It could be an injury, but I also see some vague cloudiness behind the white stripe as well. That could be from the focus of the picture though. Also, if both eyes are affected, it is less likely to be an injury.
We need more background on the fish, as well as a video. This post explains all that:
Aquarium Fish Disease Problem Solving Determining the best course of action for a problem with your aquarium can be a difficult task. Even advanced aquarists will often need to seek the help of others for complicated or unique issues. Our intent here on Reef 2 Reef is to offer expert advice...