Turtle hypovitaminosis A: swollen eyelids, blocked ears, and the diet behind them

Quick answer

Swollen eyelids in a turtle are usually a diet problem that started months earlier. What is in the bowl matters more than anything you can put on the eye.

A turtle with puffy, closing eyelids is showing the first visible sign of vitamin A deficiency. The eyes are not the disease; they are the place where the disease becomes obvious first.

Vitamin A maintains the lining of the eyelids, the tear and Harderian gland ducts, the airway, the Eustachian tubes and the kidney tubules. Without it, that lining thickens and keratinises, ducts block, secretions accumulate, and the same process quietly sets up the aural abscess and the recurring respiratory infection that follow.

• Both eyes swelling gradually, in a turtle on a narrow diet, is hypovitaminosis A until proven otherwise.
• Dried shrimp, gammarus, feeder fish alone, muscle meat, and iceberg lettuce are the diets that cause it.
• Whole prey supplies preformed vitamin A because it includes liver. Fillet and muscle do not.
• Test the water at the same time. Ammonia and nitrite irritate the same tissue and usually accompany the same neglect.
• Correction is slow. The lining has to rebuild, so improvement takes weeks, not days.

Decide in 60 seconds

Why one vitamin controls the eyes, the ear and the airway

Vitamin A tells epithelial cells what to become. Under its influence, the linings of the eyelids, the tear ducts, the mouth, the airway, the Eustachian tubes and the kidney tubules develop into moist, secretory tissue that produces fluid and keeps surfaces clean.

Take it away and those cells default to a different fate. They become flattened, layered and keratinised, more like skin than like a mucous membrane. The change is called squamous metaplasia, and everything that follows is a plumbing consequence of it.

At the eyelid. The glands that lubricate the eye keep producing secretion, but the ducts have narrowed and thickened. Material accumulates behind the block, the lids swell, and eventually a whitish, cheesy plug of debris sits under them. The eye itself is often healthy at first and is simply buried.

At the ear. A chelonian's Eustachian tube runs from the middle ear into the back of the mouth and is unusually wide and short. When its lining keratinises, it blocks. Secretions and any bacteria present accumulate behind the tympanic membrane, and because reptile pus is solid rather than liquid, the result is a firm mass that bulges the ear scale outward. That is the aural abscess, and it is why the condition that looks like an ear problem is usually a diet problem.

At the airway. The same keratinisation removes the ciliated, mucus-producing lining that normally clears debris and organisms. Respiratory infections become easy to acquire and hard to shake.

At the kidney. Tubular metaplasia contributes to renal disease, and in a species that already handles nitrogen through urates, this pushes toward gout.

Everywhere. Vitamin A is also required for normal immune function, so a deficient turtle is worse at fighting all of the above.

Understanding this chain is what makes the deficiency worth taking seriously before the eyes close. By the time the swelling is obvious, the ear and the airway have been living with the same problem for a while.

The diets that cause it

A single dry product, fed exclusively, is the commonest route into this. Pellets can be part of a diet. They are a poor whole diet on their own.

Dried shrimp and gammarus as a staple.

These are sold as turtle food, they float attractively, and turtles eat them enthusiastically. They are dried invertebrate exoskeleton with very little else, and a turtle raised on them is the classic case.

Feeder fish or prawns as the only animal food.

Whole small fish are a reasonable component. The problem arises when the fish are large enough that the turtle eats only the flesh, or when the item is a peeled prawn or a fillet. The vitamin A in a prey animal is concentrated in the liver, so removing the viscera removes most of it.

Muscle meat.

Raw chicken, mince and similar are frequently offered to aquatic turtles. Muscle contains almost no preformed vitamin A and no meaningful carotenoid, and it also carries far too much phosphorus relative to calcium.

Iceberg lettuce and other pale salad leaves.

Mostly water and fibre. A turtle can eat a great deal of it and gain almost nothing.

A single cheap pellet, fed for years.

Formulated pellets vary widely, they lose vitamin content with age and heat, and an opened tub stored above a warm tank degrades faster than most owners assume.

Why carotenoids do not always rescue the situation.

Plants supply carotenoids, not retinol, and the animal has to convert them. Herbivorous chelonians do this reasonably well. Carnivorous and strongly omnivorous species evolved to obtain retinol ready-made from prey and convert carotenoids less efficiently. So adding grated carrot to the diet of a shrimp-fed slider helps less than it should, and the reliable fix is to restore whole animal food and a properly formulated pellet, with plant material alongside rather than instead.

What healthy eyes and skin look like

This is the baseline: lids thin and close to the eye, cornea clear and reflective, no swelling below the eye, head carried up and alert.

Look at the turtle out of the water, in good light, from the front and from each side.

Normal eyelids are thin and sit close to the globe. The eye looks large relative to the head, the cornea is clear and reflective, and there is no bulge below the eye. Both eyes open fully and blink normally.

The skin of the neck and limbs should be smooth, with fine scales that lie flat and no white flaking. Aquatic turtles shed skin in small, almost transparent pieces, which is normal; skin that comes away in thick, opaque sheets is not.

The ear region is a smooth, flat, circular scale on each side of the head just behind the jaw. It should be flush with the head and symmetrical. Any outward bulge on one or both sides is abnormal.

Take one clear photograph of your turtle's head from the front and one from each side while it is well. It costs nothing and gives you something concrete to compare against later.

Early, established and late

Early.

The lower lids look slightly full. The turtle rubs its eyes with its forelimbs after surfacing. There may be a small amount of clear nasal discharge. Appetite is normal or only slightly reduced. Almost nobody catches it here, and this is the stage at which a diet change alone fixes everything.

