Onset Of Nonarteritic Anterior Ischemic Optic Neuropathy Research Articles

Non-Arteritic Anterior Ischemic Optic Neuropathy Associated With the Use of Phosphodiesterase Type 5 Inhibitors: A Literature Review.

Phosphodiesterase type 5 (PDE5) inhibitors are frequently used for erectile dysfunction (ED) as the first line of treatment. This medication was initially developed to treat muscle spasms and pulmonary hypertension. The United States Food and Drug Administration (FDA) approved its usage for treating ED. Sildenafil, tadalafil, vardenafil, and avanafil are PDE5 inhibitors. The decrease of cyclic guanosine monophosphate (cGMP) in smooth muscle cells caused by sildenafil causes smooth muscle relaxation and penile erection. Vasodilation of the blood vessels reduces perfusion and blood flow to the optic nerve and eye. Several incidences of non-arteritic anterior ischemic optic neuropathy (NAION) have been recorded in sildenafil users, among other ocular complications. The onset of NAION is usually sudden and painless, and it is associated with any pattern of visual field loss. Possible symptoms include poor visual acuity, diminished color vision, a visual field defect, or hemorrhages in the form of flames. Nevertheless, NAION pathogenesis is still a mystery. Most visual effects are reversible weeks after the medication is stopped, and NAION does not seem to cause a permanent blindness. A small cup-to-disc ratio (disc at risk) and underlying systemic illnesses, such as hypertension, increase the risk of developing NAION. An early indicator of cardiovascular disease is ED. NAION diagnosis is challenging due to a lack of confirmatory diagnostic evidences. Normal visual acuity does not exclude NAION from being a possibility. In order to evaluate visual outcomes in NAION, data on both visual acuity (VA) and the full peripheral visual field are needed. Treatment with steroids did not seem to improve visual results.

Combination Therapy with Intravitreal Triamcinolone Acetonide and Oral Levodopa for the Treatment of Nonarteritic Anterior Ischemic Optic Neuropathy: A Pilot Study.

Purpose: To determine the clinical effectiveness of combination therapy with intravitreal injection of triamcinolone acetonide (IVITA) and oral levodopa in eyes affected by nonarteritic anterior ischemic optic neuropathy (NAION). Methods: Longitudinal study involving 45 eyes of 45 patients with NAION who were evaluated within 14 days of NAION onset. The treatment group received an IVITA 4 mg/0.1 mL followed by 25 mg carbidopa/100 mg levodopa (Sinemet 25-100) 3 times daily for 12 weeks and the control group was untreated. Best-corrected visual acuity (BCVA) converted to logarithmic minimum angle of resolution (logMAR), visual field (VF) grades based on automated or Goldman perimetry, and mean retinal nerve fiber layer (RNFL) thickness measured on optical coherence tomography were assessed at the initial visit, 1, 3, and 6 months after NAION attack. Results: At the first visit and 6 months after NAION onset, the mean logMAR BCVA in the treatment group was significantly better than the control group (P < 0.05). BCVA was not significantly different between onset and the 6-month visit for both the control and the treatment group; however, the change in BCVA after 6 months was significantly greater in the treatment group compared with the control group (P = 0.007). Concomitant systemic disease, the changes in VF grades, and RNFL thickness from initial to 6 months after NAION onset were not significantly different between 2 groups. Conclusions: Combination therapy with IVITA and oral levodopa/carbidopa appears to be effective in the treatment of recent-onset NAION.

