Temporary Vision Loss in Left Eye.

My Left Eye vision suddenly got blocked for few seconds on February 2021 first time and than it gets occurred again.. Till now I have faced this atleast 8 to 10 times within a span of 8 months... I can sense some kind of feeling in my brain when that situation occurs and within a moment the vision gets block.. it gets back to normal within a minute... I contacted eye specialist who said there's nothing wrong with my eye w.r.t. vision loss. My general physician said its a case where the blood vessels gets contracted for a specific duration and due to this the vision loss occurs... My CT Scan is Normal. Blood report showed some cholesterol. My doctor has advised exercises and daily walking which I am doing regularly... I would be helpful if I get a proper guidance to treat this permanently...