Aqueocentesis in Dogs

Within the eye, there is clear fluid that fills up the area between the cornea and the lens in the anterior (front) chamber. This fluid is known as the “aqueous humor”. In some dogs, this fluid can build up and create pressure within the eye. Pressure in the eye can lead to permanent vision loss and blindness. The cells in the aqueous humor reveal the health of the eye. If cancer of the eye is suspected, obtaining these cells can lead to a diagnosis.

The draining or collecting of this fluid is called aqueocentesis. Aqueous humor can be obtained for the identification of many diseases that affect the eye. If the aqueous humor is drained, it can relieve pressure in the eye and prevent damage. Inflammation of the eye called uveitis is often what merits further testing. This generally manifests as redness in the eyes. Complicated eye problems in dogs are usually referred to an ACVS board-certified veterinary ophthalmologist. These professionals complete their residency in ophthalmology and take an additional three-day exam to be properly accredited. 

When inflammation of the eye is present, aqueocentesis is often used at the beginning of the diagnostic process to determine what the underlying issue is. It is only used as therapy when extreme pressure has built in the eye and other forms of relief have failed. You may notice inflammation of the eye by redness or enlargement of the eyeball. Your veterinarian can confirm this, and may refer you to a specialist at this time.

To complete an aqueocentesis, the dog will need to be sedated with a short-acting local anesthesia. Once the animal is calmed, the eye will be secured open using forceps. At this point, a needle with a syringe is inserted into the front portion of the eyeball. Fluid is then collected and sent for histopathological examination at a lab. A bacterial culture or a PCR test may also be run on the fluid during this examination. If the aqueocentesis is for therapy, no syringe is needed. The fluid will be drained out after the needle is inserted and pressure should instantly be lessened. This procedure does not take a long time to perform. 

Aqueocentesis carries very minimal risks and is not invasive to the dog. It is routinely used with great success as a diagnostic tool to correctly determine what eye disease is present. Aqueocentesis, while not permanent, is a very effective way to reduce extreme eye pressure. The blood-aqueous barrier often breaks down after this procedure, but should repair within five days on its own. To reduce damage, using a 27-30 gauge needle has been shown to be less traumatic to the eye.

As aqueocentesis is a minimally invasive method for diagnosis, the recovery period for the procedure is almost non-existent. In some cases, the blood-aqueous barrier is damaged after aqueous humor has been removed. This issue generally resolves on its own within one week. If the aqueocentesis was done to obtain cells for evaluation, after the test results have been obtained you will need to go back to the veterinary clinic for another appointment. At this appointment, the veterinarian will go over the diagnosis and form a treatment regime if necessary. If cancer has been found, chemotherapy, radiation therapy, or surgery may be needed.

The cost of aqueocentesis alone is not high, with bill totals not typically exceeding $500. The procedure is fast and only requires local anesthesia to be completed. If it is performed by an ophthalmologist, the cost will likely be higher than if performed by a general veterinarian. Aqueocentesis is generally just a small part of the treatment process, so the overall cost to resolve the issue will generally be much higher than the cost of aqueocentesis on its own. If surgery or long-term medications are needed, the total cost of treatment can easily exceed $3,500.

Having aqueocentesis performed to diagnose eye disease in your dog is an effective way to identify underlying problems. There are very few risks associated with the procedure and none of them are serious. It should be noted that if aqueocentesis is being used as glaucoma therapy, it is not curative and the eye may eventually need to be removed. Some may opt to skip aqueocentesis and go straight to removal surgery, as dogs often cope with blindness quite well.

To prevent the need for aqueocentesis, certain measures may be taken throughout the dog's life. Many forms of glaucoma have found to be genetic, so always asks for your dog's family medical history when obtaining the animal. If your dog has been diagnosed with severe glaucoma, it may be best to refrain from breeding it. 

The risk of developing many forms of cancer are also genetically linked. Certain things have been found to exacerbate these susceptibilities, bringing on the cancer earlier or increasing its aggression. Feeding your dog a high-quality diet free from preservatives may reduce the chance that it will develop cancer. Keeping your home free of cancer-causing carcinogens such as cigarette smoke will also be healthier for both you and your dog. Daily exercise has been shown to promote better health by reducing cases of obesity.