We present a case of sudden loss of vision in left eye due to occlusion of the infero-temporal branch of the retinal artery. The patient had no previous history of cardiac disease. Cardiologist's review revealed the diagnosis of severe mitral valve stenosis as a source of embolism. This is a very rare presentation of mitral valve stenosis which usually presents with pulmonary symptoms and stroke. Mitral stenosis must be considered as an important differential diagnosis in any thromboembolic phenomenon including retinal arterial occlusion.