Pathogenesis of nonarteritic anterior ischemic optic neuropathy.

Based on histopathology, electron microscopic corrosion cast studies, optic nerve blood flow studies, and clinical data, the pathogenesis of idiopathic nonarteritic ischemic optic neuropathy includes the following features: (1) structurally crowded optic discs are predisposed; (2) laminar and retrolaminar regions are the most common locations for infarction; (3) there is flow impairment in the prelaminar optic disc during the acute phase; (4) lack of consistent choroidal flow impairment and the retrolaminar location of infarcts suggest vasculopathy within or distal to the paraoptic branches of the posterior choroidal arteries; (5) diabetes is the most consistently identified vasculopathic risk factor; (6) impaired autoregulation of the disc circulation by atherosclerosis, with a possible contribution from serotonin and endothelin-mediated vasospasm, may play a role; and (7) progression may be caused by secondary cell death after the initial ischemic insult or compression from cavernous degeneration and mechanical axonal distortion.     

Posner-Schlossman syndrome and nonarteritic anterior ischemic optic neuropathy.

A 41-year-old woman with acute OD pain and decreased visual acuity presented with anterior uveitis, an intraocular pressure of 56 mm Hg, an open angle, ipsilateral nerve fiber bundle visual field defects, and optic nerve edema. With control of intraocular pressure and uveitis, visual acuity improved to 20/25, visual field defects persisted, and optic disc pallor developed. She has remained stable over 23 months of follow-up. This case represents a concurrence of glaucomatocyclitic crisis (Posner-Schlossman syndrome, PSS) and nonarteritic ischemic optic neuropathy (NAION). Although this combination occurs rarely, patients with PSS and other risk factors for NAION, including an optic disc that lacks a physiologic cup, should be protected against NAION by prophylactic treatment with ocular antihypertensive medications.     

Occurrence of familial nonarteritic anterior ischemic optic neuropathy in a case series.

OBJECTIVE: To report on the occurrence of familial nonarteritic anterior ischemic optic neuropathy (NAION) in our NAION series. METHODS: One hundred forty-eight consecutive retrievable cases of NAION were surveyed regarding the occurrence of NAION in other family members. Medical records of affected family members were reviewed, and clinical characteristics of documented familial NAION cases were described. RESULTS: Of 79 patients who returned the survey, four reported one or more relatives with previously diagnosed NAION. There were nine cases of documented NAION in these four families. All cases occurred in siblings, with a mean age at onset of 55 years. Six patients had second eye involvement and in five, involvement became bilateral within 4 years after initial onset. None of the patients had diabetes; two had hypertension. CONCLUSION: A small number of patients with NAION may belong to a familial subclass. Three previous reports of familial NAION further support this hypothesis.     

Change of retinal nerve fiber layer thickness in patients with nonarteritic inflammatory anterior ischemic optic neuropathy

In this study, 16 patients (19 eyes) with nonarteritic anterior ischemic optic neuropathy in the acute stage (within 4 weeks) and resolving stage (after 12 weeks) were diagnosed by a series of complete ophthalmic examinations, including fundus examination, optical coherence tomography and fluorescein fundus angiography, and visual field defects were measured with standard automated perimetry. The contralateral uninvolved eyes were used as controls. The retinal nerve fiber layer thickness was determined by optical coherence tomography which showed that the mean retinal nerve fiber layer thickness and the retinal nerve fiber layer thickness from temporal, superior, nasal and inferior quadrants were significantly higher for all measurements in the acute stage than the corresponding normal values. In comparison, the retinal nerve fiber layer thickness from each optic disc quadrant was found to be significantly lower when measured at the resolving stages, than in the control group. Statistical analysis on the correlation between optic disc nerve fiber layer thickness and visual defects demonstrated a positive correlation in the acute stage and a negative correlation in the resolving stage. Our experimental findings indicate that optical coherence tomography is a useful diagnostic method for nonarteritic anterior ischemic optic neuropathy and can be used to evaluate the effect of treatment.     

Intravitreal triamcinolone improves recovery of visual acuity in nonarteritic anterior ischemic optic neuropathy.

