The Pathogenesis of Nonarteritic Anterior Ischemic Optic Neuropathy

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.

Imageology of internal carotid artery siphon in non-arteritic anterior ischaemic optic neuropathy

AIM

To evaluate whether narrowing of internal carotid artery siphon (ICAS) may increase the risk of developing non-arteritic anterior ischaemic optic neuropathy (NAION).

METHODS

Totally 30 consecutive patients who had unilateral NAION and 30 gender-matched control subjects were recruited in the present study. The diameter of ICAS of all the participants were measured using head-and-neck computed tomographic angiography (CTA). Color doppler flow imaging (CDI) was used to measure the haemodynamics parameters of ICAS and short posterior ciliary arteries (SPCAs) in all subjects. Comparison of parameters between the NAION patients and controls as well as between the two sides within the patients were performed. The correlation between the diameter of ICAS and NAION was analyzed.

RESULTS

A comparison of parameters between the affected side of the NAION patients and the controls, including the diameter of ICAS, the resistance index (RI) of ICAS, the blood flow velocities of SPCAs and RI of SPCAs, showed significantly difference (P<0.01), while there was no significant difference in terms of the mean blood flow velocity (Vm) of ICAS; Similar results were found while comparing all the measurements of the affected and unaffected side of patients (P for RI of SPCAs <0.05). No marked difference was detected in nearly all parameters except for RI of ICAS and SPCAs between the unaffected side of the NAION patients and the controls (P<0.05). The diameter of ICAS were significantly positive correlated with both peak systolic velocity (PSV) of SPCAs and end diastolic velocity (EDV) of SPCAs in patients with NAION (r=0.514, P<0.01 and r=0.418, P<0.05, respectively).

CONCLUSION

Narrowing of ICAS may increase the risk of developing NAION.

Pupillometric evaluation of the melanopsin containing retinal ganglion cells in mitochondrial and non-mitochondrial optic neuropathies

In recent years, chromatic pupillometry is used in humans to evaluate the activity of melanopsin expressing intrinsic photosensitive retinal ganglion cells (ipRGCs). Blue light is used to stimulate the ipRGCs and red light activates the rod/cone photoreceptors. The late re-dilation phase of pupillary light reflex is primarily driven by the ipRGCs. Optic neuropathies i.e. Leber hereditary optic neuropathy (LHON), autosomal dominant optic atrophy (ADOA), nonarteritic anterior ischemic optic neuropathy (NAION), glaucoma, optic neuritis and idiopathic intracranial hypertension (IIH) are among the diseases, which have been subject to pupillometric studies. The ipRGCs are differentially affected in these various optic neuropathies. In mitochondrial optic neuropathies, the ipRGCs are protected against degeneration, whereas in glaucoma, NAION, optic neuritis and IIH the ipRGCs are damaged. Here, we will review the results of pupillometric, histopathological and animal studies evaluating the ipRGCs in mitochondrial and non-mitochondrial optic neuropathies.