Intravitreal triamcinolone injections in non-arteritic anterior ischemic optic neuropathy – A retrospective report

Non-arteritic anterior ischemic optic neuropathy (NAION) is a common cause of vision loss but no treatment has demonstrated its efficiency. A preliminary study showed an improvement on the visual acuity (VA) in a group of patients who received intravitreal administration of triamcinolone acetonide (IVTA) versus a non-treated group. In the present series, the visual outcome of IVTA in NAION was evaluated on a larger group of patients. This retrospective, unmasked and non-randomized study took place at Reims University Hospital between 2009 and 2017. The data of consecutive patients presenting with isolated optic disc edema characteristic of recent NAION (<1month of visual acuity loss) were included. After informed consent, a single intravitreal injection of filtrated 4mg/0.1mL triamcinolone acetonide were administered. Twenty-seven control patients chose not to be injected and therefore served as controls. LogMar visual acuity (VA), VA rating (VAR) (1 line=0.1LogMAR=5 VAR letters), retinal nerve fiber layer thickness assessed by OCT and static visual field were evaluated at presentation, after 7days, after 3months and after 6months. Sixty-eight patients with NAION were evaluated. Forty-one received IVTA, 29 were injected within 15days after the onset of symptoms and 12 after 15days. There was a higher proportion of patients improving VA of 2 lines or more (10 or more VAR letters) in the injected group (49%) compared with the non-injected group (11%, P=0.019). Among the patients injected before 15days, the proportion improving for 2 lines or more (55% vs. 11%, respectively, P=0.013) and for 3 lines or more (45% vs. 11%, respectively, P=0.035) were significantly higher than in the non-injected group. Also, comparing the VA at presentation with the VA after 6months in the injected eyes, it improved significantly (P=0.003) and also in the subgroup injected within 15days (P=0.0007) but not in the injected group after 15days (P=0.801). Visual field improvement was only observed in the subgroup of patients injected within 15days with a significant improvement of the mean deviation (dB) within 6months (P=0.015). This follow-up study confirms the results of the previous series displaying an apparent benefit of intravitreal steroids injected in the acute phase of NAION. Only patients receiving IVTA within 15days from onset of NAION have a significant improvement of VA and visual field during the follow-up period of 6months.

Evaluation of hemodynamic changes in nonarteritic anterior ischemic optic neuropathy using multimodality imaging.

Nonarteritic anterior ischemic optic neuropathy (NAION) patients experience hypo-perfusion in the short posterior ciliary arteries (SPCAs), however, the cause of hypo-perfusion is unclear. Real-time dynamic hemodynamic observations may provide clues into specific NAION pathogenic mechanisms. We aim to analyze hemodynamic changes occurring in NAION using multimodality imaging. Our specific focus is identifying pathogenic mechanisms underlying SPCA insufficiency in NAION. Three-dimensional arterial spin labeling (3D ASL) magnetic resonance imaging (MRI) and three-dimensional time-of-flight (3D-TOF) magnetic resonance angiography (MRA) were performed on 25 NAION patients (50 eyes) and 22 (44 eyes) normal cases were recruited. The diameter of the initial part of the ophthalmic artery and internal carotid artery siphon were measured using MRA. Blood vessel identification and blood flow (BF) were detected using 3D ASL MRI. We measured BF values of the optic nerve head (ONH) region of the retina/choroid complex, optic nerve (ON), temporal lobe, and occipital lobe. We studied 32 NAION affected eyes, 18 NAION uninvolved eyes, and 44 normal eyes. Diameter of the initial part of ophthalmic artery in the NAION affected eyes was significantly larger than the uninvolved eyes (P=0.026). Diameter of the NAION eyes was 1.33±0.19 mm [mean ± standard deviation (SD)], uninvolved eyes were 1.15±0.21 mm. At a photolabeling delay times (PLD) of 1,500 and 2,500 ms, BF of the ONH and ON in NAION affected eyes was significantly less than uninvolved and normal eyes (pONH <0.001 both at 1,500 and 2,500 ms, pON <0.001 and pON =0.001 at 1,500 and 2,500 ms, respectively). ONH of uninvolved eyes was also significantly less than normal eyes. Additionally, BF of the ONH region correlated with temporal lobe BF, with an R2=0.3231 and 0.2397 at 1,500 and 2,500 ms, respectively. BF of the ONH region also correlated with occipital lobe BF, with an R2=0.2534 and 0.4397 at 1,500 and 2,500 ms, respectively. ON and temporal lobe BF also correlated, with an R2=0.226 and 0.1504 at 1,500 and 2,500 ms, respectively. Abnormal hemodynamics of small cerebral vessels existed prior to the onset of NAION. A candidate mechanism underlying NAION appears to be transient insufficiency of blood supply and decompensation of ocular vascular regulation.