BACKGROUND: The visual outcome in untreated nonarteritic anterior ischemic optic neuropathy (NAION) is dismal. Because intravitreal triamcinolone (IVTA) has shown promise in improving edematous retinal disorders, a pilot trial of this therapy in NAION was considered reasonable. METHODS: Four eyes of 4 patients with severe visual loss due to NAION were treated with 4 mg IVTA (study group). The control group consisted of 6 consecutive patients with NAION who received no treatment. Patients were evaluated by the visual acuity and visual field measurements of the Early Treatment Diabetic Retinopathy Study (ETDRS) and fluorescein angiography. RESULTS: All patients completed at least 9 months of follow-up. In the study group, the mean improvement in visual acuity were 4, 5.8, and 6.2 ETDRS lines at the first and third weeks and final visit, respectively. Optic disc swelling and leakage had markedly decreased at the first postinjection week and had disappeared by the third week examination in all eyes. In the control group, the mean improvements in visual acuity were 0, 0.7, and 1.3 ETDRS lines at the first and third weeks and final visit, respectively. Control eyes showed resolution of the optic disc swelling between the fourth week and third month visits. No marked change in visual field defects was observed in either group. CONCLUSIONS: IVTA provided relatively improved recovery of visual acuity and relatively rapid resolution of optic disc swelling in a small sample of patients with acute NAION. It did not provide visual field improvement. A larger trial is merited by the results of this small pilot study.     

A comparison of risk factors for postoperative and spontaneous nonarteritic anterior ischemic optic neuropathy.

BACKGROUND:: Whether postoperative non-arteritic ischemic optic neuropathy (NAION) is caused by surgery is unsettled. To provide further evidence on this issue, it is useful to compare the characteristics of patients who develop NAION following intraocular surgery to those who develop NAION spontaneously. METHODS:: In a retrospective review of patients diagnosed with NAION between January 1, 1993 and December 31, 1999, 12 cases of NAION in 11 subjects were identified as occurring within 30 days of cataract extraction or intraocular lens exchange (postoperative NAION group). Using Fisher exact test, the prevalence of NAION risk factors (hypertension, diabetes mellitus, hypercholesterolemia, smoking, small cup-to-disc ratios) was compared with that of a similarly aged control group of 37 subjects diagnosed with spontaneous NAION (spontaneous NAION group). RESULTS:: Patients with postoperative NAION had a lower prevalence of hypertension than did those with spontaneous NAION (27% versus 68%, P = 0.034) and a lower prevalence of cup-to-disc ratios of less than or equal to 0.2 (55% vs. 94%, P = 0.006). The prevalence of elevated cholesterol, diabetes mellitus, and tobacco use was similar in the two groups. CONCLUSIONS:: The prevalence of hypertension and low cup-to-disc ratios is significantly lower in subjects with NAION following lens-related intraocular surgery than in those with spontaneous NAION, indicating that risk factors for NAION in these settings may be different.     

Bilateral anterior ischemic optic neuropathy after liposuction.

A 30-year-old woman had bilateral anterior ischemic optic neuropathy after undergoing large-volume liposuction. Visual function remained stable over a four-month follow-up, with decreased visual acuity and marked constriction of the visual fields. To our knowledge, this is the second reported case of ischemic optic neuropathy in this setting.     

Prolonged premonitory optic disc signs in anterior ischemic optic neuropathy.

A patient displayed a pink mass on the right optic disc and normal visual function that was diagnosed as a capillary hemangioma. Seven months later, he developed typical features of nonarteritic anterior ischemic optic neuropathy (NAION) in that eye. Such a long latency between "preeruptive" and "eruptive" disc edema has not been well documented in NAION.     

中医药治疗前部缺血性视神经病变疗效观察

目的探讨中医药治疗前部缺血性视神经病变的临床疗效。方法对26例(33只眼)曾经用过激素药物治疗而疗效欠佳的前部缺血性视神经病变患者,辨证分型为阴虚阳亢、气滞血瘀、气虚血亏3型应用中药进行治疗,同时配合灯盏花素注射液静滴。结果治疗观察1~2个月,追踪随访4~12个月,基本治愈1例(1只眼),显效17只眼,有效13只眼,无效2只眼,总有效率93.9%。结论对应用激素药物疗效欠佳的前部缺血性视神经病变患者,重新应用中药进行治疗仍可以取得较好的疗效,且无不良反应,复发少,是治疗本病较理想的方法之一。     

Anterior ischemic optic neuropathy associated with viagra.

