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

Purpose

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

Methods

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

Results

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

Conclusions

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

The Benefits and Hazards of Intravitreal Mesenchymal Stem Cell (MSC) Based-Therapies in the Experimental Ischemic Optic Neuropathy

Mesenchymal stem cell (MSC) therapy has been investigated intensively for many years. However, there is a potential risk related to MSC applications in various cell niches. Methods: The safety of intravitreal MSC application and the efficacy of MSC-derived conditioned medium (MDCM) were evaluated in the normal eye and the diseased eye, respectively. For safety evaluation, the fundus morphology, visual function, retinal function, and histological changes of the retina were examined. For efficacy evaluation, the MDCM was intravitreally administrated in a rodent model of anterior ischemic optic neuropathy (rAION). The visual function, retinal ganglion cell (RGC) density, and neuroinflammation were evaluated at day 28 post-optic nerve (ON) infarct. Results: The fundus imaging showed that MSC transplantation induced retinal distortion and venous congestion. The visual function, retinal function, and RGC density were significantly decreased in MSC-treated eyes. MSC transplantation induced astrogliosis, microgliosis, and macrophage infiltration in the retina due to an increase in the HLA-DR-positive MSC proportion in vitreous. Treatment with the MDCM preserved the visual function and RGC density in rAION via inhibition of macrophage infiltration and RGC apoptosis. Conclusions: The vitreous induced the HLA-DR expression in the MSCs to cause retinal inflammation and retina injury. However, the MDCM provided the neuroprotective effects in rAION.

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

Purpose

The purpose of this study was to describe capillary changes in patients with nonarteritic anterior ischemic optic neuropathy (NAION) using optical coherence tomography-angiography (OCT-A) and correlate the results with best corrected visual acuity (BCVA), visual field, OCT retinal nerve fiber layer (RNFL), and combined thickness of ganglion cell and inner plexiform layers (GCIPL) thicknesses.

Methods

We enrolled 22 eyes with acute NAION and 30 normal control (NC) subjects in this study. Whole en face image vessel density (WiVD) was measured in the radial peripapillary capillary plexus (RPC), superficial capillary plexus (SCP), and deep vascular complex (DVC) using OCT-A. The examination was repeated at 1 (M1), 3 (M3), 6 (M6), and 9 (M9) months after presentation for NAION.

Results

The initial RPC WiVD was significantly reduced in the acute NAION group compared to the NC group (P < 0.0001). Over the course of NAION follow-up, RPC WiVD was significantly reduced at M1 (P < 0.001 compared to M0) and M3 (P < 0.0001 compared to M1). However, there was no significant further decrease at M6 and M9. The initial SCP WiVD was significantly reduced in the NAION group compared to the NC group (P < 0.0001 for both). Over the course of NAION follow-up, a significant decrease was observed for SCP WiVD at M1 (P < 0.001 compared to M0), but no significant change was seen at M3, M6, or M9. DVC was normal in the NAION group. Correlations were found between GCIPL and SCP WiVD in the NAION acute phase (R = 0.604, P = 0.003) and in the M9 atrophic stage (R = 0.551, P = 0.009). At M9, RPC WiVD was correlated with BCVA (R = -0.562, P = 0.007), mean deviation (R = 0.518, P = 0.01), and RNFL (R = 0.655, P = 0.001).

Conclusions

Over the course of NAION, OCT-A provided detailed visualization of retinal capillary plexus involvement.

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

PURPOSE

To compare macular vasculature in patients with primary open-angle glaucoma (POAG) and atrophic nonarteritic anterior ischemic optic neuropathy (NAION).

DESIGN

Prospective, cross-sectional study.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Retinal Vessel Phenotype in Patients with Nonarteritic Anterior Ischemic Optic Neuropathy

PURPOSE

The pathophysiology of nonarteritic anterior ischemic optic neuropathy (NAION) is not completely understood. Studies of the retinal vasculature phenotype in patients with NAION could help us to understand vascular abnormalities associated with the disease.

DESIGN

Retrospective case series with matched control subjects.

METHODS

Study population: 57 patients with NAION and 57 control subjects matched to NAION patients for sex, age, systemic hypertension, diabetes, and obstructive sleep apnea syndrome between September 2007 and July 2017.

MAIN OUTCOME MEASURES

All patients and control subjects underwent a complete ocular examination and 45° funduscopic color photographs. The widths of the 6 largest arteries in zone B (between 0.5 and 1 optic disc diameter from the optic disc), summarized by the central retinal artery equivalent (CRAE), the widths of the 6 largest veins in zone B, summarized by the central retinal vein equivalent (CRVE), the arteriole to venule ratio, tortuosity, and fractal dimension were measured on the 2 groups using Vessel Assessment and Measurement Platform for Images of the Retina, a software tool for efficient semiautomatic quantification of the retinal vasculature morphology in fundus camera images. The Wilcoxon signed-rank test and MacNemar χ² test for paired sample and generalized estimating equations for modeling the Vessel Assessment and Measurement Platform for Images of the Retina parameters as dependent variables were used.

RESULTS

CRVE and fractal dimension (D0a) were significantly higher in the NAION group when compared with the control group, whereas the arteriole to venule ratio and vascular tortuosity were significantly lower. Compared with control subjects, acute NAION yielded an increased CRAE value (174 ± 33 vs 160 ± 13 μm) while resolution NAION yielded a decreased CRAE value (152 ± 12 vs 156 ± 33 μm). Acute NAION yielded an increased CRVE value (244 ± 35 vs 210 ± 21 μm) while resolution NAION yielded an unchanged CRVE value. We found no difference between groups for age, refraction, optic disc diameter, CRAE, or fractal dimension.

CONCLUSIONS

Retinal vascular parameters were different in our sample between NAION and control patients, especially at the acute stage of the disease. Our results suggest a normalization of the same parameters at the resolution stage.

Neuroenhancement and neuroprotection by oral solution citicoline in non-arteritic ischemic optic neuropathy as a model of neurodegeneration: A randomized pilot study

Purpose

To evaluate whether treatment with Citicoline in oral solution (OS-Citicoline) would increase visual function, retinal ganglion cells (RGCs) function, and neural conduction along visual pathways (neuroenhancement), and/or induce preservation of RGCs fibers’ loss (neuroprotection) in non-arteritic ischemic optic neuropathy (NAION), a human model of neurodegeneration.

Methods

Thirty-six patients with NAION and 20 age-matched controls were enrolled. Nineteen NAION patients received 500 mg/day of OS-Citicoline for a 6-month period followed by 3-month of wash-out (NC Group); 17 NAION patients were not treated (NN Group) from baseline to 9 months. In all subjects at baseline, and in NC and NN eyes at 6 and 9 months of follow-up, we assessed Visual Acuity (VA), Pattern Electroretinogram (PERG), Visual Evoked Potentials (VEP), retinal nerve fiber layer thickness (RNFL-T), and Humphrey 24–2 visual field mean deviation (HFA MD). Mean differences were statistically evaluated with ANOVA between Groups, and linear correlations were analysed with Pearson’s test.

