Nonarteritic Anterior Ischemic Optic Neuropathy Eyes Research Articles

Choroidal Thickness in Acute Non-arteritic Anterior Ischemic Optic Neuropathy.

PurposeTo compare the choroidal thickness in eyes with acute non-arteritic anterior ischemic optic neuropathy (NAION) with healthy contralateral eye and normal controls.MethodsThirty-eight eyes with NAION, thirty-eight unaffected fellow eyes, and seventy-four eyes from 37 healthy, age- and sex-matched subjects were included in this prospective comparative case-control study. Choroidal thickness was measured by enhanced depth imaging (EDI) of spectral domain optical coherence tomography (SD-OCT). Peripapillary choroidal thickness (PCT) was measured at 1000 and 1500 m from Bruch's membrane opening (BMO). Subfoveal choroidal thickness (SFCT) was measured in central subfoveal area, and 500 microns apart in temporal and nasal sides. Choroidal thickness among NAION eyes, uninvolved fellow eyes, and control eyes were compared.Results The mean of PCT at 1000 m was significantly thicker in NAION and fellow eyes compared to control eyes (169.7 47, 154.4 42.1, and 127.7 49.9 m, respectively, P 0.001 and P = 0.42). The mean PCT at 1500 m was also significantly thicker in NAION and fellow eyes compared to control eyes (178.6 52.8, 162.6 46.1, and 135.1 59 m, respectively, P = 0.007 and P = 0.048). The mean PCT at 1000 and 1500 m was significantly greater in NAION compared to fellow eyes (P = 0.027 and P = 0.035, respectively). The mean of SFCT was significantly thicker in NAION compared to control eyes (P = 0.032); however, there was no significant difference between uninvolved fellow and control eyes (P = 0.248).ConclusionThicker choroidal thickness in acute NAION and uninvolved fellow eyes compared to normal eyes suggests a primary choroidal role in NAION pathophysiology.

Assessment of peripapillary vessel density in acute non-arteritic anterior ischemic optic neuropathy.

To assess the peripapillary perfusion in eyes with acute non-arteritic anterior ischemic optic neuropathy (NAION) using optical coherence tomography angiography (OCTA). Twenty-five patients with unilateral acute NAION were included in this observational cross-sectional study. They were divided into two groups: group I (25 eyes) included eyes with acute NAION, and group II (25 eyes) included fellow normal eyes. Diagnosis of NAION was based on clinical examination and fluorescein angiography. OCTA (AngioVue, Optovue) was used to evaluate the optic nerve head perfusion and measure the peripapillary vessel density in all eyes included in the study. Fourteen male and 11 female patients with a mean age of 60.2 ± 3.5years were included in this study. The mean duration of presentation was 4.3 ± 0.6days. Mean BCVA was 0.13 ± 0.06 and 0.69 ± 0.18 in eyes with NAION and normal eyes, respectively (p < 0.001). The peripapillary vessel was significantly decreased in all eyes with NAION compared with normal ones (p < 0.001). Two morphological changes were noted in eyes with NAION: vascular dropout related to area of disc edema in 25 eyes (100% of eyes) and vascular dilatation with tortuosity in 17 eyes (68%). Eyes with NAION have decreased peripapillary vessel density with peripapillary vascular dilatation and tortuosity as assessed by OCTA.

Prospective analysis of macular and optic disc changes after non-arteritic anterior ischemic optic neuropathy

To prospectively analyse macular and optic disc changes after the occurrence of non-arteritic anterior ischemic optic neuropathy (NAION) and study possible predictors of final visual outcome. Patients with NAION underwent a complete ophthalmic examination, including spectral-domain optical coherence tomography of the macula and optic nerve head. The examination was repeated 1, 3, 6, 9 and 12 months after onset. Final visual prognosis was evaluated by visual field (VF) and best-corrected visual acuity (BCVA) at the final visit. Data within the NAION group were analysed over the course of the disease and compared to a disease-free control group at each visit. Twenty-two eyes with NAION and 43 eyes from a control group were included. The retinal nerve fiber layer (RNFL) was significantly thicker in NAION eyes than controls at presentation (P=0.00), and significantly decreased during the next 3 months after presentation (P=0.02). The ganglion cell+inner plexiform layer (GCIPL) was thinner in the NAION group throughout the course of the disease (all P<0.05). Although the acute NAION eyes had significantly lower cup/disc ratios and higher neuroretinal and disc sizes (all P=0.00), there were no significant differences between groups from the third month onwards (all P>0.05). The best predictors of BCVA and VF were GCIPL at 3 months of follow-up (r2=0.32; P=0.03) and RNFL at 6 months of follow-up (r2=0.41; P=0.01) respectively. RNFL and optic disc changes occur during the first 3 months after the onset of NAION, whereas GCIPL is affected soon after the onset of symptoms. GCIPL and RNFL are useful predictors of final visual outcome.

