There is a common misconception that merles have more health problems which has stemmed from the fact that there in an inherited risk with accidental merle to merle breedings, as opposed to a merle to non-merle breeding.

A MAS breeder should be willing and able to show you copies of results from DNA tests, eye exams, hip and elbow screening reports.  If you are looking at a specific litter and the breeder does not own the sire, he should have a copy of the dog’s certificates or be willing to get them for you.

Blue eyes are not more susceptible to eye defects and disease but they are more sensitive to bright light (as they are in blue-eyed people.)  There is no clear association of blue eyes to deafness in MAS, deaf MAS virtually always have too much white or are double merle.