Analysis of risk factors, clinical features and visual outcome in cases of non-arteritic anterior ischemic optic neuropathy (NA-AION) at a tertiary eye care centre in India

We did an analysis of risk factors, clinical features and visual outcome in cases of non-arteritic anterior ischemic optic neuropathy (NA-AION) at a tertiary eye care centre in India. This is a prospective, observational, clinical study. A total of 60 eyes of 60 consecutive adult patients with disc oedema, due to non-arteritic AION, presenting in the Neuro-ophthalmology clinic of a tertiary care eye hospital, were enrolled over a period of 18 months (in specified period) according to the inclusion criteria. The study, including patient recruitment and data collection, was approved by the Institutional Review Board. All patients provided written informed consent after they received information about the disease and its relevant investigations along with the risks associated. Sample collection was done by application of inclusion and exclusion criteria on the patients presenting to the clinic. The study was carried out for a period of 6 months for each subject. The major outcomes of the study were: Metabolic Syndromes are the most significantly associated risk factors for the occurrence of NA AION. Clinical investigations mainly show the characteristic findings as mentioned in literature, with very little variation. However the importance of clinical examination, mainly pupillary reaction and fundus evaluation by slit lamp biomicroscopy, cannot be overlooked. Visual acuity is highly variable at presentation with cases even presenting with normal or near normal visual acuity. Visual outcome showed significantly improvement within 6 months of presentation. Non arteritic anterior ischemic optic neuropathy (NAION) was the most common form of ischemic optic neuropathy in our study. It is an idiopathic, ischemic insult of the optic nerve head characterized by acute, monocular, painless visual loss with optic disc swelling. The systemic risk factor which we found to be most strongly associated with was diabetes mellitus followed by systemic hypertension. Also an ocular risk factor of small cup size. We have few inherent limitations in the study mainly with the occurrence of symptoms and time of presentation of the patient, which may have a bearing on the final outcome of the disease. Also a short follow up limited us regarding study of the stabilization of visual acuity over a longer duration. However our study gives an overview of prevalent risk factors and clinical characteristics. It also shows a significant visual outcome after 6 months in NA-AION.