This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to diagnose collie eye in shelties 
Test your dog's eyesight. 
If you want to know if your sheltie has cea, then test his eyesight. In mild cases, your dog may be able to see well enough to cope.

pick from the following. (1). But in severe cases, condition your dog and test his eyesight. Common symptoms a dog has and is regularly exhibiting are : White eyes in older dogs enlargement when taken by calipers eye discharge swelling pupils Listen to your dog.. (2). On the other hand, in serious cases, it can be possible to diagnose retinal cancer. Take your dog to see a vet if you suspect this.. (3). However, if it is difficult for your dog to recognize objects that he can't easily see, then he might have cea. This is another risk factor for german shepherds, as them are tall and tend to have cloudy vision.. (4). In severe cases, your dog may be blind. Place objects in your dog's path and see if he avoids them or bumps into the obstruction..
The answer is:
(4).