Evaluation of enhanced external counterpulsation therapy for nonarteritic anterior ischemic optic neuropathy

BackgroundTo explore the effects of enhanced external counterpulsation (EECP) and its underlying influencing factors in nonarteritic anterior ischemic optic neuropathy (NAION) patients.MethodsPatients at Zhongshan Ophthalmic Center with recent-onset (< 8 weeks) NAION were retrospectively recruited. The patients had decided whether or not they would undergo EECP treatment, and the patients who declined were included in the control group. The effectiveness of EECP was evaluated by comparing the visual function and fellow eye involvement in patients with and without EECP treatment.ResultsIn total, 61 patients (76 eyes) were included. Twenty-nine patients (37 eyes) underwent EECP treatment, while 32 patients (39 eyes) were included in the control group. Mean time from NAION onset to EECP initiation was 27.59 ± 16.70 days. In the EECP group, the mean EECP duration was 31.57 ± 18.45 days. EECP was well tolerated by all patients. However, there was no significant difference in visual function between the EECP and control groups. Furthermore, there was no evidence of the effectiveness of EECP in the subgroup analysis of patients with different systemic health conditions. Among the 42 patients with monocular NAION, the sequential attack rate was comparable between the EECP (27.78%) and control (25.00%) groups.ConclusionThis study is the first nonrandomized controlled study to evaluate the effectiveness of EECP in NAION patients. Unfortunately, we failed to demonstrate the effectiveness of EECP in NAION at the 6-month follow-up. Any further application of EECP in NAION patients should be cautious.

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

To investigate the natural course, visual outcome, and risk factors for visual loss after nonarteritic anterior ischemic optic neuropathy (NAION) attack in Chinese patients from a tertiary medical center in Southern Taiwan. This is a longitudinal observational study that included sixty NAION patients, who were seen in our neuro-ophthalmology clinic from 2007 to 2016. Records of their ophthalmic history, medical history, best-corrected visual acuity (BCVA), visual field (VF) testing, and optical coherence tomography (OCT) were obtained for analysis. When the first visit was within two weeks after NAION onset, 62% of patients had BCVA of less than 0.1 (logMAR BCVA ≥ 1) and 38% had at least moderate-severe depression (VF grade ≥ 3) on VF on the initial visit. VA stabilized at three months after onset and was predictive of VA at 12months. Diabetes mellitus was a risk factor associated with VA worsening. Sixty-one percent of patients had BCVA of less than 0.1 at 12months after onset. VF remained relatively unchanged during the disease, with 41% eyes having VF grade ≥ 3 at 12months after onset. On OCT, all quadrants of retinal nerve fiber layer thickened initially, returned to the level of the fellow eye at one month, and continued thinning up to 12months slowly. In Southern Taiwan, a higher proportion of Chinese patients (over half) presented with severe visual loss during the first two weeks of NAION attack and at 12months after the onset of NAION as compared to the findings previously reported in Caucasians. Understanding the natural course of NAION in Chinese patients may provide insights toward a possible therapeutic window for NAION treatments in this group of patients.

Prevalence of Optic Disc Drusen in Young Patients With Nonarteritic Anterior Ischemic Optic Neuropathy: A 10-Year Retrospective Study.

