There are a few different reasons why bearded dragons' eyes may droop, including dehydration and blindness. Dehydration is the most common cause of poor vision in reptiles, and is caused by not getting enough water. Bearded dragons are very sensitive to water loss, so it's important to keep them hydrated throughout the day. Additionally, if your beardie is losing his vision, he may droop his eyes in an effort to conserve energy. Providing him with a bright light and proper sunlight exposure can help improve his vision.