Steroids in the treatment of nonarteritic anterior ischemic optic neuropathy: A PRISMA-compliant meta-analysis.

Background:Non-arteritic anterior ischemic optic neuropathy (NAION) is the common cause of acute and subacute optic neuropathy in adults over the age of 50. Steroid administration in NAION seems to be in practice and is advised frequently by neurologists. The controversy regarding steroid usage in NAION is far from settled, with strong opinions on both sides. Despite a large amount of articles on this topic, but the results have not always been consistent. To address this gap, we decided to conduct a meta-analysis of all available published studies in order to better understand the effectiveness of steroids in treating NAION.Objectives:To identify the effectiveness of steroids in treating NAION.Methods:We performed a meta-analysis using databases, including PUBMED EMBASE, and the Cochrane library, to find relevant studies. The weighted mean difference (WMD) was determined for BCVA in steroid and nonsteroid groups.Results:Eight studies were included and summarized in this analysis. The studies included 720 eyes (392 NAION eyes and 328 eyes of normal controls). Heterogeneity among these studies was low (I2 = 0%). Because of the presence of heterogeneity, we conducted a fixed effects model to assess the effect of steroids on visual acuity in patients with NAION. The meta-analysis clearly demonstrated that in NAION, steroids did not significantly improve visual acuity (WMD = −0.02 [95% CI: −0.10 to 0.06], Z = 0.40, P = .69). After sensitivity analysis via the leave-one-out method, WMD was not significantly changed.Conclusions:Our meta-analysis found that steroids do not significantly improve visual acuity in NAION. In view of their long list of side effects, attempts at reversing ischemia should not involve the use of steroids.

Macular Vascularity in Ischemic Optic Neuropathy Compared to Glaucoma by Projection-Resolved Optical Coherence Tomography Angiography

To compare macular vasculature in patients with primary open-angle glaucoma (POAG) and atrophic nonarteritic anterior ischemic optic neuropathy (NAION). Prospective, cross-sectional study. Thirty-seven eyes with moderate and advanced POAG, 19 eyes with atrophic NAION, and 40 eyes of normal subjects were imaged using optical coherence tomography angiography (OCT-A). Macular ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer (RNFL) thicknesses were measured in addition to macular superficial and deep vasculature after projection removal using custom software. Linear models showed that while averaged peripapillary RNFL and macular GCC were not different between NAION and POAG eyes, both were significantly thinner than control eyes. Whole image macular superficial vessel density was significantly lower in NAION and glaucoma eyes (P= .003 and <.001, respectively) than in normal eyes, with lower vessel density in glaucoma than in NAION eyes (P= .01). Whole image and parafoveal deep macular vessels in glaucoma eyes (21.0%±8.7%, 24.4%±9.6%) were significantly lower than in control eyes (27.4%±8.6%, 31.9%±10.6%) (P= .01 and P= .01, respectively). No significant differences in deep vessels were observed between NAION and control eyes. Glaucomatous eyes had lower temporal and inferior parafoveal deep vasculature values than NAION eyes (P= .007 and .03, respectively). In NAION and POAG with similar RNFL and macular damage, macular OCT-A shows less involvement of superficial and deep vascular plexus in NAION in contrast to POAG, which might show a primary vascular insult in addition to secondary vascular damage due to ganglion cell damage.

Optical Coherence Tomography Angiography of a Pale Optic Disc in Demyelinating Optic Neuritis and Ischemic Optic Neuropathy.

In the setting of a pale optic disc, distinguishing a previous episode of optic neuritis (ON) from that of nonarteritic anterior ischemic optic neuropathy (NAION) may be difficult on clinical examination. Differences in peripapillary vascular network structures, if present, might be of diagnostic utility. Thirty-five eyes with demyelinating ON, 33 eyes with NAION, and 81 eyes of normal subjects were imaged with optical coherence tomography angiography (OCT-A) to assess peripapillary vascular density (VD). In addition, OCT was used to measure peripapillary retinal nerve fiber layer (RNFL) thickness. Areas under the receiver operating characteristic curves were used to differentiate ON vs NAION. NAION eyes had significantly thinner RNFL thickness than ON eyes. Age-adjusted analysis showed that the peripapillary VD values were significantly reduced in NAION (48.3 ± 7.4%) and ON eyes (54.7 ± 6.1%) compared with healthy controls (62.1 ± 4.6%); pairwise comparisons showed statistically significant differences among all 3 groups. After adjustment for severity of optic nerve injury according to mean RNFL thickness, all VD parameters were not significantly different between ON and NAION eyes. The area under the receiver operating characteristic curves for differentiating NAION from ON eyes was similar for VD (0.75) and RNFL thickness (0.74). Peripapillary VD measurement performs as well as RNFL thickness for distinguishing previous episodes ON and NAION. VD decline might be secondary to RNFL damage and, therefore, VD data have a limited role differentiating these 2 disorders.