Nonarteritic anterior ischemic optic neuropathy (NAION) in young patients (age ≤50) accounts for a minority of all cases of NAION and is more highly associated with crowding of the optic nerves and bilateral involvement than NAION in older patients. Optic disc drusen (ODD) are likewise associated with crowded optic nerves and are located in the prelaminar optic nerve head where they could contribute to NAION pathogenesis. The purpose of this study was to determine the prevalence of ODD in the eyes of young NAION patients using modern imaging methods and to compare it to the baseline 1.8%-2.0% prevalence of ODD in the general population. In this retrospective study, all young NAION patients (ages 18-50 years, inclusive) seen in 2 tertiary care neuro-ophthalmology clinics (in London, Canada and Copenhagen, Denmark) in the ten-year interval between April 1, 2009, and March 31, 2019, were identified and their medical charts reviewed. Patients were included in the study if ODD were diagnosed by any method (including ophthalmoscopy, ultrasound [US], fundus autofluorescence [FAF], computed tomography [CT], or any optical coherence tomography [OCT] method), or if ODD were excluded by enhanced-depth imaging OCT (EDI-OCT) using the ODD Studies (ODDS) Consortium protocol. The presence or absence of ODD was recorded for each eye. There were 37 eligible patients (74 eyes). Mean age of NAION onset was 38.5 ± 10.0 years, and 23 patients (62%) were men. Patients had undergone the following methods of ODD detection: ophthalmoscopy (37 patients), EDI-OCT (36 patients), FAF (31 patients), US (9 patients), and CT orbits (8 patients). We found a prevalence of ODD of 56.7% in NAION-affected patients and 53.3% in NAION-affected eyes. Only 35.9% of ODD were visible on ophthalmoscopy. Twenty of 21 ODD patients (95.2%) had bilateral ODD. Age of onset and sex did not differ significantly between the ODD-positive group and the ODD-negative group. EDI-OCT outperformed any combination of ophthalmoscopy, US, FAF, and CT at detecting ODD. ODD were found with much higher prevalence in young patients with NAION than in the general population and were usually bilateral and buried. ODD may contribute to NAION pathogenesis by exacerbating an underlying compartment syndrome in the crowded "disc at risk." EDI-OCT may be the best imaging modality for ODD detection in future studies.

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.

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.

Structural changes of macula and optic disk of the fellow eye in patients with nonarteritic anterior ischemic optic neuropathy.

The aim was to assess the ganglion cell complex (GCC) thickness, retinal nerve fiber layer (RNFL) thickness and optic disk features in the affected eyes (AE) and unaffected fellow eyes (FE) of subjects with unilateral nonarteritic anterior ischemic optic neuropathy (NAION) and to compare with healthy control eyes (CE) using spectral domain-optical coherence tomography (SD-OCT). This study included 28 patients and age, sex and refraction-matched 28 control subjects. Mean GCC thickness and peripapillary RNFL thickness in four quadrants measured by cirrus SD-OCT were evaluated in both AE and FE of patients and CE. In addition, optic disk measurements obtained with OCT were evaluated. Mean GCC thickness was significantly lower in AE compared with both FE and CE (P < 0.001), and mean GCC thickness in FE was significantly lower than CE (P = 0.022). In addition, mean RNFL thickness in superior and nasal quadrants significantly decreased in FE compared with CE (P = 0.020 and 0.010, respectively). Furthermore, AE had significantly greater optic disk cupping compared with both FE and CE (P < 0.001). GCC and RNFL thickness decreased significantly at late stages of NAION, in both AE and FE compared with CE, suggesting that some subclinical structural changes may occur in FE despite lack of obvious visual symptoms. In addition, there was no significant difference in optic disk features between the CE and FE. And significantly greater optic disk cupping in the AE compared with both FE and CE supports the acquired enlargement of cupping after the onset of NAION.

Structure-Function Analysis of Nonarteritic Anterior Ischemic Optic Neuropathy and Age-Related Differences in Outcome.

