups. A P-value was used to study the statistical significance and was considered to be statistically significant if ≤0.05.

RESULTS

The mean age for patients in group 1 was 64.3 years, with a male to female ratio of 1.1 to 1. In group 2, the mean age was 66.2 years, with a male to female ratio of 1.2 to 1. The total number of patients in group 1 was 7375, among whom 68 patients had non-arteritic ischemic optic neuropathy. While in group 2, the total number was 2468 and 49 of them had non-arteritic ischemic optic neuropathy. Most cases of non-arteritic ischemic optic neuropathy were seen in patients who had received three or more injections.  Conclusion: Intravitreal bevacizumab in diabetic patients is considered a risk factor for the development of non-arteritic ischemic optic neuropathy, especially in patients receiving more than three injections.

Optical Coherence Tomography of Peripapillary Vessels in Giant Cell Arteritis and Ischaemic Ocular Disease

With normal retinal blood flow, cross-sectional optical coherence tomography (OCT) of retinal vessels shows a structured intravascular reflectivity profile, resembling a 'figure-of-8'. Altered profiles have been reported in vascular occlusive and haematological diseases. Giant cell arteritis (GCA) can cause visual loss, usually due to anterior ischaemic optic neuropathy (AION) or retinal artery occlusion. Our aim was to extend the assessment of OCT vascular profiles to patients with suspected GCA and to determine if any abnormalities were related to GCA per se or to ischaemic ocular conditions. This nested retrospective study included 61 eyes of 31 patients (13 with GCA). Six eyes had arteritic and seven eyes non-arteritic AION, three eyes had non-arteritic retinal artery occlusion, 11 eyes had other ocular conditions and 34 were unaffected control eyes. For each eye the appearance of structured intravascular profiles on peripapillary OCT was graded as present, partial, absent or uncertain. Non-presence of structured intravascular profiles was more frequent in AION and retinal artery occlusion than in other ocular conditions or unaffected eyes (Fisher's test, p = .0047). Based on follow-up of 25 eyes, reflectivity profiles normalised in three out of four eyes after 85 (35-245) days. Vessel profiles were not associated with GCA (p = .32) and were similar in arteritic and non-arteritic AION (p = .66). In conclusion, absence of structured intravascular reflectivity profiles may be a marker of acute ischaemia in the anterior optic nerve or inner retina. However, it did not seem specific for GCA. The prognostic value warrants further studies.

Clinical and Mechanistic Review of Amiodarone-Associated Optic Neuropathy

Amiodarone-associated optic neuropathy (AAON) is a complex clinical diagnosis, requiring distinction from non-arteritic ischemic optic neuropathy (NAION) due to a shared at-risk patient population. Diagnosis of AAON is complicated by a varied clinical presentation and incomplete pathophysiologic mechanisms. This article reviews pertinent literature for describing and clinically delineating AAON from NAION, as well as newly reported protective mechanisms of insulin-like growth factor 1 (IGF-1) and PI3K/Akt against amiodarone-induced oxidative and apoptotic injury in retinal ganglion and pigment epithelial cells. These studies offer a basis for exploring mechanisms of amiodarone toxicity in the optic nerve.

Retinal Vascular Occlusion after COVID-19 Vaccination: More Coincidence than Causal Relationship? Data from a Retrospective Multicentre Study

Background: To investigate whether vaccination against SARS-CoV-2 is associated with the onset of retinal vascular occlusive disease (RVOD). Methods: In this multicentre study, data from patients with central and branch retinal vein occlusion (CRVO and BRVO), central and branch retinal artery occlusion (CRAO and BRAO), and anterior ischaemic optic neuropathy (AION) were retrospectively collected during a 2-month index period (1 June–31 July 2021) according to a defined protocol. The relation to any previous vaccination was documented for the consecutive case series. Numbers of RVOD and COVID-19 vaccination were investigated in a case-by-case analysis. A case–control study using age- and sex-matched controls from the general population (study participants from the Gutenberg Health Study) and an adjusted conditional logistic regression analysis was conducted. Results: Four hundred and twenty-one subjects presenting during the index period (61 days) were enrolled: one hundred and twenty-one patients with CRVO, seventy-five with BRVO, fifty-six with CRAO, sixty-five with BRAO, and one hundred and four with AION. Three hundred and thirty-two (78.9%) patients had been vaccinated before the onset of RVOD. The vaccines given were BNT162b2/BioNTech/Pfizer (n = 221), followed by ChadOx1/AstraZeneca (n = 57), mRNA-1273/Moderna (n = 21), and Ad26.COV2.S/Johnson & Johnson (n = 11; unknown n = 22). Our case–control analysis integrating population-based data from the GHS yielded no evidence of an increased risk after COVID-19 vaccination (OR = 0.93; 95% CI: 0.60–1.45, p = 0.75) in connection with a vaccination within a 4-week window. Conclusions: To date, there has been no evidence of any association between SARS-CoV-2 vaccination and a higher RVOD risk.

