Hello, It seems from the history that your husband is having sudden and transient loss of vision. This is called as transient ischemic attack. This can occur as prodromal symptom before retinal artery occlusion in carotid artery stenosis and many other conditions. All these indicate reduced blood supply for a moment from thickened arteries as a result of age related atherosclerosis. Hence this requires evaluation and treatment accordingly. He is required undergo investigations like eye examination by fundoscopy, doppler of carotid arteries in neck to rule out obstruction... Hence I advice you to consult eye doctor at the earliest for evaluation and treatment accordingly. Thank you