Symptoms of heart palpitations may include a passing sensation of a pounding, rapid, fluttering, or skipped heartbeat. These sensations are usually felt in the chest but may also be felt in the neck and/or the throat. Generally, there are 2 broad types of palpitations.
Flashes of light that appear as jagged lines or heat waves in both eyes, often lasting 10-20 minutes, are different. They are usually caused by migraine, a spasm of blood vessels in the brain.
So whether there is light entering the eye or not, any stimulation of the retina will be translated into a light show by the brain. If you see stars or flashes after sneezing, it could be from a pressure on the eye itself, or from stimulation of the nerves that have to do with sight.