Large Animals
Pendular nystagmus is seen in various breeds of dairy cattle. Pendular nystagmus is caused by a congenital abnormality in the visual pathway. No other neurologic signs are present, and the condition is nonprogressive and of no clinical significance.
Congenital deafness has rarely been reported in horses and is thought to be pigment-associated. Brain stem auditory evoked responses (BAER) provide diagnosis of deafness.
Small Animals
Pendular nystagmus is seen in various breed of Asian cats. Compared with pathologic forms of nystagmus, in pendular nystagmus there is no fast or slow phase, and the nystagmus arcs are similar to the pendulum movement of a clock. Pendular nystagmus is caused by a congenital abnormality in the visual pathway. No other neurologic signs are present, and the condition is nonprogressive and of no clinical significance.
Congenital deafness is primarily associated with Dalmatians but has also been recorded in a number of breeds, including Doberman Pinschers, Puli dogs, Australian Blue Heelers and Shepherds, English Setters, Boston Terriers, and Old English Sheepdogs. It is pigment-associated in Dalmatians and not pigment-associated in Doberman Pinschers and Puli dogs. It is linked to blue eye color in white cats. The brain stem auditory evoked response (BAER) is a useful diagnostic test primarily used to identify carriers in a litter of affected animals. (Also see Deafness.)
