ASSOCIATION OF SYSTEMIC RISK FACTOR WITH NON ARTERITIC ANTERIOR ISCHEMIC OPTIC NEUROPATHY: A CASE CONTROL STUDY

Abstract

Introduction: Non - Anterior ischemic optic neuropathy (NAION) is the most common acute optic neuropathy mainly affecting adults more than 50 yrs. NAION is mainly because of ischemia of optic nerve head. It’s mainly of two types arteritic and non arteritic. The exact mechanism of vasculopathy in NAION remain unknown3, however several risk factors have been found to be associated with NAION, which can be further classified into ocular risk factor and systemic risk factor. Ocular risk factor includes small crowded disc often defined as disk at risk, optic nerve head drusen’s, vascular disorder in the nutrient vessels of the optic nerve head, cataract extraction, markedly increased intraocular pressure and marked optic disc edema due to any cause. 60% of NAION patients have systemic risk factor affecting small vessels like arterial hypertension, diabetes mellitus, arteriosclerosis, atherosclerosis, cigarette smoking, nocturnal arterial hypotension, ischemic heart diseases, cerebrovascular accidents, hyperhomocystenemia, thyroid disease 2,3,5. Recently OSA as a risk factor has also been identified6
.
Materials and Methods: This case control study was carried out in the Department of Ophthalmology, S.S.Medical
College and associated GM Hospital, Rewa, over a period of 18 months among 32 consented patients presenting to the department with features suggestive of NAION and 32 age and gender matched control, with no ocular pathology. Detailed history was recorded and thorough clinical and comprehensive ophthalmic examination was carried out. Data was collected, compiled and analyzed using SPSS 22.0 (trial version).
Result: Mean age of study group was 53.34±9.10 years. Mean VA in affected eye was 1.36±0.74 log MAR units. Color vision of NAION patient was defective in almost all patients. Mean number of Ishihara plates read was
5.41±1.55. Mean contrast sensitivity was 0.67±0.43 log units. The most common systemic disease associated with
NAION was diabetes mellitus (62.5%) followed by hypertension (46.87%). NAION patients had higher incidence of
OSA. None of patients had history of IHD, TIA or stroke.
Conclusion: The data for NAION comes mainly from western literature as there have been only few studies in Indian population. Through this study, we aimed to provide an overview of NAION, systemic risk factors associated with it in Indian Population