Eye defects

Question
QUESTION: My Australian shepherd has what seems to be a slight blur at the bottom of his pupil  and i was reading about this and i am worried that he might be going blind in one eye

ANSWER: Aussies are subject to eye anomalies, and blindness, especially if they were products of merle to merle breeding.  Have your veterinarian check the dog.  But, if it turns out that your dog has vision problems, don't despair.  Blind dogs can be trained, and go on to live very full lives.  (Good book: "Living With Blind Dogs")  Dogs rely more on scent than sight, unlike humans.

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QUESTION: but is it possible that he may not be blind and if he is would it be in both eyes even though only one eye is defected

i am also thinking about getting a new Australian shepherd for my original Aussie and breeding them but will this eye defect be a problem and is Merle to Merle breeding all that bad

Answer
Please, please, please, do NOT breed a dog with an eye defect - this is like dooming generations of puppies to more eye defects.  
And, yes, merle to merle breeding is very bad:
When Aussie puppies inherit two merle genes, the result is what's known as a double merle white, or homozygous white.  These puppies are almost white in appearance and may or may not have some merle spots.  They can have defective organs, and severely impaired hearing or vision.  Sometimes, pups are even born without eyes.  Defective merled whites occur in roughly 25 percent of a merle to merle bred litter.
While you can breed merle to merle, you open yourself up to having to cull (kill) these pups, or dump them on the rescuers and shelters which are already overburdened trying to find homes for sound dogs.  That's not ok, in my book.
If you are wanting to breed any dog, first PLEASE get a mentor from the Australian Shepherd Club (www.akc.org or www.asca.org).  This is a breed with a very small gene pool, some significant genetic problems (not the least of which is epilepsy), and it is completely irresponsible to breed them without a good body of knowledge about the breed, and about dogs in general - because, while you may love your Aussie (I love mine, too!), the last thing we need for these wonderful dogs is more backyard breeding, and irresponsible breeding.  Plus, they are not great pets for just any home - you need to know about bloodlines, too, because that tells you whether the dog is from show or working lines, and perhaps even what you can expect for temperament as well as any performance or working ability you might be seeking from the pups.  Trust me, if you are thinking of doing it for the money, forgettaboutit.  Besides, if you have a pet that is unspayed or unneutered, that tells me that your own breeder may have been disreputable.  Show prospects and working prospects are sometimes sold that way, but pet contracts should have a spay/neuter clause in them.

Unfortunately, the truth hurts, and I am absolutely willing to subject myself to poor "ratings" to make the point about irresponsible breeding.  Once you are better educated about this breed and breeding in general, you will be apologizing for calling ME impolite, and will, instead, likely direct your ire at the people who are disregarding the health and welfare of your chosen breed.