Swollen, inflamed eyes are commonly seen in a wide variety of captive turtles. Strangely, the hardy Red Eared Slider seems especially prone to this annoying and potentially life-threatening condition (as we’ll see, popular feeding practices may partially explain this). From childhood through my career as a herpetologist, standard wisdom has blamed the condition on a Vitamin A deficiency. Today we also know that poor water quality is responsible for many, if not most, of the eye problems seen in Sliders, Cooters, Painted Turtles and similar species. In this article we will look at the symptoms, causes, prevention and treatment of various turtle eye maladies.
Most eye problems first manifest as a slight but noticeable puffiness of the eyelids. Vitamin A deficiencies and fungal/bacterial infections can cause tissue within and around the eyes to degrade. As a result, epithelial cell “debris” collects along the eye rims and under the lids. Pressure and irritation causes the lids and tear ducts to swell.
At first, an afflicted turtle may paw at its eyes but otherwise behave normally. In time, swelling will increase and the animal will be unable to open its eyes. Even if the condition originally began as a nutritional deficiency, bacterial and/or fungal infections often take hold at this point, causing the turtle to become listless and decline further in condition.
Vitamin A Deficiencies
Red Eared Sliders, Painted and Map Turtles, Cooters and many others begin life as carnivores but gradually shift to a plant-based diet as they mature. When purchased as hatchlings, many such turtles become accustomed to eating insects, fish, earthworms and high protein turtle chows, and steadfastly refuse to accept Vitamin A-rich greens as they reach adulthood. Efforts must be made to introduce these healthy foods early, and reluctant adults must be “re-educated”. Please see this article for further information.
Preventing Vitamin A Deficiencies
While kale, collard greens, dandelion and similar foods are the best sources of Vitamin A (technically, they supply Beta Carotene, a precursor to the vitamin), turtle chows and pellets should also be considered as sources. Always choose products offered by well-respected companies, such as Tetra, Zoo Med, Exo-terra and Hikari. I have long relied upon Reptomin and, more recently, on various Zoo Med products for the turtles under my care at home and in zoos.
The proper use of vitamin supplements such as ReptiVite can also go a long way in assuring good eye health. Please post below if you have any questions or related observations.
Treating Vitamin A Deficiencies
Adding the proper foods to your turtle’s diet can halt and reverse an early stage Vitamin A deficiency. If the condition is advanced, however, or if the turtle has other health problems, Vitamin A injections will be necessary. Please post below if you need help in locating a vet experienced in turtle medicine.
Commercial turtle eye washes can be used to flush and moisten eye tissue, but are not effective in supplying Vitamin A.
Vitamin A deficiencies have declined among turtles in recent years, due to our increased knowledge of their dietary needs, and the availability of high quality commercial pellets. Judging from the questions I receive from readers, it seems that poor water quality is a leading cause of swollen eyes in aquatic turtles. Aquatic turtles are messy feeders. Water contaminated by leftover food and waste products provides an ideal breeding ground for harmful bacteria and fungi, some of which can invade the eye.
Opportunistic bacteria and fungi, which are always present in turtle tanks, often attack the eyes of Vitamin A-deficient turtles. Veterinarians usually check for this possibility when treating such turtles, especially if Vitamin A injections do not reverse the symptoms.
Preventing Eye Infections
Proper filtration, or the use of a plastic enclosure that can be easily dumped and cleaned, is essential to the good health of all turtles. Even with excellent filtration (I favor the ZooMed Turtle Clean), however, I always advise turtle owners to feed their pets in a separate feeding enclosure rather than in the aquarium. I have found this to be the single most important step that can be taken to improve water quality. Please see the articles linked below for information on useful filters and feeding techniques.
Good health and a strong immune system will go a long way in helping your turtle fight off harmful micro-organisms. In addition to clean water, always provide heat, UVB exposure and nutrition that are appropriate to the species you keep. Please see this article for information on the proper care of Sliders and similar turtles, and post questions concerning other species below.
Treating Eye Infections
Infections may respond to antibacterial/antifungal drops and creams, but resistant pathogens are always a possibility. Infections that have become systemic (established within the body) must be treated with injectable medications.
Other Causes of Swollen Eyes
Turtles lose water through the eye tissue at a rapid rate…at least 2/3 greater than by other forms of diffusion. While dehydration is not usually a concern in healthy turtles, ailing, listless specimens may be at risk. Dehydrated turtles often exhibit swollen eyes.
Swollen or inflamed eyes may also be associated with traumatic injuries (bite wounds, poking eye on wood), debris under the lid and ear infections (particularly common in American Box Turtles, Terrapene spp.).