Non-arteritic anterior ischemic optic neuropathy versus cerebral ischemic stroke

Early effects of cardiopulmonary bypass surgery on retinal nerve fiber layer and ganglion cell layer

PURPOSE

To determine the effects of cardiopulmonary bypass surgery on retinal nerve fiber layer, ganglion cell layer, and macula by optic coherens tomography (OCT).

METHOD

Sixty-six eyes of 33 patients aged between 44 and 74 who were indicated for cardiopulmonary bypass surgery in the cardiovascular surgery clinic were included in the study. Routine ophthalmologic examinations of all patients were performed before and 1 week after surgery. In addition, 3D(H) Macula+5 Line Cross 12 × 9 mm mod and Peripapilar 3D Disk 6 × 6 mm mod data were analyzed with OCT (Topcon, Triton Swept Source-OKT, Tokyo, Japan) device. Peripapillary total, superior, inferior retinal nerve fiber layer (RNFL), optic disc cavity volume, cup-to-disc ratio, macular ganglion cell layer (GCL), macular thickness were compared before and after surgery.

RESULTS

After cardiopulmonary bypass surgery, thickening was detected in the total RNFL (p<0.001), superior RNFL (p = 0.01) and inferior RNFL (p<0.001) layers. There was no change in the values of GCL, macular thickness, optic disc cupping volume, cup-to-disc ratio after surgery (p>0.05). There was a positive correlation (r = 0.392 p<0.05) between the patients' blood oxygen (PO2) values during bypass surgery with their post-surgical GCL+ values, and a negative correlation between optic disc cup volumes (r=-0.349 p<0.05).

CONCLUSION

RNFL thickening has been detected in patients undergoing cardiopulmonary bypass surgery. This thickening may occur secondary to ischemic edema that occurs during surgery. Considering the late complications of ischemic edema in the RNFL, oxygen levels should be kept at an optimum level during surgery and long-term ophthalmologic follow-ups should be performed.

The Usefulness of the Erythrocyte Sedimentation Rate and C-reactive Protein for the Differential Diagnosis of Non-Arteritic Anterior Ischemic Optic Neuropathy in the Era of Microinflammation

PURPOSE

The presence of a microinflammatory response is one of the possible pathological mechanisms related to the development of nonarteritic anterior ischemic optic neuropathy (NAAION), a common cause of optic neuropathy in old age.We tested whether individuals with NAAION harbor a heightened microinflammatory response compared to controls.

METHODS

We measured the erythrocyte sedimentation rate (ESR) and high sensitivity C-reactive protein (hs-CRP) in NAAION patients during hospital admission and in four matched controls for each patient, retrieved from a large cohort of 20,000 apparently healthy individuals.

RESULTS

We included 128 NAAION patients and 512 controls. No significant differences were found between patients and controls regarding the inflammatory biomarkers.

CONCLUSIONS

This is the first report showing a lack of difference in ESR and hs-CRP levels between NAAION patients and matched controls, suggesting NAAION is not associated with a heightened inflammatory response, such as the one associated with multiple atherothrombotic risk factors.

Association Study of MTHFR Polymorphisms with Nonarteritic Anterior Ischemic Optic Neuropathy in a Spanish Population

Introduction

Nonarteritic anterior ischemic optic neuropathy (NAION), painless loss of central and/or peripheral vision, is a multifactorial disease caused by insufficient blood flow through the posterior ciliary arteries to the optic nerve head. Mutations in the methylenetetrahydrofolate reductase (MTHFR) gene, triggering hyperhomocysteinemia as a consequence of a decreased activity of the codified enzyme, have been considered to be among the risk factors of NAION.

Objective

The main aim was to study the association of the most common MTHFR genetic polymorphisms C677T and A1298C with NAION in a Spanish population.

Methods

In this case-control study, the association of the most common MTHFR polymorphisms was investigated in 94 unrelated native Spanish patients diagnosed with NAION and 204 healthy controls. Two single nucleotide polymorphisms located in the MTHFR gene, C677T (rs1801133) and A1298C (rs1801131), were analyzed by DNA sequencing and TaqMan assays.