Optical coherence tomography evaluation of retinal nerve fiber layer thickness in non-arteritic anterior ischemic optic neuropathy and primary open angle glaucoma: a systematic review and Meta-analysis

AIM

To assess the differences in average and sectoral peripapillary retinal nerve fiber layer (pRNFL) thickness using spectral domain optical coherence tomography (SD-OCT) in patients with non-arteritic anterior ischemic neuropathy (NAION) compared with those with primary open angle glaucoma (POAG).

METHODS

A comprehensive literature search of the PubMed, Cochrane Library, and Embase databases were performed prior to October, 2021. Studies that compared the pRNFL thickness in NAION eyes with that in POAG eyes with matched mean deviation of the visual fields were included. The weighted mean difference (WMD) with 95% confidence interval (CI) was used to pool continuous outcomes.

RESULTS

Ten cross-sectional studies (11 datasets) comprising a total of 625 eyes (278 NAION eyes, 347 POAG eyes) were included in the qualitative and quantitative analyses. The pooled results demonstrated that the superior pRNFL was significantly thinner in NAION eyes than in POAG eyes (WMD=-6.40, 95%CI: -12.22 to -0.58, P=0.031), whereas the inferior pRNFL was significant thinner in POAG eyes than in NAION eyes (WMD=11.10, 95%CI: 7.06 to 15.14, P≤0.001). No difference was noted concerning the average, nasal, and temporal pRNFL thickness (average: WMD=1.45, 95%CI: -0.75 to 3.66, P=0.196; nasal: WMD=-2.12, 95%CI: -4.43 to 0.19, P=0.072; temporal: WMD=-1.24, 95%CI: -3.96 to 1.47, P=0.370).

CONCLUSION

SD-OCT based evaluation of inferior and superior pRNFL thickness can be potentially utilized to differentiate NAION from POAG, and help to understand the different pathophysiological mechanisms between these two diseases. Further longitudinal studies and studies using eight-quadrant or clock-hour classification method are required to validate the obtained findings.

Transcript-Targeted Therapy Based on RNA Interference and Antisense Oligonucleotides: Current Applications and Novel Molecular Targets

The development of novel target therapies based on the use of RNA interference (RNAi) and antisense oligonucleotides (ASOs) is growing in an exponential way, challenging the chance for the treatment of the genetic diseases and cancer by hitting selectively targeted RNA in a sequence-dependent manner. Multiple opportunities are taking shape, able to remove defective protein by silencing RNA (e.g., Inclisiran targets mRNA of protein PCSK9, permitting a longer half-life of LDL receptors in heterozygous familial hypercholesteremia), by arresting mRNA translation (i.e., Fomivirsen that binds to UL123-RNA and blocks the translation into IE2 protein in CMV-retinitis), or by reactivating modified functional protein (e.g., Eteplirsen able to restore a functional shorter dystrophin by skipping the exon 51 in Duchenne muscular dystrophy) or a not very functional protein. In this last case, the use of ASOs permits modifying the expression of specific proteins by modulating splicing of specific pre-RNAs (e.g., Nusinersen acts on the splicing of exon 7 in SMN2 mRNA normally not expressed; it is used for spinal muscular atrophy) or by downregulation of transcript levels (e.g., Inotersen acts on the transthryretin mRNA to reduce its expression; it is prescribed for the treatment of hereditary transthyretin amyloidosis) in order to restore the biochemical/physiological condition and ameliorate quality of life. In the era of precision medicine, recently, an experimental splice-modulating antisense oligonucleotide, Milasen, was designed and used to treat an 8-year-old girl affected by a rare, fatal, progressive form of neurodegenerative disease leading to death during adolescence. In this review, we summarize the main transcriptional therapeutic drugs approved to date for the treatment of genetic diseases by principal regulatory government agencies and recent clinical trials aimed at the treatment of cancer. Their mechanism of action, chemical structure, administration, and biomedical performance are predominantly discussed.

Foster Kennedy Syndrome (FKS): A Case Report

(1) Background: Foster Kennedy syndrome (FKS) is an ophthalmological condition characterized by an insidious reduction in vision in one eye, accompanied by clinically significant papilledema in the fellow eye. The unilateral loss of vision and optic atrophy is due to compressive optic atrophy, which causes elevated intracranial pressure that leads to swelling in the fellow eye. The risk factors for FKS include the presence of mass lesions in radiographic imaging, female gender, and increased body mass index. Differential diagnoses of FKS include tumors and pseudotumor of the frontal lobe and cranial meninges. (2) Methods: We present two cases of FKS diagnosed in February 2021 and December 2021. (3) Results: A 52-year-old male with a history of poor vision in one eye after trauma complained of constant headache. Ocular examination revealed disc pallor in his right eye with disc edema in the contralateral eye. The patient was sent for computerized tomography (CT) and placed on oral prednisolone tablets. The CT scan confirmed the diagnosis of FKS. A 30-year-old female presented to the emergency department for poor vision in her left eye and headache on the left side. Medication included dexamethasone, chloramphenicol, timolol eyedrops, furosemide, and anti-oxidant tablets dispensed from a previous private eye clinic. Ophthalmoscopy showed disc pallor with 0.1 cupping and arteriolar attenuation in both eyes with macular hemorrhages in her left eye. Bilateral papilledema secondary to raised intracranial hyper-tension was suspected. CT scans showed an intracranial mass. (4) Conclusions: These two cases show the importance of ocular examination in the diagnosis of serious systemic conditions. A concise case history, extensive ocular workup, and cranial imaging with magnetic resonance imaging and/or CT scans are indicative of patients showing acute visual loss and retro-orbital pain, which can give rise to the diagnosis of sight-threatening, permanent and fatal conditions, such as FKS. Non-surgical treatments include oral steroidal therapy, radiotherapy, and chemotherapy; however, neurosurgery is normally required.

The Efficacy of Glucocorticoids in the Treatment of Nonarteritic Anterior Ischemic Optic Neuropathy: A Systematic Review and Meta-Analysis

Background. To evaluate the clinical effects and safety of glucocorticoids for patients with nonarteritic anterior ischemic optic neuropathy (NAION). Methods. The databases MEDLINE, Embase, PubMed, Cochrane Database, and Web of Science were used to search for the relevant studies, and full-text articles that reported on the evaluation of glucocorticoids vs. no-treatment or placebo for patients with NAION. Review Manager 5.4 was used to estimate the pooled effects of the results among selected studies. Forest plots, funnel plots, and Begg’s rank correlation were also performed on the included articles. Results. A total of 983 patients were contained in the 9 studies that satisfied the eligibility criteria. The meta-analysis showed that, compared with the control group, the glucocorticoid group had significantly improved the VA (MD: -0.25, 95% CI [-0.45, -0.05], $P=0.02$ ), VF (MD: -0.50, 95% CI [-0.94, -0.07], $P=0.02$ ), and RNFL (MD: -14.10, 95% CI [-26.41, -1.79], $P=0.02$ ) in NAION patients and had a high improvement rate of VA (RR 1.31, 95% CI [1.12, 1.52], $P=0.0005$ ). No significant publication bias was observed in our study. Discussion. Our research preliminarily confirmed the effectiveness of glucocorticoids for NAION treatment, but more high-quality RCTs focusing on the hormone adverse reactions should be performed to verify our conclusions.

Case Report: Bilateral Cecocentral Visual Field Defect Secondary to Congenital Optic Disc Pit

SIGNIFICANCE

Congenital optic disc pits are known to cause complications, commonly maculopathy due to retinoschisis and/or neurosensory retinal detachment. Retinal nerve fiber layer defects with associated visual field defects without maculopathy are another complication and can result in decreased visual function but have rarely been reported in the literature, especially bilaterally.

PURPOSE

This case report describes a patient with bilateral cecocentral visual field defects due to congenital optic nerve pits without associated maculopathy.

CASE REPORT

A 42-year-old Black man presented with blur symptoms at near uncorrected. Of note, there was no history of substance abuse or nutritional deficiencies. Best-corrected acuities were 20/20 in the right eye and 20/30 in the left eye. Clinical examination revealed bilateral focal grayish depression of the temporal optic nerve cup with associated papillomacular retinal nerve fiber layer defects. Optical coherence tomography (OCT) imaging revealed bilateral focal excavation of the temporal cup, temporal thinning of the retinal nerve fiber layer, and correlated binasal thinning of the ganglion cell complex, in the absence of retinoschisis or neurosensory detachment. Threshold visual field testing revealed stable bilateral cecocentral visual field defects. A diagnosis of bilateral cecocentral visual field defect secondary to congenital optic disc pits was made based on the patient's history and clinical examination.

CONCLUSIONS

A cecocentral visual field defect, unrelated to maculopathy, is a less common complication of congential optic disc pits that can cause decreased visual function. This case report provides evidence of this bilateral ocular condition and reviews the reported clinical, OCT, and threshold visual field manifestations of the disease. Specifically, spectral-domain OCT ganglion cell analysis seems useful in localizing the visual field defect.

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.

Long term therapeutic effects of icariin‐loaded PLGA microspheres in an experimental model of optic nerve ischemia via modulation of CEBP ‐β/ G‐CSF /noncanonical NF‐ κ B axis

An ischemic insult at optic nerve (ON) is followed by detrimental neuroinflammation that results in progressive and long‐lasting retinal ganglion cell (RGC) death and vision loss. Icariin was reported to be a safe and effective natural anti‐inflammatory drug. Herein, we evaluated the long‐term therapeutic effects of a single intravitreal injection of poly(lactide‐co‐glycolide) PLGA–icariin in a rat model of anterior ischemic optic neuropathy (rAION). Treatment with PLGA microspheres of icariin preserved the visual function and RGC density for 1 month in the rAION model. In addition, ON edema and macrophage infiltration were inhibited by treating PLGA microspheres of icariin. We found that the binding complex of icariin and CCAAT enhancer binding protein beta (CEBP‐β) significantly induced endogenous granulocyte colony‐stimulating factor (G‐CSF) expression to activate noncanonical nuclear factor kappa B (NF‐κB) signaling pathway by promoting an alternative phosphorylation reaction of IKK‐β. Activation of noncanonical NF‐κB signaling pathway promoted the M2 microglia/macrophage polarization and AKT1 activation, which prevented neuroinflammation and RGC apoptosis after ON infarct. This study concluded that protective mechanism of icariin is a CEBP‐β/G‐CSF axis‐induced noncanonical NF‐κB activation, which provides the long‐term neuroprotective effects via anti‐inflammatory and antiapoptotic actions after ON ischemia.

The pathophysiology of Sumatriptan induced non-arteritic anterior ischemic optic neuropathy

Objective: To report a case of a non-arteritic anterior ischemic optic neuropathy (NAAION) in a patient treated with Sumatriptan. Materials and methods: NAAION represents a severe affection that frequently determines irreversible visual acuity damage. The exact cause is yet to be identified, but is usually connected to the systemic status of the patient. We presented the case of a 53-year-old female patient who complained of visual acuity loss in her right eye, associated with inferior visual field (VF) damage. Patient history revealed migraine attacks, raised arterial blood pressure (BP), mitral valve insufficiency and dyslipidemia. Systemic treatment included Sumatriptan for migraine attacks and Bisoprolol for arterial hypertension. Results: A complete ophthalmologic examination was performed, including a visual field examination and optic coherence tomography. Interdisciplinary consults, along with inflammatory biomarkers, brain scan and cardiovascular Doppler echography were used to establish the final diagnosis. Considering the patient's history, systemic medication, clinical picture, paraclinical findings and interdisciplinary check-ups, NAAION was established as a diagnosis. Discussion: NAAION occurs more frequently after the age of 50 years old and may be associated with systemic factors such as nocturnal hypotension, diabetes, atherosclerosis, sleep apnea. In the present case, the association of medically induced nocturnal hypotension and vasoconstriction led to optic nerve ischemia. Conclusions: In a patient with multiple pathology, we must consider the systemic therapy when performing any clinical examination. Abbreviations: AAION = arteritic anterior ischemic optic neuropathy, AION = anterior ischemic optic neuropathy, BCVA = best corrected visual acuity, BP = blood pressure, CS = corticosteroid, IOP = intraocular pressure, LE = left eye, MRI = magnetic resonance imaging, NAAION = non-arteritic anterior ischemic optic neuropathy, OCT = optical coherence tomography, ON = optic nerve, OU = both eyes, RE = right eye.

Follow-up of Nonarteritic Anterior Ischemic Optic Neuropathy With Optical Coherence Tomography Angiography

BACKGROUND

Peripapillary and macular microvasculature alterations after nonarteritic ischemic optic neuropathy (NAION) have been investigated in several studies. We aimed to explore the vascular changes from acute NAION (aNAION) to chronic NAION (cNAION).

METHODS

This prospective observational study composed of 16 eyes with aNAION and 40 healthy age-matched controls. Eyes with NAION were followed up for more than 6 months after acute event. Optical coherence tomography angiography (OCTA) was used to evaluate peripapillary and macular vessel densities (VDs). The customized software was used for calculating deep retinal VD to attenuate the large superficial vessel projection effect.

RESULT

The mean age of patients with NAION and controls was 56.13 ± 13.2 and 54.46 ± 15.5 years, respectively (P = 0.195). Radial peripapillary capillary density was significantly lower in both eyes with aNAION and eyes with cNAION than healthy eyes. Peripapillary capillary density decreased significantly from the acute to the chronic phase of NAION with values of 41.77 ± 4.05% and 34.35 ± 7.30%, respectively (P < 0.001). The mean superficial macular VD was 46.83 ± 3.47% in aNAION and 44.49 ± 4.50% in cNAION eyes with no significant difference between them (P = 0.252), but both were lower than control eyes. Deep macular VD was not affected in aNAION and cNAION eyes compared with control eyes. Correlation analysis in eyes with cNAION revealed that there were significant correlations between peripapillary nerve fiber layer and the capillary density (r = 0.772, P < 0.001) and between ganglion cell complex thickness and corresponding superficial macular VD.

CONCLUSIONS

Although a decrease in peripapillary capillary density in aNAION eyes with active disc edema progressed when evaluated in the cNAION state, progressive VD loss was not observed in the macular area, suggesting a nonprogressive nature of macular vessel involvement in NAION.

Clinical profile, diagnostic challenges, and outcomes in subacute/chronic cerebral sinus venous thrombosis

Purpose:

To report clinical profile, diagnostic challenges, and outcomes in cases of subacute/chronic cerebral sinus venous thrombosis (CSVT) presenting to neuro-ophthalmologists/neurologists.

Methods:

This was a multicentric, retrospective, observational study. Records of patients with neuroimaging proven subacute/chronic CSVT seen the from January 1, 2016 to March 31, 2020 were analyzed. Data collected included duration of symptoms, diagnosing physician, ophthalmological vs. focal/generalized neurological symptoms, optic disc examination, perimetry, and neuroimaging findings. Statistical analysis was performed using STATA software.

Results:

Forty-three patients with subacute (30)/chronic (13) CSVT were identified (32 males, 11 females). Median age was 37 (IQR 27–47) years. The presenting complaints were blurred vision 34 (79%), headaches in 25 (58%), vomiting 12 (28%), and diplopia 11 (26%). Eleven patients had associated sixth cranial nerve palsy. All but two patients had either disc edema/optic atrophy; four had unilateral disc edema at presentation. Ophthalmologists and neurologists diagnosed/suspected CSVT correctly in 13/29 (45%) and 11/14 (78.5%) patients, respectively. Most common initial alternate diagnosis was idiopathic intracranial hypertension in 12 (28%). Female gender, age ≤36, unilateral papilledema, not obtaining venogram at initial workup increased chances of initial alternate diagnosis. Median follow-up duration was 21 days. Average visual function remained stable in majority of patients at last follow-up. In total, 47.6% of patients had best-corrected visual acuity ≥20/30 at the final follow-up.

Conclusion:

In our series, subacute or chronic CSVT presented presented primarily with symptoms of intracranial hypertension. Unilateral papilledema, middle-aged patients, female gender, lack of focal/generalized neurological symptoms created diagnostic dilemma. Visual function remained stable in majority of patients.

Risk Factors for Non-arteritic Anterior Ischemic Optic Neuropathy: A Large Scale Meta-Analysis

Objective: We conducted a meta-analysis to explore all the potential risk factors for non-arteritic anterior ischemic optic neuropathy (NAION) based on the published literature. Methods: A comprehensive literature search through the online databases was performed to obtain studies concerning the risk factors of NAION up to June 2020. Pooled unadjusted odds ratios (ORs) or rate ratios (RRs) were calculated to evaluate the weight of risk factors. This study was registered in PROSPERO under the number CRD42018084960. Results: Our meta-analysis included 49 original studies comprising of more than 10 million patients. The following risk factors were proved to be significantly associated with NAION: male gender (OR = 1.67, 95% CI: 1.50-1.85, P < 0.00001), hypertension (RR = 1.28, 95% CI: 1.20-1.37, P < 0.00001), hyperlipidemia (RR = 1.43, 95% CI: 1.26-1.62, P < 0.00001), diabetes mellitus (DM) (RR = 1.53, 95% CI: 1.36-1.73, P < 0.00001), coronary heart disease (CHD) (RR = 1.68, 95% CI: 1.24-2.27, P = 0.0008), sleep apnea (RR = 3.28, 95% CI: 2.08-5.17, P < 0.00001), factor V Leiden heterozygous (RR = 2.21, 95% CI: 1.19-4.09, P = 0.01), and medication history of cardiovascular drugs. Conclusion: We concluded that the above risk factors were significantly related to NAION. Better understanding of these risk factors in NAION can help the direct therapeutic approaches.

Altered Brain Functional Connectivity at Resting-State in Patients With Non-arteritic Anterior Ischemic Optic Neuropathy

Purpose: To investigate the possible changes in functional connectivity (FC) in patients with non-arteritic anterior ischemic optic neuropathy (NAION) using resting-state functional MRI (fMRI).

Methods: Thirty-one NAION patients and 31 healthy controls were recruited and underwent resting-state fMRI scans. Regions of interest (ROIs) were defined as bilateral Brodmann’s area 17 (BA17). FC analysis was performed between the ROIs and the rest of the brain regions, and the between group comparisons of FC were performed. We conducted correlation analysis between the FC changes and the clinical variables in NAION patients.

Results: Compared with healthy controls, patients with NAION showed significantly decreased FC between the left BA17 and the right inferior frontal gyrus, left caudate nucleus. As for the right BA17, patients exhibited significantly increased FC with the left olfactory gyrus and decreased FC with the right superior frontal gyrus (SFG), right insula. Moreover, FC values between the right insula and the right BA17 were positively correlated with the right side of mean sensitivity in the central visual field (r = 0.52, P < 0.01) and negatively correlated with the right side of mean defect in the central visual field (r = −0.55, P < 0.01).

Conclusion: Our study indicated that patients with NAION showed significantly abnormal functional reorganization between the primary visual cortex and several other brain regions not directly related to visual function, which supports that NAION may not only be an ophthalmic disease but also a neuro-ophthalmological disease.

The Associations of Obstructive Sleep Apnea and Eye Disorders: Potential Insights into Pathogenesis and Treatment

Purpose of Review

Obstructive sleep apnea (OSA) patients are at significantly increased risks for cardiovascular and cerebrovascular morbidities. Recently, there has been heightened interest in the association of OSA with numerous ocular diseases and possible improvement of these conditions with the initiation of OSA treatment. We reviewed the current evidence with an emphasis on the overlapping pathogeneses of both diseases.

Recent Findings

Currently available literature points to a substantial association of OSA with ocular diseases, ranging from those involving the eyelid to optic neuropathies and retinal vascular diseases. Since the retina is one of the highest oxygen-consuming tissues in the body, the intermittent hypoxia and hypercapnia ensuing in OSA can have deleterious effects on ocular function and health. Tissue hypoxia, autonomic dysfunction, microvascular dysfunction, and inflammation all play important roles in the pathogenesis of both OSA and ocular diseases. Whether OSA treatment is capable of reversing the course of associated ocular diseases remains to be determined. It is anticipated that future therapeutic approaches will target the common underlying pathophysiologic mechanisms and promote favorable effects on the treatment of known associated ocular diseases.

Summary

Emerging evidence supports the association of ocular diseases with untreated OSA. Future studies focusing on whether therapeutic approaches targeting the common pathophysiologic mechanisms will be beneficial for the course of both diseases are warranted.

siRNA: Mechanism of action, challenges, and therapeutic approaches

Owing to specific and compelling gene silencing, RNA interference (RNAi) is expected to become an essential approach in treating a variety of infectious, hemato-oncological, cardiovascular, and neurodegenerative conditions. The mechanism of action of small interfering RNA (siRNA) is based on post-transcriptional gene silencing. siRNA molecules are usually specific and efficient in the knockdown of disease-related genes. However, they are characterized by low cellular uptake and are susceptible to nuclease-mediated degradation. Therefore, siRNAs require a carrier for their protection and efficient delivery into target cells. The current review highlights the siRNA-based mechanism of action, challanges, and recent advances in clinical applications.

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.

Clinical characteristics of progressive nonarteritic anterior ischemic optic neuropathy

AIM

To study whether patients with progressive nonarteritic anterior ischemic optic neuropathy (NAION) present earlier than patients with stable NAION and to describe their clinical characteristics and visual outcome.

METHODS

This was a retrospective chart review. All patients with NAION seen during the acute stage from January 2012 to December 2018 were reviewed. Patients were included if they had documented disc edema and follow up of at least 3mo. Patients with progressive NAION were identified if they worsened in 2 out of 3 parameters: visual acuity ≥3 Snellen lines; Color vision ≥4 Ishihara plates; the visual field defect involved a new quadrant. The clinical characteristics, time from symptom onset to presentation, systemic risk factors and visual outcome were compared to patients with stable NAION.

