French Bulldog puppies are often born with blue eyes as they have little or no melanin in the front and back layers of their eyes. Their eyes may appear completely blue or have tinges of other shades like green, brown, or grey.
By the time they are about 10-weeks old, the melanin amount begins increasing, and the eye color transforms from blue to grayish and finally brown — the typical eye color for most adult Frenchies.
They may retain the blue eye color in specific cases. The main reason a Frenchie may have blue eyes all its life may be the presence of an M-locus (merle) or an S-locus (piebald or white spotting) gene. In most cases, both eyes are blue, while some dogs might have one blue and one brown eye, depending on the gene they carry.
Another French Bulldog variety that could stay blue-eyes all its life is the blue-coated one. In this case, the blue coat and eyes result from the recessive diluted ‘d’ gene.
Blue-eyed Frenchies are more prone to eye ailments like cherry eyes, entropion, juvenile cataract, and even blindness. It may also affect their hearing resulting in deafness, especially in the Merle and Piebald Frenchies. If a blue-eyed dog has two Merle parents (double Merle), they run a higher risk of blindness and deafness.
A sudden change in eye color in your adult French Bulldog could indicate a health issue, needing a veterinarian’s consultation at the earliest.