Gonioimplantation in Dogs

A gonioimplant is a tube-like device (or shunt) that is surgically introduced into a dog’s eye to aid the drainage of aqueous fluid from the front of the eye to the outside. The objective of this treatment is to prevent high fluid pressure and help retain visual acuity in animals suffering from glaucoma.

The process of performing the implantation is relatively straightforward. Firstly, the patient receives a general anesthesia and is placed in a safe bracing device (similar to the braces used during laser eye surgery). Next, the surgeon will cut a small hole through the membranes at the top of the eye and thread the 'intake-pipe' of the implant onwards into the body of aqueous fluid. The regulatory valve component will then sit on the surface of the eyeball, only releasing fluid when pressures build beyond the desirable level. Due to the size of the valve section of the implant, there is no danger of it being drawn into the eyeball.

The effects of successful implantation are immediate, with further deterioration of vision halted for the lifetime of the implant. However, its effects are somewhat short-lived. As the months go by, the body will naturally start to form scar tissue around the implant, eventually blocking the valve that regulates the pressure of the aqueous fluid and stopping the gonio implant from functioning. This typically takes place approximately six months after surgery (although some implants have taken over a year to cease functioning). At this point, vision in the eye will start to deteriorate again, necessitating either the replacement of the implant or investigation of other treatment options. In all, it is important to remember that whilst the goni implant is very effective for most dogs in the short term, it is by no means a cure for glaucoma, instead merely warding off the onset of blindness for a few extra months.

Following surgery, the eye will need to be kept covered for a period of time to ensure the site of the implant heals adequately. It may be necessary to fit dogs with an E-collar to mitigate the chances of accidentally dislodging the implant in the weeks immediately after the operation. It will also be necessary to administer anti-inflammatory drugs and antibiotics to prevent soreness and infection prior to the healing of the wound. A series of follow-up visits to the vet will also be required both to check the progress of healing and to measure the functionality of the implant. These visits will continue for the duration of the service life of the device, as any complication or change in effectiveness will require an immediate response.

The cost of a gonioimplantation surgery can typically be expected to range between $600 and $800. The price of aftercare elements such as antibiotics will depend entirely on your provider and the choice of drugs used. Whilst these elements constitute a base rate, there are additional factors that may impact upon the cost of obtaining a gonio implant for a dog. These include (but are by no means limited to): age of the animal, previous operations on the eye being treated, previous treatments for glaucoma and aggressiveness of the condition.

While the benefits of gonioimplantation are manifold (i.e. prolonged use of the eye, easing of discomfort resulting from high aqueous fluid pressure, immediate results), there are some drawbacks that dog owners considering this treatment should be aware of. Whilst most implants will stay in place, there is potential for the device to move and either obstruct vision or become uncomfortable. There is also a risk of inflammation and, if antibiotics are not properly used, infection. Another problem that can occur is intraocular hemorrhage, meaning that fluid could drain into other spaces in the eye.

The best way to avoid requiring a gonio implant for your dog is to tackle the root causes of glaucoma before they have a chance to worsen. While age or breed-related glaucoma may not be entirely prevented, regular veterinary examinations and the use of medications may help manage and stabilize the condition. When the root cause of glaucoma is untreated infection of the inner eye due to injury, prompt treatment can be essential to preventing its progression. Keep alert for any sudden changes in your dog's behavior and temperament that could be indicative of them experiencing eye pain. Upon noticing an eye injury, have them examined by a vet as soon as possible in order to prevent infection and diagnose any other issues that could be in play. Additionally, making sure they have a clean living space can help prevent infection and inflammation of wounds.