The optic nerve head is vulnerable to ischemia leading to anterior ischemic optic neuropathy (AION), the most common acute optic neuropathy in those older than 50 years of age. We performed a cross-sectional study of 55 nonarteritic anterior ischemic optic neuropathy (NAION) eyes in 34 patients to assess clinical outcome and perform structure-function correlations. The peak age of NAION onset was between 50 and 55 years. Sixty-seven percent of patients presented with their first event between the ages of 40 and 60 years, and 32% presented at ≤50 years. Those with NAION onset at age ≤50 years did not have significantly better visual outcome per logMAR visual acuity, automated perimetric mean deviation (PMD) or optical coherence tomography (OCT) measurements. Kaplan-Meier survival curve and multivariate Cox proportional regression analysis showed that age >50 years at NAION onset was associated with greater risk of second eye involvement, with hazard ratio of 20. Older age at onset was significantly correlated with greater thinning of the ganglion cell complex (GCC) (P = 0.022) but not with logMAR visual acuity, PMD, or thinning of retinal nerve fiber layer (RNFL). Using area under receiver operating characteristic curve analyses, we found that thinning of RNFL and GCC was best able to predict visual outcome, and that mean RNFL thickness >65 μm or macular GCC thickness >55 μm significantly correlated with good visual field outcome. We showed that NAION onset at age >50 years had a greater risk of second eye involvement. Patients with OCT mean RNFL thickness >65 μm and mean macular ganglion cell complex thickness >55 μm had better visual outcomes.

Prospective Case-crossover Study Investigating the Possible Association Between Nonarteritic Anterior Ischemic Optic Neuropathy and Phosphodiesterase Type 5 Inhibitor Exposure

To evaluate the association between intermittent phosphodiesterase type 5 inhibitor (PDE5i) exposure and risk of acute nonarteritic anterior ischemic optic neuropathy (NAION) using a case-crossover design. Male adults with suspected NAION were enrolled at 41 US ophthalmology sites from 2010 to 2015 and were interviewed regarding risk factors for NAION, medical history, and PDE5i use before NAION onset (index date of onset [IDO]). An adjudication committee confirmed the NAION cases. The primary analysis, using the person-time method, examined the rate of PDE5i exposure within 5 half-lives of NAION onset relative to PDE5i exposure over a 30-day study period preceding the IDO in men exposed to PDE5i intermittently as a measure of NAION risk associated with PDE5i exposure. Rate ratios were estimated using the Mantel-Haenszel estimator. Secondary analyses included person-time analyses over the 12-months preceding the IDO and matched-interval analyses over 42 days preceding the IDO. Of 279 men with confirmed NAION, 22 were exposed to PDE5i intermittently within 30 days of IDO. The Mantel-Haenszel rate ratio for risk of NAION associated with PDE5i exposure within 5 half-lives of IDO was 2.27 (95% confidence interval [CI]: 0.99-5.20) over the 30-day period (n = 22) and 3.52 (95% CI: 1.59-7.79) over the 12-month period (n = 26). Sensitivity analyses showed similar results and were statistically significant. The matched-interval method found no association (hazard ratio = 1.64 [95% CI: 0.60-4.51]). Overall, the study suggests an increased risk of NAION associated with PDE5i use. Patients and health-care providers should continue to weigh the risks and benefits of PDE5i use, including the potential for NAION.

Assessment of functional and morphometric endpoints in patients with non-arteritic anterior ischemic optic neuropathy (NAION)