RESULTS

Totally 122 NAION cases met the inclusion criteria. Mean age was 58.1y (range 22-74), 70% were men. Twenty cases (16.4%) had progressive NAION. Patients with progressive NAION did not differ from stable NAION in their demographics, systemic risk factors or in their initial visual deficit. At last follow up, median visual acuity was 1.0 logMAR (IQR 0.64-1.55) in patients with progressive NAION, vs 0.18 (IQR 0.1-0.63) in stable NAION (P<0.001). Median color vision testing was 0 plates correct (IQR 0-2.5%) vs 92% plates correct (IQR 50%-100%) in the stable NAION group (P<0.001). Patients with progressive NAION differed in the time from symptom onset to presentation (median 2d vs 5d, P=0.011).

CONCLUSION

We find no identifiable risk factors associated with progressive NAION. Progressors arrive earlier for ophthalmological evaluation.

Alterations in retinal and choroidal thickness following nonarteritic anterior ischemic optic neuropathy

PURPOSE

To show alterations of retinal arteriolar caliber (RAC), retinal venular caliber (RVC), retinal nerve fiber layer thickness (RNFLT), peripapillary choroidal thickness (ppCT), and central macular thickness (CMT) in acute and chronic phases of nonarteritic anterior ischemic optic neuropathy (NAION).

METHODS

Forty-one eyes of 41 patients with NAION were included in this retrospective study. RAC, RVC, RNFLT, ppCT, and CMT measurements were performed via spectral-domain optical coherence tomography in the acute and chronic phases of NAION.

RESULTS

RVC, RNFLT, ppCT, and CMT were significantly thinner in the chronic phase compared to the acute phase (p < 0.001), whereas RAC remained similar throughout the visits (p = 0.26). The visual acuity difference between the acute and chronic phases was not correlated with the changes of RAC, RVC, RNFLT, ppCT, or CMT.

CONCLUSIONS

RVC, RNFLT, ppCT, and CMT decreases in the chronic phase when compared to the acute phase of NAION, whereas RAC does not change significantly.

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.

Bilateral diabetic papillopathy developed after starting insulin treatment. Potential toxic effect of insulin? A case report

BACKGROUND

Diabetic papillopathy is a complication of diabetes. It presents with edema, uni or bilateral and vascular alteration of the anterior optic nerve. Often this complication is observed in patients with severe diabetic retinopathy, but is rarely observed in isolated form. Some authors believe that diabetic papillitis is a particular form of non-arteritic anterior ischemic optic neuropathy (NAION). But there is important evidence that confers an inflammatory component to diabetic papillopathy. We report in this work a rare case of isolated acute bilateral diabetic papillopathy developed in a diabetic patient after adding the insulin to the oral hypoglycemic therapy.

CASE PRESENTATION

Male patient, 49-years-old, diabetic type 2, with altered glycemia at follow up, with clinical history of HbA1c 8% to 12% in the last 2 years, on oral hypoglycemic therapy for 10 years. He never had a history of diabetic retinopathy. At the last check-up, this patient presented bilateral papillopathy, without reduction of visual acuity bilaterally. The patient reports he added 10 days before the insulin therapy to the oral hypoglycemic therapy, under medical supervision. Hematochemical and serological tests were requested, which excluded the presence of inflammatory and infectious diseases. The brain magnetic resonance imaging (MRI) with gadolinium excluded the hypothesis of optic neuritis or intracranial hypertension. Cardio-circulatory tests were normal. Fluorescein angiographic examinations and optical coherence tomography (oct) confirmed the bilateral edema and the thickening of optic nerve without other retinal damage. Therefore he was diagnosed with bilateral diabetic papillopathy. Then, diabetologists added pump insulin treatment to the oral hypoglycemic therapy. After 2 months, his blood sugar levels and HbA1C improved and papillopathy regressed.

CONCLUSION

We have reported a rare case of bilateral acute diabetic papillopathy associated with the addition of insulin to the oral hypoglycemic therapy. A randomized control study with diabetic patients, would be useful to verify the possible injuries of the optic nerves during the delicate transition to insulin therapy.

