The condition, called oculocutaneous albinism, occurs in  an estimated 1 in 20,000 people born worldwide, according to the National Institutes of Health.

When Leo was fitted with glasses that would allow him to see clearly, his father, David Reppond, recorded the moment on video.

The 30-second clip shows 4-month-old Leopold beam as he recognizes his mother's face.

"When he finally did look up that second time and you see that recognition on his face, that's a smile we just hadn't really seen before," Leo's mother, Erin Reppond, told ABC News. "He's a pretty happy baby and he smiles and I feel like he generally is pretty happy but that smile was something that was so different for me to see."

Watch the adorable video below: