Well, yes, it is normal to have flashes of light after you have taken the surgery. Generally speaking, you should know that it occurs when your eyes are infected. Some reasons, such as different diseases, disorders can lead to this symptom. While according to some researches, an infection or inflammation which irritates the eyes can also be the cause, especially you have a surgery. So you should be careful about your eyes. Remember that you should not use your hands to touch your eyes frequently. Also, when having a shower, do not let the water get into your eyes, or it can just make eye infection in your eyes, and then lead to flashes of light.