Glaucoma is a condition where the pressure inside the eye becomes increased to the point that it produces changes in the structures and function of the eye.  Glaucoma can be classified as secondary due to some injury or other eye disease, or primary and due to genetic anatomical variations in the eye.  The American College of Veterinary Ophthalmologists has defined 42 different breeds with these genetic predispositions.  These breeds are listed below.  When diagnosed early and treated properly, vision can usually be restored and the pressure in the eye controlled.  With humans, there are early warning signs of glaucoma such as blurred vision and chronic headaches.  Unfortunately, our pets cannot tell us when their vision is blurred or if they are having headaches.  Generally, we as veterinarians see these cases only when there has been sufficient increases in pressure to produce obvious symptoms such as very red painful eyes, cloudy corneas, or markedly swollen, protruding eyes.  At this point it is almost too late to save the animals sight and, in many cases even to save the eye. 

Early diagnosis is best made by measurement for the pressure within the eye.  If the pressures are above normal ranges then, it is suspicious of glaucoma.  Unfortunately, in dogs, what is considered "normal" has a wide variation and there is some controversy over what normal really is.  Ranges as large as 10 to 31mm of mercury have been proposed by various ophthalmologists as normal for that animal can be sufficient to cause problems with vision.  It follows, then, that it would be important to establish what is normal for each individual.  This is best done while the dogs are puppies when they receive their first vaccinations.  Once the normal for that animal is established, the pressures should be checked annually for changes which would be an early warning of glaucoma.  Veterinary ophthalmologists are recommending such a program for all breeds of dogs, and particularly for those breeds with established genetic predispositions for glaucoma.  Pressures should be monitored in adult dogs annually even if puppy normals are not available for comparison.