Results

At 6 months, significant differences between groups for all parameters were observed (ANOVA, p<0.01). In NC eyes, VA increased, PERG responses increased, VEP recordings improved and were significantly correlated with increases in HFA MD (p<0.01), and RNFL-T was unmodified or improved. In contrast, in NN eyes, VA, PERG, VEP responses, RNFL-T, and HFA MD were further worsened. Significant differences were still present at 9-month follow-up in the NN Group and after 3 months of OS-Citicoline wash-out in NC eyes.

Conclusions

OS-Citicoline treatment induced neuroenhancement (improvement in RGCs function and neural conduction along visual pathways related to improvement of visual field defects) and neuroprotection (unmodified or improved RNFL morphological condition) in a human model of NAION involving fast RGCs degeneration.

Trial registration

ClinicalTrials.gov NCT03758118.

Intravitreal Triamcinolone Acetonide Injection in a Rodent Model of Anterior Ischemic Optic Neuropathy

INTRODUCTION

The management of nonarteritic anterior ischemic optic neuropathy centers around prevention of second eye involvement, without a uniformly accepted therapy for the involved eye. Several researchers have assessed the benefit of steroids with conflicting results. This experimental study was designed to evaluate the efficacy of a single intravitreal triamcinolone acetonide injection (IVTA) in preserving retinal ganglion cells (RGCs) in a rodent model of anterior ischemic optic neuropathy (rAION).

METHODS

The rAION was induced in female Wistar rats. Animals were randomized into 3 groups: 1) untreated, 2) treated with 56 μg IVTA, and 3) intravitreal saline (placebo). Procedures were performed in the left eye, with the right eye serving as control. After 30 days, animals were sacrificed and eyes were assessed histologically for RGC number.

RESULTS

The average number of RGC was significantly lower in rAION subgroups when compared with the control group (P < 0.001). No significant difference was seen between rAION eyes treated with IVTA, placebo, and untreated eyes (P > 0.05%).

CONCLUSIONS

In this rodent model for AION, no therapeutic benefit of intravitreal steroid injection was identified.

Quantitative analysis of optical coherence tomographic angiography (OCT-A) in patients with non-arteritic anterior ischemic optic neuropathy (NAION) corresponds to visual function

Purpose

Non-arteritic anterior ischemic optic neuropathy (NAION) is the most common cause of non-glaucomatous optic neuropathy in older adults. Optical coherence tomographic angiography (OCT-A) is an emerging, non-invasive method to study the microvasculature of the posterior pole, including the optic nerve head. The goal of this study was to assess the vascular changes in the optic nerve head and peripapillary area associated with NAION using OCT-A.

Design

Retrospective comparative case series.

Methods

We performed OCT-A in 25 eyes (7 acute and 18 non-acute) in 19 patients with NAION. Fellow, unaffected eyes were analyzed for comparison. Patent macro- and microvascular densities were quantified in the papillary and peripapillary regions of unaffected, acutely affected, and non-acutely affected eyes and compared across these groups according to laminar segment and capillary sampling region, and with respect to performance on automated visual field testing.

Results

In acutely affected eyes, OCT-A revealed a reduction in the signal from the major retinal vessels and dilation of patent superficial capillaries in the peripapillary area. By contrast, non-acutely affected eyes showed attenuation of patent capillaries. The peripapillary choriocapillaris was obscured by edema in acute cases, but was similar between non-acute and unaffected eyes. The degree of dilation of the superficial microvasculature in the acute phase and attenuation in the non-acute phase each correlated inversely with visual field performance. The region of reduced patent capillary density correlated with the location of visual field defects in 80% of acute cases and 80% of non-acute cases.

Conclusions

OCT-A reveals a dynamic shift in the superficial capillary network of the optic nerve head with strong functional correlates in both the acute and non-acute phases of NAION. Further study may validate OCT-A as a useful adjunctive diagnostic tool in the evaluation of ischemic optic neuropathy.

The relation between retrobulbar blood flow and posterior ocular changes measured using spectral-domain optical coherence tomography in patients with obstructive sleep apnea syndrome

PURPOSE

To investigate the effect of posterior ocular hemodynamics on the retinal nerve fiber layer (RNFL), choroid thickness (CT) and central macular thickness (CMT) in patients with obstructive sleep apnea syndrome (OSAS) and to reveal the association with glaucomatous optic neuropathy.

METHODS

The research was planned as a prospective, randomized study. The ophthalmic, retinal and posterior ciliary artery pulsatile index (PI) and resistive index (RI) were measured by colored Doppler sonography. RNFL thickness, CMT and CT were then measured by spectral-domain optical coherence tomography.

RESULTS

Sixty subjects were divided into four groups-mild, moderate and severe OSAS and a control group. There were 16 subjects in the control group, 14 in the mild OSAS group, 15 in the moderate OSAS group and 15 in the severe OSAS group. Ophthalmic artery and central retinal artery PI and RI values of the OSAS patients did not show statistically significant difference than those of the control group, but posterior ciliary artery (PCA) PI and RI values were significantly higher. In addition, mean, superior and inferior RNFL thickness values were significantly lower than those in the control group. Moreover, the glaucoma prevalence of the OSAS patients in this study was 6.8% and all of these patients were in the severe OSAS group.

CONCLUSION

PI and RI values of the PCA, which supplies the optic nerve, show a linear increase as the apnea hypoxia index values in OSAS. As the grade of OSAS improves, this situation leads to a more serious ischemic optic neuropathy. Furthermore, the prevalence of glaucoma in this study is found to be higher in the severe OSAS group.

Retrobulbar and intraocular blood flow in anterior ischaemic optic neuropathy are linked to the functional impairment

PURPOSE

Evaluation of ocular haemodynamics in patients with acute non-arteritic anterior ischaemic optic neuropathy (NAION) by colour Doppler imaging and fluorescein angiography and correlation of blood flow parameters to visual field loss and visual acuity.

METHODS

Blood flow velocities (peak systolic velocity (PSV), end-diastolic velocity (EDV)) of the ophthalmic artery (OA), central retinal artery (CRA) and nasal and temporal posterior ciliary arteries (PCAs) were measured via colour Doppler imaging. Resistive index (RI) of all vessels was calculated (PSV-EDV/PSV). Retinal arteriovenous passage times (AVP) were evaluated using fluorescein angiography (scanning laser ophthalmoscope) and digital image analysis. The visual field global index mean deviation (MD, 30-2 programme, Humphrey Field Analyzer) and visual acuity (logMar) was used for analysis of functional impairment after NAION.

RESULTS

Twenty patients (age: 64.62 ± 11.63 years) with acute NAION were included. Mean duration of symptoms was 7.6 ± 6.9 days. Mean defect was 15.4 ± 8.9 dB, AVP was determined with 1.66 ± 0.37 s. EDV of the CRA was significantly correlated to visual field MD (r = 0.52, p = 0.017) and AVP (r = - 0.49, p = 0.025). The RI of the OA was significantly correlated to visual acuity (r = 0.493, p < 0.037). No significant correlations were recorded for the PCAs. A significant correlation was found between AVP and the EDV of the CRA (r = - 0.49, p = 0.025).