The primary objective of this bi-center explorative pilot study was the quantitative assessment of visual field defects and retinal nerve fiber layer thickness (RNFT) over 6months in patients with acute non-arteritic anterior ischemic optic neuropathy (NAION), in order to elucidate the natural course of NAION and provide a reference dataset for future treatment studies. 16 patients (age 41-80years, nine males, seven females) suffering from acute NAION and presenting within 7days after onset of symptoms were included in this study. The following examinations were carried out at the initial visit (month 0) and at months 2, 4 and 6: entire (90°) visual field examination with automated static white-on-white perimetry, quantified by mean defect (MD); peripapillary retinal nerve fiber layer thickness (RNFT) measurement with spectral domain optical coherence tomography (SD-OCT); assessment of distant best correct visual acuity (D-BCVA) and a quantification of the relative afferent pupillary defect (RAPD) using the swinging flashlight test with neutral density filters. Perimetric Mean Defect (MD) and RNFT values were each compared between the consecutive visits using the non-parametric Friedman test. The initial MD was 6.2dB (IQR 5.0-7.4) without significant changes further on. RNFT was 183μm (IQR 148-252) initially, decreased significantly at month 2 (78μm (IQR 71-93) and further at month 4 (64μm (IQR 58-74) and 6 (61μm (IQR 52-81), Friedman test, p < 0.001). Initially, RNFT was above normal limits (due to swelling) in 15/16 patients; at month 2 it was below normal limits in 13/16 patients, at month 4 in 12/13 patients and at month 6 in 9/10 patients. 7/16 patients exhibited segmental swelling of the optic disc, whereas the entire circumference of the optic disc showed RNFL thickening in 9/16 patients. Functional deficits were present directly after onset of NAION and did not change relevantly further on. Morphological changes comprise severe swelling after onset of NAION, which rapidly turns into atrophy. Already after 2months more than 80% of the patients showed a RNFT below normal limits. Progressive RNFL thinning between month 2 and month 4 suggests ongoing atrophy, whereas a stable morphologic end point is reached after month 4.

Intravitreal bevacizumab for the treatment of nonarteritic anterior ischemic optic neuropathy: a prospective trial

There is currently no accepted treatment for Nonarteritic Anterior Ischemic Optic Neuropathy (NAION). One new therapeutic approach involves decreasing optic nerve edema with intravitreal bevacizumab in order to resolve a proposed compartment syndrome. In this non-randomized controlled clinical trial, 1.25 mg intravitreal bevacizumab was compared with natural history. Patients were examined at baseline, 1, 3, and 6 months with a full neuro-ophthalmic exam, automated perimetry, and optic nerve optical coherence tomography (OCT) measurements. The primary outcome measure was change in mean deviation on Humphrey visual field testing. Secondary outcome measures were change in visual acuity and optic nerve OCT thickness. Incidence and type of complications were also recorded. Twenty-five patients were enrolled (17 treatment and 8 control). There was no significant effect of treatment on the primary outcome measure of mean deviation score (P=0.4). There was similarly no effect of group assignment on the secondary outcome measures of change in mean Early Treatment Diabetic Retinopathy Study letters (P=0.33) or nerve fiber layer thickness on OCT (P=0.11). In the bevacizumab group, there was one case of a corneal abrasion and two cases of recurrent NAION. No other complications were noted. We found no difference between bevacizumab and natural history for change in visual field, visual acuity, or optic nerve OCT thickness. Based on the current evidence we would not recommend the use of intravitreal bevacizumab to treat patients with the new onset of NAION.

Long-term retinal nerve fiber layer changes following nonarteritic anterior ischemic optic neuropathy

BackgroundIn cases of nonarteritic anterior ischemic optic neuropathy (NAION), retinal nerve fiber layer (RNFL) thickness changes have been described during the first 12 months following the acute event. The purpose of this study was to report on the long-term RNFL changes in these eyes beyond the first year following onset of NAION.MethodsFourteen eyes of 13 patients with NAION were analyzed in this retrospective observational case series study. Uninvolved eyes served as controls. All patients underwent a complete neuro-ophthalmological examination and repeat measurements of peripapillary RNFL thickness using Stratus optical coherence tomography.ResultsOn optical coherence tomography scan performed on average 6 months following onset of NAION, the mean global RNFL thickness (59.8 ± 11.8 μm) was significantly thinner (P < 0.001) compared with uninvolved eyes (95.1 ± 13.9 μm). In a second optical coherence tomography scan performed on average 13 (range 12–23) months later, the mean global RNFL thickness (58.9 ± 6.5 μm) was not significantly different (P = 0.702) from the first scan.ConclusionThere appears to be no further RNFL loss beyond the first 6 months following an acute event of NAION.

