By Nadine Gill
One of the most common conditions we have reported from keepers of aquatic turtles is that the eyes of their terrapin have swollen or closed. These symptoms can be the result of several conditions, and a prompt diagnosis can allow for effective treatment to begin without delay. Early intervention is critical because, as sight feeders, aquatic turtles will stop eating once their eyes are closed.
Pet stores commonly sell vitamin A drops that claim to cure vitamin A deficiencies and eye infections. These products are ineffective in resolving either of these conditions, and though they may cause no direct harm, they delay proper diagnosis and treatment.
In order to accurately diagnosis the cause of a swollen or closed eye, a veterinarian experienced in treating chelonians will not only rely on clinical signs, but will also ask the owner about the turtle's history, including its dietary regime and the environmental conditions in which it is maintained. It is too often the case, however, that these factors are not even considered, and that the swollen or infected eye is incorrectly diagnosed as the result of a vitamin A deficiency.
Vitamin A deficiency is one possible cause for an eye infection, and is the result of diets that rely on foods deficient in beta carotene or preformed vitamin A, such as insects, ant eggs, dried shrimp and other poorly formulated commercial foods. This deficiency is unlikely to develop, however, when a turtle's diet contains a fortified commercial turtle food, such as Reptomin, vegetation and leafy salad greens rich in beta-carotene (the precursor to vitamin A), or has been provided with a multivitamin supplement once a week.
When a turtle does become Vitamin A deficient, it causes changes in the epithelial tissues that begin to breakdown and become predisposed to infection. Early signs include eyelid edema, as the tear secreting glands swell outward and cellular debris accumulates underneath the eyelids, and these symptoms will progress until the eyelid remains closed or even appears to be fused. Respiratory symptoms may also be present, and renal, pancreatic, and gastrointestinal epithelium may be affected as well. In the early stages, correcting the diet to include vitamin A may successfully treat the deficiency, but more advanced cases may require vitamin A injections.
Secondary bacterial and fungal infection can also be present, as opportunistic pathogens attack the compromised epithelial barriers, and it is important to note that any such infection will need to be treated. Simply correcting the deficiency will not resolve a resulting infection. Eye infections can usually be successfully treated with antibiotic eye drops or ointment, but if the particular microorganism is resistant to the antibiotic used, or the infection has become systemic, more specific treatment would obviously be required. The sooner a vitamin A deficiency is corrected and any secondary infections treated, the better the chances for a full and more rapid recovery.
Vitamin A deficiency is a serious condition that requires prompt medical intervention and dietary modification. If it is determined, however, that the turtle's requirement for vitamin A has been met through the provision of beta carotene rich foods or a multivitamin supplement, other possible causes for eye conditions should be considered.
When the exact cause for the condition is diagnosed, addressing the following aspects of husbandry will support your turtle's recovery and will greatly reduce the chance of it developing eye problems (as well as other illnesses) in the future. Poor water quality is often the cause of eye and skin infections. Husbandry related infections could be easily prevented by providing adequate water volume for the number of turtles maintained and to purchase equipment powerful enough for effective filtration.
Introduction of new turtles, especially those acquired from pet stores (where improper handling is common), can result in cross infections. I personally quarantine any new reptile for at least two years, particularly if it came from a pet store or its background is unknown. Some viruses can remain dormant much longer than that, so there is still a possibility for cross infection, albeit very slight, even after that length of time. Improper handling can lead to cross infection between turtles. Simply washing your hands well with an antibacterial soap will prevent most cross infections, but it is highly recommended to use a solution including chlorhexidine or povidone iodine after handling turtles suffering from illness or infection or those that have a high probability of carrying potential pathogens.
Most eye problems we have reported to us are not related to vitamin A deficiency, and could have been easily avoided through the provision of better environmental conditions, precautionary quarantine, and better handling procedures in large and mixed collections. Following these guidelines will greatly reduce the chances that your turtle will ever suffer from these all too common, but easy to prevent eye conditions.