CONCLUSION

Decreased EDV in the CRA and increased RI in the OA seem to be linked to the functional damage in NAION. An improvement of the retrobulbar circulation might be beneficial in the treatment of NAION.

[PSYCHOGENIC FACTORS IN THE PATHOGENESIS OF ANTERIOR ISCHEMIC OPTIC NEUROPATHY (REVIEW)]

The purpose of this systematic review is to describe the influence of psychogenic factors on the pathogenesis and course of anterior ischemic optic neuropathy (AION). Analysis of randomized clinical trials published in the journal indexed in PubMed in the period from 1978 to 2016, devoted to the study of the influence of various factors on the epidemiology, pathogenesis and course of AION. The review of the literature presents basic information on the psychogenic factors that affect the course of AION and the areas of clinical application of the data under study. Physiological and pathological ways of influence of psychogenic factors on regulation of angiogenesis are considered. The main properties of the disturbance of retinal microcirculation, the role in the regulation of the vascular bed in the norm and under the influence of psychogenic factors in patients with AION are described.

Differences in pupillary light reflex between optic neuritis and ischemic optic neuropathy

Objectives

To determine the differences in pupillary light reflex (PLR) between the acute and chronic phases of optic neuritis (ON) and nonarteritic anterior ischemic optic neuropathy (NAION).

Methods

The study included 30 patients with ON and 22 patients with NAION whose PLR were measured by a dynamic pupillometer (PLR-200; NeurOptics Inc., Irvine, USA). Age-matched controls included 58 healthy individuals with normal vision and optic nerve function. Pupil diameters, latency, constriction ratio, constriction velocity and dilation velocity were noted. The differences in PLR measurements were compared among the acute and chronic phases of ON and NAION, and in age-matched controls. Regression analysis determined factors associated with PLR measurements, including visual acuity, color vision defect, visual field defects and retinal nerve fiber layer thickness measurements on optical coherence tomography.

Results

Pupillary constriction velocity, constriction ratio and latency were all significantly decreased in the acute phase of ON and NAION. ON showed significantly delayed constriction latency compared to NAION (P = 0.047). Pupillary constriction velocity, constriction ratio and latency were recovered in the chronic phase of ON (P = 0.038, 0.018, and 0.045), however, these parameters were not recovered in NAION (P = 0.693, 0.173 and 0.994).

Conclusions

Pupillary constriction velocity, constriction ratio, and latency were significantly decreased in the acute phase of ON and NAION compared to normal controls. ON showed delayed constriction latency compared to NAION. Decreased PLR were recovered in the chronic phase of ON, but not in NAION.

Evaluation of optic nerve head blood flow in normal rats and a rodent model of non-arteritic ischemic optic neuropathy using laser speckle flowgraphy

PURPOSE

To evaluate optic nerve head (ONH) blood flow in normal rats and a rodent model of non-arteritic ischemic optic neuropathy (rNAION) in vivo using laser speckle flowgraphy (LSFG).

METHODS

Rats were under general anesthesia; to induce NAION, Rose Bengal (RB) was injected into the tail vein. After the administration of RB, the left ONH was photoactivated using an argon green laser. We measured ONH blood flow in the normal rats and the rNAION group (at 1, 3, 7, 14, and 28 days after the induction of NAION) using an LSFG-Micro. We used the mean blur rate (MBR) of the vessel region (MV) and MBR of the tissue region (MT) as indicators of blood flow. We compared the MBR of the right and left eyes in both the normal rats and the rNAION group.

RESULTS

In the normal rats, there were no significant differences in MV or MT between the right and left eyes. In the rNAION group, the MV and MT of the affected eyes were significantly lower than those of the unaffected eyes at all time points. There were significant differences between the left/right MV and MT ratios seen before the induction of NAION and those observed at 1, 3, 7, 14, and 28 days after the induction of NAION. However, there were no significant differences in these parameters among any of post-NAION induction time points.

CONCLUSION

Our results indicated that the ONH blood flow of the rNAION rats fell in the acute and chronic phases.

SUR1-Associated Mechanisms Are Not Involved in Ischemic Optic Neuropathy 1 Day Post-Injury

Ischemia-reperfusion injury after central nervous system (CNS) injury presents a major health care challenge with few promising treatments. Recently, it has become possible to reduce edema after CNS injury by antagonizing a sulfonylurea receptor 1 (SUR1) regulated ion channel expressed after injury. SUR1 upregulation after injury is a necessary precondition for the formation of this channel, and has been implicated in white matter injury after clinical spinal cord trauma. Glibenclamide, an SUR1 antagonist, appears to have neuroprotective effect against cerebral stroke in an open-label small clinical trial and great effectiveness in reducing damage after varied experimental CNS injury models. Despite its importance in CNS injuries, SUR1 upregulation appears to play no part in rodent anterior ischemic optic neuropathy (rAION) injury as tested by real-time PCR and immunohistochemical staining of rAION-injured rat optic nerve (ON). Furthermore, the SUR1 antagonist glibenclamide administered immediately after rAION injury provided no protection to proximal ON microvasculature 1 day post-injury but may reduce optic nerve head edema in a manner unrelated to ON SUR1 expression. Our results suggest that there may be fundamental differences between rAION optic nerve ischemia and other CNS white matter injuries where SUR1 appears to play a role.

Retinal Ganglion Cell Layer Thinning Within One Month of Presentation for Non-Arteritic Anterior Ischemic Optic Neuropathy

PURPOSE

Optical coherence tomography reveals retinal ganglion cell layer (GCL) and retinal nerve fiber layer (RNFL) thinning in chronic optic nerve injury. With acute optic nerve injury, as in acute nonarteritic anterior ischemic optic neuropathy (NAION), swelling obscures early demonstration of RNFL thinning, which might be used to evaluate therapies. We hypothesized that measurement of GCL plus inner plexiform layer (IPL) thickness and trajectory of thinning would show it is an earlier and more accurate biomarker of early permanent neuronal injury.

METHODS

We prospectively studied 29 acute NAION eyes with standard automated perimetry and spectral domain (SD) optical coherence tomography for 6 months. We used a three-dimensional layer segmentation (method 1) and a commercial proprietary (method 2), to compute the combined thickness of macular GCL+IPL and method 2 to compute peripapillary RNFL thickness.

RESULTS

At presentation, the mean GCL+IPL thickness (78.7 μm ± 8.9) for NAION eyes, did not differ from unaffected fellow eyes (83 μm ± 6.4), using method 1 while method 2 (66.8 μm ± 18.7) failed in 34% of NAION eyes. At 1 to 2 months, 12% had RNFL loss compared to baseline, while 68% of NAION eyes had GCL+IPL thinning. The ganglion cell layer plus inner plexiform layer reduction was greatest at 1 to 2 months (19.6 μm ± 12.6) and was minimally worse after month 3. Ganglion cell layer plus inner plexiform layer thinning showed moderate to strong significant correlation with the visual acuity and mean deviation at each exam time. The retinal nerve fiber layer was not thinned until month 3.