A 42-year-old male presented with acute onset of an inferior visual field defect OD after sildenafil citrate use. Examination revealed a right relative afferent pupillary defect and a swollen disc with a 0.1 cup-to-disc ratio and a prominent disc hemorrhage. Anterior ischemic optic neuropathy (AION) is associated with acute episodes of hypotension in patients with structurally crowded discs. Sildenafil citrate may cause episodes of hypotension and was temporally related to the onset of symptoms in this patient. Because patients are often reluctant to volunteer their history of sildenafil citrate use, the physician may need to ask specifically about use of this medication. Physicians should counsel patients with crowded optic discs and a history of nonarteritic anterior ischemic optic neuropathy in one eye that use of sildenafil citrate might increase their risk of ischemic optic neuropathy in the fellow eye.     

Electrophysiological assessment of visual function in patients with non-arteritic ischaemic optic neuropathy

Background and purpose:  Our study aims to evaluate retinal function and neural conduction in post-retinal visual pathways of patients with non-arteritic ischaemic optic neuropathy (NION).
Methods:  Twenty patients (mean age: 63.7 ± 5.96 year) with NION and 20 age-similar control subjects were enrolled. Simultaneous recording of pattern electroretinograms (PERGs) and visual evoked potentials (VEPs), and Log of minimum angle resolution (MAR) visual acuity (VA) were assessed in NION patients and controls.
Results:  Significantly ( anova , P  < 0.01) abnormal PERG and VEP responses, delayed retinocortical time (RCT, difference between VEP P100 and PERG P50 implicit times), and reduced VA were found in NION patients with respect to control subjects. The delay in RCT was not significantly (Pearson's test, P  > 0.01) correlated with the PERG impairment. The reduction in VA was significantly (Pearson's test, P  < 0.01) correlated to the increase in VEP P100 implicit time and RCT, whereas no correlations ( P  > 0.01) were found with PERG abnormalities.
Conclusions:  Non-arteritic ischaemic optic neuropathy patients with a reduction in VA may present two different, unrelated impairments: a dysfunction of the inner retinal layer (abnormal PERG) and abnormal post-retinal neural conduction (abnormal VEP and RCT). The reduction in VA seems to be related to the post-retinal impairment and seems to be independent from the retinal dysfunction.     

Migrainous ischemic optic neuropathy

Anterior ischemic optic neuropathy (AION) is a stroke syndrome of the eye seen in isolation or as a manifestation of underlying disease. A case of migrainous AION is reported, and the implications of anterior visual pathway migraine discussed.     

Bilateral non-arteritic anterior ischemic optic neuropathy following second-trimester spontaneous abortion-related haemorrhage

Bilateral anterior ischemic optic neuropathy is a rare complication of massive haemorrhage and related hypotension and anaemia in young individuals. We report a 34-year-old woman with bilateral non-arteritic ischemic optic neuropathy (NAION) after a massive spontaneous abortion-related haemorrhage who presented with sudden painless visual loss in her left eye. Visual acuity was 20/20 in the right eye with only hand motion discernible in the left eye. There was a left relative afferent papillary defect (RAPD). Fundus examination revealed bilateral swollen, hyperaemic optic discs and nerve fiber layer haemorrhages. Brain MRI and magnetic resonance venography were normal. The diagnosis of bilateral NAION was made and intravenous pulse corticosteroid therapy (1000 mg/day) was administered for three days. On the sixth day, optic disc oedema regressed bilaterally and on the third week, the visual acuity improved to 20/80 in the left eye. The visual field showed only a small spared area in the nasal region, and persistent RAPD was present. After two months, fundus examination showed a small and crowded optic disc on the right and a pale optic disc on the left. Severe acute haemorrhage is an important risk factor for NAION in healthy young individuals. In addition to correction of hypotension and anaemia, intravenous high dose corticosteroid might be beneficial for treatment.     

