Bacterial eye infections can move from the eyes to a turtle's nasal passage which can result in fatal respiratory tract infections. Swollen eyelids can result in blindness which makes it difficult for the turtle to feed itself.
Conjunctiva reddening and excessive tear production are both signs that a turtle may be experiencing swollen eyelids. Eye infections can be facilitated by swollen eyelids. Puffy and watery eyes are also possible signs of eye infections.
In most cases, eye diseases in turtles are very treatable. Harderian gland swelling is an indication of Vitamin A deficiencies from poor diet. In this case, a shot can be administered to stabilize the turtle's condition. A diet change will have to occur to include more Vitamin A after the injection.
Aside from Vitamin A deficiencies, turtles can get eye diseases from being kept in dirty water. They can also get eye infections just by having other conditions like respiratory tract infections.
Making sure that a turtle gets enough Vitamin A in its diet is critical to lowering the likelihood of a turtle getting eye disease. Being knowledgeable on a specific species of turtle's dietary requirements and keeping its habitat clean are also factors that help prevent eye disease.