CONCLUSIONS

Ganglion cell layer plus inner plexiform layer is acutely unaffected and provides a reliable measure of retinal neuronal structure using three-dimensional segmentation. Thinning develops within 1 to 2 months of onset, which is prior to RNFL swelling resolution. This suggests GCL+IPL measurement is better than the RNFL thickness to use as biomarker of early structural loss in NAION.

Comparison of the Deep Optic Nerve Head Structure between Normal-Tension Glaucoma and Nonarteritic Anterior Ischemic Optic Neuropathy

Purpose

To compare the deep optic nerve head (ONH) structure between normal-tension glaucoma (NTG) and nonarteritic anterior ischemic optic neuropathy (NAION) and also in healthy subjects as a control using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT).

Methods

This prospective cross-sectional study included 21 NAION patients who had been diagnosed as NAION at least 6 months prior to study entry, and 42 NTG patients and 42 healthy controls who were matched with NAION patients in terms of age, intraocular pressure (IOP), and optic disc area. The retinal nerve fiber layer (RNFL) thickness in the affected sector was also matched between NAION and NTG patients. The ONH was imaged using SD-OCT with the EDI technique. The anterior lamina cribrosa surface depth (LCD) and average prelaminar tissue (PT) thickness were measured in a sector of interest in each eye and compared among the three groups.

Results

In the sector-matched comparison, LCD was largest in NTG patients, followed by NAION patients, while PT was thinner in NTG patients than in NAION patients (all P < 0.001). NAION patients had a comparable LCD and a thinner PT relative to normal controls (P = 0.170 and < 0.001, respectively).

Conclusion

The deep ONH configuration is strikingly different between NTG and NAION. The differing features provide comparative insight into the pathophysiology of the two diseases, and may be useful for differential diagnosis.

[ORIGINAL PERFORMANCE OF THE INTEGRATED CIRCUITS NEUROPROTECTIVE LECHNIYA ANTERIOR ISCHEMIC OPTIC NEUROPATHY DEPENDING ON BLOOD PRESSURE]

Anterior ischemic optic neuropathy (AION) is one of the main reasons of vision disorders among middle-aged and elderly people. During the examination of patients with AION, we were interested by the fact of low efficiency of the standard treatment course. Moreover, over 60% of such patients underwent the development of AION on the other eye during 1 year after the beginning of the disease. The purpose of the given study is the development of efficient and original neuroprotection treatment scheme for AION, depending on the arterial pressure rate. We examined 58 patients (65 eyes) with AION, depending on the arterial pressure rate. The patients were divided into two clinical groups. For the first group of 38 patients (38 eyes), we used the original AION treatment scheme developed by us. The group was divided into 3 subgroups, depending on their arterial pressure rate: patients with normal ap., patients with hypertension of I-II stages and patients with hypotension. For the control group, the standard treatment scheme was used. The results received allow us to make a conclusion that the original treatment scheme, developed by us, is more efficient, and it can be recommended as a neuroprotection treatment scheme for AION among the patients with arterial hypertension of I-II stages.

Study of perfusion changes in the optic disc of patients with fibromyalgia syndrome using new colorimetric analysis software

PURPOSE

We measured the amount of hemoglobin at the optic nerve head of fibromyalgia (FM) patients using new colorimetric analysis software. We also investigated whether perfusion defects of the optic nerve head in patients with FM lead to tissue atrophy and corresponding retinal nerve fiber layer (RNFL) thinning measured by optical coherence tomography (OCT).

METHODS

We recruited for this cross-sectional study 118 FM patients and 76 sex- and age-matched healthy controls. All subjects underwent a complete neuro-ophthalmologic examination, which also included visual field testing using the Spark strategy in an Easyfield perimeter, and OCT examinations using the Spectralis. One photograph of the optic disc was obtained using a Cirrus™ Photo 800 multi-modality imager. We analyzed fundus photographs using Laguna ONhE software, a new method that allows hemoglobin levels to be measured at the optic nerve head. We compared hemoglobin percentages in different sectors of the nerve head and RNFL thicknesses between the two groups.

RESULTS

Mean hemoglobin percentages and hemoglobin content in all optic nerve head sectors calculated by the Laguna ONhE program were significantly lower in FM patients than in healthy controls, and the main differences were detected in the outer ring, which corresponds with the neuroretinal rim. However, only the differences in the superotemporal RNFL were statistically significant. Correlations between the RNFL thickness and the percentage of hemoglobin in the different sectors were weak.

CONCLUSION

Optic disc perfusion was decreased in patients with FM, especially within the neuroretinal rim, without clear involvement in the RNFL.

Postoperative visual loss in orthopedic spine surgery in the prone position: a case report

Postoperative visual loss is rare but a devastating postoperative complication. It is a multifactorial etiology. The practice advisory for perioperative visual loss associated with spine surgery reported by the American Society of Anesthesiologists task force on perioperative visual loss was developed from several case reports and case series. We reported a new case of postoperative visual loss diagnosed as ischemic optic neuropathy after undergoing a spine surgery in prone position. This case should be added to the overall incidence of postoperative visual loss. The possible risk factors were categorized in order to identify the POVL-susceptible patients. The pathophysiology of ischemic optic neuropathy was briefly reviewed.

[Determination of the individual normal range of intraocular pressure in differential diagnosis between pseudonormal tension glaucoma and ischemic optic neuropathies]

The study investigated the relation between the actual intraocular pressure (IOP) and its individual normal range in normal-tension glaucoma (NTG) and ischemic optic neuropathy (ION) outcome. A total of 39 patients (61 eyes) were examined. Group 1 included 19 patients (35 eyes) with newly diagnosed NTG, group 2--20 patients (26 eyes) with the ION outcome. Besides conventional tests, the ophthalmic assessment in all patients included determination of the individual normal range of IOP and evaluation of biomechanical properties of the cornea. It is showed that determination of the individual normal range of IOP may play a key role in confusing cases of differential diagnosis between NTG and ION. The average actual IOP in patients with NTG generally exceeds the individual normal range by 40% (more than 5 mmHg), whereas in patients with the ION outcome--by only 11.7% (less than 5 mmHg - buffer range). No statistically significant difference in IOP measurements by different tonometry methods was found in either NTG or ION patients with corneal compensated IOP less than 21 mmHg.