The blood perfusion changes of peripapillary and macular vessels in patients with nonarteritic anterior ischemic optic neuropathy

Objective To observe the blood perfusion changes of peripapillary and macular vessels in patients with nonarteritic anterior ischaemic optic neuropathy (NAION). Methods Retrospective cohort study. Thirty-six eyes (19 affected eyes and 17 fellow eyes) of 19 patients with NAION diagnosed in People’s Hospital of Wuhan University from November 2017 to January 2019 were included in this study. There were 10 males and 9 females, with the mean age of 55.05±7.11 years. Forty eyes of 20 normal subjects matched with NAION patients were included as controls. BCVA, fundus color photography, SD-OCT and OCT angiography were performed in normal controls and repeated in NAION affected eyes at 1-2 weeks, 1-2 months, 3-5 months intervals. OCT quantitative measurements: average retinal nerve fiber layer thickness (aRNFL) of the disc and its superior values (sRNFL) and the inferior values (iRNFL), average ganglion cell complex thickness(aGCC) in macular region and its superior values (sGCC) and the inferior values (iGCC). OCTA quantitative measurements: average radial peripapillary capillary density (aRPC) and its superior values (sRPC) and the inferior values (iRPC), average vascular density of superficial retina (aSVD) in macular region and its superior values (sSVD) and the inferior values (iSVD), average vascular density of deep layer retina (aDVD), areas of foveal avascular zone (FAZ). The differences of OCT and OCTA quantitative measurements between NAION eyes and the fellow eyes and normal controls were comparatively analyzed. Independent sample t test, paired sample t test or nonparametric rank sum test were performed for comparison among three groups. Pearson or Spearman correlation analysis were used to analyze the correlation between RNFL and RPC, GCC and SVD, RNFL and GCC, RPC and SVD. Results At baseline, the aRNFL, aRPC and aDVD of NAION patients were significantly higher than those of normal controls. Compared with the fellow eyes, the aRNFL increased significantly and the aRPC decreased significantly in NAION affected eyes. The overall differences of aRNFL, aRPC, aGCC and aSVD at four intervals within NAION affected eyes were statistically significant (P<0.05). The average sRNFL, sRPC, sGCC and sSVD at 1-2 months interval were significantly lower than the average iRNFL, iRPC, iGCC and iSVD (P<0.05). Correlation analysis: at 1-2 months interval, aGCC was positively correlated with aSVD (r=0.482, P=0.037); at 3-5 months interval, aRNFL was positively correlated with aRPC(r=0.631, P=0.037). Conclusion There is a sectorial reduction of vascular density of peripapillary RPC and macular SVD with the disease progression of NAION. Key words: Optic neuropathy ischemic; Optic disk; Macula lutea; Regional blood flow; Tomography, optical coherence

Choroidal Vascularity in Non-arteritic Anterior Ischaemic Optic Neuropathy

ABSTRACTThis study evaluates the peripapillary choroidal vascularity in eyes with non-arteritic anterior ischaemic optic neuropathy (NAION) and compares it with the vascularity of healthy fellow eyes and age-matched subjects. The peripapillary choroidal vascularity index (CVI), a new tool of measurement, was calculated using horizontal swept-source optical coherence tomography scans. CVI was calculated using a previously validated automated algorithm. CVI in NAION and fellow eyes of NAION patients were compared with age-matched eyes of healthy individuals using Kruskal–Wallis test. A total of 20 eyes of 20 patients with acute unilateral NAION with healthy fellow eyes (20 eyes) and 40 eyes of 40 healthy patients were included in the study. The average age of patients with NAION was 56 ± 8 and 55 ± 7 years in age-matched healthy controls. NAION eyes had a significantly lower CVI than age-matched controls in both nasal and temporal areas. NAION nasal CVI was 0.47 ± 0.47 compared to 0.62 ± 0.04 in controls (p < 0.001). NAION temporal CVI was 0.45 ± 0.48 compared to 0.58 ± 0.04 in controls (p < 0.001). Temporal CVI was 0.45 ± 0.48 in NAION eyes and was significantly lower than counterpart healthy fellow eyes 0.48 ± 0.02 (p = 0.007). In conclusion, NAION eyes have significantly reduced vascularity in the peripapillary area. CVI is lower in the nasal and temporal of the optic disc compared to healthy individuals. This may suggest those with smaller CVI are more prone to ischaemia from reduced vascularity resulting in NAION.

