Several genetic eye defects affect Australian shepherds, resulting in a range of consequences. Some may affect his eyes' appearance, while others impact how well he sees. If you have an Aussie pup, have his eyes examined each year by a veterinary ophthalmologist.
A Hole in the Eye
A coloboma is a piece of missing tissue in the eye, and in the Australian shepherd, it's most likely to manifest in his iris. If your pup has iris coloboma, he may be sensitive to bright light and have a misshapen iris. Fortunately, his vision will probably be fine. Multiple iris colobomas gives his pupil an oval or askew appearance and potentially results in a bit of vision loss. If it looks like your dog's pupil overlaps into his iris, it's likely an iris coloboma.
Not For Seniors Only
In the case of an Australian shepherd, cataracts aren't just for geriatric dogs. Because this congenital illness affects even a young Aussie, these cataracts are known as juvenile cataracts. Juvenile cataracts are associated with the merle gene -- the same gene responsible for the dappled appearance and blue irises of some Aussies. This defect occurs when the lens tissue gradually, painlessly deteriorates, leaving a dog partially or completely blind by 2 to 5 years of age.
Retina at Risk
The Australian shepherd is one of many breeds of dogs prone to progressive retinal atrophy. This serious disease usually shows up in a dog's early adolescence, potentially blinding a pup by the time he's 8 months, although sometimes the condition presents later in a dog's life. Symptoms begin with night blindness and eye dilation that develop to total blindness. Detached retinas, where the retina separates from the back of the eye, is another potentially blinding condition.
Keep an Eye Open
Several other eye problems exist with the breed, such as persistent pupilary membrane. This develops when the membrane covering a puppy's eye doesn't break away by 8 weeks of age. The pup's vision suffers in varying degrees, depending on where the membrane hangs on and how many strands exist. If your Aussie has a small eye, he has microphthalmia, which can leave a pup blind at birth in severe cases. If the eye is missing, he has anophthalmia, which is a more serious case of microphthalmia. The Australian shepherd may have some distant collie ancestors, which may account for his susceptibility to collie eye anomaly, a host of eye disorders ranging from mild to serious.