[Nonarteritic ischemic optic neuropathy animal model and its treatment applications]

Nonarteritic ischemic optic neuropathy (NAION) is one of the most common acute unilaterally onset optic nerve diseases. One management problem in terms of NAION is the difficulty of differential diagnosis between NAION and anterior optic neuritis (ON). A second problem is that there is no established treatment for the acute stage of NAION. A third problem is that there is no preventive treatment for a subsequent attack on the fellow eye, estimated to occur in 15 to 25% of patients with NAION. For differentiation of acute NAION from anterior optic neuritis, we investigated the usefulness of laser speckle flowgraphy (LSFG). In the normal control group, the tissue blood flow did not significantly differ between the right and left eyes. In the NAION group, all 6 patients had 29.5% decreased mean blur rate (MBR), which correlates to optic disc blood flow, of the NAION eye compared with the unaffected eye. In the anterior ON group, all 6 cases had 15.9% increased MBR of the anterior ON eye compared with the unaffected eye. Thus, LSFG showed a difference of the underlying pathophysiology between NAION and anterior ON despite showing disc swelling in both groups and could be useful for differentiating both groups. For the treatment of acute stage of NAION, we tried to reproduce the rodent model of NAION (rNAION) developed by Bernstein and colleagues. To induce rNAION, after the administration of rose bengal(RB) (2.5 mM) into the tail vein of SD rats, the small vessels of the left optic nerve were photoactivated using a 514 nm argon green laser (RB-laser-induction). In the RB-laser-induction eyes, the capillaries within the optic disc were reduced markedly, the optic disc became swollen, and fluorescein angiography showed filling defect in the choroid and the optic disc at an early stage, followed by hyperfluorescence at a late stage. Electrophysiological evaluation revealed that visual evoked potential (VEP) amplitude was significantly decreased but an electroretinogram (ERG) did not show a significant difference either in the b wave or in the oscillatory potentials. The scotopic threshold response (STR) was significantly reduced 3 days after induction. These findings are similar to those of rNAION and indicate that we succeeded in reproducing the rNAION. Histopathologic examination in the acute phase of rNAION, showed acellular NFL swelling anterior to the optic disc. No accumulation of inflammatory cells was noted in several microscopic sections of the optic nerve. In addition, immunochemical staining was negative throughout the retina and optic nerve. These results suggested that the rNAION-induced NFL swelling was not a result of inflammation. In the chronic phase of rNAION, the morphologic retinal changes were apparent in only the retinal ganglion cell(RGC) layer, with a reduction in the number of cells in the RGC layer. Thus, we need to evaluate the degree of the NFL swelling in the acute phase and the following thinning of the NFL in the chronic phase for efficacy of the treatment of rNAION. Therefore, we used optical coherence tomography (OCT) for the objective and quantitative evaluation of the retinal nerve fiber layer (RNFL) thickness around the optic disc changes in rNAION. The second method was to use the STR for the evaluation of the RGC function. The third method was to count the number of surviving RGCs observed and photographed through the fluorescence microscope with the Fluorogold staining. A possible rationale for treatment of NAION is that dilation of the posterior ciliary artery (PCA) increases the blood flow to the optic nerve and could improve the optic nerve function. To clarify the vasodilatory effects of medications, we used in vitro isometric tension recording methods and examined the vasodilatory effects of bevacizumab as an anti-vascular endothelial growth factor (VEGF) antibody, methylprednisolone as a corticosteroid and sodium nitroprusside (SNP, a nitric oxide donor) as a vasodilator on high-K (potassium) solution-induced contraction in isolated rabbit PCA. Bevacizumab did not relax rabbit PCA. Methylprednisolone relaxed rabbit PCA nitric oxide (NO) independently. SNP relaxed rabbit PCA by exogenous NO. On the basis of these results, we selected the following candidates for rNAION treatment: methylprednisolone as the corticosteroid and L-arginine as the NO related agent. Intravenous infusion of methylprednisolone significantly decreased the degree of acute disc edema but did not reduce inner retinal thinning, decrease STR amplitude, or decrease RGC numbers in rNAION. Intravenous infusion of L-arginine after rNAION induction significantly decreased the disc edema at the acute stage and the thinning of the inner retina, reduced the decrease in STR amplitude, and reduced the decrease in RGC numbers during rNAION. These results indicated that L-arginine treatment is effective for reducing the anatomical changes and improving visual function in the acute stage of rNAION. To strengthen the neuroprotective effect for rNAION, we tried treatment using transcorneal electric stimulation (TES). We evaluated the effect using STR and survival RGCs. Decreased amplitude in the STR of the TES group was significantly better preserved than in the control group on the 28th day after treatment. RGC survival in the TES group was significantly larger than in the control group on the 14th and 28th days. The neuroprotective effect of TES was better than that of L-arginine. For preventive treatment of subsequent attack in the fellow eye, we investigated whether pretreatment with L-arginine might reduce the severity of the anatomical changes associated with NAION and preserve the visual function when NAION occurs in the other eye. In the L-arginine pretreated eyes, the disc edema at the acute stage and the thinning of inner retina were significantly decreased, and the decrease of STR amplitude and the decrease in RGC numbers during rNAION were reserved. These results indicate that pretreatment with L-arginine is effective for the reduction of the severity during recurrence in the other eye. We will perform clinical trials in a small series of cases, and if the treatment is effective, we will proceed to multicenter randomized treatment trials. In addition to that, more work needs to be done to discover better treatment options for NAION.

Intravitreal triamcinolone injections in non-arteritic anterior ischemic optic neuropathy

BACKGROUND

In non-arteritic anterior ischemic optic neuropathy (NA-AION), no treatments have demonstrated to be effective in recovering visual loss in randomized clinical trials. Oral steroids have been evaluated, and small series of intravitreal triamcinolone acetonide (IVTA) injection in NA-AION have been reported. The purpose of our study was to report the visual outcome and morphological changes in response to a single IVTA injection as a treatment for patients with NA-AION.

PATIENTS AND METHODS

The charts of 36 patients with visual symptoms and optic disc swelling caused by NA-AION were evaluated. Twenty-one patients had received 4 mg IVTA and were compared with 15 non-treated patients. Visual acuity (VA), retinal nerve fiber layer thickness and static visual field were evaluated after 6 months.

RESULTS

VA improvement at 6 months is statistically better in the treated group than in the non-treated group (p = 0.0035). In the treated group, there was a significant inverse correlation between the delay of the injection and the visual acuity achieved at 6 months (p < 0.0083**, r = -0.56). A significant improvement of the visual field was noted in the injected group when compared with the non-treated group at 6 months (p < 0.0028).

DISCUSSION

In this retrospective study, patients receiving IVTA in the acute phase of NA-AION have better improvement of VA and visual field during the follow-up period of 6 months. However, only a large randomized controlled trial may enable to evaluate the benefits of IVTA Injections on visual outcome in NA-AION.

