When we say "see the light", we usually refer to a sudden realization or understanding about something. However, there are several other phrases that convey the same meaning. For example, you can say "the penny dropped" to describe a moment when someone finally understands something that was previously unclear. "Eureka moment" is another phrase used to refer to a sudden realization or breakthrough in understanding. Additionally, "light bulb moment" is a popular phrase that also describes a moment of clarity or understanding. Seeing or experiencing a "revelation" can also describe the same experience. So, if you want to express a sudden understanding or realization, you can use any of these synonyms for "see the light".