Non-arteritic anterior ischemic optic neuropathy: role of systemic corticosteroid therapy

To investigate systematically the role of systemic corticosteroid therapy in non-arteritic anterior ischemic optic neuropathy (NA-AION). The study consists of a cohort of 613 consecutive patients (696 eyes), first seen in our clinic from 1973 to 2000. Of this cohort, 312 patients (364 eyes) voluntarily opted for systemic steroid therapy, and 301 (332 eyes) for no treatment. At first visit, all patients in both groups had a detailed ophthalmic and medical history, and comprehensive ophthalmic evaluation. Visual evaluation was done by recording Snellen visual acuity, and visual fields with a Goldmann perimeter. The same ophthalmic evaluation was performed at each follow-up visit. Patients in the steroid-treated group were initially given 80 mg Prednisone daily for 2 weeks, and then tapered down to 70 mg for 5 days, 60 mg for 5 days, and then cutting down by 5 mg every 5 days. Visual outcome in the two groups was compared Median follow-up was 3.8 years. At 6 months from onset of NA-AION, of the eyes with initial visual acuity 20/70 or worse and seen within 2 weeks of onset, there was visual acuity improvement in 69.8% (95% confidence interval (CI): 57.3%, 79.9%) in the treated group, compared to 40.5% (95% CI: 29.2%, 52.9%) in the untreated group (odds ratio of improvement: 3.39; 95% CI:1.62, 7.11; p = 0.001). Comparison of visual field defect at 6 months from onset of NA-AION, among those seen within 2 weeks of NA-AION onset with moderate to severe initial visual field defect, there was improvement in 40.1% (95% CI: 33.1%, 47.5%) of the treated group, and 24.5% (95% CI: 17.7%, 32.9%) of the untreated group (odds ratio: 2.06, 95% CI: 1.24, 3.40; p = 0.005). In both treated and untreated groups, the visual acuity and visual fields kept improving up to about 6 months from onset of NA-AION, and very little thereafter. This study suggested that NA-AION eyes treated during the acute phase with systemic corticosteroids resulted in a significantly higher probability of improvement in visual acuity (p = 0.001) and visual field (p = 0.005) than in the untreated group. Both visual acuity and visual fields improved up to 6 months after onset of NA-AION.

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.

Development and validation of a computerized expert system for evaluation of automated visual fields from the Ischemic Optic Neuropathy Decompression Trial

BackgroundThe objective of this report is to describe the methods used to develop and validate a computerized system to analyze Humphrey visual fields obtained from patients with non-arteritic anterior ischemic optic neuropathy (NAION) and enrolled in the Ischemic Optic Neuropathy Decompression Trial (IONDT). The IONDT was a multicenter study that included randomized and non-randomized patients with newly diagnosed NAION in the study eye. At baseline, randomized eyes had visual acuity of 20/64 or worse and non-randomized eyes had visual acuity of better than 20/64 or were associated with patients refusing randomization. Visual fields were measured before treatment using the Humphrey Field Analyzer with the 24-2 program, foveal threshold, and size III stimulus.MethodsWe used visual fields from 189 non-IONDT eyes with NAION to develop the computerized classification system. Six neuro-ophthalmologists ("expert panel") described definitions for visual field patterns defects using 19 visual fields representing a range of pattern defect types. The expert panel then used 120 visual fields, classified using these definitions, to refine the rules, generating revised definitions for 13 visual field pattern defects and 3 levels of severity. These definitions were incorporated into a rule-based computerized classification system run on Excel® software. The computerized classification system was used to categorize visual field defects for an additional 95 NAION visual fields, and the expert panel was asked to independently classify the new fields and subsequently whether they agreed with the computer classification. To account for test variability over time, we derived an adjustment factor from the pooled short term fluctuation. We examined change in defects with and without adjustment in visual fields of study participants who demonstrated a visual acuity decrease within 30 days of NAION onset (progressive NAION).ResultsDespite an agreed upon set of rules, there was not good agreement among the expert panel when their independent visual classifications were compared. A majority did concur with the computer classification for 91 of 95 visual fields. Remaining classification discrepancies could not be resolved without modifying existing definitions.Without using the adjustment factor, visual fields of 63.6% (14/22) patients with progressive NAION and no central defect, and all (7/7) patients with a paracentral defect, worsened within 30 days of NAION onset. After applying the adjustment factor, the visual fields of the same patients with no initial central defect and 5/7 of the patients with a paracentral defect were seen to worsen.ConclusionThe IONDT developed a rule-based computerized system that consistently defines pattern and severity of visual fields of NAION patients for use in a research setting.