[Peculiarities of ocular blood flow in ischemic optic neuropathy and normal tension glaucoma]

Characteristics of ocular hemodynamics in ischemic optic neuropathy (ION) outcome and normal tension glaucoma (NTG), the conditions that are difficult to be differentially diagnosed, have been investigated. The study enrolled 32 patients (40 eyes) with ION outcome, 26 patients (46 eyes) with NTG, and 20 patients (32 eyes) with no ocular pathology. Besides the standard ophthalmological examination, color Doppler imaging of ocular vessels, evaluation of ocular blood flow volume and individual normal range of intraocular pressure (flowmetry) were performed in all cases. The results showed that an excess of the actual intraocular pressure (IOP) over the individual normal range was much higher in patients with NTG than in patients with ION (39% and 14.5% correspondingly). It was also found that NTG is associated with a more significant decrease of ocular blood flow volume (30.1% in average) in comparison to ION outcome (11%). In both conditions a decrease in velocity parameters of the blood flow in main ocular vessels was registered, however, ocular hemodynamics changes appeared to be more severe in patients with glaucomatous optic neuropathy. A statistically reliable correlation between volumetric and velocity parameters of ocular blood flow has been discovered.

Vasodilatory effects of antivascular endothelium growth factor (VEGF) antibody, corticosteroid, and nitric oxide on the posterior ciliary arteries

PURPOSE

The purpose of this study was to determine whether an antivascular endothelium growth factor (VEGF) antibody, a corticosteroid, and sodium nitroprusside (SNP) [a nitric oxide (NO) donor] are possible treatment agents for nonarteritic ischemic optic neuropathy (NAION) by clarifying their effects on high-K (potassium) solution-induced contraction in isolated rabbit and human posterior ciliary arteries (PCA).

METHODS

Vascular ring segments were cut from the distal section of the PCA and mounted in a double-myograph system. After obtaining the maximal contraction following the administration of high-K solution, bevacizumab as an anti-VEGF antibody, methylprednisolone as a corticosteroid, and SNP were administered separately. When a vasodilatory effect was observed, carboxy-PTIO (a NO scavenger) or L-NAME (a NO synthase inhibitor) was administered.

RESULTS

Bevacizumab did not relax either the rabbit or the human PCA, whereas methylprednisolone relaxed both. Neither carboxy-PTIO nor L-NAME inhibited methylprednisolone-induced relaxation. SNP relaxed the rabbit PCA. Carboxy-PTIO inhibited SNP-induced relaxation, but L-NAME did not. In the human PCA, the vasodilatory effect of SNP was present, but weaker than in the rabbit PCA.

CONCLUSIONS

A corticosteroid has NO-independent vasodilatory effects. Exogenous NO has a weak dilating effect in the human PCA. Therefore, corticosteroid could be effective for the treatment of NAION.

Diffusion MRI and tensor tractography in ischemic optic neuropathy

Ischemic optic neuropathies (IONs) are among the most prevalent diseases causing visual impairment in middle-aged and elderly people. While arteritic ION is an ocular emergency and requires early diagnosis and immediate treatment with systemic high-dose corticosteroids to prevent further visual loss, treatment options for non-arteritic ION remain limited. We describe the case of a woman with unilateral right-sided non-arteritic posterior ischemic optic neuropathy. The diagnosis was made on clinical and radiographic grounds. Diffusion-weighted sequences and apparent diffusion coefficient maps revealed markedly restricted diffusion in the right optic nerve. It was very helpful to precise the posterior topography of the optic nerve lesion. Furthermore, we reported the diffusion tensor tractography study which appears to be an objective tool to assess the incomplete visual recovery. These MRI techniques including tensor tractography remain to be evaluated in large cohort of ION patients' particularly in future therapeutic trials.

Optic nerve head change in non-arteritic anterior ischemic optic neuropathy and its influence on visual outcome

PURPOSE

To evaluate changes in cup/disc (C/D) diameter ratios and parapapillary atrophy in patients with non-arteritic anterior ischemic optic neuropathy (NA-AION), using morphometric methods.

METHODS

The clinical non-interventional study included 157 patients with unilateral or bilateral NA-AION. Optic disc photographs taken from both eyes at the end of follow-up were morphometrically examined.

RESULTS

Follow-up was 86.3±70.3 months. Horizontal and vertical disc diameters (P = 0.30;P = 0.61, respectively), horizontal and vertical C/D ratios (P = 0.47;P = 0.19,resp.), and size of alpha zone and beta zone of parapapillary atrophy (P = 0.27;P = 0.32,resp.) did not differ significantly between affected eyes and contralateral normal eyes in patients with unilateral NA-AION. Similarly, horizontal and vertical disc diameters, horizontal and vertical C/D ratios, and size of alpha zone and beta zone did not vary significantly (all P>0.05) between the unaffected eyes of patients with unilateral NA-AION and the eyes of patients with bilateral NA-AION. Optic disc diameters, C/D ratios, size of alpha zone or beta zone of parapapillary atrophy were not significantly associated with final visual outcome in the eyes affected with NA-AION (all P>0.20) nor with the difference in final visual acuity between affected eyes and unaffected eyes in patients with unilateral NA-AION (all P>0.25).

CONCLUSIONS

NA-AION did not affect C/D ratios nor alpha zone and beta zone of parapapillary atrophy. Optic disc size was not related to the final visual acuity outcome in NA-AION.

Vision impairment during cardiac surgery and extracorporeal circulation: current understanding and the need for further investigation

The aim of this article was to provide a comprehensive review of current knowledge regarding ocular hemodynamic alterations affecting the retinal neuroglial cells and optic nerve head (ONH) function during cardiac surgery. Literature indicates that visual loss after heart surgery is a rare but devastating complication provoked by two main causes of optic ischaemia and infarction during on-pump cardiac procedures: microembolism and/or hypoperfusion. Retinal ischaemia and ischaemic optic neuropathy are two possible major consequences of extracorporeal circulation in cardiac surgery. The hemodynamic modifications within the vascular beds of retina and ONH during cardiovascular operations have been incompletely studied. Consequently, it is of great interest to investigate the hemodynamic changes during cardiopulmonary bypass within the choroidal, retinal and optic nerve microcirculations as well as other potential causes of vaso-occlusion. Maintaining stable hemodynamic parameters during cardiovascular surgery seems to be the key to prevent visual impairment.

[Optic neuritis and optic ischemic neuropathy: the problem of differential diagnosis]

Based on a numerous data (220 patients, 285 eyes) clinical criteria of differential diagnosis of optic neuritis and nonarteritic ischemic optic neuropathy are studied. Neuronal network method was used for multivariate analysis of studied parameters, that allowed to estimate linear and nonlinear correlations of different factors, significance of every diagnostic criteria for the identification of etiology of optic neuropathies.

Non-arteritic anterior ischaemic optic neuropathy (NA-AION): outcome for visual acuity and visual field defects, the Singapore scene 2

We report the six months follow-up findings in relation to visual acuity and visual field defects in a series of Singaporean patients with non-arteritic anterior ischaemic optic neuropathy seen in the neuro-ophthalmology service of the Singapore National Eye Centre. 90% of the patients were Chinese, and the most common vascular risk factor was hypertension. Visual acuity was normal at the outset in 40% of cases and unchanged in 85%, and the assessment of visual acuity alone was not found to be a satisfactory method to determine prognosis. Visual field defects were found in all the affected patients, the most common being in the inferior fields. After six months, visual field defects were found to be unchanged in 77% of cases, improved in 15.5% and worse in 7.5%. Overall visual function (visual acuity plus visual field) was unchanged in 81% of cases, and no patient had complete recovery.

