Aqueocentesis in Cats

Aqueocentesis is a simple procedure which is used in cats to diagnose and treat certain eye conditions. During the procedure, the veterinary ophthalmologist will draw a sample of the aqueous humor – the eye fluid which is located between the lens and cornea – into a syringe. The sample will then be examined under a microscope. It should be noted that aqueocentesis is most commonly used to discover the underlying cause of eye disease rather than diagnose the eye disease itself.  Aqueocentesis may be used to as a temporary treatment method for select cases of eye disease and glaucoma. If aqueocentesis is performed as a treatment measure, the ophthalmologist will not use a syringe. Instead, a small needle will be inserted, allowing the excess aqueous humor to drip out.

1. Before aqueocentesis is performed, the vet will first conduct a standard eye exam.
2. The cat will be sedated or given local or general anesthesia.
3. The ophthalmologist will administer special eye drops to cleanse the eye.
4. The eye will be immobilized using forceps.
5. The veterinary ophthalmologist will use a syringe to draw a sample of aqueous humor from the anterior part of the eye.
6. If aqueocentesis is being performed to relieve intraocular pressure, the vet will simply insert a needle without a syringe attached to allow the fluid to drip out.
7. The ophthalmologist will examine the aqueous humor under a microscope.

Aqueocentesis is somewhat effective as a diagnostic tool in cats. It is most effective in diagnosing lymphoma. However, there are some drawbacks of relying on aqueocentesis to confirm the underlying cause of eye disease. This is largely due to the small sample size of aqueous humor collected during the procedure. Only 1 ml of aqueous humor is taken for most samples.

Because aqueocentesis is a diagnostic rather than a treatment method, cats will not need to recover from the procedure. It is typically short, and only takes a few minutes to complete. Though there is generally no pain associated with the procedure, cats may be lethargic once the procedure has completed. If cats show any signs of pain, the vet may administer a short-term pain management medication. Owners should ensure no swelling or inflammation occurs following the procedure.

The average cost of aqueocentesis will vary based on standards of living and additional costs incurred, including medications and supportive care. The cost of treating anterior uveitis in cats – inclusive of aqueocentesis – ranges from $200 to $800. On average, the national cost of diagnosing and treating anterior uveitis is $500.

Aqueocentesis is not generally the first diagnostic method veterinarians employ when it comes to anterior uveitis. This is because simpler techniques can confirm diagnoses without the need for sedation or anesthetic. Aqueocentesis is most commonly used to discover the underlying cause of anterior uveitis, especially if lymphoma is suspected.

Complications associated with aqueocentesis are rare, but possible. Complications of aqueocentesis may include:

• Trauma to the cornea
• Eye hemorrhage
• Uveitis*
• Detachment of the retina
• Subluxation of the cataract or lens
• Endophthalmitis: intraocular infection

*Though the procedure is used to diagnose uveitis, it may also cause uveitis if it is not already present.

When used as a therapeutic measure, aqueocentesis can only provide a temporary resolution to increased intraocular pressure associated with glaucoma. Aqueocentesis may be recommended in addition to other, long-term treatment methods to manage glaucoma.

Aqueocentesis should not be used in animals that suffer from coagulopathy, a condition in which the blood is thinner than normal due to the inability to clot properly.

Prevention measures will depend on the underlying condition. It is difficult to prevent eye cancer and similar diseases. Owners should ensure their cats do not engage in any activities which result in eye trauma. Cat owners should also make sure that all chemicals and other toxic substances are kept out of reach of their pets.