Macular evaluation of the retinal and choroidal vasculature changes in anterior ischemic optic neuropathy-a case control study

BackgroundThis study aimes to characterize the fundus structural changes in patients with nonarteritic anterior ischemic optic neuropathy (NAION) and the correlation between macular vessel density, retinal nerve fibre layer (RNFL) parameters and visual field sensitivity (VFS) in NAION patients.MethodsA retrospective case control study was performed using 37 eyes with NAION, 30 uninvolved contralateral eyes, and 27 eyes of healthy age-matched subjects. Data on the retinas and choroidal vessel densities and VFS were compared among the three groups.ResultsThe NAION group exhibited significantly lower RNFL thicknesses, lower ganglion cell complexes (GCC), larger global loss volume (GLV) values and focal loss volume (FLV) values when compared with both uninvolved eyes and healthy eyes (p < 0.01 for all comparisons). The superficial vessel density (SVD) valus (whole, parafovea, superior-hemi and inferior-hemi) were significantly lower in NAION eyes, followed by uninvolved eyes and healthy eyes (p < 0.01; LSD, p < 0.05 for all comparisons). The deep vessel density (DVD) values (parafovea, superior-hemi and inferior-hemi) were the lowest by a significant value in NAION eyes, followed by uninvolved eyes and healthy eyes (p < 0.01; LSD, p < 0.05 for all comparisons). However, DVD value measurements (whole and fovea) of healthy and uninvolved eyes were not significantly different. The average threshold deviation (TD) was − 11.02 ± 3.75 dB for the overall field region, − 6.01 ± 2.21 dB for the affected superior field region and − 9.98 ± 3.34 dB for the affected inferior field region in NAION eyes. A statistically significant correlation was found between the RNFL thickness and visual field(VF) loss (r = − 0.788, p < 0.001).ConclusionIn addition to peripapillary vascular changes occurring in NAION eyes, macular vessel density is also involved. Furthermore, NAION-uninvolved eyes exhibited abnormalities compared with healthy eyes. This indicates that vascular changes may occur before changes in retinal thickness at the early stages of NAION.

Early Macular Vessel Density Loss in Acute Ischemic Optic Neuropathy Compared to Papilledema: Implications for Pathogenesis.

PurposeThis study compares macular and parafoveal vasculature in patients with optic disc swelling.MethodsTwenty eyes with acute nonarteritic anterior ischemic optic neuropathy (NAION), 39 eyes with papilledema at first presentation, and 22 eyes of normal subjects were imaged using optical coherence tomography angiography (OCT-A). Macular ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer thicknesses were measured in addition to macula and parafovea superficial and deep vasculature.ResultsAge- and gender-mixed models showed that the macular and parafoveal superficial and deep vasculature density values were significantly lower in NAION eyes than control eyes (P ≤ 0.0001 for all comparisons). All vessel density values were not statistically different between papilledema eyes and control eyes. Whole superficial and deep macula vasculature in the NAION eyes (45.9% ± 4.2%, 50.9% ± 6.5%) were significantly lower than in papilledema eyes (50.5% ± 4.6%, 57.3% ± 6.1%) (P = 0.03 and P = 0.01, respectively). No significant differences in GCC thickness were observed among NAION, papilledema, and control eyes. Whole superficial and deep macular vasculatures, but not macular GCC thickness, were significantly correlated with visual field mean deviation (r = 0.39, P = 0.001 and r = 0.41, P < 0.001, respectively).ConclusionsMacular OCT-A is able to show early macular vasculature abnormalities associated with optic nerve damage; this change occurs before detectable macular GCC atrophy.Translational RelevanceMacular vessel density measurement offers an opportunity to evaluate the optic nerve damage at initial presentation, but further longitudinal studies are needed.

Spectral-Domain Optical Coherence Tomography of the Vitreopapillary Interface in Acute Nonarteritic Anterior Ischemic Optic Neuropathy

