Keratoconus. Thickening of the posterior capsule laser treatment laser after cataract surgery. Chronic glaucoma the causes, what happens, the treatment, and investigations, in Good Hope Eye Department. Non Arteritic Anterior Ischemic Optic Neuropathy NAIONOriginal article contributed by Dean Cestari, M. D. All contributors Aaron M. Miller, MD, MBA, FAAP, Andrew Go Lee, MD, Dean Cestari, M. D., Mark J. Kupersmith, MD and Stacy L Pineles, M. DA1-DB3-DC1-C23-FF5.gif' alt='Soft Drusen Hard Drusen' title='Soft Drusen Hard Drusen' />D. Assigned editor Dean Cestari, M. D. Review Assigned status Up to Date by Stacy L Pineles, M. D.  on August 1. 0, 2. Ischemia of the optic nerve can occur in different anatomical locations and can have a myriad of etiologies. It is helpful to classify these syndromes by location and etiology if known since their presenting signs and symptoms as well as treatment and prognosis will vary. By definition, anterior ischemic optic neuropathy AION involves the 1mm segment of the optic nerve head, also known as the optic disc, and results in visible disc swelling. AION has two varieties. The first is non arteritic NAION and the second is arteritic AAION and is almost always associated with giant cell arteritis. Posterior ischemic optic neuropathy PION encompasses those conditions that result in ischemia to any portion of the optic nerve posterior to the optic disc. By definition, PION will not cause disc edema. The vast majority of cases of NAION are idiopathic but some specific etiologies have been reported to be associated with NAION although in all of the cases, no causal relationship has been definitively established. Sleep Apnea Syndrome SASedit edit sourceThere have been case series that have demonstrated a possible association between SAS and NAION 4. MacularProtect Complete AREDS2 is a convenient, allinone formula providing powerful protection for macular whole body health. It offers nutrients at levels found. Salve, ho fatto l OCT E LA FLUORANGIOGRAFIA e mi risultatodrusen al polo posteriore temporalmente alla macula. Sono una donna di 45 anni e vorrei avere da voi un. The best evidence comes from a case control study of 1. NAION who were compared to 1. In this study, 7. NAION met criteria for SAS compared to 1. Nokia C6 Pc Suite Software on this page. It is unclear how SAS can cause NAION but it is hypothesized that apneic spells might result in acute increases in blood pressure, intracranial pressure or nocturnal hypoxemia which could cause optic nerve edema and ischemia 4. The interferons are a group of glycoproteins with complex antiviral, antitumor, and antiangiogenic activities. In 1. 99. 5 Purvin reported the development of acute bilateral, sequential vision loss, likely from NAION, in 2 patients taking interferon alpha for malignant neoplasms 4. It has been hypothesized that interferon alpha might cause an NAION by depositing immune complexes in the optic disc circulation that leads to ischemia 4. Since her original report in 1. Sildenafil is an effective treatment for erectile dysfunction ED by inhibiting phophodiesterase type 5 PDE5, an enzyme that regulates blood flow in the penis. Therapeutic doses of these medications used to treat ED can cause systemic hypotension. It has been hypothesized that these medications might exaggerate the physiologic nocturnal hypotension resulting in ischemia to the optic nerve head and compartment syndrome in susceptible patients with small cup to disk ratios 5. Additionally, these medications might interfere with the autoregulation of blood flow thereby decreasing perfusion to the optic nerve head 5. This association remains very controversial and a prospective study has been conducted and has shown that the patients at risk for ED agents had prior NAION is 5. Optic disc drusen might increase the risk of developing NAION by theoretically contributing to the crowded optic nerve in discs with small cup to disc ratios. There are anecdotal reports of NAION occurring in patients with optic disc drusen but a causal relationship has not been proved 5. Download Bomberman For Pc Multiplayer Games'>Download Bomberman For Pc Multiplayer Games. The vast majority of cases of AION are non arteritic 1. NAION affects between 2. There are approximately 6. Caucasians account for nearly 9. Dos Database Software Ware'>Dos Database Software Ware. Men and women are nearly equally affected and the mean age at symptom onset varies between 5. However, one retrospective study demonstrated 2. NAION were less than 5. The pathophysiology of NAION is controversial and no one mechanism had been definitively demonstrated. It is presumed to result from a circulatory insufficiency, or infarct, within the retrolaminar portion of the optic nerve head that is supplied by the short posterior ciliary arteries SPCA. This presumption is based upon indirect evidence from atypical forms of NAION 1. Additional fluorescein and indocyanine studies have shown delayed optic disc filling in the prelaminar layers of the optic disc with normal choroidal circulation suggesting that the vasculopathy is located in the para optic branches of the SPCA after their branching from the choroidal branches rather than in the short ciliary arteries themselves 1. The cause of optic disc edema is unclear but there is general agreement that the final common pathway leads to a compartment syndrome from axonal edema in a structurally crowded optic disc 2. Many mechanism have been presumed to be involved in the optic disc edema and it is worthwhile to explore them in a little more details. Up to 9. 7 of patients with NAION have small optic discs with small or absent optic cups. Acutely, it can be difficult to determine the cupdisc ratio because of optic nerve edema and the clinician should note the cupdisc ratio in the fellow eye. It is typically less than 0. The role of the small cupdisc ratio is unclear but there are probably contributory mechanical effects of the small cupdisc ratio in the pathogenesis of NAION. A crowded disc can exacerbate chronic mechanical obstruction to axoplasmic flow resulting in secondary compression and ischemia. An inhibition in axoplasmic flow can inhibit critical neurotrophins leading to additional ganglion cell death 2. The optic nerve head efficiently autoregulates blood flow 3. Flow is normally maintained constant despite variations in perfusion pressure and intraocular pressure under various metabolic conditions and different diseases can impair the optic nerves ability to autoregulate its blood flow 3. Systemic hypertension, arteriosclerosis, vasospasm or medications may reduce the autoregulatory capacity of the optic disc 3. Vasoactive substances might be released in response to ischemia that influence the autonomic control of blood vessels. Intravitreal and intravenous injections of endothelin 1 have been shown to decrease optic nerve head blood flow and produce chronic optic disc ischemia in rabbits 3. Hayreh has postulated that the release of endogenous serotonin may contribute to optic nerve ischemia by vasoconstricting arterioles and impairing autoregulation 3. There are normal nocturnal fluctuations in blood pressure and Hayreh has theorized that nocturnal systemic hypotension may contribute to NAION. Patients with chronically altered optic disc autoregulation, from such diseases as systemic hypertension and atherosclerosis, might be susceptible to exaggerated decreases in nocturnal blood pressure. This effect might be exacerbated in patients treated with aggressive antihypertensive therapy, especially if taken right before bedtime 3. Levin et al. believe the clinical and pathological evidence does not support arterial occlusion in NAION and they have theorized that NAION might result from venous insufficiency that occurs from closure of tributary venules receiving blood from optic nerve capillaries that drain into the central retinal vein posterior to the optic nerve head 3. They argue that NAION does not have the clinical characteristics of an arterial disease. AAION causes a pallid edema that ultimately resolves leaving significant excavation and atrophy of the disc whereas NAION typically exhibits normal or hyperemic edema that resolves leaving relatively preserved disc substance 4.