Companion Animal Eye Center, Ltd.

4708 Olson Memorial Hwy
Golden Valley, MN 55422

(763)529-7591

www.companionanimaleyecenter.com

Glaucoma video (click here)

Glaucoma is one of the most common vision threatening diseases in dogs. Increased intraocular pressure (IOP) is identified as the main risk factor in optic nerve damage, resulting visual field loss and blindness. In the dog, the IOP increases because the outflow of fluid from the anterior chamber is either reduced or absent. The fluid in the eye (aqueous humor) is produced by the ciliary body which is located behind the iris. Fluid exits the eye mainly by the iridocorneal angle. The iridocorneal angle (drainage angle) is located at the junction of the iris and the cornea. In a normal eye, the production of fluid and the drainage of fluid are equal to maintain a fairly constant IOP. When production remains constant and drainage is decreased, the IOP rises.

Glaucoma is a progressive disease which means it gets worse over time. When uncontrolled, glaucoma not only leads to blindness, but it is also painful. Therapy is aimed at saving vision for as long as possible, reducing IOP's rapidly and safely, and relieving the associated pain. The therapeutic plan for your pet will be based on type of glaucoma (primary or secondary).

Primary glaucomas are those associated with an abnormal anatomy of the iridocorneal angle. Primary open angle glaucoma is common in people, yet rare in dogs. This type is mainly seen in Beagles. Closed or narrow angle glaucoma is very common in dogs. This type occurs in many breeds including but not limited to Cocker Spaniels, Basset Hounds, Miniature Poodles, Boston Terriers, Dalmations, and Arctic breeds. Both types of primary glaucoma are incurable but can be managed for variable periods of time with medical and surgical therapy. Primary glaucoma is an inheritable disease and will likely affect both eyes.
Diagnosis of primary glaucoma is made by tonometry and gonioscopy. These tests are performed by first anesthetizing the surface of the eye with topical drops. A Tonopen is used to measure the intraocular pressure. A goniolens is placed on the corneal surface and looked through with a biomicroscope to determine the anatomy of the iridocorneal angle.

Secondary glaucomas are those that occur following another disease such as trauma, inflammation, hemorrhage, or a tumor inside the eye. These glaucomas can often be treated and vision saved if the underlying cause can be identified and corrected. Treatment will also need to address the secondary glaucoma.

After establishing a diagnosis of glaucoma, therapy depends of whether or not there is still potential for vision. Topical therapies (eye drops) may be used alone or in combination with IV mannitol and/ or surgeries.
Laser therapy (cyclophotocoagulation) is performed under general anesthesia. This procedure is designed to decrease the production of aqueous fluid by destroying some of the tissue that produces it (the ciliary body). Gonioimplants are placed under general anesthesia as well. These are valves that allow for an accessory drainage of fluid from the eye.
Both laser therapy and gonioimplants are helpful in controlling pressures and prolonging vision when used in combination with medical therapy. Glaucoma medications will still be necessary. Success is dependent on close monitoring and adequate follow-up.

If your pet has a blind eye, therapy is directed at maintaining long term comfort. Evisceration with intrascleral prosthesis, enucleation with or without an intraorbital prosthesis, and pharmacologic ablation of the ciliary body are treatment options. These are not procedures used on potentially sighted eyes.
Evisceration of the globe with an intrascleral prosthesis has the most cosmetic result. The blind eye is surgically opened, its contents removed, and a silicone implant placed. The eye and the lids move normally and your pet will maintain the appearance of their eye without the chronic pain associated with glaucoma. This procedure requires general anesthesia, post-op pain medication,and post-op topical and oral antibiotics. A follow-up recheck examination will be scheduled at 7-14 days post-op at no charge. Additional exams and medications will be assessed the normal fees.
Enucleation is removal of the entire globe with permanently closed lids. This procedure requires general anesthesia and post-op pain and antibiotic medications. A follow-up recheck examination is scheduled 7-21 days post-op at no charge. Additional exams and medications will be assessed the normal fees.
Pharmacologic ablation of the ciliary body is an alternative to intrascleral prosthesis or enucleation that we will use in aged patients with marked discomfort when risk of general anesthesia is very high. Following IV sedation and topical anesthetic, two pharmaceutical agents gentamicin and dexamethasone are injected directly into the vitreous to destroy ciliary tissue. Unfortunately, results can be somewhat unpredictable with this procedure. Possible complications include chronic discomfort, too much ciliary destruction of ciliary tissue with shrinkage of the globe (phthisis bulbi), and not enough ciliary destruction with persistence of elevated intraocular pressures