To use spectral-domain optical coherence tomography (SD-OCT) to assess whether epipapillary vitreous traction from evolving posterior vitreous detachment (PVD) is mechanistically involved in the pathogenesis of nonarteritic anterior ischemic optic neuropathy (NAION). Retrospective cohort study. Setting: Single academic center. Patient or Study Population: Eighty eyes in 74 subjects presenting within 2weeks of symptom onset of NAION. Intervention or Observation Procedures: SD-OCT imaging of the optic nerve head, macula, and peripapillary retinal nerve fiber layer (pRNFL) were reviewed for PVD and vitreopapillary traction (VPT). Prevalence and incidence of PVD and VPT, logMAR best-corrected visual acuity (BCVA), mean deviation (MD) on automated perimetry, and pRNFL thickness at presentation and final follow-up. The co-prevalence of PVD at the time of acute presentation for NAION was 30% (n= 24/80). This was similar to the prevalence of PVD in contralateral uninvolved eyes (34.5%, n= 19/55). In 8 NAION eyes, PVD had been documented prior to the onset of NAION. No eyes had SD-OCT evidence of VPT on presentation or final follow-up. Only 5 eyes developed a PVD following the development of NAION, and this typically occurred months after resolution of optic disc edema. When comparing eyes with PVD and withoutPVD, there was no significant difference in BCVA, MD, and pRNFL thickness at baseline, final follow-up, or the change from baseline to final follow-up (all P > .10). VPT was not mechanistically related to the development of classic NAION. Preexisting PVD did not preclude the future development of NAION. The co-prevalence of PVD with acute NAION had no impact on final visual outcome.

Optical coherence tomography angiography at the acute phase of optic disc edema

BackgroundThe differential diagnosis of optic disc edema at the acute phase can be challenging. OCT angiography (OCTA) is a new technology allowing the visualization of the peripapillary vascular network and optic disc capillaries. The peripapillary network alterations of glaucoma and chronic non-arteritic anterior ischemic optic neuropathy (NAION) were reported. However, no OCTA studies on acute optic disc edema from various causes. The aim of this project was to use OCTA to demonstrate the vascular changes the optic nerve head of various types of optic disc edema at the acute phase.MethodsIn this retrospective study, patients with non-arteritic anterior ischemic optic neuropathy (NAION), papillitis or papilledema were recruited. Each patient was imaged using the AngioPlex™ CIRRUS™ HD-OCT device(model 5000, Carl Zeiss Meditec, Inc., Dublin, USA) with a scanning area of 6 × 6 mm2 centered on the optic disc. A morphological analysis of the peripapillary network was performed. For some patients with unilateral optic disc edema, a quantitative analysis was performed using a swept-source OCT-A system (PLEX® Elite 9000, Carl Zeiss Meditec, Inc., Dublin, USA). Vessel perfusion density and flux index of the peripapillary area were calculated.ResultsEight eyes with NAION (4 patients), 12 eyes with papillitis (6 patients) and 25 eyes with papilledema (13 patients) were imaged. The apparent disappearance or moderate pattern alteration of the peripapillary capillary vessels were observed in patients with NAION or papillitis, respectively. For papilledema, the capillaries at the surface of the optic disc were dilated and tortuous, but no peripapillary network pattern changes were observed. The quantitative analysis did not show any difference of peripapillary network between NAION and healthy eyes. For papillitis, the flux index was higher in inflammatory eyes compared to the healthy eyes in average (p = 0.03).ConclusionAt the acute phase, the morphological analysis of OCT-A appeared to be more useful than the quantification analysis, facilitating the differentiation between the three kinds of ONH edema: ischemic, inflammatory and papilledema.

Optical Coherence Tomography Angiography in Optic Disc Swelling

To compare optical coherence tomography angiography (OCT-A) of peripapillary total vasculature and capillaries in patients with optic disc swelling. Cross-sectional study. Twenty nine eyes with acute nonarteritic anterior ischemic optic neuropathy (NAION), 44 eyes with papilledema, 8 eyes with acute optic neuritis, and 48 eyes of normal subjects were imaged using OCT-A. Peripapillary total vasculature information was recorded using a commercial vessel density map. Customized image analysis with major vessel removal was also used to measure whole-image capillary density and peripapillary capillary density (PCD). Mixed models showed that the peripapillary total vasculature density values were significantly lower in NAION eyes, followed by papilledema eyes and control eyes, using commercial software (P < .0001 for all comparisons). The customized software also showed significantly lower PCD of NAION eyes compared with papilledema eyes (all P < .001), but did not show significant differences between papilledema and control subjects. Our software showed significantly lower whole image and PCD in eyes with optic neuritis than papilledema. There was no significant difference between NAION and optic neuritis using our software. The area under the receiver operating curves for discriminating NAION from papilledema eyes and optic neuritis from papilledema eyes was highest for whole-image capillary density (0.94 and 0.80, respectively) with our software, followed by peripapillary total vasculature (0.9 and 0.74, respectively) with commercial software. OCT-A is helpful to distinguish NAION and papillitis from papilledema. Whole-image capillary density had the greatest diagnostic accuracy for differentiating disc swelling.

Automated Evaluation of Choroidal Thickness and Minimum Rim Width Thickness in Nonarteritic Anterior Ischemic Optic Neuropathy.

