A bulging and painful eye is never a good sight. Some breeds (pugs specifically) have eyes that naturally seem to bulge a bit more, but if your dog all of a sudden seems to have a painful eye that looks larger than the other one, it’s time to schedule a visit with your Veterinarian. Today we are going to talk about Glaucoma. Yes, dogs get Glaucoma just like humans do. What is it? What symptoms should you watch for? Are certain breeds more prone to the condition? What can be done to help your dog or cat?
Let’s dive in! First we should discuss the anatomy of the eye and fluid production in the eye. The eye or “globe” has two distinct sections separated by the lens. The front part of the eye behind the cornea is the anterior chamber.
The back part of the eye, including the retina, and optic nerve is the posterior chamber. The fluid and pressure within the eye is under very tight regulation by the body. The body produces fluid, aqueous humor, in the eye to maintain its shape and provide nutrients to the various structures within the eye. The eye has what is called a “drainage angle” where the colored part of the eye, the iris, meets the white part of the eye, the sclera. This is where the aqueous humor can drain from the front portion of the eye to maintain an appropriate pressure.
Glaucoma is when the pressure within the eye elevates. There are two kinds of Glaucoma: open angle and closed angle.
This has to do with whether or not the drainage angle is open or closed. Normal ocular pressure for dogs and cats is between 15 and 25. When the pressure in the eye starts to increase, the pet will start to feel uncomfortable. This will lead to squinting, pawing at the eye, scratching at the eye, digging the face into the couch cushions or carpeting, or simply sitting with the eye closed. As the pressure continues to rise, the discomfort becomes true pain. The dog or cat with an eye pressure in the 50s, 60s, 70s or 80s is in a lot of pain!
When an owner schedules an appointment to have me examine their pet’s eyes, there are many things I examine. Are the eyes symmetrical, or is one bulging? Is there an ulcer on the surface of the cornea? Is there discharge coming from the eye, and if so, what color is it? Is the sclera (white part of the eye) red and angry? Does the cornea (clear part of the eye) have a bluish haze? Are the pupils the same size? How do the pupils respond to light? How do the retinas and optic nerves look? Finally, what breed is this dog? There are certain breeds that are more prone to Glaucoma - Pugs, Boston Terriers, Cocker Spaniels, Huskies, and Beagles to name a few.
If I am concerned about Glaucoma - bulging eye, bluish haze in the cornea, red sclera, squinting, the first test I am going to do is an Intraocular pressure. To do this there are a couple instruments that can be used.
I am a fan of the TonoVet, but the TonoPen is another great tool. Many people are used to the puff of air to check pressures in the eye. This is different, in that a small probe is bounced against the surface of the cornea. Sounds crazy, right? The dog or cat can barely feel it, and are typically quite good for this part of the exam. The probe is bounced six times against the cornea and an average pressure will be displayed on the screen. This is done three times in each eye. We always measure the pressure in the more “normal” eye as well. Why? Because if the dog or cat has Glaucoma in one eye, the second eye is predisposed to developing Glaucoma in the next 6 months as well. You need a baseline reading from BOTH eyes.
If the pet is determined to have Glaucoma it’s time to do something NOW. If the pressure in the eye gets above a certain point and stays elevated for over 24 hours, the pet can go irreversibly blind in that eye. In the Animal Hospital, your pet may be given a medication called Latanoprost. This is administered by drop into the eye and can bring pressures down dramatically within 45 minutes or less. A different maintenance medication will be prescribed for home use. If the eye pressure is just mildly increased, I typically start with the home maintenance medication.
A recheck examination of your pet’s eyes should be scheduled within the next 1-3 days depending on the starting value of the eye pressure. Our goal is to make sure that the pressures come down to near normal quickly on the medication we have prescribed. After that initial recheck, it is best to schedule another pressure check after 1-2 weeks, then every 3 to 6 months if the pet appears stable at home. Remember to be watching the other eye, as that second eye is prone to developing Glaucoma in the next 6 months!
Maintenance medications for Glaucoma are typically Dorzolamide (Trusopt) as a first option, or Dorzolamide + Timolol (Cosopt) if the Dorzolamide alone is not enough to control intraocular pressure. I have successfully managed many pets over many years with these two medications. Often their owner may not have noticed that they were becoming less active or interactive with the family if the pressures were slowly rising in the eye. After becoming comfortable again with medication, they get a renewed sense of play and seem much younger again.
What happens, though, if the medications don’t help? This is a real possibility for some dogs. Some cases of Glaucoma just are not reversible. Either blindness occurs, or the eye is constantly painful. Our options here are either referral to an Ophthalmology specialist, or removal of the eye (enucleation). I do everything in my power to try to prevent this scenario, but in some cases it is not possible. Removal of the eye is a permanent cure to the Glaucoma case that is beyond management. Dogs and cats can do great with one eye (or even no eyes) after an adjustment period. Usually in this case, the eye was already blind, and it was painful, so they are just thankful to be feeling better again.
If you suspect your dog or cat may have Glaucoma, please schedule a visit with your Veterinarian today! Remember, with Glaucoma, if the pressures remain too high for over 24 hours, irreversible blindness can result!
Let’s dive in! First we should discuss the anatomy of the eye and fluid production in the eye. The eye or “globe” has two distinct sections separated by the lens. The front part of the eye behind the cornea is the anterior chamber.
Glaucoma is when the pressure within the eye elevates. There are two kinds of Glaucoma: open angle and closed angle.
When an owner schedules an appointment to have me examine their pet’s eyes, there are many things I examine. Are the eyes symmetrical, or is one bulging? Is there an ulcer on the surface of the cornea? Is there discharge coming from the eye, and if so, what color is it? Is the sclera (white part of the eye) red and angry? Does the cornea (clear part of the eye) have a bluish haze? Are the pupils the same size? How do the pupils respond to light? How do the retinas and optic nerves look? Finally, what breed is this dog? There are certain breeds that are more prone to Glaucoma - Pugs, Boston Terriers, Cocker Spaniels, Huskies, and Beagles to name a few.
If I am concerned about Glaucoma - bulging eye, bluish haze in the cornea, red sclera, squinting, the first test I am going to do is an Intraocular pressure. To do this there are a couple instruments that can be used.
A recheck examination of your pet’s eyes should be scheduled within the next 1-3 days depending on the starting value of the eye pressure. Our goal is to make sure that the pressures come down to near normal quickly on the medication we have prescribed. After that initial recheck, it is best to schedule another pressure check after 1-2 weeks, then every 3 to 6 months if the pet appears stable at home. Remember to be watching the other eye, as that second eye is prone to developing Glaucoma in the next 6 months!
What happens, though, if the medications don’t help? This is a real possibility for some dogs. Some cases of Glaucoma just are not reversible. Either blindness occurs, or the eye is constantly painful. Our options here are either referral to an Ophthalmology specialist, or removal of the eye (enucleation). I do everything in my power to try to prevent this scenario, but in some cases it is not possible. Removal of the eye is a permanent cure to the Glaucoma case that is beyond management. Dogs and cats can do great with one eye (or even no eyes) after an adjustment period. Usually in this case, the eye was already blind, and it was painful, so they are just thankful to be feeling better again.
If you suspect your dog or cat may have Glaucoma, please schedule a visit with your Veterinarian today! Remember, with Glaucoma, if the pressures remain too high for over 24 hours, irreversible blindness can result!
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