[Increased ocular perfusion--visual field preservation]

Adjustment of the ocular flow has clear implications in glaucomatous pathology. It cannot be drawn a clear barrier between causality and effect of ocular vascular factor in glaucoma but altered hemodynamics leads clearly to node loss. Unstable ocular perfusion creates a low blood flow to the optic nerve directly involved in glaucomatous optic neuropathy , ocular perfusion pressure (PPO) being a risk factor predictor of progression associated with impairment of visual function in glaucoma.

Two presentations of nonarteritic ischemic optic neuropathy

BACKGROUND

Nonarteritic ischemic optic neuropathy (NAION) is the most common acute optic neuropathy in adults over the age of 50. Patients affected notice sudden and painless loss of vision in 1 eye, often upon awaking. Studies have found that the opposite eye may be affected in approximately 15% to 20% of cases within a 5-year period. NAION vision loss results from an ischemic event often affecting the short posterior ciliary arteries. This results in optic nerve pallor, nerve fiber layer defects, and corresponding visual field defects.

CASE REPORTS

Two cases of NAION are discussed here. The first patient, a 57-year-old woman, had a 10-year history of visual symptoms, and the second, a 66-year-old man, presented in less than a week after first noticing symptoms. Both had predisposing systemic risk factors and resultant visual field loss and decreased visual acuity.

CONCLUSIONS

Predisposing factors for NAION include small cup-to-disc ratios of the optic nerve, obstructive sleep apnea, nocturnal hypotension, diabetes, and other vascular diseases. The vision loss is irreversible, and there is no known effective treatment to prevent subsequent disc atrophy or recurring episodes.

Acute visual loss after spinal surgery

PURPOSE

To report visual loss after prone spinal surgery.

METHODS

Computed tomography scan, fundus photography, optical coherence tomography (OCT).

RESULTS

A 56-year-old man demonstrated loss of vision in the left eye after cervical spinal surgery. Clinical examination revealed loss of vision to finger counting, severe visual field defect and blurred neural rim area around the optic disc in the left eye. Six weeks later, visual acuity in the left eye was 6/9 and there was inferior visual field defect. Six months after the surgery, significant reduction of retinal nerve fibre layer thickness around the optic nerve head was measured with OCT, consistent with the visual field defect.

CONCLUSION

Ischemic optic neuropathy is the most common cause of visual loss after spine surgery and special emphasis should be given to protect the eye against possible pressure during the surgery.

[Optic disc drusen. Communication 2. Their role in the etiopathogenesis of optic neuropathy]

Forty-five patients (83 eyes) aged 17 to 80 years with optic disc drusen (ODD) were examined. Acute anterior ischemic optic neuropathy (AION) was detected in 6% of all the cases. Chronic optic neuropathy (ON) was revealed in 60%, which was predominantly slowly, progressive, asymptomatic and manifested as changes in the paracentral and peripheral fields of vision. Ultrasound study showed small-sized ODD in patients without clinical signs of optic nerve pathology and large-sized ODD in patients with manifestations of chronic ON. ODD affected central retinal artery blood flow (CRABF): in 96.8% of the patients with chronic ON and in 45.5% of those without visual impairments. There was a relationship of the values of the field of vision and CRABF to the extent of ODD.

Bilateral non-arteritic anterior ischemic optic neuropathy (NA-AION): case report and review of the literature

PURPOSE/METHOD

To present a 72-year-old woman affected by non-arteritic anterior ischemic optic neuropathy (NA-AION). To our knowledge, this clinical case, showing a bilateral form of NA-AION, is uncommon as only very few similar reports have been published in the scientific literature at this time.

RESULTS/CONCLUSIONS

Visual acuity was reduced to 6/20 in both eyes, color vision was absent and computerized perimetry showed an absolute and general reduction of the retinal sensibility within 30 degrees around the fixation point. Pattern visual evoked potentials and pattern electroretinograms showed normal morphologies but delayed latencies and reduced amplitudes. An updated review of the literature has also been done.

Clinical profile of patients with nonarteritic anterior ischemic optic neuropathy presented to a referral center from 2003 to 2008

BACKGROUND

We conducted this study to report the demographics and clinical profile of patients with nonarteritic anterior ischemic optic neuropathy referred to a referral neuro-ophthalmology center in Iran.

METHODS

During a five-year period, 107 patients with nonarteritic anterior ischemic optic neuropathy were studied. A detailed history of previous or current systemic diseases was obtained and a complete ophthalmic evaluation including best corrected visual acuity, color vision testing, and computerized perimetry was performed.

RESULTS

Sixty-six men and 41 women with a mean+/-SD age of 52.7+/-10.3 (range: 30 - 80) years were studied. Most (62.2%) of the patients aged more than 50 years. Twenty-two (20.5%) patients had had an episode of nonarteritic anterior ischemic optic neuropathy in the fellow eye. Overall, 51 (47.7%) patients had no evidence of a previous or current systemic disease. Diabetes mellitus and hypertension were reported in 40.1% and 26.1% of the patients, respectively. The best corrected visual acuity was 20/200 or worse in 43 (40.1%) eyes and 20/40 or better in 43 (40.1%) eyes. The best corrected visual acuity was significantly better in nondiabetic patients (0.62+/-0.69 LogMAR) than diabetics (0.96+/-0.84, P=0.03). The visual field analysis of reliable fields (76 eyes) revealed that the mean deviation ranged from -32.6 to -1.3 dB with a mean+/-SD of -19.7+/-8.08 dB. Diffuse defect was the most prevalent defect detected on 36.8% of visual fields of the study eyes followed by inferior altitudinal defect (26.3+/-). In the fellow eyes, without any evidence of prior optic nerve problem, inferior and superior arcuate scotoma were found in 30% and 20% of the eyes, respectively.

CONCLUSION

Characteristics of nonarteritic anterior ischemic optic neuropathy patients in a population of Iranian patients were similar to nonarteritic anterior ischemic optic neuropathy as described in previous studies, with the exception of higher proportion of younger patients and a higher propensity for diabetes. Visual field defects were common in clinically normal fellow eyes.

[Serious loss of vision in bilateral anterior ischemic optic neuropathy caused by interferon]

BACKGROUND

We treated a patient with anterior ischemic optic neuropathy caused by peginterferon.