Results

The allelic and genotypic frequencies of the MTHFR variants obtained in the NAION group were not significantly different when compared with the control group. A higher frequency of the C677T/A1298C genotype, codifying the nonmutated MTHFR form, was obtained in control subjects (11.27%) compared to NAION patients (4.26%), suggesting a protective effect of the wild-type protein, although this result was not conclusive considering the obtained confidence interval (CI) (95% CI: 0.13-1.06). Study of additional clinical factors including hypertension, diabetes mellitus, and dyslipidemia showed no association with a higher risk of NAION. Conversely, the clinical history of heart or cerebrovascular diseases was significantly higher in NAION patients compared to controls. Over the world, risk variants of the MTHFR gene are highly frequent, excluding African black populations, indicating a racial influence.

Conclusions

The MTHFR variants did not significantly increase the risk of suffering from NAION. However, considering that individuals with at least one of the risk variants have the MTHFR enzyme with decreased activity, it cannot be ruled out that these mutations are relevant for the development of NAION in a subgroup of the population with other specific characteristics. These may include high plasma levels of homocysteine along with nutritional deficiencies including low folate or vitamin B12 and the combination of systemic and local risk factors.

Natural history and visual outcome of nonarteritic anterior ischemic optic neuropathy in Southern Taiwan: a pilot study

PURPOSE

To investigate the natural course, visual outcome, and risk factors for visual loss after nonarteritic anterior ischemic optic neuropathy (NAION) attack in Chinese patients from a tertiary medical center in Southern Taiwan.

METHODS

This is a longitudinal observational study that included sixty NAION patients, who were seen in our neuro-ophthalmology clinic from 2007 to 2016. Records of their ophthalmic history, medical history, best-corrected visual acuity (BCVA), visual field (VF) testing, and optical coherence tomography (OCT) were obtained for analysis.

RESULTS

When the first visit was within two weeks after NAION onset, 62% of patients had BCVA of less than 0.1 (logMAR BCVA ≥ 1) and 38% had at least moderate-severe depression (VF grade ≥ 3) on VF on the initial visit. VA stabilized at three months after onset and was predictive of VA at 12 months. Diabetes mellitus was a risk factor associated with VA worsening. Sixty-one percent of patients had BCVA of less than 0.1 at 12 months after onset. VF remained relatively unchanged during the disease, with 41% eyes having VF grade ≥ 3 at 12 months after onset. On OCT, all quadrants of retinal nerve fiber layer thickened initially, returned to the level of the fellow eye at one month, and continued thinning up to 12 months slowly.

CONCLUSION

In Southern Taiwan, a higher proportion of Chinese patients (over half) presented with severe visual loss during the first two weeks of NAION attack and at 12 months after the onset of NAION as compared to the findings previously reported in Caucasians. Understanding the natural course of NAION in Chinese patients may provide insights toward a possible therapeutic window for NAION treatments in this group of patients.

The Use of Vitamins and Coenzyme Q10 for the Treatment of Vascular Occlusion Diseases Affecting the Retina

Nutritional supplementation with antioxidants and vitamins is widely recommended in the treatment of vascular disorders affecting the retina, although there is insufficient evidence on its effectiveness. The vitamin-like compound coenzyme Q10 (CoQ10) is a nutritional supplement of current interest to treat neurodegenerative diseases. Here, we report a retrospective clinical case series study of 48 patients diagnosed with retinal vascular diseases, including non-arteritic ischemic optic neuropathy (NAION), retinal artery occlusion (RAO), and homonymous hemianopia or quadrantanopia following stroke, treated with oral supplementation with CoQ10 (100 mg per day) and vitamins. Patient follow-up was performed using the Humphrey field analyzer and 30-2 testing algorithm to determine the visual field index (VFI) and progression rates. All treated patients showed positive VFI progression rates per year: +11.5 ± 15% for NAION patients (n = 18), +22 ± 17% for RAO patients (n = 7), +9.3 ± 10.5% for hemianopia/quadrantanopia patients (n = 10), and +11 ± 21% for patients with other conditions (n = 13). The interruption of CoQ10 supplementation in one patient resulted in a pronounced decrease of the VFI, which was partially recovered when treatment was restored. This study supports the role of CoQ10 as a nutritional therapeutic agent for vascular diseases affecting the retina. Owing to decreased VFI after interruption of CoQ10, its beneficial effects may be reversible.