The aim of this study was to evaluate and compare peripapillary choroidal thickness (pCT) and macular choroidal thickness (CT), Bruch membrane opening-minimum rim width (BMO-MRW), retinal nerve fiber layer (RNFL) thickness, and optic disc area among nonarteritic anterior ischemic optic neuropathy (NAION) eyes, the contralateral unaffected eyes, and healthy control eyes. Twenty-six patients diagnosed with NAION (29 affected and 21 unaffected eyes) and 29 healthy matched control individuals (29 eyes) were analyzed by swept-source optical coherence tomography. All participants underwent scanning by Spectralis optical coherence tomography to analyze BMO-MRW, RNFL thickness, and optic disc area. Mean pCT in the NAION eyes, unaffected fellow eyes, and the control group was 130.5 ± 72.1 μm, 149.6 ± 75.7 μm, and 103.7 ± 36.7 μm, respectively (analysis of variance [ANOVA], P = 0.04). Mean macular CT in the NAION eyes, unaffected fellow eyes, and the control group was 226.1 ± 79.8 μm, 244.6 ± 81.4 μm, and 189.9 ± 56.4 μm, respectively (ANOVA, P = 0.03). Mean and all sectorial RNFL and BMO-MRW thickness values were significantly thinner in the NAION eyes vs the unaffected fellow and control eyes (P ≤ 0.00). The unaffected fellow eyes in NAION patients showed a significantly thicker average and sectorial BMO-MRW values than control eyes (P ≤ 0.02) except for the nasal sector (P = 0.09). Mean optic disc area derived from BMO analysis was not significantly different among groups (ANOVA, P = 0.86). The fellow unaffected eyes in patients with NAION showed significantly thicker mean peripapillary and macular choroidal and BMO-MRW thicknesses than disease-free control eyes. No differences in the mean optic disc area were found. Both a thick peripapillary choroid and a thick neuroretinal rim might contribute to the development of NAION or possibly be a secondary phenomenon.

Retinal and Choroidal Microvasculature in Nonarteritic Anterior Ischemic Optic Neuropathy: An Optical Coherence Tomography Angiography Study

To analyze retinal and choroidal microvasculature in patients with nonarteritic anterior ischemic optic neuropathy (NAION) by using optical coherence tomography angiography (OCT-A). In this case-control retrospective observational study, patients with atrophic NAION (at least 3 months after onset of symptoms) and normal subjects underwent a complete ophthalmic examination including spectral-domain OCT, visual field (VF), and OCT-A. Whole en face image vessel density (wiVD) was used to assess retinal blood flow of the radial peripapillary capillaries (RPCs), circumpapillary RPC vessel density (cpVD), superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC). Statistical correlations between wiVD measurements and visual acuity, VF parameters, retinal nerve fiber layer (RNFL), and combined thickness of retinal ganglion cell and inner plexiform layers were analyzed. Twenty-four patients (26 eyes) with NAION and 24 age-matched normal controls (NCs) (24 eyes) were included. OCT-A showed significant reduction of the RPC wiVD (P < 0.0001) and the cpVD (P < 0.0001) in NAION eyes compared with NC and correlated with RNFL thickness (P = 0.002, P = 0.004), visual acuity (P = 0.042), and mean deviation of the VF (P = 0.001). Macular OCT angiograms showed capillary rarefaction in the SCP (P < 0.0001) and DCP (P < 0.0001) in the NAION group, both correlated with visual acuity (P = 0.02, P = 0.024). However, wiVD of the CC was not significantly different between the two groups in the peripapillary (P = 0.218) and macular (P = 0.786) areas. OCT-A provided detailed visualization of the peripapillary and macular retinal capillary rarefaction, correlated with VF and visual acuity loss. OCT-A could be a useful tool for quantifying and monitoring ischemia in NAION.

Optical Coherence Tomography Angiography of the Peripapillary Retina in Normal-Tension Glaucoma and Chronic Nonarteritic Anterior Ischemic Optic Neuropathy