Visual Field Abnormalities in Nonarteritic Anterior Ischemic Optic Neuropathy

To evaluate the pattern of various types of visual field defects and their prevalence at initial examination of nonarteritic anterior ischemic optic neuropathy (NA-AION). The data were compiled from 312 consecutive eyes (in 265 patients) that fulfilled our inclusion and exclusion criteria. A comprehensive ophthalmic evaluation was performed, including recording of visual acuity, visual fields with a Goldmann perimeter (using I-2e, I-4e, and V-4e targets regularly), and intraocular pressure; slitlamp examination of the anterior segment; ophthalmoscopy; color fundus photography; and in acute cases, fluorescein fundus angiography. The visual field defects were divided into 2 groups: (1) general field defects and (2) various types of scotoma in the central 30 degrees . The prevalence of various types of visual field defects was estimated for I-2e, I-4e, and V-4e isopters by dividing the total number of eyes with the defect by the total number of eyes that could see that particular target. Exact 95% confidence limits for the prevalence were computed. Of the 265 patients, 169 (63.7%) were male and the mean +/- SD patient age was 55.0 +/- 9.1 years. The median interval between the first visual field test and the onset of NA-AION was 2 weeks. Of the 312 eyes, the I-2e target was seen by 75.3%, the I-4e target by 90.7%, and the V-4e target by 100%. Overall prevalence of general visual field defects was 83.4% with I-2e, 78.8% with I-4e, and 68.9% with V-4e, whereas the prevalence of scotoma(s) within the central 30 degrees was 55.3%, 49.5%, and 36.2%, respectively. Central scotoma was seen in 48.5% with I-2e, 43.8% with I-4e, and 29.2% with V-4e. A detailed prevalence of various types of visual field defects is given. Relative inferior altitudinal defect was most common (34.9% with I-2e and 22.3% with I-4e), but the absolute inferior altitudinal defect was seen in only 8.0%. By contrast, absolute inferior nasal sector visual loss was the most common defect detected in NA-AION (22.4%), but it occurred in only 3.4% with I-2e and 11.0% with I-4e. Overall, loss of the nasal part of the visual field was the most common occurrence. Our study demonstrated that NA-AION eyes may initially show a variety of optic nerve-related visual field defects. Our study also showed that an absolute inferior nasal visual field defect is much more common (22.4%) than an absolute inferior altitudinal visual field defect (8.0%) in NA-AION and could be considered the most characteristic single field defect in NA-AION. We found that a combination of relative inferior altitudinal defect with absolute inferior nasal defect is usually the most common pattern in NA-AION.

Nonarteritic anterior ischemic optic neuropathy in patients with sleep apnea while being treated with continuous positive airway pressure

To report three cases of nonarteritic anterior ischemic optic neuropathy (NAION) that occurred in patients with sleep apnea syndrome (SAS) while being treated with continuous positive airway pressure (CPAP). A prospective, noncomparative case series. Prospective review of 108 patients with NAION diagnosed between 2002 and 2003 to identify any patients who developed NAION while being treated for SAS with CPAP. One patient had bilateral sequential NAION and two patients had unilateral NAION despite treatment with CPAP for SAS. All the patients were being treated with CPAP for a period ranging from 4 months to 6 years before the onset of NAION. In this series, CPAP did not prevent the development of NAION in SAS patients. Larger observational studies are needed to study the benefit of CPAP in preventing NAION in patients with SAS.