Establishing an experimental model of photodynamic induced anterior ischemic optic neuropathy

BACKGROUND: Scholars have supposed to establish animal models of optic neuropathy by pressing and partially amputating optic nerve, increasing intraocular pressure and injecting vasoconstrictor, etc., but the models are greatly different from anterior ischemia optic neuropathy. Therefore, a more ideal method is needed to establish animal model of anterior ischemic optic neuropathy (AION). OBJECTIVE: To establish AION models in rats, observe the functional changes of fundus, fundus fluorescein angiography (FFA), optical coherence tomography (OCT), flash visual evoked potential (F-VEP), and histopathologically confirm its reliability. DESIGN: A randomized control trial. SETTINGS: Department of Ophthalmology, Xi'an Fourth Hospital; Xi'an Institute of Ocular Fundus Diseases. MATERIALS: The experiments were carried out in the research room of Xi'an Institute of Ocular Fundus Diseases from February 2005 to May 2006. Thirty healthy male SD rats of 4－5 weeks old, weighing 140－160 g, were provided by the animal experimental center of the Fourth Military Medical University of Chinese PLA [SCXK(Military)2002-005], and those without eye disease examined by slit lamp and direct ophthalmoscope after mydriasis were enrolled. The conditions for feeding mice without special pathogen were strictly followed. The rats were randomly divided into blank control group (n =5), laser group (n =5), hematoporphyrin derivative (HPD) group and AION group (n =15), each group was numbered randomly. For each rat, the right eye was taken as the experimental eye, and the left one as the control one. METHODS: In the AION group, the rats were injected with HPD (10 mg/kg) via caudal vein, and then the optic discs were exposed to krypton red (647 nm, 80 mV) for 120 s, and the rats were in avoidance of light for 2 weeks postoperatively. Rats in the laser group were only exposed to krypton red (647 nm, 80 mV) for 120 s, and in avoidance of light for 2 weeks postoperatively; Those in the HPD group were only injected with HPD (10 mg/kg) via caudal vein; Those in the blank control group were untouched. ① Visual electrophysiological test: The F-VEP was used to evaluate the function of visual nerve. ② FFA: After mydriasis and anesthesia as describe above, the fluorescein sodium parenteral solution (1 mL/kg) was injected via caudal vein and finished within about 3 s, the time of FFA was recorded from the beginning of injection, the video sight aimed at the optic disc and the surrounding area. ③ After mydriasis and anesthesia as describe above, the rats were examined with OCT. ④ Histological observation: After hematoxylin and eosin (HE) staining, the optic disc and surrounding blood vessels of retina were observed under light microscope at high power field. MAIN OUTCOME MEASURES: The results of fundus, FFA, visual electrophysiological test and OCT detection within 90 days after model establishment were observed. RESULTS: Of the 30 rats, 1 died after anesthesia in the laser group and 2 died in the AION group respectively, and finally 27 rats were involved in the analysis of results. ① Changes in fundus: In the AION group, there was edema in upper optic disc and unclear boundary at 1 day after establishment, edema still could be observed at 6 days, and upper optic disc atrophied and appeared as pale at 90 days. ② FFA results: In the AION group, early "low fluorescence", middle and late "high fluorescence" were observed in upper optic disc 1 day after model establishment, and there was "low fluorescence" at 6 days, and the low fluorescence could be observed all the time at 23 days. ③ Visual electrophysiological changes: In the AION group as compared with the control eyes, the experimental ones had prolonged F-VEP P100 latency [(71.65±8.81), (57.58±8.38) ms, t =3.148, P =0.012], and decreased wave amplitude [(4.77±1.90), (10.06±3.66) μV, t =4.082, P =0.003], and these changes lasted to 35 days after model establishment. ④ OCT results: In the AION group, the reflection surface of part nerve fiber layer was higher than the retina plane, the surface was rough and the thickness was increased at 6 days after model establishment. ⑤ Histopathological results: At 1 day after model establishment, part optic discs had highly edema, edema of nerve fibers, and loose tissue, also accompanied by the displacement of surrounding retina; At 23 days, the optic disc and surrounding nerve fiber layers became thinner, and the numbers of ganglion nuclei in the retina tissue sections were obviously decreased. These changes were not observed in the laser group, HPD group and blank control group. CONCLUSION: The changes of fundus, FFA, OCT, visual electrophysiology and histopathology confirmed that the krypton red laser irradiation (647 nm) at 2 hours after HPD was injected via caudal vein can establish more ideal animal models of AION.