CASE

Upon medical examination of the eyes before starting interferon therapy for chronic hepatitis C at Saiseikai Izuo hospital, a 64-year-old man showed corrected visual acuity of 0.9 in the right eye and 1.0 in the left. No abnormality was visible in either eye except for mild cataracts. Six weeks after combination therapy with peginterferon alpha-2b and ribavirin was started, corrected visual acuity was found to have decreased in the right eye, and swelling of the optic nervehead in both eyes was evident. Bilateral anterior ischemic optic neuropathy caused by interferon therapy was diagnosed. Combination therapy with peginterferon alpha-2 b and ribavirin was discontinued, and administration of prednisolone was started at a dose of 60 mg. However, visual acuity declined in both eyes and the visual field defects worsend. At the most recent examination, visual acuity was 1.0 in the right eye and 0.01 in the left. The visual field included only the temporal periphery in the left eye, and part of the central and upper temporal periphery in the right.

CONCLUSION

Since the outcome of visual acuity and visual fields in anterior ischemic optic neuropathy caused by interferon can be poor, an effective therapy for this complication needs to be developed.

Correlation of Fourier domain optical coherence tomography retinal nerve fiber layer maps with visual fields in nonarteritic ischemic optic neuropathy

BACKGROUND AND OBJECTIVE

To correlate peripapillary retinal nerve fiber layer (NFL) loss and visual field defects in nonarteritic ischemic optic neuropathy (NAION).

PATIENTS AND METHODS

Patients with NAION and control subjects were enrolled in a case-control study. Participants were scanned with a Fourier domain optical coherence tomography (OCT) system. Peripapillary NFL thickness was averaged in hemispheric, quadrant, and octant divisions. Standard achromatic static perimetry was used to assess visual fields.

RESULTS

The reproducibility of peripapillary NFL parameters was excellent in both the healthy and NAION groups. Eyes in the NAION group showed a significant decrease of peripapillary NFL thickness in terms of the overall average, all quadrant averages, and all octants. There were statistically significant correlations between the peripapillary NFL and visual fields in terms of both overall averages and superior-inferior differences.

CONCLUSION

In NAION, the visual field and peripapillary NFL losses are correlated in both severity and location. Fourier domain OCT provides reproducible measurement of the peripapillary NFL and may be useful in the assessment of NAION.

Optic disc edema in non-arteritic anterior ischemic optic neuropathy

We investigated the clinical characteristics, time to resolution and the factors that influence it, and evolutionary pattern of optic disc edema (ODE) in non-arteritic anterior ischemic optic neuropathy (NA-AION). Our study was conducted in 591 consecutive patients (749 eyes) with NA-AION who fulfilled our inclusion criteria. On their first visit to our clinic, all patients had a detailed ophthalmic and medical history, a comprehensive ophthalmic evaluation, and stereoscopic color fundus photography and fluorescein fundus angiography. On each follow-up visit, the same ophthalmic evaluation was performed, except for fluorescein fundus angiography. The effect of steroid therapy on ODE was evaluated in a "patient choice study" in 723 eyes, i.e., patients who voluntarily opted to have (343 eyes) or not have (380 eyes) this therapy. To identify the factors that influence time to ODE resolution, parametric regression models for interval-censored data were fitted by maximum likelihood estimation using an SAS procedure. Our results indicate that the overall median time (25-75th percentile) to spontaneous resolution of ODE from the onset of visual loss was 7.9 (5.8-11.4) weeks. The ODE resolution time was longer in diabetics than in non-diabetics (p = 0.003) in the single factor model. Multi-factor analysis showed that worse initial visual field defects (p < 0.0001) and worse visual acuity (p = 0.04) were associated with a faster resolution of ODE. Those treated with steroid therapy within 2 weeks after onset of NA-AION had significantly (p = 0.0006) faster ODE resolution than untreated cases. Severity of initial visual loss and systemic diseases were identical in steroid treated and untreated patients. A characteristic evolutionary pattern of ODE in NA-AION was observed. In conclusion, our study showed that in NA-AION the time course for resolution of ODE is shorter with greater severity of initial visual field and visual acuity loss, which may relate to the number of axons permanently damaged during the acute stage. Steroid therapy was associated with shorter time to resolution of ODE. Resolution of ODE goes through a characteristic evolutionary process.

Role of retinal hypoxia in diabetic macular edema: a new concept

BACKGROUND

To report the role of retinal hypoxia in development of diabetic macular edema and its management--a new concept.

CASE REPORT

A 24-year-old diabetic female was seen with bilateral visual blurring for 3 weeks, associated with marked diabetic macular edema, diabetic retinopathy, and non-arteritic anterior ischemic optic neuropathy (NA-AION) in both eyes. She was taking three blood pressure lowering drugs for diabetic neuropathy and nephropathy. Stopping two of those arterial hypotensive drugs, without any of the conventional treatments for diabetic macular edema, resulted in rapid improvement of visual acuity from counting fingers to 20/50 in the right eye, and from 20/80 to 20/25 in the left eye, and complete resolution of macular edema and improvement of retinopathy. Similarly, visual field defects in both eyes improved to almost normal.

CONCLUSIONS

The evidence from this diabetic patient suggests that hypoxia caused by fall in perfusion pressure in the retinal capillaries may be playing an important role in the development of diabetic macular edema in some, perhaps many, of these cases.

Retinal nerve fiber structure versus visual field function in patients with ischemic optic neuropathy. A test of a linear model

PURPOSE

To test a linear model relating the regional loss in retinal nerve fiber (RNFL) thickness to the corresponding regional loss in sensitivity with data from patients with previous anterior ischemic optic neuropathy (AION).

DESIGN

Case-control study.

PARTICIPANTS

Twenty-four individuals with AION and 20 with normal vision were tested. The time since the AION attack ranged from 5.2 months to more than 20.3 years (median, 2.95 years).

METHODS

Eyes were tested with standard automated perimetry (SAP) and with optical coherence tomography (OCT), both RNFL thickness scans. The average RNFL thickness of the inferior and superior disc sectors was plotted against the average total deviations (linear units) of the corresponding superior and inferior arcuate field regions, and a linear model was fitted. According to the model, the RNFL thickness R=s(o)T+b, (1), where T is the relative SAP sensitivity loss (on a linear scale; e.g., for -3 dB, T = 0.5), s(o) is the RNFL thickness attributable to axons in the healthy or normal state (T = 1.0), and b is the residual RNFL measured when all sensitivity and axons are lost.

MAIN OUTCOME MEASURES

Optical coherence tomography RNFL thickness and SAP sensitivity.

RESULTS

The data from the AION patients resembled the data from glaucoma patients previously tested and were described by the linear model. For patients with SAP losses of more than -10 dB in the arcuate region, the RNFL thickness provided an estimate of residual RNFL thickness, b. The median value of b (45.5 microm) was similar to the value for patients with glaucoma. It varied among individuals (range, 30.4-63.3 microm), showing a very weak correlation with patient's age (r = 0.30) and the time since the AION episode (r = 0.26), but an excellent correlation (r(2) = 0.94; P<0.01) with the value of s(o), estimated from the unaffected eyes.

CONCLUSIONS

The relationship between a structure (OCT RNFL thickness) and function (SAP sensitivity loss) is the same for patients with AION and glaucoma and can be approximated by a simple linear model. The model may provide a framework for identifying those patients with ganglion cell axons that are malfunctioning but are alive.