Transcriptomic Analysis of circRNAs in the Peripheral Blood of Nonarteritic Anterior Ischemic Optic Neuropathy

The aim of the study is to explore the expression profile variation of circular RNAs (circRNAs) in the peripheral blood of subjects with nonarteritic anterior ischemic optic neuropathy (NAION) and without NAION, to analyze the differential expression results, and to predict the role of circRNAs in disease development, providing novel ideas and methods for treatment and diagnosis. High-throughput sequencing to explore the expression profiles of RNAs in the peripheral blood of 6 NAION patients and 5 healthy controls was applied. Quality control obtained the advanced data from the original data by ticking out the unqualified data. Then, cluster analysis, volcano plot, coexpression network, and protein-protein interaction network (PPI) were performed. Gene ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were used to analyze the whole expressed genes. Lastly, the quantitative real-time Polymerase Chain Reaction (qRT-PCR) was used to verify those significantly differentially expressed circRNAs and do some bioinformatics analysis and prediction in 12 NAION patients and 12 controls. There were significant differences in the expression of 49 circRNAs in the peripheral blood of NAION patients, in which there were 24 upregulations and 25 downregulations (variation folds > 2 and P < 0.05), and it was confirmed that hsa_circ_0005583, hsa_circ_0003922, hsa_circ_0002021, and hsa_circ_0000462 were significantly downregulated (variation folds > 2 and P < 0.05), especially hsa_circ_0005583 which was the most significantly changed one (P < 0.001), and are related to processes such as neurodegeneration, oxidative stress, immunity, and metabolism. The expression profile of circRNAs in the peripheral blood of NAION patients is significantly changed, enriching our understanding of the disease.

[Non-arteritic ischaemic optic neuropathy as a target organ lesion in arterial hypertension]

A 39-year-old black male who consulted with sudden and painless loss of vision in his right eye in the context of a hypertensive crisis. A history of essential arterial hypertension uncontrolled at home due to lack of therapeutic adherence and with target organ involvement: lacunar infarct, grade IV hypertensive retinopathy and left ventricular concentric hypertrophy. Renal function was normal, without albuminuria. The clinical picture was classified as non-arteritic ischaemic optic neuropathy after ruling out vascular, traumatic, infectious and autoimmune disease. The patient presented discrete improvement of the visual deficit with the control of blood pressure. From his history and complementary tests, it was concluded that the ischaemic optic neuropathy was due to malignization of his arterial hypertension.

[Ischemic optic neuropathies]

Ischemic optic neuropathies include any vascular disease of the optic nerve. Anterior ischemic optic neuropathies are classically distinguished from posterior ischemic optic neuropathies by the presence of optic disc edema in the former, and the absence thereof in the latter. Non-arteritic acute anterior ischemic optic neuropathy is the most common ischemic optic nerve disease. Its exact cause remains unknown. A disc at risk (small and crowded optic nerve) is a typical backdrop for the development of non-arteritic ischemic optic neuropathy. There is no curative or preventive treatment. Posterior ischemic optic neuropathy is exceedingly rare, compared to anterior ischemic optic neuropathy. It is more frequent in patients with cardiovascular risk factors or in the perioperative period. There is no treatment. In any case of ischemic optic neuropathy, an arteritic cause must be ruled out urgently through clinical and paraclinical examinations. The most frequent cause is giant-cell arteritis. In this case, emergency treatment with intravenous methylprednisolone is required in order to limit vision loss in the affected eye and to prevent vision loss in the other eye.

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.

Ocular blood flow as a clinical observation: Value, limitations and data analysis

Alterations in ocular blood flow have been identified as important risk factors for the onset and progression of numerous diseases of the eye. In particular, several population-based and longitudinal-based studies have provided compelling evidence of hemodynamic biomarkers as independent risk factors for ocular disease throughout several different geographic regions. Despite this evidence, the relative contribution of blood flow to ocular physiology and pathology in synergy with other risk factors and comorbidities (e.g., age, gender, race, diabetes and hypertension) remains uncertain. There is currently no gold standard for assessing all relevant vascular beds in the eye, and the heterogeneous vascular biomarkers derived from multiple ocular imaging technologies are non-interchangeable and difficult to interpret as a whole. As a result of these disease complexities and imaging limitations, standard statistical methods often yield inconsistent results across studies and are unable to quantify or explain a patient's overall risk for ocular disease. Combining mathematical modeling with artificial intelligence holds great promise for advancing data analysis in ophthalmology and enabling individualized risk assessment from diverse, multi-input clinical and demographic biomarkers. Mechanism-driven mathematical modeling makes virtual laboratories available to investigate pathogenic mechanisms, advance diagnostic ability and improve disease management. Artificial intelligence provides a novel method for utilizing a vast amount of data from a wide range of patient types to diagnose and monitor ocular disease. This article reviews the state of the art and major unanswered questions related to ocular vascular anatomy and physiology, ocular imaging techniques, clinical findings in glaucoma and other eye diseases, and mechanistic modeling predictions, while laying a path for integrating clinical observations with mathematical models and artificial intelligence. Viable alternatives for integrated data analysis are proposed that aim to overcome the limitations of standard statistical approaches and enable individually tailored precision medicine in ophthalmology.