Increased Risk of Stroke in Patients With Nonarteritic Anterior Ischemic Optic Neuropathy: A Nationwide Retrospective Cohort Study

PURPOSE

To investigate the incidence and prevalence of nonarteritic anterior ischemic optic neuropathy (NAION), and to extrapolate the risk of cerebrovascular events following NAION.

DESIGN

Retrospective cohort study.

METHODS

We identified NAION patients first, and then looked for the diagnosis of stroke after the diagnosis of NAION.

SETTING

The study group was composed of patients diagnosed with NAION seeking ambulatory care from 2000 to 2011. The control group was extracted from a database by randomly selecting 2 patients for every NAION patient, matched by age and sex.

MAIN OUTCOME MEASURES

Cox proportional hazards regression analysis was performed to calculate adjusted hazard ratio (aHR) of stroke for the 2 groups. Subgroup analysis of subjects with or without comorbidities was also investigated.

RESULTS

Four hundred and fourteen patients were included in the study group and 789 in the control group. The mean follow-up period was 5.9 years. The incidence of NAION was 3.72/100 000 person-years in Taiwan, and the prevalence of NAION was 48.18/100 000 persons. The study group was more likely to have ischemic stroke (aHR = 2.03, P = .003), but not hemorrhagic stroke (aHR = 1.24, P = .696), than the control group. Among the subgroup with comorbidities, the risk of ischemic stroke among the subjects with NAION was 3.35 times higher than those without NAION (95% confidence interval: 1.67, 6.70).

CONCLUSIONS

Patients with NAION have an increased risk of ischemic stroke. Physicians should refer all patients with NAION for systemic survey of vasculopathy and control of modifiable risk factors to prevent irreversible neurological sequelae.

The Association Between Obstructive Sleep Apnea and Nonarteritic Anterior Ischemic Optic Neuropathy: A Systematic Review and Meta-Analysis

PURPOSE

Nonarteritic anterior ischemic optic neuropathy (NAION) is a multifactorial disease, and recently epidemiologic studies have investigated the association between obstructive sleep apnea (OSA) and NAION. A systematic review of the association of OSA and NAION has not been performed. Therefore, the current meta-analysis was performed to assess such potential association between OSA and risk of NAION.

METHODS

A systematic search of PubMed and EMBASE databases was performed for published studies evaluating the association between OSA and NAION. The summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for categorical risk estimates. Sensitivity analyses and subgroup analyses were also performed to assess the robustness of pooled outcomes.

RESULTS

A total of four prospective cohort studies and one case-control study met our inclusion criteria. The pooled OR of developing NAION in the subjects with OSA was 6.18 (95% CI, 2.00-19.11) versus non-OSA controls. Sensitivity analyses showed that no matter one study excluded, the pooled OR did not change significantly, which indicated that the evidence was robust. In subgroup analyses, a significant association was seen in studies matched systemic risk factors (OR, 5.00; 95% CI, 2.22-11.25), but not in those non-matched. The magnitude and direction of effects were also affected by methodological variability, including study design, and diagnosis of OSA.

CONCLUSIONS

The findings from this meta-analysis supported the robust evidence that OSA was a strong independent risk factor of NAION. Relative to non-OSA controls, the subjects with OSA were found to have a more than sixfold risk of NAION. In future, more well-designed studies are needed to confirm these findings.

Ischemic optic neuropathies - where are we now?

Ischemic optic neuropathy is of two types: anterior and posterior. Non-arteritic anterior ischemic optic neuropathy (NA-AION) is the most common type of ischemic optic neuropathy. There are three major misconceptions about NA-AION: (1) that its pathogenesis is not known, (2) that NA-AION and ischemic cerebral stroke are similar in nature, pathogenetically and in management, and (3) that there is no treatment. All these misconceptions are based on lack of in-depth knowledge of the subject. They are discussed in the light of our current scientific knowledge. The pathogenesis of NA-AION is known but is highly complex. NA-AION and ischemic cerebral stroke are very different clinical entities, pathogenetically and in management. Aspirin has no beneficial effect. Corticosteroid therapy during the initial stages can be beneficial. To reduce the risk of development of NA-AION in the other eye or of further visual loss in the same eye, it is essential to reduce as many risk factors as possible. Management of arteritic anterior ischemic optic neuropathy and of posterior ischemic optic neuropathy is discussed.