Deaf part-blind dog Bronte’s microphthalmia is visible here
changes are mild, there is usually no visual impairment. With moderate microphthalmia, the eyeball fills about half of the opening. About 50 percent of pups born this way will be blind. Where the defect is severe, all of the pups will be blind. In general, microphthalmia is evident as soon as a pup's eyes open. Pups with microphthalmia with cataracts will usually have some visual impairment. The cataracts may be progressive resulting in a worsening of vision, or they may mature and be reabsorbed, resulting in improved vision. This is unpredictable. In the process of resorption, liquefied lens material may leak into the eye causing inflammation.
Deaf and Blind Dogs (Bilateral or Partial)
7-year-old deafblind Sheltie, Treasure
needed a high level of management, very structured and predictable environments and have responded to change or stress with high levels of anxiety and repetitive behaviors, including selfharming. As always, expert help early on is absolutely essential and training plans must be informed by the individual dog’s behavior rather than general expectations. We need to collect much more information about how to help these dogs fulfil their potential.
Old Age - Vision and Hearing
Just as with humans, dogs may experience loss of sight and hearing with age due to natural changes and progressive diseases such as cataracts, retinal degeneration and glaucoma. It is worth asking your vet to double check the vision and hearing in your older dog so that you are ready to introduce touches or hand signals before deafness or blindness really set in. Older dogs may also suffer from canine dementia (canine
These dogs are most often the result of merle to merle matings resulting in homozygous merles (carrying two copies of the merle gene). Such dogs generally have a degree of hearing impairment and also limited sight due to microphthalmia or other eye defects Breed Specific Inherited (eccentric or starburst pupils, corectopia or subluxated pupil. They may be partially vision and hearing im) paired or completely deaf-blind. The degree to which such dogs cope with “normal” life varies hugely, and it is often difficult to tell whether a deaf-blind dog is struggling to cope specifically because of his disabilities. There are several deaf-blind ambassador dogs promoted on social media, and it is well worth checking out the White Dog Blog by Debbie Bauer. In the interest of transparency, I should say that my personal experience has sadly been less positive than Bauer’s. The completely deaf-blind collies I have known or worked with have all 20
BARKS from the Guild/July 2017
Photo: Deb Bauer
COVER STORY
Conditions that Affect Vision