ABSTRACTPurpose: To analyze the retinal radial peripapillary capillary (RPC) network in normal-tension glaucoma (NTG) and nonarteritic anterior ischemic optic neuropathy (NAION) eyes using optical coherence tomography angiography (OCTA).Material and Methods: Twenty-two patients with NTG, 22 patients with unilateral chronic NAION, and 23 age-matched controls were enrolled. Patients underwent OCTA to obtain en face angiograms of the peripapillary region. The main outcome measures were as follows: (1) the whole en face image perfusion density (WPD) and (2) the circumpapillary perfusion density (CPD).Results: Mean ± SD age was 66.3 ± 7.0 years in the NTG group, 68.1 ± 4.3 years in the NAION group, and 63.9 ± 7.0 years in the control group (p > 0.05 for all the comparisons). The visual field mean defect (MD) was worse in patients than in controls (p < 0.0001), but did not differ between NTG and NAION (−9.6 ± 2.6 dB and −8.2 ± 2.6 dB, respectively). The WPD was 0.41 ± 0.04 in the NTG group (p < 0.0001 in comparison with healthy subjects and NAION patients), 0.46 ± 0.04 in the NAION group (p < 0.0001 in comparison with the control group), and 0.56 ± 0.03 in the control group.The CPD was significantly reduced in both NTG (0.48 ± 0.04, p < 0.0001) and NAION eyes (0.52 ± 0.05, p < 0.0001), after comparison to control eyes (0.59 ± 0.03). Moreover, the CPD was significantly lower in NTG than in NAION eyes (p = 0.006).Conclusions: OCTA documented a reduction of the peripapillary perfusion in NTG and unilateral NAION. In presence of similar functional damage, the lower perfusion densities in NTG may indicate greater vascular alterations in chronic compared to acute ischemic optic neuropathies.

The characteristics of multifocal microperimetry and its relationship with visual acuity and multifocal ganglion cell complex in nonarteritic anterior ischemic optic neuropathy

Objective To observe the characteristics of multifocal microperimetry and its relationship with visual acuity and multifocal ganglion cell complex (GCC) in nonarteritic anterior ischemic optic neuropathy (NAION). Methods A retrospective case study. A total of 38 patients (54 eyes) with NAION were enrolled in this study. 25 NAION eyes (25 patients) and 29 contralateral health eyes (29 patients) were randomly selected into case group and control group respectively. All eyes underwent best corrected visual acuity (BCVA), slit lamp microscope, indirect ophthalmoscope, color fundus photography, optical coherence tomography (OCT), visual field and multifocal microperimetry. Logarithm of the minimum angle of resolution (logMAR) was used to calculate BCVA. There were no significantly differences on age (t=−0.647), gender, dominant eyes ( χ2=0.128, 0.099), intraocular pressure (t=0.376) between two groups (P>0.05). Macular GCC thickness, superior and inferior GCC thickness were measured by OCT, focal loss volume (FLV) and global loss volume (GLV) were obtained at the same time. Microperimetry were measured by macular integrity assessment instrument (MAIA microperimetry), and mean retinal sensitivities (MS) in macular area 10° and fixation rate in the macular central 2° and 4° were determined. The relationship between MS, macular GCC and BCVA were analyzed by Spearman correlation analysis. Results The mean logMAR BCVA of case group and control group were 0.68±0.79 and 0.07±0.06, respectively. There was significantly statistical difference in MS between two groups (t=−2.507, P=0.037). There were no significantly statistical difference in mean GCC (t=−1.245, P=0.259), superior and inferior GCC (t=−1.336, −1.024; P=0.230, 0.346), FLV (t=1.058, P=0.331) and GLV (P=0.182) between two groups. The correlation between BCVA and MS (r=−0.809, P=−0.005) was observed. However, there were no correlation between BCVA and GCC, superior and inferior GCC, FLV, GLV (r=−0.98, −0.466, −0.061, 0.442, 0.442; P=0.817, −0.244, 0.885, 0.273, 0.273). And also, there were no correlation between MS and GCC, superior and inferior GCC, FLV, GLV (r=0.238, 0.524, 0.286, 0.643, −0.619; P=0.570, 0.183, 0.493, 0.086, 0.102). Conclusions MS reduced in early stage NAION eyes, which did not correlate with macular GCC. Key words: Optic neuropathy, ischemic; Visual fields; Tomography, optical coherence

Establishment and assessment of a rat model of nonarteritic anterior ischemic optic neuropathy

Objective To establish and evaluate a rat model of nonarteritic anterior ischemic optic neuropathy (NAION). Methods The rats were randomly divided into control group (n=13), sham laser group (n=11) and NAION group (n=23). The right eye was set as the experimental eye. NAION model was induced by directly illuminating the optic nerve (ON) of the right eye with 532 nm green laser, after intravenous infusion with the photosensitizing agent Rose Bengal. Sham laser treatment consisted of illuminating the ON region with 532 nm laser without Rose Bengal injection. Rats in control group underwent no intervention. The appearance of optic disc was observed with funduscope at 12 hours, 1, 3, 7, 28 days post-illumination. The histologic changes in the retina and ON of the NAION model were evaluated qualitatively with hematoxylin and eosin (HE) staining and transmission electron microscopy. The retrograde-labeled retinal ganglion cells (RGC) were counted on photographs taken from retinal flat mounts in a masked fashion. Results The optic disc in NAION eyes were swollen 3 days after photodynamic treatment. HE-stained longitudinal ON sections of NAION revealed vacuolar degeneration on day 3 after induction. Besides, ultrastructural study showed axonal edema and collapsed sheaths in the ischemic optic nerve at the same time point after modeling. ON edema resolved 7 days after induction. The final results revealed optic disc atrophy, extensive axonal loss, severe glial scar, and RGC death in large numbers 4 weeks after modeling. There were no aforementioned manifestations in control and sham laser group. The RGC density of the right eyes was statistically significantly lower in NAION group than that in control group and in sham laser group (t=−14.142, −14.088; P=0.000, 0.000). The survival rate of RGC was statistically significantly lower in NAION group than in control group and in sham laser group (t=−17.048, −16.667; P=0.000, 0.000). There was no difference of RGC density and survival rate of RGC between control and sham laser group (t=0.050, 0.348; P=0.961, 0.731). Conclusion A rat model of NAION was established successfully by photodynamic treatments with Rose Bengal, which induce optic nerve damage and RGC death. Key words: Optic neuropathy, ischemic; Retinal ganglion cells; Disease models, animal