Established.

Both lids are visibly swollen and the turtle keeps its eyes closed. White or yellowish material may be visible when the lids are gently parted. The turtle stops eating, partly from the disease and partly because it cannot see food. It may bask more than usual or stop basking altogether. The skin becomes rough. Nasal discharge becomes more obvious.

Late.

Complete functional blindness from the swelling. Marked weight loss and muscle wasting on the limbs, which retract less firmly into the shell. An aural abscess appears on one or both sides. Respiratory infection becomes established, showing as open-mouth breathing, listing to one side while swimming, and an inability to submerge evenly. Kidney disease and gout may develop. Death is by starvation, by pneumonia, or by sepsis from the abscess.

The reason to name the stages is that owners routinely present at the established stage believing it started that week. It did not.

The look-alikes

Bacterial conjunctivitis from poor water.

Ammonia and nitrite in an under-filtered turtle tank irritate the conjunctiva directly, and bacteria do the rest. It can also be bilateral. The distinguishing features are a shorter history, more discharge relative to swelling, and a water test that comes back bad. In practice the two often coexist, because the same tank produces both.

Chemical irritation.

Water conditioners, medications added to the whole tank, and cleaning residues can inflame the eyes. History is the clue.

Trauma or a foreign body.

Usually one eye, sudden onset, often with a scratch on the cornea or a visible object.

Retained skin around the eye.

A ring of unshed skin can constrict and swell the lid region. Look closely for an edge.

Corneal drying from prolonged dry docking.

Turtles kept out of water for shell rot treatment sometimes develop dry, dull corneas. The treatment causes the sign.

Aural abscess.

Behind and below the eye, not the eye itself. Firm, and often confused with swelling of the eye when it is large.

Hypervitaminosis A.

Not an eye problem at all. Dry skin that blisters and peels away in sheets, usually within days to weeks of a vitamin A injection. Anyone who tells you a peeling turtle needs more vitamin A has it exactly backwards.

Fixing the diet

Variety is the mechanism, not a garnish. Dark leafy greens and orange vegetables supply carotenoids, whole animal prey supplies retinol, and a formulated pellet fills the gaps between them.

Aquatic omnivores such as sliders, cooters and map turtles.

Build the diet on a good quality pellet formulated for aquatic turtles, kept sealed, cool and within date. Add whole animal items rather than fillets: whole small fish appropriate to the species and size, earthworms, snails and whole invertebrates. Offer dark leafy greens and aquatic plants, and increase the proportion of plant material as the turtle matures, because many aquatic species become progressively more herbivorous with age.

Strongly carnivorous species such as musk and snapping turtles.

Whole prey is the point. Muscle meat alone will not do it regardless of how much you feed.

Tortoises and other herbivores.

Broad-leaf weeds, dark leafy greens and appropriate flowers, with fruit kept to a minimum in species that do not naturally eat it. A tortoise fed a varied weed diet is unlikely to become deficient in vitamin A, and unnecessary supplementation is a bigger risk than the deficiency.

Which greens.

Dark and leafy rather than pale and crisp. Iceberg lettuce contributes little. Rotate what you offer, because rotation is what covers the gaps in any single item.

Storage matters.

Vitamins degrade with heat, light and time. A tub of pellets stored on top of a lit, warm tank for a year is not delivering what the label says.

Expect it to take time.

Even with the diet corrected and the vet's treatment given, the epithelium has to re-differentiate. Weeks of gradual improvement is normal, and a turtle that has stopped eating may need assisted feeding in the meantime.

Fix the water at the same time.

Turtles are messy, and most home turtle tanks are under-filtered for the bioload. Test ammonia, nitrite and nitrate, increase filtration and water change frequency if needed, and feed in a separate container if that helps keep the main tank clean.

What never to do

Do not buy an injectable vitamin A product and use it yourself. Dosing is calculated, the margin is not generous, and the consequence of getting it wrong is a turtle with skin sloughing off.

Do not treat swollen eyes with a human eye drop and wait. Drops do not reach a blocked duct, and the days spent trying are days the turtle is not eating.

Do not assume the eyes are the whole problem. Ask the vet to check the ears and listen to the respiratory system, because the same deficiency is working on both.

Do not feed shrimp, gammarus or dried invertebrates as a staple, however keen the turtle is on them.

Do not offer only muscle meat, and do not fillet the fish.

Do not correct the diet and skip the water. A perfect diet in a tank with measurable ammonia will not resolve the conjunctivitis.

Do not force the eyelids apart. If they are stuck, that is a job for a vet with proper flushing and lubrication.

When to get help

Contact a reptile or exotics veterinarian the same day for:

• Open-mouth breathing, bubbles at the nostrils, or listing to one side while swimming
• A turtle that cannot open either eye
• Skin blistering or peeling away in sheets after a vitamin injection

Within the week for:

• Swelling of one or both eyelids
• A firm bulge on the side of the head behind the eye
• Refusal to eat for more than a couple of days
• Rough, flaking skin with any eye change

Bring these to the appointment: photographs of the head from the front and both sides, a written list of everything the turtle has eaten over the last month including brands and how often each item is given, how old the pellet tub is and where it is stored, your ammonia, nitrite, nitrate and pH readings, the water temperature, the basking surface temperature, the UVB lamp type and how many months it has been running, the tank volume and filtration, and the turtle's weight history.

The diet list is the part owners tend to compress into "pellets and greens". Write down what actually goes in, in what proportion, because the answer to this condition is almost always in that list.