Pattern of peripapillary capillary density loss in ischemic optic neuropathy compared to that in primary open-angle glaucoma.

PurposeBoth non-arteritic anterior ischemic optic neuropathy (NAION) and primary open-angle glaucoma (POAG) damage retinal ganglion cell axons, which are perfused by the radial peripapillary capillaries. To evaluate the pattern of ischemia, we compared peripapillary capillary density (PCD) in NAION eyes to POAG eyes matched for visual field mean deviation and retinal nerve fiber layer thickness.Methods31 chronic NAION (>6 months after the acute event) and unaffected fellow eyes (31 subjects), 42 moderate and severe POAG eyes (27 subjects), and 77 control eyes (46 healthy subjects) were imaged with a commercial optical coherence tomography angiography system (AngioVue, Avanti RTVue-XR, Optovue, CA) at two academic institutions. Two concentric circles of diameters 1.95mm (inner) and 3.45mm (outer) were manually placed on images centered on the optic nerve head, producing an annular region-of-interest. Image analysis with major vessel removal was performed using a custom program. Whole-image, whole-annulus, and sectoral PCDs were measured.ResultsWhole-image and whole-annulus PCDs in NAION and moderate and severe POAG eyes were significantly decreased compared to unaffected fellow eyes and control eyes (all P<0.001). Superior and temporal PCD values were affected more than other sectors in both NAION and POAG groups compared to control group. Whole-image and whole-annulus PCDs were not statistically different between NAION and POAG eyes (both P = 0.99). However, of all peripapillary sectors, the inferior sector PCD value was less affected in POAG eyes compared to NAION eyes (P = 0.001). Univariate analysis results also revealed a significant positive correlation between superior and inferior PCDs and corresponding RNFL thicknesses. The inferior sector correlation was greater in POAG than NAION eyes.ConclusionWhile the whole PCD values were not different in chronic NAION and POAG, the greater correlation of inferior PCD with corresponding RNFL sectors in POAG compared to NAION suggests greater susceptibility of the inferior radial peripapillary capillary in the pathogenesis of POAG.

Choroidal thickness in Chinese patients with non-arteritic anterior ischemic optic neuropathy

Objective To observe the peripapillary choroidal thicknesses (pCT) and subfoveal choroidal thicknesses (SFCT) of nonarteritic anterior ischemic optic neuropathy (NAION). Methods Fortyfour Chinese patients with unilateral NAION were recruited and compared with 60 eyes of 60 normal age and refractive-error matched control subjects. pCT and SFCT were measured by enhanced depth imaging optical coherence tomography. Choroidal thicknesses of eyes with NAION and unaffected fellow eyes were compared with normal controls. Choroidal thicknesses of NAION eyes with or without optic disc edema were also compared. The correlation between choroidal thickness and retinal nerve fiber layer (RNFL) thickness, logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA), and the mean deviation(MD) of Humphrey static perimetry in NAION eyes were analyzed. Results The pCT at the nasal, nasal inferior and temporal inferior quadrants in NAION eyes with optic disc edema were significantly thicker than that of normal subjects (t=3.152, 3.166, 2.808; P 0.05). No significant correlation between choroidal thickness (r=-0.220,-0.140, 0.110), SFCT (r=0.096,-0.148,-0.131) and logMAR BCVA, perimetry MD and RNFL was found in eyes affected by NAION (P>0.05). Conclusions The peripapillary choroidal thicknesses increase in some quadrants in NAION eyes with optic disc edema. However, the choroidal thickness of NAION eyes is the same in age and refractive error-matched normal subjects. Key words: Non-arteritic anterior ischemic optic neuropathy; Choroidal thickness; Optical coherence tomography